ALBERT

Beschreibung: Abstract Aims As global temperatures rise, the survival of many species may hinge on whether they can shift their climatic niches quickly enough to avoid extinction. Previous analyses among species and populations suggest that species’ niches change far slower than rates of projected climate change. However, it is unclear how quickly niches can change over the timeframe most relevant to global warming (decades instead of thousands or millions of years). Here, we use data from introduced species to assess how quickly climatic niches can change over decadal timescales. Location Global. Methods We analyse climatic data from 76 reptile and amphibian species introduced into the USA. We test for a relationship between species climatic‐niche values in their native and introduced ranges. We also quantify niche shifts in introduced populations relative to their native ranges and the rate of change associated with these shifts. We then compare these rate estimates to those estimated among species and to projected rates of future climate change. Results Remarkably, niche shifts in introduced species are roughly a million times faster than niche shifts among species in their native ranges and roughly 10 times faster than rates of projected climate change. Main conclusions Our results demonstrate that dramatic and rapid niche shifts are possible, although these may be limited in species’ native ranges by biotic interactions and other factors.

Beschreibung: Abstract Aim Understanding how spatial scale of study affects observed dispersal patterns can provide insights to spatiotemporal population dynamics, particularly in systems with significant long‐distance dispersal (LDD). We aimed to investigate the dispersal gradients of two rusts of wheat with spores of similar size, mass and shape, over multiple spatial scales. We hypothesized that a single dispersal kernel could fit the dispersal from all spatial scales well, and that it would be possible to obtain similar results in spatiotemporal increase of disease when modelling based on differing scales. Location Central Oregon and St. Croix Island. Taxa Puccinia striiformis f. sp. tritici, Puccinia graminis f. sp. tritici, Triticum aestivum. Methods We compared empirically derived primary disease gradients of cereal rust across three spatial scales: local (inoculum source and sampling unit = 0.0254 m, spatial extent = 1.52 m) field‐wide (inoculum source = 1.52 m, sampling unit = 0.305 m and spatial extent = 91.4 m) and regional (inoculum source and sampling unit = 152 m, spatial extent = 10.5 km). We then examined whether disease spread in spatially explicit simulations depended upon the scale at which data were collected by constructing a compartmental time‐step model. Results The three data sets could be fit well by a single power law dispersal kernel. Simulating epidemic spread at different spatial resolutions resulted in similar patterns of spatiotemporal spread. Dispersal kernel data obtained at one spatial scale can be used to represent spatiotemporal disease spread at a larger spatial scale. Main Conclusions Organisms spread by aerially dispersed small propagules that exhibit LDD may follow similar dispersal patterns over a several hundred‐ or thousand‐fold expanse of spatial scale. Given that the primary mechanisms driving aerial dispersal remains constant, it may be possible to extrapolate across scales when empirical data are unavailable at a scale of interest.

Beschreibung: Abstract Aim To identify the effect of multiple, temporally close, forcing events (i.e. climate‐driven habitat fragmentations/homogenizations) in shaping current patterns of biodiversity in alpine areas. Given their spatial configuration, alpine areas have been traditionally seen as islands surrounded by an “ocean” of unsuitable lands. A quantitative assessment of the effects of Holocene climate fluctuations on islands area and inter‐island connectivity is crucial to finely reconstruct past biodiversity dynamics and forecast species responses to future changes. Location Italy. Taxa Carabidae (Ground beetles), Chrysomelidae (Leaf beetles), Elateridae (Click beetles), Orthoptera (Grasshoppers and Crickets) and Papilionoidea (Butterflies and Skippers). Methods A total of 1,077 species for 128,093 records were analysed and a classification based on their functional traits allowed identifying groups of good and poor dispersers within each taxon. A dynamic discrete model of ecosystem evolution provided the spatio‐temporal context to test two competing (transient equilibria vs. nonequilibrium) dynamics based on different colonization capabilities. In the transient equilibria dynamic the species are able to respond to island evolution through successful dispersal and colonization events, whereas in the nonequilibrium dynamic ineffective immigration constrains the current species richness to that generated by the strongest island contraction. Results With the exception of Elateridae, good dispersers (Chrysomelidae and Papilionoidea) responded to environmental changes by establishing a series of transient equilibria. In contrast, the nonequilibrium dynamic better described patterns of species richness in poor dispersers (Carabidae and Orthoptera). Main conclusions Our approach could be used as the basis for the development of spatially and temporally explicit models of island evolution and could be a valuable tool for quantifying the sensitivity of single taxa to climate‐driven habitat changes. It also represents a further step towards the forecasting of future responses to climate change and the accompanying development of conservation strategies that more effectively respond to the detrimental impacts of climate change on biodiversity.

Beschreibung: Front cover: The cover image is based on the Original Article The herbivorous fish family Kyphosidae (Teleostei: Perciformes) represents a recent radiation from higher latitudes by Steen Knudsen et al., https://doi.org/10.1111/jbi.13634.

Beschreibung: Abstract Aim To test two prominent, alternate hypotheses that provide explanations for the great accumulation of endemic species in the Kimberley bioregion in north‐western Australia, using an extensively sampled, region wide phylogeny of northern Australia's most species‐rich freshwater fish family, Terapontidae. Specifically, we test whether the Kimberley may act as (1) a “museum” accumulating taxa and endemic species over time or (2) a “cradle” of more recent diversification and neoendemism. Location The Australian monsoonal tropics. Taxon Grunters (Terapontidae). Methods We obtained a robust and well‐supported Bayesian phylogeny for the family using DNA sequences from mtDNA and nuclear gene regions. We performed molecular phylogenetic analyses using species tree methods including molecular dating analysis, ancestral range reconstruction and diversification analysis. Results Based on our phylogeny, the combined molecular clock estimates and likelihood‐based historical‐biogeographic reconstructions suggest that terapontids recently transitioned into the Kimberley from the east during the late‐Miocene. We found that 80% of Kimberley terapontids diversified within the Kimberley in the last 3 Ma. Furthermore, diversification analyses identified a single significant shift in diversification rates ~1.4 Ma that corresponds with a change in global climate midway through the Pleistocene that was predominantly driven by speciation in the Kimberley. Main conclusions The weight of evidence suggests that the Kimberley has been a “cradle” of evolution for Terapontidae, rather than a “museum”. Our analysis provides strong evidence for a geologically recent transition of terapontids into the Kimberley from regions to the east during the late‐Miocene followed by a significant increase in speciation rates during the Pleistocene, driven by speciation in the Kimberley. The results provide important insight into the evolutionary and biogeographical processes that have shaped the regions unique biota, which will inform land managers working to protect and conserve both species and the processes responsible for generating and sustaining them.

