ALBERT

Description: Abstract Aim Understanding biodiversity–ecosystem function (BEF) relationships in forest systems is crucial for effective forest management and restoration, yet testing these relationships is often limited by biased diversity patterns in forestry plantings (biased towards commercially valuable species) and uncontrollable diversity in mature natural forests. Multispecies reforestation plantings present a valuable opportunity to investigate BEF relationships in woody systems, especially across large environmental gradients. Location Reforestation plantings across the arable region of Australia. Time period 1951–2012. Major taxa studied Three hundred and sixty‐four woody plant species. Methods We examined relationships between productivity and diversity using inventory data from 977 plots in 386 multispecies reforestation plantings. Diversity was estimated using observed species richness and three functional diversity indices calculated from four functional traits: specific leaf area, wood density, seed mass and maximum attainable height. We modelled how plot‐level biomass accumulation (a productivity proxy) correlated with these diversity indices, as well as age since planting, plant density and three environmental variables: solar radiation, moisture availability and soil sand content. These models were fitted across Australia and, separately, within eight groups of plantings with similar environmental conditions. Results We found no correlation between diversity and productivity, regardless of the diversity metric or spatial scale used (continent‐wide or within environment groups). Instead, productivity was best explained by local environmental conditions and plant density. Main conclusions A positive relationship between diversity and productivity was not evident in planted forests across a wide range of Australian woodland and forest systems, at least in the first few decades of growth. Our findings suggest that the positive relationship between diversity and productivity commonly reported in experimental settings should not be assumed for all systems and conditions.

Description: Abstract Aims Phylogenetic endemism describes the extent to which unique phylogenetic lineages are constrained to restricted geographic areas. Previous studies indicate that species endemism is related to both past and modern climate, but studies of phylogenetic endemism are relatively rare and mainly focused on smaller regions. Here, we provide the first assessment of the patterns of species and phylogenetic endemism in angiosperm trees across the Northern Hemisphere as well as the relative importance of modern climate and glacial–interglacial climate change as drivers of these patterns. Location Northern Hemisphere. Major taxa Angiosperm trees. Methods Using tree assemblages at the scale of 100 km × 100 km grid cells and simultaneous autoregressive (SAR) models, we assessed the relationships between species endemism, phylogenetic endemism and modern climate variables, Last Glacial Maximum (LGM) to present temperature velocity. Results Species and phylogenetic endemism were associated with both modern climate and glacial–interglacial climate change, with higher values in areas with stable historical climate and warmer and wetter modern conditions. Notably, the multivariate SAR analyses showed that the combinations of variables with highest Akaike’s information criterion (AIC) weight always included both LGM–present climate instability and modern climate, that is, modern precipitation and temperature. Main conclusions Our results show that high phylogenetic endemism is partially dependent on long‐term climate stability, highlighting the threat posed by future climate changes to the preservation of rare, phylogenetically distinct lineages of trees.

Description: Severe winter windstorms have become an increasingly common occurrence over recent decades in northwestern Europe. Although there exists considerable uncertainty, storminess is projected to increase in the future. On centennial to millennial time scales in particular, the mechanisms forcing storminess remain unsettled. We contribute to available palaeostorm records by reconstructing changes over the last 6670 years using a coastal peat sequence retrieved from the ombrotrophic Laphroaig bog on Islay, southwestern Scotland. We use a combination of ash content, grain size and elemental chemistry to identify periods of greater storminess, which are dated to 6605, 6290–6225, 5315–5085, 4505, 3900–3635, 3310–3130, 2920–2380, 2275–2190, 2005–1860, 1305–1090, 805–435 and 275 cal. a BP. Storm signals in the first half of the record up to ~3000 cal. a BP are mainly apparent in the grain‐size changes. Samples from this time period also have a different elemental signature than those later in the record. We speculate that this is due to receding sea levels and the consequent establishment of a new sand source in the form of dunes, which are still present today. The most significant events and strongest winds are found during the Iron Ages Cold Epoch (2645 cal. a BP), the transition into, and in the middle of, the Roman Ages Warm Period (2235 and 1965 cal. a BP) and early in the Little Ice Age (545 cal. a BP). The Laphroaig record generally agrees with regionally relevant peat palaeostorm records from Wales and the Outer Hebrides, although the relative importance of the different storm periods is not the same. In general, stormier periods are coeval with cold periods in the region as evidenced by parallels with increased ice‐rafted debris in the North Atlantic, highlighting that sea‐ice conditions could impact future storminess and storm track position.

Description: Abstract Aim The geographic range and ecological niche of species are widely used concepts in ecology, evolution and conservation and many modelling approaches have been developed to quantify each. Niche and distribution modelling methods require a litany of design choices; differences among subdisciplines have created communication barriers that increase isolation of scientific advances. As a result, understanding and reproducing the work of others is difficult, if not impossible. It is often challenging to evaluate whether a model has been built appropriately for its intended application or subsequent reuse. Here, we propose a standardized model metadata framework that enables researchers to understand and evaluate modelling decisions while making models fully citable and reproducible. Such reproducibility is critical for both scientific and policy reports, while international standardization enables better comparison between different scenarios and research groups. Innovation Range modelling metadata (RMMS) address three challenges: they (a) are designed for convenience to encourage use, (b) accommodate a wide variety of applications, and (c) are extensible to allow the research community to steer them as needed. RMMS are based on a metadata dictionary that specifies a hierarchical structure to catalogue different aspects of the range modelling process. The dictionary balances a constrained, minimalist vocabulary to improve standardization with flexibility for users to modify and extend. To facilitate use, we have developed an R package, rangeModelMetaData, to build templates, automatically fill values from common modelling objects, check for inconsistencies with standards, and suggest values. Main conclusions Range Modelling Metadata tools foster cross‐disciplinary advances in biogeography, conservation and allied disciplines by improving evaluation, model sharing, model searching, comparisons and reproducibility among studies. Our initially proposed standards here are designed to be modified and extended to evolve with research trends and needs.

Description: Holocene sedimentation patterns and environmental development in Aarhus Bay, Denmark, were reconstructed based on proxy analyses of two sediment cores (M1 and M5). Together, the two cores offer an opportunity to examine the history of the area during the past c. 10 000 years. The investigation consisted of acoustic mapping and multi‐proxy analyses of the sediment cores including macrofossils, sediment physical properties, sediment accumulation rates, grain size, and X‐ray fluorescence elemental counts. Radiocarbon dating of the two sediment successions revealed that they cover the periods c. 10 000–3700 cal. a BP (M1) and c. 4400 cal. a BP to the present (M5). The data from the M1 site indicate the presence of a near‐shore lake environment between c. 10 000 and 9000 cal. a BP. The first intrusion of marine water into the area is dated to c. 9000 cal. a BP. In the following c. 1300 years, brackish‐water conditions prevailed in the area characterized by a mixture of taxa from marine, limnic and terrestrial habitats, reflecting a shallow estuarine environment. Around 7700 cal. a BP full marine conditions were established, accompanied by a marked increase in sedimentation rates. The changes to full marine conditions and higher sedimentation rates are probably due to a significant sea‐level rise leading to flooding of former land areas and intensified erosion. A subsequent distinct decrease in sedimentation rates around 6350 cal. a BP is presumably linked to a previously documented sea‐level drop about this time. Continuous sedimentation ceased around 3700 cal. a BP in the central part of the bay, most probably due to a major sea‐level lowering involving widespread erosion. In the eastern and deeper part of the bay, sedimentation continued until today. Fully marine conditions prevailed there for at least the last 4400 years.

Description: Abstract Background Studies that attempt to measure shifts in species distributions often consider a single species in isolation. However, understanding changes in spatial overlap between predators and their prey might provide deeper insight into how species redistribution affects food web dynamics. Predator–prey overlap metrics Here, we review a suite of 10 metrics [range overlap, area overlap, the local index of collocation (Pianka's O), Hurlbert's index, biomass‐weighted overlap, asymmetrical alpha, Schoener's D, Bhattacharyya's coefficient, the global index of collocation and the AB ratio] that describe how two species overlap in space, using concepts such as binary co‐occurrence, encounter rates, spatial niche similarity, spatial independence, geographical similarity and trophic transfer. We describe the specific ecological insights that can be gained using each overlap metric, in order to determine which is most appropriate for describing spatial predator–prey interactions for different applications. Simulation and case study We use simulated predator and prey distributions to demonstrate how the 10 metrics respond to variation in three types of predator–prey interactions: changing spatial overlap between predator and prey, changing predator population size and changing patterns of predator aggregation in response to prey density. We also apply these overlap metrics to a case study of a predatory fish (arrowtooth flounder, Atheresthes stomias) and its prey (juvenile walleye pollock, Gadus chalcogrammus) in the Eastern Bering Sea, AK, USA. We show how the metrics can be applied to understand spatial and temporal variation in the overlap of species distributions in this rapidly changing Arctic ecosystem. Conclusions Using both simulated and empirical data, we provide a roadmap for ecologists and other practitioners to select overlap metrics to describe particular aspects of spatial predator–prey interactions. We outline a range of research and management applications for which each metric may be suited.

Description: Abstract Aim Establishments of non‐native forest pests (insects and pathogens) continue to increase worldwide with growing numbers of introductions and changes in invasion pathways. Quantifying spatio‐temporal patterns in establishment locations and subsequent invasion dynamics can provide insight into the underlying mechanisms driving invasions and assist biosecurity agencies with prioritizing areas for proactive surveillance and management. Location United States of America. Time period 1794–2018. Major taxa studied Insecta, plant pathogens. Methods Using locations of first discovery and county‐level occurrence data for 101 non‐native pests across the contiguous USA, we (a) quantified spatial patterns in discovery points and county‐level species richness with spatial point process models and spatial hotspot analyses, respectively, and (b) identified potential proxies for propagule pressure (e.g., human population density) associated with these observed patterns. Results Discovery points were highly aggregated in space and located in areas with high densities of ports and roads. Although concentrated in the north‐eastern USA, discovery points also occurred farther west and became less aggregated as time progressed. Invasion hotspots were more common in the north‐east. Geographic patterns of discovery points and hotspots varied substantially among pest origins (i.e., global region of pests’ native ranges) and pest feeding guilds. Significant variation in invasion richness was attributed to the patterns of first discovery locations. Data and shapefiles comprising analyses are provided. Main conclusions Use of spatial point pattern analyses provided a quantitative characterization of the central role of human activities in establishment of non‐native pests. Moreover, the decreased aggregation of discovery points through time suggests that invasion pathways to certain areas in the USA have either been created or intensified by human activities. Overall, our results suggest that spatio‐temporal variability in the intensity of invasion pathways has resulted in marked geographic patterns of establishment and contributed to current macroscale patterns of pest invasion in the USA.

Description: Quaternary fluvial succession of the Jászság Basin (Hungary) was investigated, challenging the stratigraphical potential of ‘early postglacial fluvial magnetic susceptibility episodes' recognized earlier in the Körös Basin. Low field magnetic susceptibility (MS) was measured in four boreholes from the basin centre and margins, representing channel and flood‐plain environments. Statistical distributions of MS data contain significant sets of outliers, regardless of facies conditions. The downhole distribution of these outliers produces magnetic susceptibility cycles. Supported by magnetic susceptibility cycles, high‐resolution facies correlations were performed reflecting a steady palaeohydrographical situation in the area, with a trunk river to the southeast and tributaries to the northwest. SEM‐EDX data revealed that ferromagnetic grains are responsible for the outlying MS values. The heterogeneous association of magnetite indicates a catchment area with volcanic and metamorphic rocks, while the group of small (〈5 μm) magnetite octahedrons originated from nearby rhyolitic tuff formations. Magnetic grains were transported along channel belts, while small (〈2 μm) magnetic particles were floated onto flood‐plains attached to clays. Climatic control is indicated by peaks at ~100 ka frequency in spectra of MS records and was also detected in palaeosol development and in flood frequency using the spectra of measured colour (~100 ka) and logged resistivity (~100 ka, ~41 ka), respectively. The climate‐dependent MS signal traceable far into the basin in both channel and flood‐plain environments can be summoned when the Quaternary fluvial succession of the Pannonian Basin is investigated, assuming some sources of magnetite in the catchment areas. According to the concept of ‘fluvial magnetic susceptibility episodes’, the early postglacial escape and spreading of the magnetite fraction control the MS signal that can support mapping of the unconformable Quaternary base and building of high‐resolution models of aquifers.

Description: Abstract Aim The importance of framing investigations of organism–environment relationships to interpret patterns at relevant spatial scales is increasingly recognized. However, most research related to environmental relationships is single‐scaled, implicitly or explicitly assuming that a “species characteristic selection scale” exists. We tested the premise that a single characteristic scale exists to understand species–environment relationships within species by asking (a) what are the characteristic scales of species’ relationships with environmental predictors, and (b) is within‐species, cross‐predictor consistency in characteristic scales a general phenomenon. Location Nebraska, USA. Time period 2016. Major taxa studied Birds. Methods We used data from 86 species at 〉 500 locations to build hierarchical N‐mixture models relating species abundance to land cover variables. By incorporating Bayesian latent indicator scale selection, we identified the spatial scales that best explain species–environment relationships with each land cover predictor. We quantified the extent of cross‐predictor consistency in characteristic scales, and contrasted this to the expectation given a single species’ characteristic scale. Results We found no evidence for a characteristic spatial scale explaining all abundance–environment relationships within species, rather we found substantial variation in scale‐dependence across multiple environmental attributes. Furthermore, 33% of species displayed evidence of multiple important spatial scales within environmental attributes. Major conclusions Within species there is little evidence for a single characteristic scale of environmental relationships and considerable variation in species’ scale dependencies. Because species may respond to multiple environmental attributes at different spatial scales, or single environmental attributes at multiple scales, we caution against any unoptimized single‐scale studies. Our results demonstrate that until a framework is developed to predict the scales at which species respond to environmental characteristics, multi‐scale investigations must be performed to identify and account for multi‐scale dependencies. Natural selection acting on species’ response to distinct environmental attributes, rather than natural selection acting on species’ perception of spatial scales per se, may have shaped patterns of scale dependency and is an area ripe for investigation.

Description: Abstract Aim The rate and magnitude of climate‐induced tree range shifts may be influenced by range‐wide variation in recruitment, which acts as a bottleneck in tree range dynamics. Here, we compare range predictions made using standard species distribution models (SDMs) and an integrated metamodelling approach that assimilates data on adult occurrence, seedling recruitment dynamics, and seedling survival under both current and future climate, and evaluate the degree to which information provided by seedling data can improve predictions of range dynamics. Location The interior west region of the United States. Time period 1990–2015. Major taxa studied Five widespread conifer tree species. Methods We used a previously published metamodelling framework to combine information from SDMs of adult tree occurrence and sub‐models describing seedling recruitment dynamics and seedling survival into a single set of predictions for the probability of occurrence for each species. The integrated framework links sub‐models to a SDM to generate cohesive predictions that consider information and uncertainty contained in all datasets. We then compared predictions from the integrated model to SDM predictions. Results Integration of seedling information served primarily to improve characterization of model uncertainty, particularly in regions where recruitment may be limited by temperatures that exceed seedling tolerance. Integration constrained response curves very slightly across most climate gradients, particularly across temperature gradients. These differences were primarily attributable to the isolated effects of temperature on seedling survival and not to recruitment dynamics. Main conclusions Our results indicate that range‐wide variation in recruitment both now and in the future is most uncertain along the edges of occupied regions, which increases uncertainty in projections of future species occurrence along range margins. Overall, the broad‐scale climatic dependence of the regeneration niche appears weaker than that of the adult climatic niche, and this enhances uncertainty in predicting range‐wide responses of these species to climate change.

Description: Nares Strait, a major connection between the Arctic Ocean and Baffin Bay, was blocked by coalescent Innuitian and Greenland ice sheets during the last glaciation. This paper focuses on the events and processes leading to the opening of the strait and the environmental response to establishment of the Arctic‐Atlantic throughflow. The study is based on sedimentological, mineralogical and foraminiferal analyses of radiocarbon‐dated cores 2001LSSL‐0014PC and TC from northern Baffin Bay. Radiocarbon dates on benthic foraminifera were calibrated with ΔR = 220±20 years. Basal compact pebbly mud is interpreted as a subglacial deposit formed by glacial overriding of unconsolidated marine sediments. It is overlain by ice‐proximal (red/grey laminated, ice‐proximal glaciomarine unit barren of foraminifera and containing 〉2 mm clasts interpreted as ice‐rafted debris) to ice‐distal (calcareous, grey pebbly mud with foraminifera indicative of a stratified water column with chilled Atlantic Water fauna and species associated with perennial and then seasonal sea ice cover) glacial marine sediment units. The age model indicates ice retreat into Smith Sound as early as c. 11.7 and as late as c. 11.2 cal. ka BP followed by progressively more distal glaciomarine conditions as the ice margin retreated toward the Kennedy Channel. We hypothesize that a distinct IRD layer deposited between 9.3 and 9 (9.4–8.9 1σ) cal. ka BP marks the break‐up of ice in Kennedy Channel resulting in the opening of Nares Strait as an Arctic‐Atlantic throughflow. Overlying foraminiferal assemblages indicate enhanced marine productivity consistent with entry of nutrient‐rich Arctic Surface Water. A pronounced rise in agglutinated foraminifers and sand‐sized diatoms, and loss of detrital calcite characterize the uppermost bioturbated mud, which was deposited after 4.8 (3.67–5.55 1σ) cal. ka BP. The timing of the transition is poorly resolved as it coincides with the slow sedimentation rates that ensued after the ice margins retreated onto land.

Description: Global Ecology and Biogeography, Volume 28, Issue 4, Page 415-417, April 2019.

Description: Abstract Aim Tropical species are thought to experience and be adapted to narrow ranges of abiotic conditions. This idea has been invoked to explain a broad array of biological phenomena, including the latitudinal diversity gradient and differential rates of speciation and extinction. However, debate continues regarding the broad‐scale applicability of this pattern and potential processes responsible. Here, we use a simulation approach to test two propositions: (a) strong geographical patterns in realized niche breadth variation can arise in the absence of variance in fundamental niche breadth size, and (b) realized niche breadths can show latitudinal patterns as a consequence of spatio‐temporal climate change, even when fundamental niche breadths are unrelated to latitude and dispersal abilities are held constant. Location Global. Time period Simulations were conducted using climate models from over the last 120 ka, with trait dynamics captured at 95 ka and in the Modern. Major taxa studied We used virtual species with traits based loosely on plants. Methods We simulated latitudinal trends of niche breadth and range size for virtual species using a cellular automaton algorithm that linked a gridded geographical domain with a three‐dimensional environmental landscape. Results In all simulations, strong spatial patterns in realized niches were obtained in the absence of niche evolution, and realized niches showed geographical patterns deriving only from realistic, spatio‐temporal variation in climate. We noted contrasting patterns of niche breadth in different environmental dimensions, with temperature breadth increasing with latitude, but precipitation breadth decreasing with latitude. Overall, simulation outcomes mimicked the real‐world pattern of latitudinal range extent co‐varying with amount of land area. Main conclusions Tropical species can have narrower niche breadths for maximum and minimum temperature ranges compared with temperate species solely as the result of the spatial arrangement of environments. We therefore suggest that the complex spatio‐temporal distribution of global abiotic environments has strong potential for structuring observed latitudinal gradients of niche breadths.

Description: Abstract Aim Mesophotic coral ecosystems (MCEs) are unique communities that support a high proportion of depth‐endemic species distinct from shallow‐water coral reefs. However, there is currently little consensus on the boundaries between shallow and mesophotic coral reefs and between upper versus lower MCEs because studies of these communities are often site specific. Here, we examine the ecological evidence for community breaks, defined here as species loss, in fish and benthic taxa between shallow reefs and MCEs globally. Location Global MCEs. Time period 1973–2017. Major taxa studied Macrophytes, Porifera, Scleractinia, Hydrozoa, Octocorallia, Antipatharia and teleost fishes. Methods We used random‐effects models and breakpoint analyses on presence/absence data to identify regions of higher than expected species loss along a depth gradient of 1–69 m, based on a meta‐analysis of 26 studies spanning diverse photoautotrophic and heterotrophic taxa. We then investigated the extent to which points of high faunal turnover can be explained by environmental factors, including light, temperature and nutrient availability. Results We found evidence for a community break, indicated by a significant loss of shallow‐water taxa, at ~ 60 m across several taxonomically and functionally diverse benthic groups and geographical regions. The breakpoint in benthic composition is best explained by decreasing light, which is correlated with the optical depths between 10 and 1% of surface irradiance. A concurrent shift in the availability of nutrients, both dissolved and particulate organic matter, and a shift from photoautotroph to heterotroph‐dominated assemblages also occurs at ~ 60 m depth. Main conclusions We found evidence for global community breaks across multiple benthic taxa at ~ 60 m depth, indicative of distinct community transitions between shallow and mesophotic coral ecosystems. Changes in the underwater light environment and the availability of trophic resources along the depth gradient are the most parsimonious explanations for the observed patterns.

Description: Only a few chronological constraints on Lateglacial and Early Holocene glacier variability in the westernmost Alps have hitherto been obtained. In this paper, moraines of two palaeoglaciers in the southern Écrins massif were mapped. The chronology of the stabilization of selected moraines was established through the use of 10Be cosmic ray exposure (CRE) dating. The equilibrium line altitude (ELA) during moraine deposition was reconstructed assuming an accumulation area ratio (AAR) of 0.67. Ten pre‐Little Ice Age (LIA) ice‐marginal positions of the Rougnoux palaeoglacier were identified and seven of these have been dated. The 10Be CRE age of a boulder on the lowermost sampled moraine indicates that the landform may have been first formed during a period of stable glaciers at around 16.2±1.7 ka (kiloyears before AD 2017) or that the sampled boulder experienced pre‐exposure to secondary cosmic radiation. The moraine was re‐occupied or, alternatively, shaped somewhat before 12.2±0.6 ka when the ELA was lowered by 230 m relative to the LIA ELA. At least six periods of stable ice margins occurred thereafter when the ELA was 220–160 m lower than during the LIA. The innermost dated moraine stabilized at or before 10.9±0.7 ka. Three 10Be CRE ages from a moraine of the Prelles palaeoglacier indicate a period of stationary ice margins at or before 10.9±0.6 ka when the ELA was lowered by 160 m with respect to the end of the LIA. The presented 10Be CRE ages are in good agreement with those of moraines that have been attributed to the Egesen stadial. Assuming unchanged precipitation, summer temperature in the southern Écrins massif at ~12 ka must have been at least 2 °C lower relative to the LIA.

Description: Abstract Aim Understanding fire effects on pollinators is critical in the context of fire regime changes and the global pollination crisis. Through a systematic and quantitative review of the literature, we provide the first global assessment of pollinator responses to fire. We hypothesize that pollinators increase after fire and during the early postfire succession stages; however, high fire frequency has the opposite effect, decreasing pollinators. Location Terrestrial ecosystems, excluding Antarctica. Time period Data collected from 1973 to 2017. Major taxa studied Insects (Coleoptera, Diptera, Hymenoptera and Lepidoptera) and a few bird species. Methods We first compiled available studies across the globe that assessed fire effects on pollinator communities. Then, by means of hierarchical meta‐analyses, we evaluated how different fire regime parameters (fire frequency, postfire time and fire type) and habitat characteristics affect the abundance and richness of animals that act as pollinators. We also explored to what extent the responses vary among taxa groups and life history traits of pollinators (sociality system, nest location and feeding specialization), and among biomes. Results The overall effect size of fire on pollinator abundance and richness across all studies was positive. Fire effect was especially clear and significant in early postfire communities, after wildfires, and for Hymenoptera. Taxonomic resolution influenced fire effects, where only studies at the species/genus and family levels showed significant effects. The main exceptions were recurrent fires that showed a negative effect, and especially wildfire effects on Lepidoptera abundance that showed a significant negative response. Main conclusions Pollinators tend to be promoted after a wildfire event. However, short fire intervals may threat pollinators, and especially lepidopterans. Given the current fire regime changes at the global scale, it is imperative to monitor postfire pollinators across many ecosystems, as our results suggest that fire regime is critical in determining the dynamics of pollinator communities.

Description: Abstract Aim Microorganisms carrying pmoA and nosZ genes are major drivers of methane and nitrous oxide fluxes from soils. However, most studies on these organisms have been conducted in mesic ecosystems; therefore, little is known about the factors driving their distribution in drylands, the largest biome on Earth. We conducted a global survey to evaluate the role of climate‐ and soil‐related variables as predictors of the richness, abundance and community structure of bacteria carrying pmoA and nosZ genes. Location Eighty dryland ecosystems distributed worldwide. Time period From February 2006 to December 2011. Major taxa studied Methanotrophic (carrying the pmoA gene) and denitrifiying (carrying the nosZ gene) bacteria. Methods We used data from a field survey and structural equation modelling to evaluate the direct and indirect effects of climatic (aridity, rainfall seasonality and mean annual temperature) and soil (organic carbon, pH and texture) variables on the total abundance, richness and community structure of microorganisms carrying pmoA and nosZ genes. Results Taxa related to Methylococcus capsulatus or Methylocapsa sp., often associated with mesic environments, were common in global drylands. The abundance and richness of methanotrophs were not associated with climate or soil properties. However, mean annual temperature, rainfall seasonality, organic C, pH and sand content were highly correlated with their community structure. Aridity and soil variables, such as sand content and pH, were correlated with the abundance, community structure and richness of the nosZ bacterial community. Main conclusions Our study provides new insights into the drivers of the abundance, richness and community structure of soil microorganisms carrying pmoA and nosZ genes in drylands worldwide. We highlight how ongoing climate change will alter the structure of soil microorganisms, which might affect the net CH4 exchange and will probably reduce the capacity of dryland soils to carry out the final step of denitrification, favouring net N2O emissions.

Description: Abstract Aim To test whether intraspecific trait responses to climate among populations across species distribution ranges can be untangled using field observations, under the rationale that, in natural forest tree populations, long‐term climate shapes population responses while recent climate change drives phenotypic plasticity. Location Europe. Time period 1901–2014. Taxa Silver fir (Abies alba Mill.) and sessile oak [Quercus petraea (Matt.) Liebl.]. Methods We estimated the variation of individual tree height as a function of long‐term and short‐term climates to tease apart provenance effects (variation among populations of different geographical origin), plasticity and their interaction, using mixed‐effect models calibrated with national forest inventory data (in‐situ models). To validate our approach, we tested the ability of in‐situ models to predict independently tree height observations in common gardens experiments where provenance and plastic effects can be measured and separated. In‐situ model predictions of tree height variation among provenances and among planting sites were compared to observations in common gardens and to predictions from a similar model calibrated using common garden data (ex‐situ model). Results In Q. petraea, we found high correlations between in‐situ and ex‐situ model predictions of provenance and plasticity effects and their interaction for tree height (r 〉 .80). We showed that the in‐situ models significantly predicted tree height variation among provenances and sites for A. alba and Q. petraea. Spatial predictions of phenotypic plasticity across species distribution ranges indicate decreasing tree height in populations of warmer climates in response to recent anthropogenic climate warming. Main conclusions Our modelling approach using national forest inventory observations provides a new perspective for understanding patterns of intraspecific trait variation across species ranges. Its application is particularly interesting for species for which common garden experiments do not exist or do not cover the entire climatic range of the species.

Description: Abstract Aim Understanding the role of interspecific interactions in maintaining diversity, ecosystem function and evolutionary processes is a major challenge in ecology. Historically, antagonistic heterospecific interactions were the focus of many studies, but the importance of facilitative interactions has become increasingly apparent over recent decades. Ecological networks can provide insights into potential interactions among co‐occurring heterospecifics. We compared the structures of temperate and tropical marine fish co‐occurrence networks to estimate their resilience and/or robustness to perturbations. Location Western Australia. Time period Present. Major taxa studied Marine fishes. Methods We compared the structure of temperate and tropical marine fish communities through interspecific co‐occurrences using joint species distribution modelling. Network analyses identified modules of co‐occurring species and those which play a strong role in the organization of communities. Results In all study locations, most interspecific co‐occurrences did not differ significantly from random, with positive co‐occurrences being more prevalent than negative non‐random co‐occurrences. The modularity of networks created from interspecific co‐occurrences tended to decrease poleward, with the opposite for species centrality. An increase in functional diversity among co‐occurring species with latitude was detected. Species centrality was greatest among the temperate endemic species, with a positive association between species centrality and intrinsic vulnerability scores. Main conclusions The differences in community structure between tropical and temperate Western Australian marine fish communities might be attributable, in part, to differing evolutionary histories. The temperate endemic species have co‐evolved in a relatively homogeneous abiotic and biotic environment, whereas the Indo‐Pacific ichthyofauna have evolved in a diverse range of environments. The temperate communities are characterized by: (a) low functional redundancy among co‐occurring species, with endemic species playing keystone roles in community structure; (b) attributes associated with increased vulnerability to perturbations; with (c) many of the species identified as potential keystone species having high intrinsic vulnerability scores and being targeted by fishers.

Description: Abstract Aim To investigate the overall effect of spiders on pest suppression and crop performance, and to explore the extent to which the biocontrol efficacy of spiders depends on the characteristics of spiders, pests, agroecosystems, climate and geography. Location Global. Time period 1970–2017. Major taxa studied Spiders. Methods We performed a meta‐analysis of 58 published studies where we investigated (a) the overall effect of spiders on pest density and crop performance; (b) the extent to which the biocontrol efficacy of spiders depends on the taxonomy of pests (aphids, leafhoppers, beetles, and lepidopteran larvae), the hunting strategy of spiders (hunters, web‐weavers), crop type (vine, cabbage, wheat, rice), climate, and geography. Results Spiders suppressed agricultural pest insects in 79% of cases. The mean effect size of increased spider density on pest suppression was large (Hedge's d = 0.89; 95% confidence interval (CI95 )= 0.66–1.12). Spider pest suppression efficacy slightly increased also with taxonomic diversity (d = 0.33; CI95 = 0.05–0.61). The effects of spiders cascaded down and improved crop performance (d = 2.3, CI95 = 0.70–3.84). The effects of spiders seemed to escalate rather than attenuate down through the agricultural food‐chains (regression slopes 〉 1). The biocontrol efficacy of spiders was highest in rice followed by grape, cabbage and wheat. The pest suppression efficacy of spiders and the positive effect of spiders on crop yield slightly increased towards the tropics and with mean annual temperature. Spiders suppressed the four pest groups with similar efficacy. Main conclusions The meta‐analysis provides strong evidence that spiders are effective in natural pest control and improve crop performance. However, the efficacy of spiders differed among crops. Our study substantiates the few earlier findings that predation pressure and the intensity of trophic cascades in terrestrial ecosystems intensify towards the tropics.

Description: Abstract Aim Many hypotheses exist to explain the astonishing variation in geographical range size across species, but these have rarely been tested under a unifying framework that simultaneously considers direct and indirect effects of ecological niche processes and evolutionary dynamics. Here, we jointly evaluate ecological and evolutionary hypotheses that might account for global interspecific patterns of range size in the most species‐rich avian order: Passeriformes (perching birds). Location Global. Time period Current. Major taxa studied Order Passeriformes. Methods We used phylogenetic path analysis to test for the relationship between eight variables and range size. Our list of predictors included a set of niche‐related variables (both Grinellian and Eltonian), species‐specific morphological and life‐history traits (body size, dispersal ability and fertility), extrinsic (human footprint) and evolutionary factors (time since divergence from the closest extant relative). Results We found that Grinellian (climatic) and Eltonian (trophic) niche breadth are crucial to account for the observed patterns, followed by reproductive effort (as measured by clutch size). We also found a negative relationship between native range size and human footprint. The significant and positive relationship between niche breadth, either Grinnellian or Eltonian, and range size was consistent across all species, irrespective of their migratory/resident status or taxonomic grouping (Passeri versus Tyranni). Main conclusions Globally, the range sizes of passerine species are associated with the Grinellian niche, meaning that species with broader environmental tolerances exhibit larger geographical ranges. These findings give further empirical support to the positive niche breadth–range size relationship as a general pattern in ecology.

Description: Aim The relationship between the proportion of sites occupied by a species and the area of a site [occupancy–area relationship (OAR)] offers key information for biodiversity management and has long fascinated ecologists. We quantified the variation in OAR for 3,157 woody species in 17 forest plots worldwide and tested the relative importance of environment and species traits for explaining this variation and evaluated overall model predictive ability. Location Global. Time period Early 21st century. Major taxa studied Woody plants. Methods We used mixed‐effect regression to examine the observed shape of the OAR (its “slope”) against species‐specific and plot‐wide predictors: coarse‐grain occupancy, tree size, plot species richness, energy availability and topographic complexity. Results We found large variation in OAR slopes, and the variation was strongest among species within plots. The OAR slopes showed a latitudinal trend and were steeper near the equator. As predicted, coarse‐grain occupancy and tree size negatively affected OAR slopes, whereas species richness had a positive effect and explained most of the variance between plots. Although hypothesized directionalities were broadly confirmed, traits and environment had relatively limited overall predictive power. Main conclusions These results document the variation of the OAR for 3,157 species at near‐global extent. We found a latitudinal gradient in OAR slopes and confirmed key hypothesized predictors. But at this global extent and over the large set of species analysed, the remaining unexplained variation in OAR slopes was substantial. Nevertheless, this large‐scale empirical analysis of the OAR offers an initial step towards a more general use of OARs for the fine‐scale prediction of species distributions and abundance.