Beschreibung: Abstract Aim Predicting future changes in species richness in response to climate change is one of the key challenges in biogeography and conservation ecology. Stacked species distribution models (S‐SDMs) are a commonly used tool to predict current and future species richness. Macroecological models (MEMs), regression models with species richness as response variable, are a less computationally intensive alternative to S‐SDMs. Here, we aim to compare the results of two model types (S‐SDMS and MEMs), for the first time for more than 14,000 species across multiple taxa globally, and to trace the uncertainty in future predictions back to the input data and modelling approach used. Location Global land, excluding Antarctica. Taxon Amphibians, birds and mammals. Methods We fitted S‐SDMs and MEMs using a consistent set of bioclimatic variables and model algorithms and conducted species richness predictions under current and future conditions. For the latter, we used four general circulation models (GCMs) under two representative concentration pathways (RCP2.6 and RCP6.0). Predicted species richness was compared between S‐SDMs and MEMs and for current conditions also to extent‐of‐occurrence (EOO) species richness patterns. For future predictions, we quantified the variance in predicted species richness patterns explained by the choice of model type, model algorithm and GCM using hierarchical cluster analysis and variance partitioning. Results Under current conditions, species richness predictions from MEMs and S‐SDMs were strongly correlated with EOO‐based species richness. However, both model types over‐predicted areas with low and under‐predicted areas with high species richness. Outputs from MEMs and S‐SDMs were also highly correlated among each other under current and future conditions. The variance between future predictions was mostly explained by model type. Main conclusions Both model types were able to reproduce EOO‐based patterns in global terrestrial vertebrate richness, but produce less collinear predictions of future species richness. Model type by far contributes to most of the variation in the different future species richness predictions, indicating that the two model types should not be used interchangeably. Nevertheless, both model types have their justification, as MEMs can also include species with a restricted range, whereas S‐SDMs are useful for looking at potential species‐specific responses.

Beschreibung: Journal of Biogeography, Volume 46, Issue 9, Page ii-iv, September 2019.

Beschreibung: Abstract Aim Major efforts have been devoted to understanding the geographic pattern of sexual size dimorphism (SSD). Rensch's rule posits that SSD increases with body size in male‐biased SSD species and decreases with body size in female‐biased SSD species. This pattern, and its inverse, have been mainly explored at the interspecific level, whereas research at the intraspecific level has been largely neglected. Here, we test whether the allometric pattern of SSD in an urodele amphibian conforms to Rensch's rule and evaluate the relative role of four potential mechanisms: sexual selection, fecundity selection, density‐dependent resource availability and differential plasticity. Location Iberian Peninsula. Taxon Lissotriton boscai (Amphibia: Caudata: Salamandridae). Methods We used original (field‐based) and published data on body size, courtship behaviour and fecundity parameters and a suite of climatic, ecological and genetic (mitochondrial and nuclear markers) predictors to assess these hypotheses. Results The results showed that SSD increased with increasing female mean body size, supporting the inverse Rensch's rule pattern. Primary productivity‐related variables and female density were among the most relevant ecological predictors of SSD after accounting for genetic structure and capture date. Main conclusions This study reveals that the interplay between the density‐dependent resource availability hypothesis and the differential plasticity hypothesis explains the inverse Rensch's rule. We discuss how combining biogeographical and experimental approaches can provide alternative interpretations to the classical sexual and fecundity selection hypotheses on the interpopulation variation in SSD.

Beschreibung: Abstract Aim To define the major biogeographical regions and transition zones for freshwater fish species. Taxon Strictly freshwater species of actinopterygian fish (i.e. excluding marine and amphidromous fish families). Methods We based our bioregionalization on a global database of freshwater fish species occurrences in drainage basins, which, after filtering, includes 11,295 species in 2,581 basins. On the basis of this dataset, we generated a bipartite (basin‐species) network upon which we applied a hierarchical clustering algorithm (the Map Equation) to detect regions. We tested the robustness of regions with a sensitivity analysis. We identified transition zones between major regions with the participation coefficient, indicating the degree to which a basin has species from multiple regions. Results Our bioregionalization scheme showed two major supercontinental regions (Old World and New World, 50% species of the world and 99.96% endemics each). Nested within these two supercontinental regions lie six major regions (Nearctic, Neotropical, Palearctic, Ethiopian, Sino‐Oriental and Australian) with extremely high degrees of endemism (above 96% except for the Palearctic). Transition zones between regions were of limited extent compared to other groups of organisms. We identified numerous subregions with high diversity and endemism in tropical areas (e.g. Neotropical), and a few large subregions with low diversity and endemism at high latitudes (e.g. Palearctic). Main conclusions Our results suggest that regions of freshwater fish species were shaped by events of vicariance and geodispersal which were similar to other groups, but with freshwater‐specific processes of isolation that led to extremely high degrees of endemism (far exceeding endemism rates of other continental vertebrates), specific boundary locations and limited extents of transition zones. The identified bioregions and transition zones of freshwater fish species reflect the strong isolation of freshwater fish faunas for the past 10–20 million years. The extremely high endemism and diversity of freshwater fish fauna raises many questions about the biogeographical consequences of current introductions and extinctions.

Beschreibung: Abstract Aim Current species distributions are shaped by present and past biotic and abiotic factors. Here, we assessed whether abiotic factors (habitat availability) in combination with past connectivity and a biotic factor (body mass) can explain the unique distribution pattern of Southeast Asian mammals, which are separated by the enigmatic biogeographic transition zone, the Isthmus of Kra (IoK), for which no strong geophysical barrier exists. Location Southeast Asia. Taxon Mammals. Methods We projected habitat suitability for 125 mammal species using climate data for the present period and for two historic periods: mid‐Holocene (6 ka) and last glacial maximum (LGM 21 ka). Next, we employed a phylogenetic linear model to assess how present species distributions were affected by the suitability of areas in these different periods, habitat connectivity during LGM and species body mass. Results Our results show that cooler climate during LGM provided suitable habitat south of IoK for species presently distributed north of IoK (in mainland Indochina). However, the potentially suitable habitat for these Indochinese species did not stretch very far southwards onto the exposed Sunda Shelf. Instead, we found that the emerged landmasses connecting Borneo and Sumatra provided suitable habitat for forest dependent Sundaic species. We show that for species whose current distribution ranges are mainly located in Indochina, the area of the distribution range that is located south of IoK is explained by the suitability of habitat in the past and present in combination with the species body mass. Main conclusions We demonstrate that a strong geophysical barrier may not be necessary for maintaining a biogeographic transition zone for mammals, but that instead a combination of abiotic and biotic factors may suffice.