Description: Abstract Aim The landscape of the Neotropical region has undergone dynamic evolution throughout the Miocene, with the extensive Pebas wetland occupying western Amazonia between 23 and c. 10 Ma and the continuous uplift of the Andes mountains. The complex interaction between the Andes and Amazonia probably influenced the trajectory of Neotropical biodiversity, but evidence from time‐calibrated phylogenies of groups that diversified during this period is lacking. We investigate the role of these landscape transformations in the dynamics of diversification in the Neotropical region using a 26‐Myr‐old endemic butterfly radiation. Location Neotropics. Time period Oligocene to present. Major taxa studied Ithomiini butterflies. Methods We generated one of the most comprehensive time‐calibrated molecular phylogenies of a large clade of Neotropical insects, the butterfly tribe Ithomiini, comprising 340 species (87% of extant species) and spanning 26 Myr of diversification. We applied a large array of birth–death models and historical biogeography estimations to assess the dynamics of diversification and biotic interchanges, especially at the Amazonia–Andes interface. Results Our results suggest that the Amazonian Pebas wetland system played a major role in the timing and geography of diversification of Ithomiini, by constraining dispersal and diversification in the Amazon basin until c. 10 Ma. During the Pebas wetland period, Ithomiini diversification mostly took place in the Andes, where terrestrial habitats were not affected. An explosion of interchanges with Amazonia and with the Northern Andes accompanied the demise of the Pebas system (11–8 Ma) and was followed by local diversification in those areas, which led to a substantial renewal of diversification. Main conclusions Many studies on Neotropical diversity have focused only on the Andes, whereas we show that it is the waxing and waning of the Pebas mega‐wetland, interacting with Andean uplift, that determined the timing and patterns of regional interchanges and diversification in Ithomiini.

Description: Abstract Aim Existing global models to predict standing biomass are based on trees characterized by a single principal stem, well developed in height. However, their use in open woodlands and shrublands, characterized by multistemmed species with substantial crown development, generates a high level of uncertainty in biomass estimates. This limitation led us to (a) develop global models of shrub individual aboveground biomass based on simple allometric variables, (b) to compare the fit of these models with existing global biomass models, and (c) to assess whether models fit change when bioclimatic variables are considered. Location Global. Time period Present. Major taxa studied 118 species of shrubs. Methods We compile a database of 3,243 individuals across 49 sites distributed worldwide. Including  stem basal diameter, height and crown diameter as predictor variables, we built potential models and compared their fit using generalized least squares. We used mixed effects models to determine if bioclimatic variables improved the accuracy of biomass models. Results Although the most important variable in terms of predictive capacity was stem basal diameter, crown diameter significantly improved the models’ fit, followed by height. Four models were finally chosen, with the best model combining all these variables in the same equation [R2 = 0.930, root mean square error (RMSE) = 0.476]. Selected models performed as well as established global biomass models. Including the individual bioform significantly improved the models’ fit. Main conclusions Stem basal diameter, crown diameter and height measures could be combined to provide robust aboveground biomass (AGB) estimates of individual shrub species. Our study supplements well‐established models developed for trees, allowing more accurate biomass estimation of multistemmed woody individuals. We further provide tools for a methodological standardization of individual biomass quantification in these species. We expect these results contribute to improve the quality of biomass estimates across ecosystems, but also to generate methodological consensus on field biomass assessments in shrubs.

Description: Abstract Aim It is unknown whether fungi show similar trends to other organisms in their macroecological patterns of abundance and spatial distribution. Here, we investigated fungal abundance–occupancy relationships to determine whether fungi that are common at a local scale tend to be more widely distributed. Location UK and Switzerland. Time period 1950–2014. Major taxa studied Fungi. Methods We used a local data set of fruiting records of 2,319 species in the UK, accumulated over 65 years, and one from Switzerland of 319 species, spanning 32 years. Using the number of records and occurrence as proxies for abundance, in each case we examined the form of species and rank abundance distributions and compared these with distributions of records in the national databases over the same time. We plotted relationships of the local number of records and regional occupancy and calculated multiscale indices of rarity for all fungal species. Results There was a remarkable congruence in the patterns found in the UK and Switzerland. Regional assemblages are characterized by many rare species, whereas few are common (fitting the lognormal distribution). However, at local scales, distributions best fitted a power law, suggesting that habitat availability or dispersal processes might play important roles. Fungi with a high number of local records are densely distributed nationally, but unlike other organisms, locally rare fungi may also be densely distributed at a wider scale. Main conclusions Fungal fruiting records can be used to infer patterns in fungal distributions. Abundances in local assemblages may be determined by the position of the assemblage in the overall geographical range of each species, dispersal ability and environmental filtering. We advocate the use of multiscale approaches to rarity in future fungal sampling programmes, to provide more reliable information for future conservation policy decisions and fungal biogeography.

Description: Abstract Aim How do factors such as space, time, climate and other ecological drivers influence food web structure and dynamics? Collections of well‐studied food webs and replicate food webs from the same system that span biogeographical and ecological gradients now enable detailed, quantitative investigation of such questions and help integrate food web ecology and macroecology. Here, we integrate macroecology and food web ecology by focusing on how ecogeographical rules [the latitudinal diversity gradient (LDG), Bergmann's rule, the island rule and Rapoport's rule] are associated with the architecture of food webs. Location Global. Time period Current. Major taxa studied All taxa. Methods We discuss the implications of each ecogeographical rule for food webs, present predictions for how food web structure will vary with each rule, assess empirical support where available, and discuss how food webs may influence ecogeographical rules. Finally, we recommend systems and approaches for further advancing this research agenda. Results We derived testable predictions for some ecogeographical rules (e.g. LDG, Rapoport's rule), while for others (e.g., Bergmann's and island rules) it is less clear how we would expect food webs to change over macroecological scales. Based on the LDG, we found weak support for both positive and negative relationships between food chain length and latitude and for increased generality and linkage density at higher latitudes. Based on Rapoport's rule, we found support for the prediction that species turnover in food webs is inversely related to latitude. Main conclusions The macroecology of food webs goes beyond traditional approaches to biodiversity at macroecological scales by focusing on trophic interactions among species. The collection of food web data for different types of ecosystems across biogeographical gradients is key to advance this research agenda. Further, considering food web interactions as a selection pressure that drives or disrupts ecogeographical rules has the potential to address both mechanisms of and deviations from these macroecological relationships. For these reasons, further integration of macroecology and food webs will help ecologists better understand the assembly, maintenance and change of ecosystems across space and time.

Description: Aim The climate tolerances of many species are broader than those estimated from current native ranges. Indeed, the niches of some Afromontane trees are up to 50% larger after incorporation of fossil data. This expansion could reduce estimates of species' future range loss owing to climate change but also implies strong non‐climatic limitations on species' current ranges. One such limitation is land use, which fossil data suggest influences Afromontane tree distribution, preventing these trees from occupying warmer conditions than they do currently. We aimed to assess the degree to which the broader climatic tolerances revealed by fossil data buffer projected range loss from climate and land use for Afromontane trees. Location Africa. Time period Last 21,000 years. Major taxa studied Afromontane trees. Methods We used species distribution models informed by both current and fossil distributions to project future ranges under climate and land‐use projections. Results We found that projected range reductions are only slightly ameliorated by incorporation of fossil distributions, and these improvements diminish further under severe land‐use or climate change scenarios. Taxa that are less impacted by climate are more impacted by intense land use. Depending on the severity of climate and land use, the geographical extent of Afromontane tree species' ranges will contract by 40–85%, and the trees will be completely lost from large portions of Africa. We projected that the surviving species' ranges will become increasingly fragmented. Main conclusions Maintaining Afromontane ecosystems will require mitigation of both climate and land‐use change and protection of areas to optimize connectivity. Our findings caution that species with climate tolerances broader than their current range might not necessarily fare better under strong changes in climate or land use.

Description: Abstract Aim To test hypothesized biogeographic partitions of the tropical Indo‐Pacific Ocean with phylogeographic data from 56 taxa, and to evaluate the strength and nature of barriers emerging from this test. Location The Indo‐Pacific Ocean. Time period Pliocene through the Holocene. Major taxa studied Fifty‐six marine species. Methods We tested eight biogeographic hypotheses for partitioning of the Indo‐Pacific using a novel modification to analysis of molecular variance. Putative barriers to gene flow emerging from this analysis were evaluated for pairwise ΦST, and these ΦST distributions were compared to distributions from randomized datasets and simple coalescent simulations of vicariance arising from the Last Glacial Maximum. We then weighed the relative contribution of distance versus environmental or geographic barriers to pairwise ΦST with a distance‐based redundancy analysis (dbRDA). Results We observed a diversity of outcomes, although the majority of species fit a few broad biogeographic regions. Repeated coalescent simulation of a simple vicariance model yielded a wide distribution of pairwise ΦST that was very similar to empirical distributions observed across five putative barriers to gene flow. Three of these barriers had median ΦST that were significantly larger than random expectation. Only 21 of 52 species analysed with dbRDA rejected the null model. Among these, 15 had overwater distance as a significant predictor of pairwise ΦST, while 11 were significant for geographic or environmental barriers other than distance. Main conclusions Although there is support for three previously described barriers, phylogeographic discordance in the Indo‐Pacific Ocean indicates incongruity between processes shaping the distributions of diversity at the species and population levels. Among the many possible causes of this incongruity, genetic drift provides the most compelling explanation: given massive effective population sizes of Indo‐Pacific species, even hard vicariance for tens of thousands of years can yield ΦST values that range from 0 to nearly 0.5.

Description: Abstract Aim The aim was to test whether large‐scale patterns of variation in the bodily proportions of small mammals relate to latitude and climate. Location The New World. Time period Current. Major taxa studied Marsupials, lipotyphlans and rodents. Methods Distributional, morphological and phylogenetic data were compiled for 149 faunal samples including 360 species of New World small mammals. Phylogenetic autocorrelation was addressed using phylogenetic generalized least squares regression. Results The faunal data show that tails are systematically larger in the tropics relative to head and body lengths. Furthermore, the data for individual species demonstrate a negative relationship between tail length and the distance of the midpoint of a geographical range from the equator. Hind foot and ear length also decline at high latitudes, but the relationships are much weaker. Allen's rule states that all extremities, including ears, feet and tails, should be larger at low latitudes because heat loss is not a limiting factor. However, no correlation between any measurement and mean annual temperature is found in two major groups (cricetid rodents and didelphid marsupials) or in all mammals combined. Main conclusions Allen's rule does not apply at the macroevolutionary scale, and a new one does. Given that long tails stabilize movement between tree branches and are better suited for being prehensile, this rule might relate to increasing arboreality in the tropics.

Description: Abstract Aim Information on the amount of carbon stored in the living tissue of tree stems (sapwood) is crucial for carbon and water cycle applications. Here, we aim to investigate sapwood‐to‐stem proportions and differences therein between tree genera and derive a sapwood biomass map. Location Northern Hemisphere boreal and temperate forests. Time period 2010. Major taxa studied Twenty‐five common tree genera. Methods First, we develop a theoretical framework to estimate sapwood biomass for a given stem biomass by applying relationships between sapwood cross‐sectional area (CSA) and stem CSA and between stem CSA and stem biomass. These measurements are extracted from a biomass and allometry database (BAAD), an extensive literature review and our own studies. The established allometric relationships are applied to a remote sensing‐based stem biomass product in order to derive a spatially continuous sapwood biomass map. The application of new products on the distribution of stand density and tree genera facilitates the synergy of satellite and forest inventory data. Results Sapwood‐to‐stem CSA relationships can be modelled with moderate to very high modelling efficiency for different genera. The total estimated sapwood biomass equals 12.87 ± 6.56 petagrams of carbon (PgC) in boreal (mean carbon density: 1.13 ± 0.58 kgC m−2) and 15.80 ± 9.10 PgC in temperate (2.03 ± 1.17 kgC m−2) forests. Spatial patterns of sapwood‐to‐stem biomass proportions are crucially driven by the distribution of genera (spanning from 20–30% in Larix to 〉 70% in Pinus and Betula forests). Main conclusions The presented sapwood biomass map will be the basis for large‐scale estimates of plant respiration and transpiration. The enormous spatial differences in sapwood biomass proportions reveal the need to consider the functionally more important sapwood instead of the entire stem biomass in global carbon and water cycle studies. Alterations in tree species distribution, induced by forest management or climate change, can strongly affect the available sapwood biomass even if stem biomass remains unchanged.

Description: Abstract Aim Global carbon cycle models do not incorporate the stabilizing effect of biodiversity on productivity despite this phenomenon has been widely described in several local scale manipulative experiments. The reason is a lack of evidence supporting the importance of biodiversity on spatial scales at which climate models are built. Here, we test the hypothesis that diversity enhances productivity stability at a large scale. Location South American dryland known as Caatinga (~830,000 km2). Time period 2001–2010. Major taxa studied Woody plants. Methods We used the enhanced vegetation index of Caatinga vegetation remnants, from 2001 to 2010, to calculate vegetation productivity stability across years. We used occurrence records of 606 woody species from floristic surveys to derive species richness and phylogenetic diversity at ~5 km and ~55 km (0.5°) resolution. Climate data were obtained from global databases. Results Plant phylogenetic diversity has a strong positive correlation with productivity stability even after controlling for several climatic variables, such as rainfall, temperature and cloudiness, at both resolutions. Species richness was not significant when climatic variables were included. Main conclusions This result expands by several orders of magnitude the spatial scale of the evidence that biodiversity strengths the resilience of key ecosystem functions. We highlight that, by incorporating plant phylogenetic diversity, regional and global climate models can generate more accurate predictions about future ecosystem functioning and services that are critical to humankind.

Description: Abstract Both conservation biology and macroecology are synthetic, and macroecological research consistently has informed the theory and practice of biological conservation. Explicit integration of the macroecology of human systems and natural systems has been rare, but can advance the incorporation of social justice, environmental justice and environmental equity into conservation biology and participatory conservation (inclusion in decision‐making of those who are affected by, or can affect, that decision). The basis of this strong link is the focus of macroecology on the relations of a given biota to environmental patterns and processes, and these patterns and processes can affect humans differentially. Macroecological integration of social justice and conservation generally requires spatial and temporal representation of all variables at resolutions and extents that allow meaningful analyses. This requirement may facilitate clarity about social metrics and norms. To illustrate, we examine applications of macroecology to analysis of the effects of climate change on social justice and biological conservation; relations among climate, violence among humans and conservation; and the response of the spread of disease to social and ecological factors. We believe that macroecology is a means of providing transparent inferences that can inform conservation, health and social policies.

Description: Abstract Aim To verify which vegetation and environmental factors are the most important in determining the spatial and temporal variability of average and maximum values of radiation use efficiency (RUEann and RUEmax, respectively) of cold and temperate forests. Location Forty‐eight cold and temperate forests distributed across the Northern Hemisphere. Major taxa studied Evergreen and deciduous trees. Time period 2000–2011. Methods We analysed the impact of 17 factors as potential determinants of mean RUE (at 8 days interval, annual and interannual level) and RUEmax (at annual and interannual level) in cold and temperate forests by using linear regression and random forests models. Results Mean annual RUE (RUEann, c. 1.1 gC/MJ) and RUEmax (c. 0.8 gC/MJ) did not differ between cold and temperate forests. However, for cold forests, RUEann was affected by temperature‐related variables, while for temperate forests RUEann was affected by drought‐related variables. Leaf area index (LAI) was important for both forest types, while N deposition only for cold forests and cloud cover only for temperate forest. RUEmax of cold forests was mainly driven by N deposition and LAI, whereas for temperate forests only a weak relationship between RUEmax and CO2 concentration was found. Short‐term variability of RUE was strongly related to the meteorological variables and varied during the season and was stronger in summer than spring or autumn. Interannual variability of RUEann and RUEmax was only weakly related to the interannual variability of the environmental drivers. Main conclusions Cold and temperate forests show different relationships with the environment and vegetation properties. Among the RUE drivers observed, the least anticipated was N deposition. RUE is strongly related to short‐term and seasonal changes in meteorological variables among seasons and among sites. Our results should be considered in the formulation of climate zone‐specific tools for remote sensing and global models.

Description: Abstract Aim Although much has been said on the spatial distribution of taxonomic and phylogenetic diversity of vertebrates, how this diversity interacts in food webs and how these interactions change across space are largely unknown. Here, we analysed the spatial distribution of tetrapod food webs and asked whether the variation in local food web structure is driven by random processes or by natural and anthropogenic factors. Location Europe. Time period Present. Major taxa studied Tetrapods. Methods We combined an expert‐based food web (1,140 species and 70,601 links) of all European tetrapods with their respective spatial distributions. We mapped 17 different food web metrics representing complexity, chain length, vertical diversity and diet strategy across Europe and tested whether their distribution reflects the spatial structure of species richness using a null model of food web structure. To avoid multicollinearity issues, we defined composite descriptors of food web structure that we related to a set of environmental layers summarizing both natural and anthropogenic influences and tested their relative importance in explaining the spatial distribution of European terrestrial vertebrate food webs. Results Of the 17 metrics, 10 showed a non‐random spatial distribution across Europe and could be summarized along two major axes of variation in food web structure. The first was related to species richness, mean trophic level and the proportion of intermediate species, whereas the second was related to the connectance and proximity of species within the web. Both descriptors varied with latitudinal gradient. The best descriptors of food web structure were mean annual temperature and seasonality (negatively correlated with the first axis), and human footprint (positively correlated with the second axis). Main conclusions We demonstrate the importance of climate and anthropogenic pressure in shaping the spatial structure of European tetrapod food webs.