Beschreibung: Abstract Aim To review the histories of the Colorado River and North American monsoon system to ascertain their effects on the genetic divergence of desert‐adapted animals. Location Lower Colorado River region, including Mojave and Sonoran deserts, United States. Methods We synthesized recent geological literature to summarize initiation phases of lower Colorado River evolution, their discrepancies, and potential for post‐vicariance dispersal of animals across the river. We simulated data under geological models and performed a meta‐analysis of published and unpublished genetic data including population diversity metrics, relatedness and historical migration rates to assess alternative divergence hypotheses. Results The two models for arrival of the Colorado River into the Gulf of California impose east‐west divergence ages of 5.3 and 4.8 Ma, respectively. We found quantifiable river‐associated differentiation in the lower Colorado River region in reptiles, arachnids and mammals relative to flying insects. However, topological statistics, historical migration rates and cross‐river extralimital populations suggest that the river should be considered a leaky barrier that filters, rather than prevents, gene flow. Most markers violated neutrality tests. Differential adaptation to monsoon‐based precipitation differences may contribute to divergence between Mojave and Sonoran populations and should be tested. Main Conclusions Rivers are dynamic features that can both limit and facilitate gene flow through time, the impacts of which are mitigated by species‐specific life history and dispersal traits. The Southwest is a geo‐climatically complex region with the potential to produce pseudocongruent patterns of genetic divergence, offering a good setting to evaluate intermediate levels of geological‐biological (geobiological) complexity.

Beschreibung: Abstract Aim Alexander von Humboldt observed that plant communities on different continents but under similar climatic conditions shared few common species but often contained representatives of the same genera or higher taxonomic groups. To test if this observation can be extended to substrate type, we explored whether a phylogenetic signature could be seen among floras growing on ultramafic substrates that present challenging edaphic conditions for plant growth and are well‐known for their distinctive vegetation. Location Cuba, Madagascar, New Caledonia. Taxon Angiosperms. Methods We compared the floras of Cuba, Madagascar and New Caledonia to test whether the same plant families were under‐ or over‐represented on the ultramafic substrates of the three islands. Results Pairwise comparisons showed that plant orders and families tended to have the same behaviour on the three islands, i.e. ultramafic substrates filtered (in favour of or against) the same plant groups in the three biogeographical distinct areas. The COM clade (comprising Celastrales, Oxalidales and Malpighiales) appears to be over‐represented on ultramafic substrates in all three islands and contains over half of the world's known nickel hyperaccumulators. Main conclusions Our analyses provide support for Humboldt's observation by showing that ecological sorting can favour the same plant lineages in similar environments in different biogeographical regions.

Beschreibung: Abstract Aim To assess habitat filtering and dispersal limitation in spore plant community assembly using bryophytes on recently emerged land uplift islands as study system. Location Gulf of Bothnia, northern Europe. Taxa Bryophytes, including the spore plant phyla Bryophyta (mosses) and Marchantiophyta (liverworts). Methods The species compositions of 20 coastal land uplift islands differing in age, area, connectivity and habitat composition were recorded in the field. In addition, we compiled a list of the regional species pool (446 species) and gathered data on species traits related to habitat affiliations (substrate, light, moisture, and pH) and dispersal capacity (regional abundance, spore size, sporophyte frequency, sexual system, vegetative propagules). For the 420 species with available trait data, we used multivariate generalized linear models to compare trait effects on species occurrence probabilities on the islands. Results Occurrence probabilities depended strongly on habitat affiliations. In addition, occurrence probabilities were lower for predominantly asexual species than for sexual species and for regionally rare than for regionally abundant species. Having specialized asexual propagules increased occurrence probabilities, but compensated only partly for the reductions in asexual species. No effect of the size of sexually produced spores was detected. Comparison of trait effects across island size and connectivity gradients revealed (a) reduced habitat filtering on larger islands and (b) decreasing negative effects of being predominantly asexual with increasing island connectivity. Conclusions Both habitat filtering and dispersal capacities affect the community assembly of spore plants on land uplift islands. Asexual mosses and liverworts show landscape scale (≤10 km) dispersal limitation. The weak or absent relationships between island connectivity and the effects of dispersal traits suggest that colonization is regulated mainly by habitat availability and the abundance of each species in a “regional spore rain” from which colonists are recruited.

Beschreibung: Abstract Aim Species distribution models (SDMs) are widely used to study geographic distributions of taxa in response to natural and anthropogenic environmental conditions. For a community, common approaches include fitting individual SDMs (iSDMs) to all taxa or directly modelling community properties such as richness. However, the parameters of iSDMs are difficult to identify for rare taxa, and community properties do not reveal taxon‐specific responses. Individual models can be combined into a hierarchical multispecies distribution model (mSDM) that constrains taxon‐specific parameters according to overarching community parameters, or a joint model (jSDM) in which interdependencies between taxa are jointly inferred. We compare how individual, hierarchical multispecies and joint SDMs differ in quality of fit, explanatory power and predictive performance, and analyse how these properties depend on the prevalence of taxa. Taxa Presence–absence observations of 245 benthic macroinvertebrate taxa identified at a mixed taxonomic resolution. Location Four hundred and ninety‐two sites in rivers throughout Switzerland. Methods Individual, hierarchical and joint hierarchical generalized linear models (GLM) were developed for all taxa. Parameters were estimated using maximum likelihood estimation or Bayesian inference with Hamiltonian Markov chain Monte Carlo simulations. Predictive performance was assessed with cross‐validation. In addition, the predicted family and species richness of the models was compared with a GLM for richness. Results Individual models show a slightly higher quality of fit largely due to overfitting for rare taxa. The mSDM achieves a similar quality of fit and explanatory power, mitigates overfitting for rare taxa and considerably improves predictive performance over the whole community. The joint models further improve the quality of fit, but decrease predictive performance and increase predictive uncertainty. Main conclusions We show that even a relatively simple mSDM combines many of the analytical capabilities of iSDMs and improves predictive performance. Increasingly complex mSDMs and jSDMs provide additional analytical possibilities, but depending on the data and research questions, different levels of complexity may be appropriate.