Description: Global Ecology and Biogeography, Volume 28, Issue 9, Page 1379-1379, September 2019.

Description: Abstract Aim Soils and their biological communities face increasing pressure from multiple global drivers, including land management and climate change. In soils, earthworms play key roles in ecosystem functioning, but the environmental controls on their global communities are not fully understood. Here, an earthworm dataset was compiled to investigate the effects of environmental variables and land management on global earthworm communities. Location 40° S–65° N. Time period 1962 to 2016. Major taxa studied Earthworms. Methods A dataset of 899 earthworm community observations, together with environmental variables, was compiled across 169 globally distributed sites. Sites included natural forest and grassland or managed arable, pasture and plantation ecosystems. Total, anecic, endogeic and epigeic abundances and total species richness were compared in natural and managed ecosystems to quantify the effects of land management across climates. A hierarchical model was used to test the importance of environmental controls in predicting the relationship between total earthworm species richness and abundance at a global scale. Results Land management prompted little change in total earthworm abundance at the global scale, but reduced species richness and shifted community composition. Endogeic earthworms were more abundant in managed ecosystems, while anecic and epigeic earthworms showed variable responses across ecosystem types. Global relationships between total earthworm species richness and abundance were explained by climate, soil pH and land management. Main conclusions Land management modulates the effects of environmental controls on global earthworm communities, through direct disturbance and indirect changes in edaphic conditions.

Description: Abstract Aim Sediment disturbances are important threats affecting marine biodiversity, but the variety of biological responses has not yet been synthesized. Here, we collate all available information to compare the extent of impacts across different taxonomic groups, habitat types and pathways of impact (light attenuation, suspended sediment and sedimentation). Location Global. Time period Data collected from 1979 to 2017. Major taxa studied Corals, fishes, seagrasses, sponges, macroalgae, ascidians, bryozoans, crustaceans, echinoderms, molluscs and polychaetes. Methods We used meta‐analyses to evaluate the effects of sediments across 842 observations found in 110 publications. We also evaluated some of the biological and methodological factors that could explain the variable effects observed in different studies. Results We found a significant negative effect of sediments on behavioural responses of species, reproduction and recruitment processes, the morphology of organisms, physiology, community abundance and diversity, and species interactions. In contrast, the overall effect on the abundance of individual species was statistically non‐significant and there was a strong positive effect on abundance for sponge and polychaete species. Many individual studies described physiological effects on coral reefs, but the effects on the diversity of soft‐bottom and coral reef communities were particularly detrimental. Phototrophic species were generally more negatively impacted by sediments than heterotrophs, driven by strong physiological responses in crustose coralline algae and seagrasses. Additionally, species with limited mobility were more vulnerable to sediment disturbances than highly mobile species. Sedimentation alone triggered more consistently negative effects on most biological responses than light depletion and suspended sediments. We found evidence for increased impacts on community diversity when more than one pathway of impact was present, indicating that these disturbances can disrupt whole ecosystems. Main conclusions Our meta‐analysis provided, for the first time, strong quantitative support of negative effects of sediments on marine biodiversity. Taxonomic groups, habitat types and life‐history characteristics were most influential in determining the biological responses to sediment disturbances, highlighting the importance of an ecosystem‐based approach when fully accounting for the impacts of sediments.

Description: Global Ecology and Biogeography, Volume 28, Issue 9, Page 1201-1203, September 2019.

Description: Abstract The idea that the number of species within an area is limited by a specific capacity of that area to host species is old yet controversial. Here, we show that the concept of carrying capacity for species richness can be as useful as the analogous concept in population biology. Many lines of empirical evidence indicate the existence of limits of species richness, at least at large spatial and phylogenetic scales. However, available evidence does not support the idea of diversity limits based on limited niche space; instead, carrying capacity should be understood as a stable equilibrium of biodiversity dynamics driven by diversity‐dependent processes of extinction, speciation and/or colonization. We argue that such stable equilibria exist even if not all resources are used and if increasing species richness increases the ability of a community to use resources. Evaluating the various theoretical approaches to modelling diversity dynamics, we conclude that a fruitful approach for macroecology and biodiversity science is to develop theory that assumes that the key mechanism leading to stable diversity equilibria is the negative diversity dependence of per‐species extinction rates, driven by the fact that population sizes of species must decrease with an increasing number of species owing to limited energy availability. The recently proposed equilibrium theory of biodiversity dynamics is an example of such a theory, which predicts that equilibrium species richness (i.e., carrying capacity) is determined by the interplay of the total amount of available resources, the ability of communities to use those resources, environmental stability that affects extinction rates, and the factors that affect speciation and colonization rates. We argue that the diversity equilibria resulting from these biodiversity dynamics are first‐order drivers of large‐scale biodiversity patterns, such as the latitudinal diversity gradient.

Description: Abstract Aim Theory suggests that increasing productivity and climate stability towards the tropics favours specialization, thus contributing to the latitudinal richness gradient. A positive relationship between species richness and specialization should therefore emerge as a fundamental biogeographical pattern. However, land‐use and climate changes disproportionally increase the local extirpation risk for specialists, potentially weakening the relationship between richness and specialization. Here, we quantify empirically the richness–specialization prediction and test how 50 years of climate and land‐use change has affected the richness–specialization relationship. Location USA. Time period 1966–2015. Major taxa studied Birds. Methods We used the North American Breeding Bird Survey to quantify bird community richness and specialization to habitat and climate. We (a) quantify temporal change in the slope of the richness–specialization relationship, using a generalized mixed model; (b) assess how this change translates spatially, using generalized additive models; and (c) attribute spatio‐temporal change in the richness–specialization relationship to land use, climate and topographic drivers. Results We found evidence for a positive but weak richness–specialization relationship in bird communities that greatly weakened over time. Given that specialization was not the main driver of richness, this relationship did not translate spatially into a linear spatial covariation between richness and specialization. Instead, the spatial covariation in richness and specialization followed a unimodal pattern, the peak of which shifted towards less specialized communities over time. These temporal changes were associated with precipitation change, decreasing temperature stability and land use. Main conclusions Recent climate and land‐use changes have induced two contrasting types of community responses. In human‐dominated areas, the decoupling of richness and specialization drove a general trend for biotic homogenization. In areas of low human impact experiencing increasing climate harshness, specialization increased, whereas richness decreased. Our results offer new support for specialization as a key driver of macroecological diversity patterns and show that global changes are weakening this fundamental macroecological pattern.

Description: Global Ecology and Biogeography, Volume 28, Issue 8, Page 1039-1041, August 2019.

Description: The cover image is based on the Research Paper A consistent species richness–climate relationship for oaks across the Northern Hemisphere by Xiaoting Xu et al., DOI: 10.1111/geb.12913. Image Credit: © Lie Zhang.

Description: Abstract Aim We test whether urbanization drives biotic homogenization. We hypothesize that declines in abundance and species diversity of aerial insects are exacerbated by the urbanization‐driven loss of species with low habitat generalism, mobility and warm‐adaptedness. We predict this homogenization to be more pronounced for nocturnal taxa, and at wider scales for mobile taxa. Location Belgium. Time period Summers 2014–2015. Major taxa studied Lepidoptera. Methods We compare communities along urbanization gradients using a shared, replicated and nested sampling design, in which butterflies were counted within 81 grassland and macro‐moths light‐trapped in 12 woodland sites. We quantify taxonomic and functional community composition, the latter via community‐weighted means and variation of species‐specific traits related to specialization, mobility and thermophily. Using linear regression models, variables are analysed in relation to site‐specific urbanization values quantified at seven scales (50–3,200 m radii). At best‐fitting scales, we test for taxonomic homogenization. Results With increasing urbanization, abundance, species richness and Shannon diversity severely declined, with butterfly and macro‐moth declines due to local‐ versus landscape‐scale urbanization (200 vs. 800–3,200 m radii, respectively). While taxonomic homogenization was absent for butterflies, urban macro‐moth communities displayed higher nestedness than non‐urban communities. Overall, communities showed mean shifts towards generalist, mobile and thermophilous species, displaying trait convergence too. These functional trait models consistently fit best with urbanization quantified at local scales (100–200 m radii) for butterfly communities, and at local to wider landscape scales (200–800 m radii) for macro‐moth communities. Main conclusions Urban communities display functional homogenization that follows urbanization at scales linked to taxon‐specific mobility. Light pollution may explain why homogenization was more pronounced for the nocturnal taxon. We discuss that urbanization is likely to impact flying insect communities across the globe, but also that impacts on their ecosystem functions and services could be mitigated via multi‐scale implementation of urban green infrastructure.

Description: Abstract Issue Approaches to predicting species assemblages through stacking individual niche‐based species distribution models (S‐SDMs) need to account for community processes other than abiotic filtering. Such constraints have been introduced by implementing ecological assembly rules (EARs) into S‐SDMs, and can be based on patterns of functional traits in communities. Despite being logically valid, this approach has led to a limited improvement in prediction, possibly because of mismatches between the scales of measurement of niche and trait data. Evidence S‐SDM studies have often related single values of a species’ traits to environmental niches that are captured by abiotic conditions measured at a much finer spatial scale, without accounting for intraspecific trait variation along environmental gradients. Many pieces of evidence show that omitting intraspecific trait variation can hinder the proper inference of EARs from trait patterns, and we further argue that it can therefore also affect our capacity to spatially predict functional properties of communities. In addition, estimates of environmental niches and trait envelopes may vary depending on the scale at which environmental and trait measurements are made. Conclusion We suggest that to overcome these limitations, surveys sampling both niche and trait measurements should be conducted at fine scales along wide environmental gradients, and integrated at the same scale to test and improve a new generation of spatial community models and their functional properties.

Description: Abstract Aim Leaf litter decomposition in freshwater ecosystems is a vital process linking ecosystem nutrient cycling, energy transfer and trophic interactions. In comparison to terrestrial ecosystems, in which researchers find that litter traits predominantly regulate litter decomposition worldwide, the dominant factors controlling its decomposition in aquatic ecosystems are still debated, with global patterns not well documented. Here, we aimed to explore general patterns and key drivers (e.g., litter traits, climate and water characteristics) of leaf litter decomposition in streams worldwide. Location Global. Time period 1977–2018. Major taxa studied Leaf litter. Methods We synthesized 1,707 records of litter decomposition in streams from 275 studies. We explored variations in decomposition rates among climate zones and tree functional types and between mesh size groups. Regressions were performed to identify the factors that played dominant roles in litter decomposition globally. Results Litter decomposition rates did not differ among tropical, temperate and cold climate zones. Decomposition rates of litter from evergreen conifer trees were much lower than those of deciduous and evergreen broadleaf trees, attributed to the low quality of litter from evergreen conifers. No significant differences were found between decomposition rates of litter from deciduous and evergreen broadleaf trees. Additionally, litter decomposition rates were much higher in coarse‐ than in fine‐mesh bags, which controled the entrance of decomposers of different body sizes. Multiple regressions showed that litter traits (including lignin, C:N ratio) and elevation were the most important factors in regulating leaf litter decomposition. Main conclusions Litter traits predominantly control leaf litter decomposition in streams worldwide. Although further analyses are necessary to explore whether commonalities of the predominant role of litter traits in decomposition exist in both aquatic and terrestrial ecosystems, our findings could contribute to the use of trait‐based approaches in modelling the decomposition of litter in streams globally and exploring mechanisms of land–water–atmosphere carbon fluxes.

Description: Abstract Aim Many studies use differences among plant populations to infer future plant responses, but these predictions will provide meaningful insights only if patterns of plasticity among populations are similar (i.e., in the absence of population‐by‐environment interaction, P × E). In this study, we tested whether P × E is considered in climate change studies. Specifically, we evaluated whether population differentiation varies across environments and whether P × E is determined by aspects of the study system and experimental design. Location Global. Methods We conducted a literature search in the Thomson Reuters Web of Science database to identify studies assessing population differentiation in a climate change context. We quantified the occurrence of P × E and performed a meta‐analysis to calculate the percentage of traits showing P × E in the study cases. Results We identified 309 study cases (from 237 published articles) assessing population differentiation in 172 plant species, of which 64% included more than one test environment and tested P × E. In 77% of these studies, P × E was significant for at least one functional trait. The overall proportion of traits showing P × E was 33.4% (95% confidence interval 27.7–39.3). These results were generally consistent across life‐forms, ecoregions and type of experiment. Furthermore, population differentiation varied across test environments in 76% of cases. The overall proportion of traits showing environment‐dependent population differentiation was 53.7% (95% confidence interval 37.9–69.3). Conclusions Our findings revealed that differences in phenotypic plasticity among populations are common but are usually neglected in order to forecast population responses to climate change. Future studies should assess population differentiation in many test environments (accounting for P × E) that realistically reflect future environmental conditions, assessing climate change drivers that are rarely considered (e.g., multifactor experiments incorporating higher CO2 levels). Our review also revealed the predominant focus of population studies on trees from temperate climates, identifying underexplored life‐forms (shrubs, annuals), phylogenetic groups (ferns, ancient gymnosperms) and ecoregions (tropical, arctic) that should receive more attention in future.

Description: Abstract Aim Climate change causes major shifts in species distributions, reshuffling community composition and favouring warm‐adapted species (“thermophilization”). The tree community response is likely to be affected by major disturbances, such as fire and harvest. Here, we quantify the relative contributions of climate change and disturbances to temporal shifts in tree composition over the last decades and evaluate whether disturbances accelerate community thermophilization. Location Québec, Canada. Time period 1970–2016. Taxa studied Trees. Methods Using 6,281 forest inventory plots, we quantified temporal changes in species composition between a historical (1970–1980) and a contemporary period (2000–2016) by measuring temporal β‐diversity, gains and losses. The effects of climate and disturbances on temporal β‐diversity were quantified using multiple regressions and variation partitioning. We compared how community indices of species temperature preference (CTI) and shade tolerance (CSI) changed for forests that experienced different levels of disturbance. We quantified the contribution of species gains and losses to change in CTI. Results Temporal β‐diversity was mainly driven by disturbances, with historical harvesting as the most important predictor. Despite the prevailing influence of disturbances, we revealed a significant thermophilization (ΔCTI = +.03 °C/decade) throughout forests in Québec. However, this shift in community composition was weakly explained by climate change and considerably slower than the rate of warming (+.14 °C/decade). Importantly, thermophilization was amplified by moderate disturbances (+.044 °C/decade), almost a threefold increase compared with minor disturbances (+.015 °C/decade). The gains and losses of a few tree species contributed to this community‐level shift. Conclusions Our study provides evidence that disturbances can strongly modify tree community responses to climate change. Moderate disturbances, such as harvesting, might reduce competition and facilitate gains of warm‐adapted species, which then accelerate thermophilization of tree communities under climate change. Although accelerated by disturbances, community thermophilization was driven by the gains and losses of a small number of species, notably gains of maples.

Description: Abstract Aim Community phylogenetic studies use information about the evolutionary relationships of species to understand the ecological processes of community assembly. A central premise of the field is that the evolution of species maps onto ecological patterns, and phylogeny reveals something more than species traits alone about the ecological mechanisms structuring communities, such as environmental filtering, competition, and facilitation. We argue, therefore, that there is a need for better understanding and modelling of the interaction of phylogeny with species traits and community composition. Innovation We outline a new approach that identifies clades that are ecophylogenetically clustered or overdispersed and assesses whether those clades have different rates of trait evolution. Ecophylogenetic theory would predict that the traits of clustered or overdispersed clades might have evolved differently, in terms of either tempo (fast or slow) or mode (e.g., under constraint or neutrally). We suggest that modelling the evolution of independent trait data in these clades represents a strong test of whether there is an association between the ecological co‐occurrence patterns of a species and its evolutionary history. Main conclusions Using an empirical dataset of mammals from around the world, we identify two clades of rodents whose species tend not to co‐occur in the same local assemblages (are phylogenetically overdispersed) and find independent evidence of slower rates of body mass evolution in these clades. Our approach, which assumes nothing about the mode of species trait evolution but instead seeks to explain it using ecological information, presents a new way to examine ecophylogenetic structure.

Description: Glacial lake outburst floods occurred frequently during the last deglaciation of the Laurentide Ice Sheet. Within the Interior Plains, these floods carved large spillway systems; however, due to a lack of abundant sediment, deposits within prairie spillways are rarely preserved. Here, we present geomorphic and sedimentary evidence and hydraulic modelling of the eastern Beaver River Spillway, formed by the catastrophic drainage of the ice‐dammed glacial Lake Algar, in north central Alberta. During this flood, coarse‐grained sediment eroded from local till formed large pendant bars. Within the first ~50 km of the spillway (Reach 1), pendant bars contain downstream orientated foresets overlain by horizontally bedded coarser gravels. The remaining pendant bars (Reach 2), present downflow of a moraine barrier, differ, comprising massive, matrix‐supported, inversely graded gravels capped by a boulder layer. We use a HEC‐GeoRAS/HEC‐RAS system in conjunction with palaeostage indicators to estimate the steady‐state water surface elevation. Modelling results show that peak discharge within Reach 1 of the eastern Beaver River Spillway was approximately 14 000–21 000 m3 s−1. For Reach 2, 30 km downstream, the peak discharge was estimated at 23 000–40 000 m3 s−1 (nbulked 18 000–26 000 m3 s−1). The downstream discharge increase, consistent with the sedimentary change in pendant bar deposits, is attributed to sediment bulking of the flood flow. This provides the opportunity to observe a range of flow conditions, and associated sedimentology, from a single flood event. The reconstructed flow conditions, coupled with lake volume estimates from the ponding above the moraine barrier suggest a minimum flow duration of 3–5 days.