Beschreibung: Abstract Aim This study aims to quantify the patterns in compositional turnover of native and exotic ants on small islands in two oceans, and to explore whether such patterns are driven by similar environmental, geographical and potentially biotic variables. Location Pacific and Atlantic islands. Time period Present. Major taxa studied Ants. Methods We applied Multi‐Site Generalised Dissimilarity Modelling (MS‐GDM), which relates zeta diversity, the number of species shared by a given number of islands, to differences in environmental, geographical and biotic drivers. The use of zeta diversity enabled us to differentiate the contribution of rare species (shared by few islands) from those of widespread ones (shared by multiple islands) to compositional turnover. For completion, we also related species richness of insular ants per island with the same set of explanatory variables using Generalised Additive Models (GAM). Results Pacific and Atlantic islands have similar patterns of ant species turnover and richness, albeit partly driven by different drivers. Native and exotic species turnover are mostly explained by the same set of variables in the Pacific (annual precipitation and distance to the nearest island), but not in the Atlantic (annual precipitation is a good predictor of native species turnover, but none of the variables considered in our study explained exotic species turnover). No signal of biotic interactions was detected at the insular community level. Main conclusions Successful invasion strategies may depend on a combination of factors specific to the region in question. In the Pacific, milder environments and the absence of natives on certain islands enable exotic ants to select the same types of environment as native ants. In the harsher Atlantic Ocean, however, native ant species are likely to be well adapted to local environmental conditions, making it harder for exotics to become established. Exotic ant species, therefore, potentially rely on other attributes to establish, such as a combination of tolerance to a wide range of environmental conditions and human‐mediated colonization.

Beschreibung: Abstract Aim To determine the role of flow intermittence and species origin in shaping freshwater fish beta diversity across dryland riverscapes. Location Verde and Little Colorado River basins, United States. Methods Fish beta diversity was investigated in two large rivers with marked differences in basin‐wide flow intermittence. Local site (continually flowing perennial vs. periodically flowing intermittent) and species (native vs. non‐native) contributions to beta diversity were compared within each basin and over multiple decades (1987–2013) in relation to changing hydrologic conditions. Metacommunity dynamics were quantified using changes in alpha‐ (local), beta‐ and gamma‐ (regional) diversity through time. Results Beta‐diversity patterns varied in relation to basin‐wide intermittence. Intermittent sites were most influential to beta diversity where basin‐wide intermittence was lower (Verde River), whereas perennial sites were most influential where basin‐wide intermittence was higher (Little Colorado River). In intermittent sites, native fish species contributions to beta diversity tended to be higher than non‐native species contributions. The relative contributions of perennial and intermittent sites to β‐diversity within each basin were invariant to annual flow regimes, whether atypically lower or higher than average flows, but somewhat related to intra‐annual flow variation. Native species contributions to β‐diversity increased in years with high flow conditions in the Verde River. Over time, beta diversity decreased in the lower intermittence Verde River, indicating taxonomic homogenization, but remained relatively unchanged in the Little Colorado River. Main Conclusions Investigations of beta‐diversity components over time are considered pivotal for conservation prioritization and planning. We found that both intermittent and perennial streams play complementary roles in supporting fish beta diversity, and that their relative contributions increase as basin wide availability of the habitat type decreases. Moreover, contributions of intermittent streams to overall beta diversity were relatively consistent through time and supported native fish diversity. Despite weakening policy protections of intermittent streams, these habitats are critical for supporting local species persistence and regional biodiversity.

Beschreibung: Abstract Aim Early warning against potentially harmful organisms of woody plant species can be achieved by sampling sentinel plants in exporting countries. However, it is unclear where sentinel plants can best be located, and how many samples are required and when and how often sampling optimally should take place for the adequate assessment of the biodiversity associated with the target plant species. We aimed to review spatial and temporal factors affecting associate biodiversity of single woody plant species and to develop guidance for the design of global biodiversity sampling studies. Location Worldwide. Taxon Insects and Fungi. Methods Literature about factors affecting the diversity of insects and fungi in association with single plant species on global, regional, local and different temporal scales was reviewed. Case studies of insect and fungal diversity, primarily collected on single plant species, and the cost of collecting and analysing samples from locations around the world were analysed. Results The review of the literature illustrated various factors affecting diversity, and the case studies allowed quantification of the relative impact of some spatial, temporal and financial aspects on captured biodiversity and, thus, illustrate the need to consider all possible factors that may affect the result of the sampling when deciding on a sampling design. Main conclusions Our study illustrates the factors that should be considered when deciding on the location and timing of sampling for sentinel plants, which is important because of the trade‐off between the number of samples and sampling locations needed to detect many of the species which may be potential pests, and the cost of (repeated) sampling in many locations. Decisions about the sampling design must be based on the objective of the sampling, but our recommendations apply irrespective of the targeted plant species or country.

Beschreibung: Abstract Aim To test if tree species richness and forest structure drive spatial variation in avian communities along a tropical elevation gradient and to present information about the role of detailed forest parameters. Location A 2,000‐m long elevational gradient of tropical forest on Mt. Cameroon, west‐central Africa. Taxon Birds and trees. Methods We performed bird censuses and vegetation mapping at the same plots across six forested sites at elevations of 350, 650, 1,100, 1,500, 1,850, and 2,200 m a.s.l., with 16 plots per elevation. We tested the effects of elevation, forest structure and tree diversity on the species richness, functional diversity and β‐diversity of birds (Bray–Curtis dissimilarity). We used conditional inference trees based on random forests (RF) to investigate these relationships across all elevation sites as well as within elevations. Results Both tree and bird species richness declined monotonically with elevation. Vegetation structure correlated with elevation, and all vegetation attributes significantly differed among elevations. The RF explained 70% of the variance in avian species richness, with the most important predictors being elevation, proportion of dead trees, tree species richness and herb layer coverage. We found that elevation (and shrub layer) was a particularly important predictor of avian functional diversity. We identified no important predictor of bird species richness after standardization within elevations, and the proportion of dead trees was the sole important predictor of functional diversity. Within‐elevation β‐diversity in avian community composition was determined by the dissimilarity of the tree community and differences in leaf area index, solar radiation and spatial distance. The functional dissimilarity was best explained by leaf area index. Main conclusions Apart from elevation itself, spatial distance even within elevations correlated with compositional and functional variation among avian assemblages. Forest structural traits can have a significant influence on distribution of birds. Thus, gaps in the spatial distribution of species such as along elevations might be caused by fine‐scale recognition of suitable habitats.

Beschreibung: Abstract Aim Statistical species distribution models (SDMs) are the most common tool to predict the impact of climate change on biodiversity. They can be tuned to fit relationships at various levels of complexity (defined here as parameterization complexity, number of predictors, and multicollinearity) that may co‐determine whether projections to novel climatic conditions are useful or misleading. Here, we assessed how model complexity affects the performance of model extrapolations and influences projections of species ranges under future climate change. Location Europe. Taxon 34 European tree species. Methods We sampled three replicates of predictor sets for all combinations of 10 levels (n = 3–12) of environmental variables (climate, terrain, soil) and 10 levels of multicollinearity. We used these sets for each species to fit four SDM algorithms at three levels of parameterization complexity. The 〉100,000 resulting SDM fits were then evaluated under environmental block cross‐validation and projected to environmental conditions for 2061–2080 considering four climate models and two emission scenarios. Finally, we investigated the relationships of model design with model performance and projected distributional changes. Results Model complexity affected both model performance and projections of species distributional change. Fits of intermediate parameterization complexity performed best, and more complex parameterizations were associated with higher projected loss of current ranges. Model performance peaked at 10–11 variables but increasing number of variables had no consistent effect on distributional change projections. Multicollinearity had a low impact on model performance but distinctly increased projected loss of current ranges. Main conclusions SDM‐based climate change impact assessments should be based on ensembles of projections, varying SDM algorithms as well as parameterization complexity, besides emission scenarios and climate models. The number of predictor variables should be kept reasonably small and the classical threshold of maximum absolute Pearson correlation of 0.7 restricts collinearity‐driven effects in projections of species ranges.

Beschreibung: Abstract Aim We assessed the validity of the division of the Magellanic Province into the four provinces as proposed by Briggs & Bowen (J Biogeogr 39 12–30, 2012): Southern Chile, Tierra del Fuego, Southern Argentina and Falkland (Malvinas) Islands. We aimed to (a) present an updated list of the fishes from the region known as ‘Magellanic Province’, (b) analyse the specific richness of fishes in the Atlantic and Pacific sectors and their degree of endemism and (c) evaluate statistically the validity of the three Provinces proposed for the Atlantic sector. Location Southern tip of the American continent at latitudes higher than 40° S in the Atlantic as well as in the Pacific Oceans. Taxon 348 South American marine fish species. Methods The list of fishes was prepared by consulting more than 140 sources, many related to observations resulting from research cruises, although two ichthyological collections and two ichthyological websites were also used. The South American species with distributions extending outside of the area corresponding to the Magellanic Province, and all cosmopolitan species, were excluded of endemism analyses. For analysing fish distributions in the Atlantic sector, the data employed are from eight research cruises carried out from 1978 to 2006 from 37° to 55° south. A total of 523 fishing trawls have been analysed, grouped into cell of 1° × 1° cells. The species composition of each cell was evaluated by multivariate analysis (non‐metric multidimensional scaling, cluster and similarity analyses). Results The percentage of endemism in each sector (Atlantic 2.87% and Pacific 2.87%) is smaller than the endemism common to both sectors (9.2%). The total of endemic species in the Province is 14.94%, which is bigger than the 10% indicated as the lower limit for defining a biogeographic province suggested by Briggs (Marine Zoogeography, 1974). In addition, multivariate analyses do not show differences in the species composition, neither between Falkland (Malvinas) Islands and ‘Southern Argentina’ nor between the latter and Tierra del Fuego. Main conclusions The ichthyological data indicate only one biogeographic province in the region not four as previously posited.

Beschreibung: Abstract Aim The main aims were to determine: (a) the relative contribution of species replacement and richness difference from components to overall taxonomic (TDβ) and functional (FDβ) beta diversity of spider communities; (b) the degree to which TDβ and FDβ components can be explained by the environmental or geographic predictors; (c) whether FDβ components were lower than expected given the underlying TDβ variation. Location This study was carried out in 22 oak forest sites across the Iberian Peninsula. The area comprises two biogeographic regions, Eurosiberian (North) and Mediterranean (Centre and South). Methods Spiders were sampled using a standardized protocol. A species x traits matrix was constructed. Total taxonomic (TDβtotal) and total functional (FDβtotal) beta diversity were calculated, by pairwise comparisons, and partitioned into their replacement (βrepl) and richness difference (βrich) components. Mantel tests were used to relate taxonomic and functional dissimilarity with environmental and geographic distances. A spatial eigenfunction model was constructed and the variation in TDβ and FDβ explained by environment and geographic predictors was quantified. Null models were used to test if FDβ was higher or lower than expected given TDβ. Results βrepl was the dominant component contributing to 84.2% and 72.8% for TDβtotal and FDβtotal, respectively. TDβtotal and FDβtotal (and their replacement components) were higher between‐ than within‐biogeographic regions. TDβtotal and TDβrepl were positively correlated with environmental and geographic distances, even when controlling for a biogeographic effect, but their functional counterparts were only correlated with environmental distance. Variation partitioning showed that pure environmental and spatially structured environmental effects had a small contribution to beta diversity, except for TDβrich. The observed slopes of the regressions of FDβtotal and FDβrepl in relation to environmental distance were slower than the null model expectations. Main Conclusions Spider assemblage variation was mainly determined by the replacement, and not the net loss, of species and traits. TDβ was influenced by niche filtering and dispersal limitation, whereas FDβ was mainly generated by niche filtering. A high level of functional convergence among spider communities, despite the high taxonomic divergence, revealed the signal of replacement of species performing similar functions across sites.

Beschreibung: Abstract Aim We test the ability of the biotic exchange across the Bering land bridge coupled to niche conservatism to explain current day mammalian diversity gradients. Location The Holarctic. Taxon Mammals. Methods We compared the diversity within clades that participated in the exchange (colonizers), whose ancestors withstood the Beringian cold temperatures, with that within clades that did not participate (sedentaries). We contrasted biogeographical patterns, tested the ability of environmental models to predict species richness of colonizers and sedentaries across continents and, compared richness‐climate relationships between colonizers and sedentaries controlling for phylogenetic effects. Results We find that assemblages of colonizers are more diverse towards higher latitudes, opposing the traditional latitudinal diversity gradient which is followed by sedentaries. Despite the long passage of time since this major dispersal event, we find that the geographic distribution of colonizers is more strongly correlated with the distributions of other colonizers inhabiting a different continent than to the distribution of sedentary species. Main conclusions Our results highlight the importance of historical migrations and dispersal in configuring present‐day diversity gradients. We also suggest that colonizers may be particularly vulnerable to future climate change because of the predicted disproportionate decrease in climate space in the extra‐tropical realm where they are currently most diverse.