Description: The azimuth of imbrication of minimum magnetic susceptibility axes in the youngest loess from Ukraine defines prevailing wind directions during aeolian sedimentation. It changes along the studied sections. These changes can be directly correlated with the fluctuations of the Fennoscandian Ice Sheet. The northern and northeastern winds noted in the loess succession separated by a period when southwestern to southeastern winds were predominant may be correlated with two main phases of ice‐sheet advance during the Last Glacial Maximum. The ice‐sheet advances towards the areas of loess deposition generated katabatic winds that influenced aeolian sedimentation in the periglacial zone. A period of relatively stable wind directions during a younger phase of the Last Glacial Maximum was interrupted by periods with more chaotic wind regime most probably caused by fluctuations of the Fennoscandian Ice Sheet during its retreat from the peri‐Baltic part of Europe. These intervals occur where initial soils developed. The distribution of anisotropy of magnetic susceptibility axes defined along the periglacial loess sections from central and eastern Europe can serve to constrain fluctuations of the Fennoscandian Ice Sheet.

Description: Understanding resource utilization and economic diversification amongst Holocene hunter‐gatherers in southern Brazil requires in‐depth taphonomic analysis of faunal assemblages. Three Early to Late Holocene archaeological sites (Garivaldino, Pilger and Sangão) in Rio Grande do Sul State, southern Brazil, revealed large assemblages of small mammal (˂1 kg) remains, composed mainly of rodents. To appreciate depositional processes of fauna in relation to human consumption, taphonomic attributes and processes were evaluated. The results indicated that the remains accumulated through different antemortem taphonomic pathways, apparently linked to the size and natural history of the species represented. The small‐ and medium‐sized (〈150 g) cricetid rodents (e.g. Pseudoryzomys simplex and Sooretamys angouya) were represented by a low proportion of teeth with lightly digestive corrosion suggesting that they were derived from the predatory activity of owls, possibly Tyto alba. In contrast, large‐sized cricetids (〉150 g; Kunsia tomentosus, Gyldenstolpia sp. and Holochilus sp.), and several caviomorph rodents with aggregated spatial distributions (Echimyidae (†Dicolpomys fossor, Phyllomys sp., †Clyomys riograndensis and †Euryzygomatomys mordax), Caviidae (Cavia sp.) and Ctenomyidae (Ctenomys sp.)) showed evidence of thermoalteration patterns and cut marks on bones, suggesting human exploitation. A postmortem depositional environment was deduced from dendritic and branched patterns of rootlet etching, apparent mostly at Garivaldino and Pilger. Polished areas and holes on bone surfaces, and impregnation of manganese showed moderate (Sangão) or low (Garivaldino and Pilger) incidence, pointing to water transport under moderate (Pilger) and low (Garivaldino and Sangão) energy over short distances. The results obtained here provide the first clear evidence of early human exploitation of small mammals in southern Brazil, suggesting a diversification of economies. In addition, as several of the recorded rodents are today regionally or biologically extinct, a preliminary discussion about the potential impact of humans on this process is provided.

Description: The Göschenertal (Göschenen valley) is the type locality of the so‐called Göschenen Cold Phases I (~3–2.3 ka) and II (~1.8–1.1 ka). According to earlier studies, these Late Holocene climatic cooling periods were characterized by changes in vegetation and pronounced glacier advances. As a peculiarity, the Göschenen Cold Phase I was thought to be connected to a local surge‐type advance of the Chelengletscher (Chelen glacier) – an exceptional event of unparalleled dimension in the European Alps. Based on cosmogenic 10Be exposure ages from moraine boulders, we investigated the local glacier chronology. In contrast to former research, moraines at different positions within the Göschenen valley (central Swiss Alps) have been dated to the Younger Dryas and the Early Holocene. This questions the applicability of palaeo‐Equilibrium Line Altitude (ELA) calculations for stadial attributions without additional numerical age constraints. Furthermore, we have found compelling evidence that the proposed non‐climatic glacier advance attributed to the Göschenen Cold Phase I did not occur. The present results, along with a reappraisal of the original study, question the scientific reliability and the glaciological definition of the Göschenen Cold Phases as glacier advances that clearly exceeded the Little Ice Age positions. While our data do not exclude potential changes in climate and vegetation, we nonetheless show that the Göschenen Cold Phases are not suitable as reference stadials in the system of Alpine Holocene glacier fluctuations.

Description: Abstract Aim We examine how environmental variability at seasonal and interannual time‐scales influences evolutionary trajectories and the role of plasticity in response to recent and future climate change at biogeographic scales. We investigate the interplay of selection pressures at chronic (performance) and acute (thermal stress) time‐scales. Location Colorado, USA. Time period 1950–2099. Major taxa studied A montane butterfly, clouded sulphur (Colias eriphyle W.H. Edwards, 1876). Methods We leverage field and laboratory data to construct phenotype‐based models that predict fitness and evolutionary responses to recent and future climate change. Our focal phenotype, wing solar absorptivity, responds plastically to developmental (pupal) temperatures and determines adult fitness via its influence on body temperature. Results We project that phenology accelerates with decreasing elevation and climate change, but gradients in pupal and adult temperature with climate change are modest. Fitness of the first generation is predicted to decrease at low elevations and increase at high elevations with warming. Elevational clines in optimal wing absorptivity shift towards lower absorptivities with warming. We project that temporal shifts from selection for wing darkening (to extend flight time) to selection for wing lightening (to avoid overheating) in some cool, montane locations will ultimately impose fitness costs. Main conclusions Our analysis suggests that shifts in the balance of selection between acute and chronic responses to environmental variation will alter biogeographic responses to climate change. Evolutionary lags may ultimately confer greater sensitivity to climate change, but plasticity can reduce evolutionary lags by facilitating trait evolution.

Description: Global Ecology and Biogeography, Volume 28, Issue 7, Page 863-865, July 2019.

Description: The cover image is based on the Research Paper Why is fruit colour so variable? Phylogenetic analyses reveal relationships between fruit‐colour evolution, biogeography and diversification by Lu Lu et al., DOI: 10.1111/geb.12900.

Description: Pronounced climatic warming associated with the Late Weichselian Pleniglacial‐to‐Lateglacial transition caused considerable environmental changes throughout the former periglacial zones (in Europe ~53°–46°N). During permafrost degradation and subsequent ground subsidence (i.e. thermokarst processes), the landscape changed rapidly. In this study we investigated a flat mid‐altitude area in south Bohemia, Czech Republic, lying close to the southern limit of the Weichselian permafrost. We discovered palaeo‐lake basins with sedimentary infillings up to 11 m in depth. According to radiocarbon and palynostratigraphical dating, these basins were formed at the onset of the Late Pleniglacial‐to‐Lateglacial transition, whereas the smaller depressions were formed later. We suggest that the basins resulted from thermal and fluvio‐thermal erosion of the former permafrost and represent remnants of discontinuous gullies and possibly collapsed frost mounds (pingo/lithalsa scars). The formation of this a fossil thermokarst landscape was climatically driven and multiple phased, with the major phase during the climatic warming and wetting at the onset of GI‐1e (Bølling) and the minor phase during GI‐1c (Allerød). This study enhances knowledge of the palaeogeography of the former European periglacial zone by showing that Late Pleistocene thermokarst activity could have had a significant impact on the evolution of the landscape of at least some regions of central Europe along the southern limit of the continuous permafrost zone. The research also points to a similar history for the physical transformation of the landscape of the former European periglacial zone and current thermokarst landscapes and could be a valuable source of information with respect to the future transformation of the Arctic under conditions of ongoing global warming.

Description: Abstract Aim The interactive effects of increased temperature and ultraviolet‐B (UV‐B) radiation on terrestrial and aquatic biota remain poorly understood. Our goal is to increase knowledge by providing a comprehensive assessment of the combined effects of warming and increased UV‐B on organisms across these domains. Location Global. Time period 1995–2016. Major taxa studied Terrestrial plants and animals, and marine and freshwater microalgae, macroalgae and animals. Methods We examined, using a meta‐analysis based on 1,139 published experimental assessments, the combined effects of temperature and UV‐B across terrestrial, freshwater and marine biota. We characterized the prevailing mode of combined effects (additive, synergistic or antagonistic), and assessed whether these were dose‐dependent or differed between terrestrial, freshwater and marine species, or between organisms growing in the Northern and Southern Hemispheres. Results Our results show that the two stressors generally acted opposingly, with a significant positive effect of increased temperature and a significant adverse effect of elevated UV‐B radiation. Regarding their interactive impact, additive interactions (84%) appeared to be much more common compared with multiplicative (16%) effects. The frequencies of interaction types differed significantly among the three habitats and different plant functional groups. The proportion of both synergistic and antagonistic effects increased with increasing magnitude of temperature and UV‐B changes, suggesting that additivity is constrained by an organism’s thermal and physiological limits. Main conclusions Our analysis demonstrates that due to their mostly opposing nature, elevated temperature, within the thermal limits of organisms, tends to compensate for the negative impact of UV‐B radiation when acting together, while their additive interaction is likely to assist impact prognosis. Our study, therefore, provides new insights into the predictions of the interactive effects of global change drivers across different habitats.

Description: Abstract The latitudinal diversity gradient (LDG) has been investigated for decades, with hundreds of studies focusing on different organisms, regions and habitat types. Meta‐analysis may be considered, therefore, a useful tool to explore the generality and limitations of this remarkable macroecological pattern. The first meta‐analysis exploring variations in the LDG, published by Hillebrand in 2004, revealed that the latitudinal decline in species richness seems to be indeed a general phenomenon. However, Kinlock et al. (2018, Global Ecology and Biogeography, 27, 125–141) revisited recently the challenge of synthesizing individual LDGs and indicated that the phenomenon is not ubiquitous among habitats of the marine realm. More precisely, they indicated that the phenomenon is non‐significant in the benthic habitat. Here, we suggest that the marine habitat categories used by them (i.e., benthic, coral reefs, coastal, open ocean) are not independent and that reclassifying the studies significantly alters one of their main results. By assigning the studies into benthic and pelagic categories, and additionally into coastal or oceanic zones, we show that non‐ambiguous, evolutionarily meaningful marine habitats display a significant latitudinal decline in species richness.

Description: Recent LiDAR surveys have revealed that on postglacially uplifting coasts of Estonia rhythmic coastal landforms (beach ridge sequences and foredune plains) occur to a considerable extent. We studied four of them to reveal age and periodicity in these multiple ridge systems and discussed their genesis in the Subatlantic (semi‐continental) conditions of the Baltic Sea area. Using recent models of Fennoscandian uplift due to glacial isostatic adjustment (GIA), we constructed Holocene apparent sea level curves for the study sites at Õngu, Mänspe, Haldi and Keibu; converted distance–height shore profiles into time series (including corrections on shore profile non‐linearity and variations in GIA‐eustasy balance); and analysed the patterns using spectral analysis. It was suggested that due to non‐tidal conditions, relatively low‐energy hydrodynamic forcing and small aeolian contribution, the ridges mark ancient shorelines. They are relatively modest in height (mostly 0.2–1 m), form regular and extensive (up to 150 ridges) patterns, and date back to ~9000 years before present. We studied 〈5‐ka‐old sections. The mean ridge spacing varied, depending also on coastal slope, between 21 and 39 m. Both simple counting and spectral analysis involved some specific limitations, yet the estimates for typical spacing were alike, at 32 (±5) years. The regular nature of the low‐ridge patterns originated from relative sea level lowering and gradual sediment accretion/erosion. However, the progradation was rather uplift‐ than accretion‐driven and the stepwise process in ridge formation was probably not autocyclic. It was governed or modulated by quasi‐periodic 25–40 year cyclicity in local wave forcing, relative sea level variations and wind conditions. Being most likely connected to the North Atlantic Oscillation, the quasi‐regular, decadal‐scale, similarly phased variations may magnify each other's effect on the westerly exposed coasts of Estonia. Additionally, some other (e.g. event‐driven) mechanisms may also be present.

Description: The aim of this contribution is to describe a femur (MCRS 199) assigned to Nothrotheriops sp. from the Late Pleistocene of Santa Fe Province (Argentina), and discuss the implications of this find in the context of the dispersal of ground sloths during the Great American Biotic Interchange. The specimen MCRS 199 is smaller than the femora referred to the North American species Nothrotheriops texanus and Nothrotheriops shastensis but shares several features with these species: (i) shape and position of the greater trochanter, (ii) development of the lesser trochanter, (iii) presence of connection between the third trochanter and the ectepicondyle, (iv) distal third of the femur wider, with ML/DW index of 1.93, and (v) location and relationship of the distal condyles. These similarities allow us to assign MCRS 199 to Nothrotheriops sp. The record of Nothrotheriops sp. from Santa Fe Province chronologically coincides with the earliest records of Nothrotheriops shastensis suggesting a broad geographical distribution of Nothrotheriops during the Late Pleistocene, ranging from 33–36°N (e.g. states of California and Arizona, USA) to 31°S (northern Salado River, Santa Fe Province, Argentina). Thus, Nothrotheriops have dispersed from North America (where Nothrotheriops has early records, Calabrian–Middle Pleistocene) to South America where localities bearing Nothrotheriops are Late Pleistocene in age. In addition, once in South America and probably during the Middle Pleistocene, Nothrotheriops probably gave rise to its sister taxon, Nothrotherium, with records from the Middle Pleistocene (e.g. 223 ka BP, northeastern Brazil) to the Late Pleistocene (e.g. 15 ka BP).

Description: Prehistoric settlements are usually perceived as being in opposition to the natural development of the landscape. Indeed, for woodland snail assemblages in anthropogenic landscapes in central Europe, considerable impoverishment is typical. However, it remains unclear whether this has been caused by humans only or also by climate effects. From an archaeological point of view, the Moravian Karst is one of the classic prehistorical locations in central Europe, but with a more humid climate than the previously studied anthropogenic areas. To learn more about coexistence of humans and natural forests during the Lateglacial and Holocene, we analysed 11 mollusc successions covering this entire area, a unique data set for such a relatively small area. These mollusc successions show several specific features compared to the standard development known from other mid‐European areas. One is that although the Moravian Karst is not far from the Western Carpathians, Carpathian species appeared relatively late, only during the second half of the Holocene climatic optimum. Similarly, some western European and Alpine elements appeared later than expected. In contrast to this, however, a number of forest species with central European range appeared relatively early during the Lateglacial or Early Holocene. Two even survived the Last Glacial Maximum in the Moravian Karst. This would suggest an early occurrence of forest patches in a mosaic landscape. Humans have apparently inhabited this area since the Lateglacial amongst islands of forests, which later changed during the Boreal and then the climatic optimum into humid canopy forests. Thus, a mosaic of anthropogenic and natural habitats persisting in close vicinity was possible in rugged and humid landscapes practically until the Industrial Revolution.

Description: Boreas, Volume 48, Issue 2, Page i-iv, April 2019.

Description: Regional‐scale, high‐resolution terrain data permit the study of landforms across south‐central Ontario, where the bed of the former Laurentide Ice Sheet is well exposed and passes downflow from irregular topography on Precambrian Shield highlands to flat‐lying Palaeozoic carbonate bedrock, and thick (50 to 〉200 m) unconsolidated sediment substrates. Rock drumlins and megagrooves are eroded into bedrock and mega‐scale glacial lineations (MSGL) occur on patchy streamlined till residuals in the Algonquin Highlands. Downflow, MSGL pass into juxtaposed rock and drift drumlins on Palaeozoic bedrock and predominantly till‐cored drumlins in areas of thick drift. The Lake Simcoe Moraines, now traceable for more than 80 km across the Peterborough drumlin field (PDF), form a distinct morphological boundary: downflow of the moraine system, drumlins are larger, broader and show no indication of subsequent reworking by the ice, whereas upflow of the moraines, a higher degree of complexity in bedform pattern and morphology is distinguished. Discrete radial and/or cross‐cutting flowset terminate at subtle till‐cored moraine ridges downflow of local topographic lows, indicating multiple phases of late‐stage ice flow with strong local topographic steering. More regional‐scale flow switching is evident as NW‐orientated bedforms modify drumlins south of the Oak Ridges Moraine, and radial flowset emanate from areas within the St. Lawrence and Ottawa River valleys. Most of the drumlins in the PDF formed during an early, regional drumlinization phase of NE–SW flow that followed the deposition of a thick regional till sheet. These were subsequently modified by local‐scale, topographically controlled flows that terminate at till‐cored moraines, providing evidence that the superimposed bedforms record dynamic ice (re)advances throughout the deglaciation of south‐central Ontario. The patterns and relationships of glacial landform distribution and characteristics in south‐central Ontario hold significance for many modern and palaeo‐ice sheets, where similar downflow changes in bed topography and substrate lithology are observed.