Beschreibung: Abstract Aim Organisms with poor intrinsic dispersal capacity, such as parasites, often rely entirely on transport with host species that have a greater dispersal capacity. Penguins, for example, are exploited by terrestrial ectoparasites when they come ashore to breed. Recent research indicates that Little Penguin (Eudyptula minor and E. novaehollandiae) hard ticks (Ixodes eudyptidis and I. kohlsi) may be capable of surviving short periods (days) at sea with their hosts, but their capacity to survive longer voyages (weeks) is not known. We here aimed to assess whether phylogeographical patterns in Little Penguins and their ticks indicate that the terrestrial ectoparasites are able to disperse long distances at sea with their swimming hosts. Location Southern Australia and New Zealand. Taxon Ixodes eudyptidis and I. kohlsi ticks. Methods We conducted a broad‐scale genomic assessment of Little Penguin ticks from across their hosts’ ranges in Australia and New Zealand. Using genotyping by sequencing, we generated SNP data sets from ticks from 14 penguin colonies, and analysed phylogeographical structure. We included ticks from some sympatric flighted seabirds to verify host specificity. Results We resolved two distinct lineages of Ixodes from Little Penguins, with one restricted to Australia, and the other found throughout New Zealand and in low numbers at some eastern Australian sites. Both lineages exhibited phylogeographical structure consistent with patterns observed in their hosts, with some evidence of occasional oceanic dispersal, including across the Tasman Sea between Australia and New Zealand. Ticks from sympatric short‐tailed shearwaters (Ardenna tenuirostris), which disperse aerially, were genetically distinct from those collected from Little Penguins, supporting prior evidence of host specificity in seabird ticks. Main conclusions The most parsimonious explanation for our results is that ticks can travel at sea with Little Penguins. We infer that some terrestrial ectoparasites associated with aquatically dispersing hosts have evolved the capacity to survive oceanic voyages.

Beschreibung: Abstract Aim Analysing the drivers of intraspecific variation and how reproductive barriers arise is an essential step to infer the mechanisms of biogeographic differentiation. In populations of a specialized alpine species, we explore the role of geography and climate in the divergence of genetic, morphological and acoustic characters, and analyse the functional consequences of variation on mate choice. Taxon Chorthippus cazurroi (Orthoptera: Caelifera, Acrididae, Gomphocerinae). Location The entire distribution of the species (23 populations from six massifs of the Cantabrian Mountains, NW Spain). Methods First, we analysed the extent of intraspecific spatial divergence and the covariation among climatic niche, genetic (mtDNA), acoustic (song structure) and morphological (body size) traits. Then, we analysed the consequences of phenotypic variation by means of a crossing experiment among populations from different elevations. This served to test for differences in sexual selection among body size‐divergent populations and for the relationship between male traits, female preference and reproduction. Results Genetic, morphologic and acoustic divergence increased with geographic distance. Female morphology was also affected by climate variation, while male one tightly covaried with the song differentiation. Females more closely approached males investing more time in song activities, but weakly responded to the rest of acoustic features and morphological variation. They also distanced themselves slightly more from males from different populations, although this behaviour did not lead to clear differences in reproductive parameters. Main conclusions The process of colonization of mountain massifs has led to significant genetic and phenotypic changes in C. cazurroi. Phenotypic divergence does not constitute a strong intrinsic barrier to reproduction and is largely unpaired from female preference, overall suggesting that sexual selection is a minor actor in the process of differentiation as compared, for instance, to drift. This does not exclude that traits associated with individual condition are under strong selection and, therefore, do not vary so extensively. This study dismisses the idea that alpine specialists with narrow distributions lack genetic and phenotypic variability, and highlights the importance of synthesizing biogeographic and experimental approaches to obtain stronger and deeper inferences about the dynamics and mechanisms of biological differentiation.

Beschreibung: Abstract Aim The spatio‐temporal distribution of biodiversity is a core field of biogeography, and the so‐termed species–time–area relationship (STAR), together with its siblings, that is the SAR (species–area relationship) and STR (species–time relationship), has achieved the rare status of classic laws in ecology and biogeography. Traditionally, the STAR or its recent generalization DTAR (diversity–time–area relationship) has been described with the bivariate power law (BPL) model or more recently with Whittaker, Triantis, and Ladle (2008, Journal of Biography; 35: 18) general dynamic model (GDM). We propose to extend the classic BPL into a more flexible DTAR model, which offers new quantitative methods for estimating maximal global diversity and charactering the relationship between local and regional diversity. Location Indoor microbiome. Taxon Microbes. Method We revise the BPL model by introducing two taper‐off (cut‐off) parameters or BPLEC (bivariate power law with exponential cutoffs) model, which eventually overwhelms the unsaturated increase of diversity over time and/or space and consequently can offer more realistic modelling of the joint spatio‐temporal distribution of biodiversity. Based on the BPLEC model, we further define three new concepts for DTAR: maximal accrual diversity (MAD) profile, local‐to‐regional diversity (LRD) ratio profile and local‐to‐global diversity (LGD) ratio profile. Results We introduce and demonstrate the new BPLEC model with the indoor microbiome datasets (Lax et al., 2014, Science; 345: 1048–1052). The new model fitted to the microbiome datasets equally well or slightly better than existing BPL and GDM models, but it possesses two advantages stated below. Main conclusion First, the new BPLEC model overcomes the unlimited diversity accrual in temporal and/or spatial dimensions and hence offers more realistic modelling to the DTAR. Second, the MAD and LRD/LGD offer useful methods for estimating the “dark” or “potential” diversity, which accounts for the species locally absent but present in a habitat‐specific regional species pool.

Beschreibung: Abstract Aim Modelling and quantifying habitat changes using three historical field surveys for four Mojave Desert species and projecting future scenarios. Location Newberry Mountains, southern Nevada, USA. Methods Three vegetation field surveys were conducted, ending in 1979, 2008 and 2016, respectively. Field data collection across three time steps resulted in a unique dataset with 100 re‐surveyed 0.06‐ha plots. Using Maxent ecological niche modelling and 800‐m resolution Parameter Elevation Regressions on Independent Slopes Model (PRISM) temperature and precipitation data, habitat was assessed for four high‐elevation species. Recognizing that missing location data is a common challenge in species distribution modelling, sensitivity analysis was conducted utilizing three high‐elevation plots that species inhabited during the first two field surveys but that were unable to be sampled in 2016. Area under the curve for three species’ model runs exceeded 0.95, while one wider‐distributed species exceeded 0.79 for all runs. Future scenarios were also modelled under temperature increases and 16% and 0% reductions in precipitation. Results The number of presence locations and densities for Juniperus californica, Pinus monophylla, Quercus turbinella and Yucca schidigera decreased from 1979 to 2016, while their average elevational distribution increased. Using the 100 plots measured each of the three study years, models for all four species indicated decreases in potential suitable habitat ranging from 10% to 45%. When including the three highest elevation plots not re‐sampled in 2016, but likely still containing the modelled species, modelled habitat loss ranged from 0% to 29%. Future model projections show drastic reductions in the suitable habitat of all four modelled species. Main conclusions While many Maxent ecological modelling studies have been conducted, few have incorporated repeat surveys of identical plots as in our study. Model projections using a unique 100‐plot dataset suggest that suitable habitat area is contracting for the species studied, and this correlated with climatic warming and drying in the Mojave Desert. Despite model projections that show nearly complete loss of suitable habitat in 2053, care should be taken given uncertain estimates of the velocity of climate change and the slower pace of habitat contractions measured in the field.

Beschreibung: Abstract Aim The former continental‐scale studies modelled coarse‐grained plant species‐richness patterns (gamma diversity). Here we aim to refine this information for European forests by (a) modelling the number of vascular plant species that co‐occur in local communities (alpha diversity) within spatial units of 400 m2; and (b) assessing the factors likely determining the observed spatial patterns in alpha diversity. Location Europe roughly within 12°W–30°E and 35–60°N. Taxon Vascular plants. Methods The numbers of co‐occurring vascular plant species were counted in 73,134 georeferenced vegetation plots. Each plot was classified by an expert system into deciduous broadleaf, coniferous or sclerophyllous forest. Random Forest models were used to map and explain spatial patterns in alpha diversity for each forest type separately using 19 environmental, land‐use and historical variables. Results Our models explained from 51.0% to 70.9% of the variation in forest alpha diversity. The modelled alpha‐diversity pattern was dominated by a marked gradient from species‐poor north‐western to species‐rich south‐eastern Europe. The most prominent richness hotspots were identified in the Calcareous Alps and adjacent north‐western Dinarides, the Carpathian foothills in Romania and the Western Carpathians in Slovakia. Energy‐related factors, bedrock types and terrain ruggedness were identified as the main variables underlying the observed richness patterns. Alpha diversity increases especially with temperature seasonality in deciduous broadleaf forests, on limestone bedrock in coniferous forests and in areas with low annual actual evapotranspiration in sclerophyllous forests. Main conclusions We provide the first predictive maps and analyses of environmental factors driving the alpha diversity of vascular plants across European forests. Such information is important for the general understanding of European biodiversity. This study also demonstrates a high potential of vegetation‐plot databases as sources for robust estimation of the number of vascular plant species that co‐occur at fine spatial grains across large areas.

Beschreibung: Abstract Liu et al. (2018) used a virtual species approach to test the effects of outliers on species distribution models. In their simulations, they applied a threshold value over the simulated suitabilities to generate the species distributions, suggesting that using a probabilistic simulation approach would have been more complex and yield the same results. Here, we argue that using a probabilistic approach is not necessarily more complex and may significantly change results. Although the threshold approach may be justified under limited circumstances, the probabilistic approach has multiple advantages. First, it is in line with ecological theory, which largely assumes non‐threshold responses. Second, it is more general, as it includes the threshold as a limiting case. Third, it allows a better separation of the relevant intervening factors that influence model performance. Therefore, we argue that the probabilistic simulation approach should be used as a general standard in virtual species studies.

Beschreibung: Abstract Aim Geodiversity underpins biodiversity, but the contribution of specific geofeatures or landforms has rarely been explored. In this study, we use multiple vascular plant species diversity measures on alpha, beta and gamma levels to explore the linkage between biodiversity and co‐located landforms (e.g. gullies, dunes and lake shores). We hypothesize that biodiversity will be positively related to geodiversity, which is founded on distinct landforms. Additionally, we propose that different landforms will sustain different amounts of biodiversity and that high alpha and gamma diversity values are related to landform‐driven moisture availability whereas high beta diversity relates especially to landform‐specific microtopographic variation. Location Rokua UNESCO Global Geopark area, Finland. Taxon Vascular plants. Methods We compare vascular plant species richness measures, Shannon's and Simpson's diversity indices, rarity‐weighted richness and local contribution to beta diversity at altogether three levels of biodiversity (alpha, beta and gamma) for different landforms. Landform information is compiled from aerial photos, spatial data layers and targeted field surveys. We compare results to control habitat (i.e. sites without any distinct landforms) within the study area. Results Vascular plant diversity was higher on landforms than in control habitat. There was also notable variation between species diversity of different landforms. Moisture‐rich gullies and river shores were especially diverse at all three levels, whereas aapa mires hosted most unique species composition (highest beta diversity). Beta diversity patterns were rather comparable with alpha and gamma diversity patterns, which contradict our hypothesis. Main conclusions This study quantitatively established a strong connection between terrestrial plant communities and multiple landforms. Our results highlighted the landform‐controlled variation in soil moisture, microclimate and microtopography in enhancing plant species diversity. Based on the results, we promote the inclusion of landform‐based geodiversity information in conservation management and in further biogeographical studies.

Beschreibung: Abstract Aim Foliar fungi – pathogens, endophytes, epiphytes – form taxonomically diverse communities that affect plant health and productivity. The composition of foliar fungal communities is variable at spatial scales both small (e.g. individual plants) and large (e.g. continents), yet few studies have attempted to tease apart spatial from climatic factors influencing these communities. Moreover, few studies have sampled in more than 1 year to gauge interannual variation in community structure. Location The Pacific Northwest of western North America. Taxon Foliar fungi associated with the deciduous tree Populus trichocarpa. Methods In two consecutive years, we used DNA metabarcoding to characterize foliar fungal communities of Populus trichocarpa across its geographic range, which encompasses a sharp climatic transition as it crosses the Cascade Mountain Range. We used multivariate analyses to (a) test for and differentiate spatial and environmental factors affecting community composition and (b) test for temporal variation in community composition across spatial and environmental gradients. Results In both study years, we found that foliar fungal community composition varied among sites and between regions (east vs. west of the Cascades). We found that climate explained more variation in community composition than geographic distance, although the majority of variation explained by each was shared. We also found that interannual variation in community composition depended on environmental context: communities located in the dry, eastern portion of the tree's geographic range varied more between study years than those located in the wet, western portion of the tree's range. Main conclusions Our results suggest that the environment plays a greater role in structuring foliar fungal communities than dispersal limitation.