Description: Ten monitoring sites were established in 1986 near the Scottbreen and Renardbreen glaciers (Bellsund, Spitsbergen) in order to determine the rates of gelifluction on raised marine terraces and on talus cones, accumulation on talus cones, and movement of the protalus rampart. The measurements were performed in 1987, 2007 and 2016. The results obtained revealed a very slow rate of changes on the surface of the analysed area. During 30 years, only one out of 84 points where the gelifluction rate was measured was displaced by 15 cm down‐slope. The maximal annual and average gelifluction rates were calculated at 0.5 cm and 0.18 cm a−1, respectively. Several measurement points did not change their position over the observation period. As shown by the observations, the gelifluction rate largely does not depend on slope inclination. Studies of talus cones allowed the level of cone increment to be determined as 314.3 kg of scree per square metre. Analysis of factors influencing the rate of mass movement allowed for correlation of the small‐scale gelifluction movement at the analysed sites with the general trends of climate warming. In this part of the Arctic, these trends are manifested by soil desiccation. It appears that slope processes depend on very local topoclimatic factors. Analysis of the obtained data with regard to palaeogeographical and climatic investigations suggests that the ice segregation forms on raised marine terraces developed during the last Holocene cooling, i.e. the Little Ice Age.

Description: Boreas, Volume 48, Issue 2, Page 269-272, April 2019.

Description: Here we investigate, for the first time, the use of optically stimulated luminescence (OSL) for dating cobbles from the body of successive beach ridges and compare cobble surface‐derived ages to standard quartz OSL ages from sand. Between four and eight cobbles and sand samples (age control) were dated with the luminescence method, taken from the modern beach and from beach ridges on the south and north extremes of a prograding spit on the westernmost coast of Lolland, Denmark. Luminescence‐depth profiles perpendicular to the surfaces of the cobbles show that the feldspar infrared signals stimulated at 50 °C were fully reset to various depths into the cobbles prior to final deposition; as a result, the equivalent doses determined from close to the surface of such cobbles can be used to calculate burial ages. Beach‐ridge burial ages given by the average of ages of individual cobbles taken from the same site are consistent, within errors, with the ages derived from the sand samples. Cobble‐ and sand‐derived ages show that the southernmost beach ridge at Albuen was formed around 2 ka ago, indicating that this sandy spit is younger than other coastal systems in Denmark. The agreement between ages derived from clasts and from standard quartz OSL in this study confirms that, even in the absence of sandy sediments, we can reliably date sites using OSL by targeting larger clasts. In addition, the record of prior light exposure contained in the shape of the cobbles’ luminescence‐depth profile removes one of the major uncertainties (i.e. the degree of signal reset prior to burial) in the luminescence dating of high latitude sites.

Description: This article reports on an Early Saalian proglacial lake formed between the Scandinavian Ice Sheet and the front of the Sudeten Mountains, Poland. Sediments investigated at Mysłów point to a transition from glacifluvial to glaciolacustrine environments. The bulk of the sediments was deposited in deep‐water Gilbert‐type deltas (A–E complexes). A delta plain (topset) gradually passes into a subaerial plateau and then a clastic shoreline and the subaquatic slope of a prograding delta (foreset). The glaciolacustrine lithofacies represent a number of lake‐basin environments, from marginal subaqueous slopes to distal parts of a subaqueous fan. Glaciolacustrine and glaciodeltaic deposits locally reach ˜50–70 m in thickness. Analyses of A–E complexes indicate that the lake existed for more than 130 years and that its origin and evolution were closely connected with the ice front. This case study records lake sedimentation at an ice‐sheet margin with cohesionless gravity flows, turbidity currents, debris‐avalanching and, to a much lesser degree, parapelagic suspension fall‐out and ice‐raft dumping. In the initial stage, the lake extended more than 10 km to the south, and the deposition was relatively slow. In the second stage, recession of the ice sheet caused rapid growth of a delta. The third and ultimate stage coincided with the final glacial recession, with rapid deposition occurring only on the lake bottom. The model of the glaciolacustrine environment presented here may also be applicable to many other proglacial lakes in mountain areas.

Description: In earlier studies, the topography and melting dynamics of ice‐cored ridges within marginal zones of the Pleistocene ice sheets were routinely reconstructed based only on conceptual and qualitative models supported by geomorphological, sedimentological and palaeogeographical studies. Here, a novel approach based on detailed structural analysis of two collapse structures affecting Pleistocene kame deposits is presented. The high regularity of the geometry of synclines and related strain fields as well as the patterns of subsidence of the folded strata are all interpreted as evidence of topography of ice‐cored ridges and their melting dynamics. The topography is described in terms of elongation, orientation and cross‐sectional shape of ice‐cored ridges. In turn, the melting dynamics are assessed based on a semi‐quantitative model of different relative rates of backwasting and downwasting. The topography of ice‐cored ridges, derived independently from the morphology of the related supraglacial landforms, is interpreted as an effect of ablation controlled by debris bands within parent ice. The reconstructed ice‐cored ridges are considered to represent the second‐order topographic features within a wide ice‐cored depression. The sedimentary evolution of collapse structures expressed as migration of their hinges/depocentres provides new semi‐quantitative insight into melting dynamics of ice showing the predominance of backwasting over downwasting. This evolution concerns the final stage of de‐icing, which was probably preceded by lowering of the ice‐cored topography and progressive formation of the ice‐cored ridges.

Description: This article presents a new comprehensive assessment of the Holocene hydrological variability of Lake Ladoga, northwest Russia. The reconstruction is based on oxygen isotopes of lacustrine diatom silica (δ18Odiatom) preserved in sediment core Co 1309, and is complemented by a diatom assemblage analysis and a survey of modern isotope hydrology. The data indicate that Lake Ladoga has existed as a freshwater reservoir since at least 10.8 cal. ka BP. The δ18Odiatom values range from +29.8 to +35.0‰, and relatively higher δ18Odiatom values around +34.7‰ between c. 7.1 and 5.7 cal. ka BP are considered to reflect the Holocene Thermal Maximum. A continuous depletion in δ18Odiatom since c. 6.1 cal. ka BP accelerates after c. 4 cal. ka BP, indicating Middle to Late Holocene cooling that culminates during the interval 0.8–0.2 cal. ka BP, corresponding to the Little Ice Age. Lake‐level rises result in lower δ18Odiatom values, whereas lower lake levels cause higher δ18Odiatom values. The diatom isotope record gives an indication for a rather early opening of the Neva River outflow at c. 4.4–4.0 cal. ka BP. Generally, overall high δ18Odiatom values around +33.5‰ characterize a persistent evaporative lake system throughout the Holocene. As the Lake Ladoga δ18Odiatom record is roughly in line with the 60°N summer insolation, a linkage to broader‐scale climate change is likely.

Description: Seismostratigraphical studies of the 11.8‐km2‐large and ~140‐m‐deep Lake Bolshoye Shchuchye, Polar Ural Mountains, reveal up to 160‐m‐thick acoustically laminated sediments in the lake basin. Using a dense grid of seismic lines, the spatial and temporal distributions of the sedimentary history have been reconstructed. Three regional seismic horizons have been identified and correlated with the well‐dated 24‐m‐long sediment core retrieved from the lake. Isopach maps constructed from the seismic data show four phases of sedimentation. A contour map of the deepest regional seismic reflector represents the earliest hemipelagic sedimentation in the lake. Three contour maps represent time intervals covering the last 23 cal. ka based on the well‐dated core stratigraphy from the lake. The detailed time constraints on the upper stratigraphical units in the lake allow calculation of the lake's development in terms of sediment fluxes and the denudation rates from the Last Glacial Maximum (LGM) to the present. The sedimentation in Lake Bolshoye Shchuchye has been dominated by hemipelagic processes during at least the last 24 cal. ka BP only locally interrupted by delta progradation and slope processes. A major shift in the sediment accumulation at c. 18.7 cal. ka BP is interpreted to mark the end of the local glacial maximum, greatly reduced denudation and the onset of the deglaciation period; this also demonstrates how fast the glaciers melted and possibly disappeared at the end of the LGM. The denudation rate during the Holocene is only a fifth of the LGM rate. The age of the oldest stratified sediments in Lake Bolshoye Shchuchye is not well constrained, but estimated as c. 50–60 ka.

Description: Abstract Issue Geodiversity (i.e., the variation in Earth's abiotic processes and features) has strong effects on biodiversity patterns. However, major gaps remain in our understanding of how relationships between biodiversity and geodiversity vary over space and time. Biodiversity data are globally sparse and concentrated in particular regions. In contrast, many forms of geodiversity can be measured continuously across the globe with satellite remote sensing. Satellite remote sensing directly measures environmental variables with grain sizes as small as tens of metres and can therefore elucidate biodiversity–geodiversity relationships across scales. Evidence We show how one important geodiversity variable, elevation, relates to alpha, beta and gamma taxonomic diversity of trees across spatial scales. We use elevation from NASA's Shuttle Radar Topography Mission (SRTM) and c. 16,000 Forest Inventory and Analysis plots to quantify spatial scaling relationships between biodiversity and geodiversity with generalized linear models (for alpha and gamma diversity) and beta regression (for beta diversity) across five spatial grains ranging from 5 to 100 km. We illustrate different relationships depending on the form of diversity; beta and gamma diversity show the strongest relationship with variation in elevation. Conclusion With the onset of climate change, it is more important than ever to examine geodiversity for its potential to foster biodiversity. Widely available satellite remotely sensed geodiversity data offer an important and expanding suite of measurements for understanding and predicting changes in different forms of biodiversity across scales. Interdisciplinary research teams spanning biodiversity, geoscience and remote sensing are well poised to advance understanding of biodiversity–geodiversity relationships across scales and guide the conservation of nature.

Description: Abstract Aim Although various theories have been proposed to explain the outstanding endemism of plants in the Cerrado, four hypotheses about the mechanisms of diversification and distribution are most supported: (a) plateau/valley, (b) stable/unstable climate, (c) core/peripheral distribution, and (d) soil fertility. The first argues that plateaus harbour more ancient lineages than valleys and therefore present higher endemism. The second theory suggests that climatically stable environments maintained more palaeoendemic species. The third scenario attributes the distribution of endemism to gradients of conditions available to locally adapted species and predicts higher endemism in nuclear than in marginal areas. The last theory suggests that soils with lower fertility account for higher endemism owing to the habitat specialization of their species. We compared endemism patterns with the predictions of each theory to discuss their importance. Location Brazil. Time period Quaternary. Major taxa studied Angiosperms. Methods We mapped the endemism using records of 311 plant species of the Cerrado and applied spatial analysis and distribution models to summarize the importance of each predictor of endemism. Results We identified 28 areas in which the higher endemism of Cerrado plants were concentrated and presented a map of their distribution. We found correlations among endemism, climate stability, elevation and marginality, which supported the plateau/valley, core/peripheral and stable/unstable hypotheses. No association between soil fertility and endemism was detected. We propose that plateaus are more stable climatic environments, and this characteristic along with their elevation and centrality are predictive of endemism. Main conclusions We concluded that most of the endemism is concentrated in overlapping areas of stability of species, which are concentrated in higher elevation central regions. Soil fertility was not linked to endemism. We recommend that central plateaus in the Cerrado require special attention in conservation to optimize the protection of endemic species in the biome.

Description: Abstract Aim We sought to characterize spatial and temporal beta diversity of birds and butterflies in the Great Basin (western U.S.A.) and to determine whether the magnitude of beta diversity was associated with spatial resolution, trait‐based groups or local environmental variables. Location Central and western Great Basin, western U.S.A. Time period 1995–2014. Major taxa studied Birds and butterflies. Methods We calculated temporal and spatial beta diversity of birds and butterflies at two spatial resolutions, points (birds) or transects (butterflies) and canyons (birds and butterflies). Points and transects corresponded to the spatial resolution of sampling, whereas canyons might be a more ecologically meaningful resolution. We partitioned beta diversity into turnover and nestedness components, and we calculated these components for entire assemblages and for trait‐based groups within assemblages. We used Bayesian hierarchical models to relate turnover and nestedness to spatial resolution, trait‐based groups and environmental variables. Results Variation in the composition of bird and butterfly assemblages was primarily associated with turnover. Species composition was more consistent at the resolution of canyons than at finer spatial resolutions. The species composition of birds changed more through space than through time, and spatial turnover of bird species tended to be higher than that of butterfly species. There were few strong associations of turnover and nestedness with environmental variables, and none with trait‐based groups. Main conclusions Our results suggest that the identities of bird and butterfly species vary at locations within canyons among years but are less variable among canyons. Decreases in temporal turnover as spatial resolution increases suggest that, at fine spatial resolutions and among years, bird and butterfly species in the Great Basin might acquire resources somewhat opportunistically rather than via strong interspecific competition (birds and butterflies) or site tenacity to breeding territories (birds).

Description: Abstract Aim Root turnover is an important process determining carbon and nutrient cycling in terrestrial ecosystems. It is an established fact that root turnover is jointly regulated by climatic, edaphic and biotic factors. However, the relative importance of these forces in determining the global patterns of root turnover time is far from clear. Location Global. Time period 1946–2017. Major taxa studied Grasslands. Methods We compiled a database of 141 sites with 433 observations on root turnover time and applied structural equation modelling (SEM) to investigate the relative contribution of climate, soil properties and vegetation type to the observed variations in root turnover time. Results Root turnover time was 3.1 years on average across the global grasslands and differed significantly among grassland types (tropical grassland and savanna, temperate grassland and meadow, alpine grassland and meadow, tundra and desert). It decreased with mean annual temperature, mean annual precipitation and Palmer drought severity index but increased with soil organic carbon content, total nitrogen content and carbon : nitrogen ratio. Soil bulk density and soil texture also significantly affected root turnover time, with clay content negatively correlating to root turnover time and explaining more variations than bulk density and sand content. The SEM showed that climatic factors had dominant effects on root turnover time when vegetation type was not considered. Vegetation type became the primary driver when it was included in the SEM. Main conclusions Our results indicate that the influences of climatic and edaphic factors on root turnover time are predominantly manifested through vegetation type. The critical role of precipitation as revealed for the first time in this study challenges our current understanding of climate impacts on root turnover time. The findings necessitate accurate representation of vegetation type in Earth system models to predict root function dynamics under global change.

Description: Abstract Aim On 11 March 2011, the Great East Japan Earthquake triggered a massive tsunami that resulted in the largest known rafting event in recorded history. By spring 2012, marine debris began washing ashore along the Pacific coast of the United States and Canada with a wide range of Asian coastal species attached. We used this unique dataset, where the source region, date of dislodgment and landing location are known, to assess the potential for species invasions by transoceanic rafting on marine debris. Location Northeast Pacific from 20 to 60°N. Time period Current. Major taxa studied Forty‐eight invertebrate and algal species recorded on Japanese tsunami marine debris (JTMD). Methods We developed maximum entropy (MaxEnt) species distribution models for 48 species recorded on JTMD to predict establishment potential along the Pacific coast from 20 to 60°N. Models were compared within the context of historical marine introductions from Japan to this region to validate the emergence of marine debris as a novel vector for species transfer. Results Overall, 27% (13 species) landed with debris at locations with suitable environmental conditions for establishment and survival, indicating that these species may be able to establish new populations or introduce greater genetic diversity to already established non‐native populations. A further 21 species have an environmental match to areas where tsunami debris likely landed, but was not extensively sampled. Nearly 100 Japanese marine species previously invaded the northeastern Pacific, demonstrating this region’s environmental suitability for rafting Japanese biota. Historical invasions from Japan are highest in California and largely known from bays and harbours. Main conclusions Marine debris is a novel and growing vector for non‐native species introduction. By utilizing a unique dataset of JTMD species, our predictive models show capacity for new transoceanic invasions and can focus monitoring priorities to detect successful long‐distance dispersal across the world’s oceans.

Description: Abstract Aim The great variation in range sizes among species has fascinated ecologists for decades. Reef‐associated fish species live in highly spatially structured habitats and adopt a wide range of dispersal strategies. We consequently expect species with greater dispersal ability to occupy larger ranges. However, empirical evidence for such a positive relationship between dispersal and range size remains scarce. Here, we unveil the role of dispersal on the range size distribution of reef‐associated fishes using empirical data and a novel spatially explicit model. Location Tropical Eastern Pacific. Major taxa studied Reef‐associated fishes. Time period Underlying records are from the 20th and 21st centuries. Methods We estimated range size distributions for all reef‐associated fishes separated into six guilds, each with different dispersal abilities. We used a one‐dimensional spatially explicit neutral model, which simulates the distribution of species along a linear and contiguous coastline, to explore the effect of dispersal, speciation and sampling on the distribution of range sizes. Our model incorporates biologically important long‐distance dispersal events with a fat‐tailed dispersal kernel and also adopts a more realistic gradual “protracted” speciation process than originally used in neutral theory. We fitted the model to the empirical data using an approximate Bayesian computation approach, with a sequential Monte Carlo algorithm. Results Stochastic birth, death, speciation and dispersal events alone can accurately explain empirical range size distributions for six different guilds of tropical, reef‐associated fishes. Variation in range size distributions among guilds are explained purely by differences in dispersal ability with the best dispersers being distributed over larger ranges. Main conclusions Neutral processes and guild‐specific dispersal ability provide a general explanation for both within‐ and across‐guild range size variation. Our results support the theoretically expected, but empirically much debated, hypothesis that high dispersal capacity promotes the establishment of large range size.

Description: Abstract Aim The aim was to assess whether and to what extent the role of local landscape attributes in shaping macroscopic biodiversity patterns is sensitive to spatial and thematic resolutions of land cover data. Location Sub‐Saharan Africa and continental China. Time period Early 21st century. Taxa studied Terrestrial mammals. Methods We conducted spatial and thematic scaling analyses to generate land cover datasets of different spatial (0.3, 0.5, 1.0 and 9.0 km) and thematic (two, three and five classes) resolutions. We calculated landscape metrics based on the resulting land cover maps and examined the power of landscape metrics for explaining species richness patterns, using non‐spatial (OLS) and spatial (SAR) linear models and random forest (RF) models. We systematically assessed the resolution dependence of explanatory power for different geographical regions, different scaling approaches and different model types. We also compared the explanatory power of landscape attributes with that of macroclimate. Results Collectively, local landscape attributes generally had strong explanatory power for species richness. For the African system, the largest explanatory power was c. 60% based on the OLS models and random forest models and c. 30% based on the non‐spatial components of the SAR models. For the Chinese system, the largest explanatory power was c. 35% based on the OLS models and c. 40% based on the SAR and random forest models. We observed a linear scaling relationship, which is robust to studied systems, scaling approaches and model types. In contrast, the scaling relationship varies substantially among single landscape metrics. At coarse resolutions, the addition of landscape attributes collectively would not improve climate‐envelope models significantly, whereas at finer resolutions, landscape attributes collectively have explanatory power that is close to or even exceeds climate. Main conclusions Local landscape attributes play an important role in shaping macroscopic biodiversity patterns. However, their strength is highly sensitive to both spatial and thematic resolutions of land cover data, with stronger explanatory power detected at finer resolutions. Strong sensitivity to spatial and thematic resolutions makes landscape attributes highly plastic determinants, leading to contrasting conclusions if based on greatly different resolutions of land cover data. Scaling analyses are needed to examine such cross‐scale effects of macroecological determinants systematically.

Description: Abstract Aim Observed, realized niche space often underestimates species’ physiological tolerances due to interactions with other species, dispersal constraints, and because some combinations of influential environmental factors do not currently exist in the real world. Conversely, correlative ecological niche models rely on the assumption that the range of environmental conditions encompassed by a species’ geographic distribution accurately reflects their environmental tolerances, including community‐level approaches like generalized dissimilarity modelling (GDM). We extend GDM to better understand what effect broader environmental tolerances could have on compositional turnover under climate change. Innovation We show how GDM can be adjusted as a function of best‐available estimates of the average ratio between realized and potential niche widths to modify projected temporal turnover. We demonstrate this approach by using the estimated niche ratios of Australian plant species (n = 7,184) relative to thermal extremes, and the rate at which this ratio varied with temperature. The modified GDMs showed existing thermal tolerance could reduce the turnover predicted by standard models under climate change by up to 11%. We further show how the reduction in expected turnover by 2090 will influence where a greater proportion of the current community will persist in a region. Main conclusions We suggest that standard spatial GDMs and their modified versions represent the extremes of ecological niche perspectives (i.e., realized and potential) and the range of tolerance communities may have when responding to environmental change. GDM projections therefore identify the range of uncertainty associated with a critical model assumption, and as climate change continues, ongoing community monitoring could be used to validate the balance between the two possibilities.

Description: Abstract Aim Leaf nutrient resorption is a key nutrient conservation trait, which also influences nutrient cycling rates and pools. Most global biogeochemical models assume that resorption is non‐varying at a temporal scale. However, this trait can differ substantially within populations among years. We assessed the commonality of attaining proficient resorption, the factors associated with proficient resorption, as well as the variability of this trait and the factors controlling trait variability. Location Global. Time period 1965–2009. Major taxa studied Plants. Methods We compiled multi‐year nutrient resorption data from the literature, representing 50 studies, 94 unique study locations, and 141 species from 53 families and 29 orders. We used multiple linear regression to relate resorption data, as well as the variability in this trait, expressed as the coefficient of variation, to environmental factors. Results Resource availability was a key driver of resorption, with nutrient‐poor soils associated with more complete resorption and lower resorption plasticity. Nitrogen and phosphorus resorption differentially responded to some drivers, such as leaf habit, soil order and mycorrhizal status. Main conclusions Overall, environmental and biological factors representing a strong selective force for nutrient conservation, such as nutrient‐poor soil orders, semi‐arid soil moisture regimes, or lack of plant mutualists, were associated with complete resorption, whereas incomplete resorption was associated with weak selective forces, such as nutrient‐rich soil orders, or factors impeding this physiological process (e.g., drought). Inter‐annual variability in resorption was common, particularly for phosphorus. This plasticity has implications for ecosystem nutrient cycling and plant productivity, and accounting for this plasticity in dynamic models of nutrient cycling will improve predictions of nutrient limitations and productivity under future climate conditions.

Description: Abstract Aim The aim was to quantify gradients in local richness levels, feeding strategies and body mass distributions in bats and relate them to environmental variation and habitat disturbance. Location The New World. Time period Present day. Major taxa studied Bats. Methods I assembled 152 local species inventories from the published literature, which include 245 species, along with body mass measurements and dietary categorizations. I quantified species richness using the Chao 1 extrapolator, obtained mean mass values for the inventories and computed proportions of species and of individuals belonging to different feeding guilds. I reduced the dimensonality of environmental variables using factor analysis and regressed richness values upon the factor scores. Results South of the Tropic of Cancer, bats exhibit sharp increases in local diversity, the abundance of frugivores and nectarivores, and mean body mass. These offsets are driven by increases in the richness and abundance of the leaf‐nosed bats (Phyllostomidae). Richness steeply declines near the Tropic of Capricorn, but the other variables do not trend strongly at this point. Most of the variance is explained by mean annual temperature, temperature seasonality and precipitation. There is no direct evidence that richness is lower in disturbed landscapes. Main conclusions The great radiation of phyllostomids in the Neotropics has created a uniquely rich biota. The reason that phyllostomids are now absent from the northern temperate zone might be that they are mostly frugivores or nectarivores. Therefore, they have prospered only in regions that provide fruit and nectar year‐round. Thus, biotic interactions might be the immediate cause of the latitudinal diversity gradient in New World bats. If so, then the biogeographical break is driven by environmental factors and is not a historical artefact. These results suggest that a more nuanced consideration of latitudinal gradients will prove to be helpful when it comes to studying many taxonomic groups.

Description: Abstract Aim We show how macroecological patterns at different phylogenetic scales below the species level may aid the identification of the predominant process controlling biological assemblages (niche versus dispersal). We compare two taxa with different ecological and dispersal requirements (terrestrial molluscs and leaf beetles) in the same geographical setting. Location Iberian Peninsula. Time period 2010–2015. Major taxa Terrestrial molluscs and leaf beetles. Methods The cox1‐5′ fragment was sequenced for 1,592 mollusc specimens in 20 localities. Leaf beetle assemblages had been sequenced previously in 15 of these localities. Species richness, distance decay of similarity, endemism and range size were measured at two levels: molecular variants (i.e., haplotypes) and putative species (i.e., operational taxonomic units). Using a multi‐hierarchical macroecology approach, distance‐decay patterns were measured at multiple intermediate genealogical levels (nested clades) to assess whether the geometry of the ranges of lineages followed a fractal pattern. Results Richness and distance‐decay patterns at both molecular variant and species levels were different in leaf beetles and terrestrial molluscs, although both taxa showed a fractal pattern in the distance decay of similarity across genealogical levels. The self‐similarity of the distance‐decay pattern across phylogenetic scales suggests a predominance of neutral, but limited, dispersal driving macroecological patterns in both taxa. Endemism was similar in both taxa at the level of molecular variants but higher at the species level in terrestrial molluscs, and range size was smaller at both levels in terrestrial molluscs. Taken altogether, our results suggest that dispersal limitation is stronger in terrestrial molluscs. Main conclusion The assessment of how diversity patterns change at different phylogenetic scales below the species level allowed us to identify unifying characteristics in otherwise seemingly heterogeneous biological systems. Congruence was observed in diversity patterns of leaf beetles and terrestrial molluscs, suggesting that dispersal is a relevant process in both taxa but acts at a different strength.

Description: Abstract Aim The diversity of birds and mammals is typically described in separate analyses, but species may play similar roles. Here, we develop a comparative trait framework for birds and mammals to provide a global quantification of the similarity of species roles (functional redundancy) and the breadth of roles across taxa (functional dispersion). We predict different contributions of birds and mammals to redundancy and dispersion, and unique geographical patterns of redundancy and dispersion by including both taxa. Location Global. Time period Contemporary. Major taxa studied Birds and mammals. Methods We systematically select, compile and impute the same six traits (i.e., a common currency of traits) across 15,485 bird and mammal species from multiple databases. We use these six traits to compute functional redundancy and functional dispersion for birds and mammals across all 825 terrestrial ecoregions. We then calculate the standardized effect size (SES) of these observed values compared with null expectations, based on a randomization of species composition (i.e., independent of differences in species richness). Results We find that species‐rich regions, such as the Neotropics, have high functional redundancy coupled with low functional dispersion, characterizing a global trade‐off. Thus, in general, as species richness increases, the similarity in species functional roles also increases. We therefore suggest that different processes generate species richness/functional redundancy and functional dispersion, leading to a novel, and generally non‐tropical, distribution of hotspots of high functional dispersion across Madagascar, Eastern Asia and Western USA. Main conclusions We recommend consideration of both the similarity and the breadth of functional roles across species pools, including taxa that may play similar roles. We therefore suggest that functional redundancy, as a means of insurance, and functional dispersion, as an indicator of response diversity, should be evaluated further as conservation objectives.

Description: To assess the reliability of arboreal phytoliths for differentiating vegetation types in temperate forest regions, we systematically analysed arboreal leaf phytoliths from 72 arboreal plants and 49 modern soils from three forest types in northeast China. The arboreal leaf phytolith production and morphotypes were highly variable between species. The arboreal leaf phytolith assemblages could clearly distinguish between broadleaf and coniferous species, but they were much less successful in differentiating broadleaved trees into subtaxa. Coniferous leaf morphotypes were successfully used to differentiate coniferous trees into families and subtaxa, especially in the Pinaceae. Two diagnostic broadleaved and six coniferous phytolith morphotypes were recognized within the modern soil beneath forest ecosystems. These arboreal phytoliths comprised up to 10–15% of the total soil phytoliths, and were dominated by coniferous types. Arboreal phytolith concentrations and phytolith assemblages in the soils fluctuated substantially amongst the three forest types. Soil arboreal phytolith assemblages were successfully used to differentiate samples from Larix mixed forest, broadleaf forest and Pinus koraiensis mixed forest. In addition, the arboreal index quantitatively distinguished the three forest types, with B/BE values 〈0.4 for Larix mixed forest samples, values from 0.4 to 0.6 for broadleaf forest samples, and values from 0.6 to 0.9 for P. koraiensis mixed forest. Thus, our surface soil arboreal phytolith assemblages and arboreal index are a useful reference for differentiating forest ecotypes, and they also provide reliable analogues for arboreal phytoliths from palaeoecological contexts in temperate forest regions.

Description: Abstract Aims Plant pH is a functional trait deserving more attention than the current few studies at local scales, given its roles in nutrient cycling and physiological processes. How plant pH varies and is regulated at large scales remain unclear. Here we explore the biogeography of foliar pH and the potential drivers. Location East–west transect of northern China with increasing aridity westward. Time period 2016–2017. Major taxa Spermatophytes. Methods We analysed foliar pH of plants from 22 sites across northern China, and investigated its spatial pattern and relationships with climate, soil, and plant functional type (PFT). Results Foliar pH was generally acidic (5.33 ± .04) in northern China, showing distinct geographical variability: foliar pH decreased significantly westward at an average rate of 0.25 units per 10° longitude. Climate, soil and PFT explained 11, 17 and 59% of the variance in foliar pH, respectively. Foliar pH decreased (about 0.16) with mean annual precipitation (per 100 mm), soil stress coefficient (per 10%) and aridity index (per 0.14), but increased with mean annual temperature (per 2 °C). Across PFTs, herbs exhibited higher foliar pH than woody plants (6.0 vs. 4.9); gymnosperms relative to angiosperms had lower foliar pH (3.7 vs. 5.6); and monocotyledons showed higher foliar pH compared with dicotyledons (6.0 vs. 5.5). Main conclusions This study provides the first comprehensive analysis of the evident pattern of foliar pH over a large spatial scale. Foliar pH is higher in warm‐arid northwestern relative to cold‐humid northeastern China and in later‐ than earlier‐evolved plants. Similar to leaf mineral elements, foliar‐pH biogeography is shaped by the joint effects of climate, soil and PFT; PFT and moisture are the most influential factors. Our findings provide a new impetus for understanding functional biogeography, and lay the groundwork for research on the linkage of foliar pH to ecological functions and macroevolutionary implications.

Description: Abstract Aim Ecological properties governed by threshold relationships can exhibit heightened sensitivity to climate, creating an inherent source of uncertainty when anticipating future change. We investigated the impact of threshold relationships on our ability to project ecological change outside the observational record (e.g., the 21st century), using the challenge of predicting late‐Holocene fire regimes in boreal forest and tundra ecosystems. Location Boreal forest and tundra ecosystems of Alaska. Time period 850–2100 CE. Major taxa studied Not applicable. Methods We informed a set of published statistical models, designed to predict the 30‐year probability of fire occurrence based on climatological normals, with downscaled global climate model data for 850–1850 CE. To evaluate model performance outside the observational record and the implications of threshold relationships, we compared modelled estimates with mean fire return intervals estimated from 29 published lake‐sediment palaeofire reconstructions. To place our results in the context of future change, we evaluate changes in the location of threshold to burning under 21st‐century climate projections. Results Model–palaeodata comparisons highlight spatially varying accuracy across boreal forest and tundra regions, with variability strongly related to the summer temperature threshold to burning: sites closer to this threshold exhibited larger prediction errors than sites further away from this threshold. Modifying the modern (i.e., 1950–2009) fire–climate relationship also resulted in significant changes in modelled estimates. Under 21st‐century climate projections, increasing proportions of Alaskan tundra and boreal forest will approach and surpass the temperature threshold to burning, with 〉 50% exceeding this threshold by 〉 2 °C by 2070–2099. Main conclusions Our results highlight a high sensitivity of statistical projections to changing threshold relationships and data uncertainty, implying that projections of future ecosystem change in threshold‐governed ecosystems will be accompanied by notable uncertainty. This work also suggests that ecological responses to climate change will exhibit high spatio‐temporal variability as different regions approach and surpass climatic thresholds over the 21st century.

Description: Abstract Aim Species–area relationships (also known as “species–area curves” and “species accumulation curves”) represent the relationship between species richness and the area sampled in a given community. These relationships can be used to describe diversity patterns while accounting for the well‐known scale‐dependence of species richness. Despite their value, their functional form and parameters, as well as their determinants, have barely been investigated in drylands. Location 171 drylands from all continents except Antarctica. Time period 2006–2013. Major taxa studied Perennial plants. Methods We characterized species–area relationships of plant communities by building accumulation curves describing the expected number of species as a function of the number of sampling units, and later compared the fit of three functions (power law, logarithmic and Michaelis–Menten). We tested the prediction that the effects of aridity, soil pH on the species–area relationship (SAR) are mediated by vegetation attributes such as evenness, cover and spatial aggregation. Results We found that the logarithmic relationship was the most common functional form (c. 50%), followed by Michaelis–Menten (c. 33%) and power law (c. 17%). Functional form was mainly determined by evenness. Power‐law relationships were found mostly under low evenness, logarithmic relationships peaked under intermediate evenness and the Michaelis–Menten function increased in frequency with increasing evenness. The SAR parameters approximated by the logarithmic model [“small‐scale richness” (b0) and “accumulation coefficient” (b1)] were determined by vegetation attributes. Increasing spatial aggregation had a negative effect on the small‐scale richness and a positive effect on the accumulation coefficient, while evenness had an opposite effect. In addition, the accumulation coefficient was positively affected by cover. Interestingly, increasing aridity decreased small‐scale richness but did not affect the accumulation coefficient. Main conclusions Our findings highlight the role of evenness, spatial aggregation and cover as the main drivers of SARs in drylands, the Earth’s largest biome.

Description: Abstract With increasing availability of plant distribution data, the information about global plant diversity is improving rapidly. Recently, Ulloa Ulloa et al. (2017) presented the first comprehensive overview of the native vascular flora of the Americas, yielding a total count of 124,993 native species. Of these, 51,241 occur in North America and 82,052 in South America. By combining these data with the information in the Global Naturalized Alien Flora (GloNAF) database of naturalized alien floras, we point out that for a complete picture of the regional and continental plant richness, the naturalized alien species need to be considered. Ignoring this novel component of regional floras can lead to an inaccurate picture of overall change in biodiversity in the Anthropocene. We show that North and South America might face contrasting challenges in terms of potential threats to biodiversity posed by alien plant species, because of the different past and present dynamics of invasions and predictions of future development. In total, there are 7,042 naturalized alien plants occurring in the Americas, with 6,122 recorded in North America and 2,677 in South America; if only introductions from other continents are considered additions to the native continental flora make up 6.9 and 1.4 %, respectively. Nevertheless, predictions of naturalized plant trajectories based on global trade dynamics and climate change suggest that considerable increases in naturalized plant numbers are expected in the next 20 years for emerging South American economies, which could reverse the present state.

Description: A multi‐channel, high‐resolution seismic reflection survey using a Micro‐GI airgun was carried out in the framework of the Russian‐German project PLOT (Paleolimnological Transect) on Lake Levinson‐Lessing, Taymyr Peninsula, in 2016. In total, ~70 km of seismic reflection profiles revealed in unprecedented detail the glacial and postglacial sedimentary infill of the lake basin. Five main seismic units have been recognized and interpreted as glacial (Unit V), subglacial and proglacial (Unit IV), marine (Unit III), fluvial‐lacustrine (Unit II) and lacustrine (Unit I) sediments. Of particular significance are imbricated, south‐orientated structures present in the southernmost part of the lake basin within Unit V and a large topographic ridge recognized in front of those structures. We interpret these structures as push moraines and an end moraine, respectively, left by the glacier after its retreat. The depositional pattern of the units above the moraines documents past lake‐level fluctuations. We interpret Unit IV, Unit III and Unit I as highstand deposits, and Unit II as lowstand deposits. Gas‐charged sediments dominate the northern part of the lake basin, whilst they occur only sporadically and in limited spatial extent in the central and southern parts of the lake. In the latter areas, the seismic and echo‐sounder data suggest recent tectonic activity. Our study contributes to the reconstruction of environmental conditions in the Taymyr Peninsula directly following the Early Weichselian deglaciation and shows that deep tectonic lake basins affected by several glaciations can preserve important palaeoenvironmental records, which contributes significantly to our understanding of palaeoenvironmental changes in the Taymyr Peninsula and the central Russian Arctic.

Description: Calcareous root tubes (CRTs) contain abundant information about palaeoenvironmental conditions and have been used for palaeoenvironmental studies in the desert hinterlands of arid regions. However, as subclasses of CRTs, calcareous sheaths and rhizocretions are formed by different processes, and it remains unclear whether these differences produce variations in the chemical element composition. Furthermore, it remains uncertain whether variations in chemical element concentrations amongst different subclasses of the CRTs can affect palaeoenvironmental reconstructions. In this study, we collected 54 CRT samples from the Tengger Desert of northwestern China. All samples were dated by accelerator mass spectrometry (AMS) 14C dating, and the chemical element composition and concentration differences of the two CRT subclasses were determined using X‐ray fluorescence spectrometry. The CRT samples were dated to the Holocene. The calcareous sheath and rhizocretion samples contained varying concentrations of the same chemical elements. The rhizocretions had high concentrations of mobile elements (Ca, Mg and Sr) and P, whereas the calcareous sheaths had high concentrations of stable elements, including Al, Si, Ti, Zr, Rb and Ba. These differences were due to the different formation processes of the two subclasses of CRTs. Moreover, the Sr/Ca and Mg/Ca ratios in the calcareous sheaths were higher than those in the rhizocretions from the same period, but these ratio differences had little effect on palaeo‐effective moisture reconstructions at the millennial scale during the Holocene. The reconstructions were not influenced by the various CRT subclasses. The Holocene millennial‐scale moisture changes in the Tengger Desert revealed by the Sr/Ca and Mg/Ca ratios showed that there was an arid period during the Early Holocene, a humid period during the Middle Holocene and a humid to arid period during the Late Holocene.

Description: Cave bears (Ursus spelaeus) are an iconic component of the European late Quaternary Ice Age megafauna. Recent demographic analyses based on cave bear mtDNA sequences and refined radiocarbon dating indicate that cave bear population size and genetic diversity started to decline some 50 kilo years ago (kya). Hence, neither the coldest phase of the last glaciation (started some 24 kya), nor the colonization of Europe by Palaeolithic hunters (started some 45 kya) coincides with the beginning of population decline. Here, we reconstructed cave bear climatic niche evolution through time. Then, we performed spatially explicit population viability analyses to assess cave bear demographics through time in response to climatic changes, human effects on bear survival and their combination. We found that climate change was responsible for a 10‐fold decrease in cave bear population size after 40 kya. However, climate change on its own could not explain U. spelaeus extinction at 24 kya. Additional negative effects consistent with human population expansion are required to explain both U. spelaeus' retreat from eastern Europe since 40 kya and its final extinction.

Description: The study presents the first description and analysis of ostracod records from three sites cored in different parts of the Baltic Sea during the IODP Expedition 347, Baltic Sea Paleoenvironment. Our data present the first high‐resolution ostracod records from the Late Weichselian and Holocene sediments collected across the Baltic Sea Basin. Using published data on modern ostracod species ecology of the Baltic Sea, we were able to provide ostracod‐based palaeoreconstructions of the history of the region. The stratigraphical framework for the sites is based on radiocarbon‐based age models. The three studied sites reveal different ostracod assemblage successions that reflect environmental changes in the study area. Site M0060, located in the Kattegat area, contains the oldest ostracod assemblages that document a marine environment with very high sedimentation rates during the most recent deglaciation. Between ~13 000 and 7500 cal. a BP a modern‐like near‐shore environment developed. Site M0059 in the southwestern Baltic Sea, Little Belt area, contains assemblages reflecting the transition from a freshwater lake to the brackish Littorina Sea between ~7500 and 7300 cal. a BP. Site M0063 is the deepest location in the central Baltic, Landsort Deep, and yielded very limited ostracod data, but comparison with our organic carbon data allowed us to distinguish the Yoldia Sea, Ancylus Lake and Littorina Sea intervals. The ostracod record correlates well with the organic carbon record with alternation between periods of hypoxia and periods of low oxygen that still supported ostracods.

Description: Rock‐Eval pyrolysis provides a quick, relatively inexpensive means of characterizing organic‐rich strata, and has been used for decades to understand global petroleum systems. Although designed to characterize ancient kerogens, pyrolysis is increasingly being used to understand Holocene systems as well. The ability of this technique to distinguish between types of preserved organic matter is useful in characterizing climatic evolution, particularly in systems sensitive to climatic fluctuation such as isolated fens and bogs. Cores collected from the Tokewanna and Garden Basin Cattail fens in central/eastern Utah exhibit variability of organic source, with the mixture of terrestrial and algal sources varying through time, as shown through the hydrogen index (HI) and oxygen index pyrolysis parameters. A sediment core was collected at each fen, and 176 samples were taken from the cores at 6‐cm intervals. Total organic carbon (TOC) for all samples ranges from 1.3 to 44.2%, with an average of 18.2% TOC. Samples range from 84 to 687 HI, equivalent to Type I (lacustrine algal) to Type III (terrestrial) organic material (OM). Variability in HI response represents mixing of the two OM sources, and the relative amount of aqueous organic input can be estimated through time based on age‐calibrated HI curves at the two sites. The balance of organic input serves as an accurate, high‐resolution proxy for climate, and calibration with palynological data near both sites confirms patterns shown by pyrolysis, showing the utility of this method in quickly, affordably and accurately characterizing Holocene sediments for use in understanding palaeoclimate.

Description: The new pollen record from the upper 12.75 m of a sediment core obtained in Lake Ladoga documents regional vegetation and climate changes in northwestern Russia over the last 13.9 cal. ka. The Lateglacial chronostratigraphy is based on varve chronology, while the Holocene stratigraphy is based on AMS 14C and OSL dates, supported by comparison with regional pollen records. During the Lateglacial (c. 13.9–11.2 cal. ka BP), the Lake Ladoga region experienced several climatic fluctuations as reflected in vegetation changes. Shrub and grass communities dominated between c. 13.9 and 13.2 cal. ka BP. The increase in Picea pollen at c. 13.2 cal. ka BP probably reflects the appearance of spruce in the southern Ladoga region at the beginning of the Allerød interstadial. After c. 12.6 cal. ka BP, the Younger Dryas cooling caused a significant decrease in spruce and increase in Artemisia with other herbs, indicative of tundra‐ and steppe‐like vegetation. A sharp transition from tundra‐steppe habitats to sparse birch forests characterizes the onset of Holocene warming c. 11.2 cal. ka BP. Pine forests dominated in the region from c. 9.0 to 8.1 cal. ka BP. The most favourable climatic conditions for deciduous broad‐leaved taxa existed between c. 8.1 and 5.5 cal. ka BP. Alder experiences an abrupt increase in the local vegetation c. 7.8 cal. ka BP. The decrease in tree pollen taxa (especially Picea) and the increase in herbs (mainly Poaceae) probably reflect human activity during the last 2.2 cal. ka. Pine forests have dominated the region since that time. Secale and other Cerealia pollen as well as ruderal herbs are permanently recorded since c. 0.8 cal. ka BP.

Description: We present a high‐resolution reconstruction of the vegetation and climate dynamics during the penultimate interglacial, corresponding with Marine Isotope Stage (MIS) 7, based on detailed palynological analyses of lacustrine sediments from Lake El'gygytgyn, northeastern Siberia. The analysed sediments were deposited between 246 and 181 ka ago (late MIS 8 to early MIS 6.6). The interglacial vegetation was characterized by herb and shrub (mainly alder and birch) dominated plant communities. Pollen‐based biome reconstruction shows a dominance of the tundra (TUND) biome, thus indicating rather open vegetation. Warmer intervals (MIS 7.5, 7.3 and 7.1) were marked by an increase in the cold deciduous forest (CLDE) biome scores and a synchronous decrease in the cold steppe (STEP) biome scores. The thermal maximum occurred during MIS 7.1, as indicated by the highest CLDE biome scores occurring in this period, and lasted ~10 ka, possibly favoured by the high precession‐related summer insolation and the legacy of the preceding mild and dry stadial (MIS 7.2). In contrast, MIS 7.3 and 7.5 were characterized by shorter durations (~4 ka) and lower summer temperatures. The preceding cold glacial and stadial (MIS 8 and 7.4, respectively) might have led to an extensive distribution of permafrost that hindered vegetation development during the subsequent warm intervals. MIS 7.4 and 6.6 were cold and wet, probably triggered by low obliquity values and coevally low precession‐related summer insolation. As a result, these periods were marked by significantly reduced summer temperatures and an enhanced snow‐ice albedo feedback. The obtained reconstructions provide potential scenarios for future climate changes and allow a better understanding of the relationship between vegetation, climate and external/internal forcings in the high latitudes.

Description: By applying advanced spatial statistical methods, spatial taphonomy complements the traditional taphonomic approach and enhances our understanding of biostratinomic and diagenetic processes. In this study, we elaborate on a specific aspect – spatial anisotropy – of taphonomic processes. We aim to unravel the taphonomic history of the Early Pleistocene vertebrate assemblage of Tsiotra Vryssi (Mygdonia Basin, Greece). Circular statistics are used for the fabric analysis of elongated elements; geostatistics (directional variograms), wavelet and point pattern analyses are applied for detecting anisotropy at the assemblage level. The anisotropy of magnetic susceptibility (AMS) of sedimentary magnetic minerals is also investigated. The results, integrated with preliminary remarks about the differential preservation of skeletal elements, sedimentological and micromorphological observations, suggest multiple dispersion events and recurrent spatial re‐arrangement of a lag, (peri)autochthonous assemblage, consistent with the cyclical lateral switching of a braided fluvial system. Furthermore, this study offers a contribution to the building of a spatial taphonomic referential framework for the interpretation of other fossil vertebrate assemblages, including archaeo‐palaeontological ones.

Description: Abstract Aim Understanding the mechanisms behind broad‐scale gradients in animal body size remains challenging. In contrast to endotherms, the extent to which biophysical properties of ectotherms scale up into interspecific size gradients at macroecological scales remains elusive. Our aim here is to investigate what latitudinal body size gradients are expected to emerge from first biophysical principles regarding heat and water balances in terrestrial vertebrate ectotherms. Location Nearctic and Western Palaearctic. Time period Theoretical model under current climatic conditions. Major taxa studied Terrestrial vertebrate ectotherms. Methods We developed a biophysical model to derive heat balances and rates of water loss of lizard‐like reptiles and anuran‐like amphibians from microclimatic variables. We projected geographically model predictions for different size classes to explore how body temperature (Tb) and cutaneous evaporative water loss (EWL) are influenced by body size at macroscales. Results Large‐bodied ectotherms (over 100 g) attain a slightly higher Tb and conserve it for longer than small animals (5 g), owing to the lower convective heat dissipation and their greater thermal inertia. While large animals are more at risk of overheating in warm regions, all organisms, irrespective of body size, are constrained by low temperatures experienced at boreal latitudes. Furthermore, because of the nonlinear decrease in EWL with increasing size, larger size allows reduction of water loss of small wet‐skinned ectotherms in more evaporative environments. Main conclusions Size differences in heat balance offer a mechanistic explanation for the pattern of increasing body size northwards, as well as for the associated decrease in species richness. Water conservation is also identified as a potential mechanism for larger body sizes in dryer areas in wet‐skinned ectotherms such as amphibians. Moreover, our model reveals nonlinear relationships involving size and optimum states of thermal and hydric functions, accounting for complexities that are unnoticeable by traditional, correlative investigations.

Description: Abstract Aim Why are so many species rare, yet persistent? Possibly, rare species experience strong negative frequency dependence (NFD, i.e. strong intraspecific competition relative to interspecific competition), which both makes them rare and buffers them against extinction. A second, not mutually exclusive, possibility is that rare species that experience weak NFD go extinct quickly due to demographic and environmental stochasticity. Both possibilities predict that persistent rare species will experience stronger NFD than common ones. A previous study confirmed this prediction in a range of mostly terrestrial communities. Here, we test that prediction in lake zooplankton and explore its theoretical basis. Location Fifty‐three temperate lakes. Time period 1970–2011. Major taxa studied Cladocerans, copepods. Methods We used long‐term time series data to estimate the covariance between strength of NFD and mean frequency (relative abundance) for crustacean zooplankton. We used a randomization test to ask whether the covariance between NFD and mean frequency is stronger than expected, given sampling error. We also calculated the covariance between NFD and mean frequency in simulated communities from three different ecological models. Results Rare species experience significantly stronger NFD than common species in over half of the communities. The distribution of associations between NFD and rarity is skewed towards weak associations, which always occur in communities with high evenness. All three theoretical models reproduce these empirical results, even though they are based on different mechanisms (demographic or environmental stochasticity, and mathematical constraints on possible NFD–frequency relationships). Main conclusions Rare species typically experience stronger NFD than common ones because there are many different ecological scenarios in which they will do so, and only a few scenarios in which they won't. Like several other macroecological patterns, the tendency for rare species to experience stronger NFD than common ones is a “statistical attractor” that is hard to avoid.

Description: Abstract Aim Experimental nitrogen (N) addition (fertilization) studies are commonly used to quantify the impacts of increased N inputs on plant biodiversity. However, given that plant community responses can vary considerably among individual studies, there is a clear need to synthesize and generalize findings with meta‐analytical approaches. Our goal was to quantify changes in species richness and abundance in plant communities in response to N addition across different environmental contexts, while controlling for different experimental designs. Location Global. Time period Data range: 1985–2016; Publication years: 1990–2018. Major taxa studied Plants. Methods We performed a meta‐analysis of 115 experiments reported in 85 studies assessing the effects of N addition on terrestrial natural and semi‐natural plant communities. We quantified local‐scale changes in plant biodiversity in relationship to N addition using four metrics: species richness (SR), individual species abundance (IA), mean species abundance (MSA) and geometric mean abundance (GMA). Results For all metrics, greater amounts of annual N addition resulted in larger declines in plant diversity. Additionally, MSA decreased more steeply with N that was applied in reduced (NH4+) rather than oxidized () form. Loss of SR with increasing amounts of N was found to be larger in warmer sites. Furthermore, greater losses of SR were found in sites with longer experimental durations, smaller plot sizes and lower soil cation exchange capacity. Finally, reductions in the abundance of individual species were larger for N‐sensitive plant life‐form types (legumes and non‐vascular plants). Main conclusions N enrichment decreases both SR and abundance of plants in N‐addition experiments, but the magnitude of the response differs among biodiversity metrics and with the environmental and experimental context. This underlines the importance of integrating multiple dimensions of biodiversity and relevant modifying factors into assessments of biodiversity responses to global environmental change.