Beschreibung: Abstract Aim We investigated turnover and richness in Antarctic springtails to understand large‐scale patterns in soil faunal diversity and how these are altered by biological invasions. Location Antarctica and the Southern Ocean Islands. Taxon Collembola (springtails). Methods We developed a database of all springtail species recorded from the Antarctic region. The relationship of species richness and turnover to high‐resolution environmental data was explored using generalized linear models and generalized dissimilarity models, and compared among indigenous and introduced species. Endemicity and species turnover were assessed using beta‐diversity and multi‐site zeta diversity metrics to explore whether introduced species have homogenized assemblages across the region. Results Indigenous, endemic and introduced species richness covaried positively with temperature. Endemic richness was further related to thermal heterogeneity, and introduced species richness to human occupancy. Indigenous and introduced species richness covaried positively. Species turnover across the region was high, and the introduction of non‐indigenous species further differentiated assemblages. Species similarity between sites was not related to distance, nor was geographic isolation correlated with species richness. Assemblage turnover was influenced by the area and temperature range of islands. Main conclusions Energy availability appears to be the primary covariate of species richness, with human presence additionally influencing introduced species richness, in agreement with other soil‐dwelling taxa. Dispersal limitation surprisingly does not seem to be important in structuring these assemblages, nor does island age appear to affect richness; this may in part reflect the severe glacial history of the region. The differentiating effect of introduced species on assemblages suggests that anthropogenic introductions originate from distinct source pools, challenging common assumptions for the Antarctic. Positive covariance between indigenous and introduced species richness accords with the “rich get richer” hypothesis. Thus, the most biotically diverse terrestrial areas of Antarctica may be the most prone to future biological invasion.

Beschreibung: Abstract Alexander von Humboldt was arguably the most influential scientist of his day. Although his fame has since lessened relative to some of his contemporaries, we argue that his influence remains strong—mainly because his approach to science inspired others and was instrumental in furthering other scientific disciplines (such as evolution, through Darwin, and conservation science, through Muir)—and that he changed the way that large areas of science are done and communicated. Indeed, he has been called the father of a range of fields, including environmental science, earth system science, plant geography, ecology and conservation. His approach was characterized by making connections between non‐living and living nature (including humans), based on interdisciplinary thinking and informed by large amounts of data from systematic, accurate measurements in a geographical framework. Although his approach largely lacked an evolutionary perspective, he was fundamental to creating the circumstances for Darwin and Wallace to advance evolutionary science. He devoted considerable effort illustrating, communicating and popularizing science, centred on the excitement of pure science. In biogeography, his influence remains strong, including in relating climate to species distributions (e.g. biomes and latitudinal and elevational gradients) and in the use of remote sensing and species distribution modelling in macroecology. However, some key aspects of his approach have faded, particularly as science fragmented into specific disciplines and became more reductionist. We argue that asking questions in a more Humboldtian way is important for addressing current global challenges. This is well‐exemplified by researching links between geodiversity and biodiversity. Progress on this can be made by (a) systematic data collection to improve our knowledge of biodiversity and geodiversity around the world; (b) improving our understanding of the linkages between biodiversity and geodiversity; and (c) developing our understanding of the interactions of geological, biological, ecological, environmental and evolutionary processes in biogeography.

Beschreibung: Abstract Aim Herbivorous reef fishes are considered to have difficulty digesting plant material at extratropical temperatures and are thus largely restricted to tropical waters where they are thought to have evolved. However, the herbivorous Kyphosidae, with both temperate and tropical species, provides an ideal opportunity to test this view. Previous studies have resolved the taxonomy and distribution patterns of all species. Here, we use a calibrated phylogeny to analyse the age, geographical origin and pattern of diversification of kyphosids to determine their origins in space and time, and thus refine hypotheses on the evolutionary origins of herbivory in reef fishes. Location Pacific Ocean, Atlantic Ocean, Indian Ocean, Western Australia. Methods The age and geographic origin of Kyphosidae were determined by incorporating fossil calibrations and species distributions onto a phylogeny of all extant species based on fragments from mitochondrial markers and three nuclear markers, and using Bayesian modelling to reconstruct ancestral distributions. Evolution of both diet and tooth shape was also examined using ancestral reconstruction. Results Ancestral reconstruction suggested a subtropical, Southern Hemisphere Indo‐Pacific origin for the family. The chronogram indicates that Kyphosus originated in the early Miocene and that tropical diversity reflects very recent diversification. Main conclusions Contrary to the general perception that herbivorous reef fishes invaded high latitudes from the tropics, herbivorous kyphosids evolved at intermediate latitudes in the Southern Hemisphere and subsequently diversified into low latitudes where several species dispersed recently to achieve circumglobal distributions. The southern temperate/subtropical reef environment appears to have generated episodes of diversification in several, well‐established, widespread reef fish taxa. Some of these reef fish taxa have remained restricted to southern temperate reef environments despite a long tenure in the Cenozoic (e.g. odacines and aplodactylids), and some such as the kyphosids which diversified very recently in both hemispheres resulting in both regional endemics and species with worldwide distributions.

Beschreibung: Abstract Aim The International Union for Conservation of Nature (IUCN) expert range maps and the Global Biodiversity Information Facility (GBIF) species occurrence data are commonly used to estimate species’ geographic range. Macroecological studies often cross‐reference geographic range data with a climate dataset, to extract the mean environmental conditions encountered by a species within its geographic range. We aimed to assess the consistency of the environmental data estimates derived from IUCN versus GBIF geographic range data, and to test whether such differences may affect estimates of ecogeographical relationships, such as Bergmann's rule. Location Worldwide. Time period Around 2000. Taxa Rodents (Rodentia). Methods We first assessed the correlation between environmental data estimates (19 bioclimatic variables and elevation) derived from IUCN versus GBIF geographic range data of 1,315 rodent species, comparing how range size, conservation status, habitat, zoogeographic realm or elevation changed these correlations. Then, we compared the association between body mass and climate (mean temperature and precipitation) when the latter are derived from IUCN or GBIF data. Results There was high correlation between environmental data estimates derived from IUCN versus GBIF data, especially when excluding GBIF occurrences outside of IUCN polygons. Species’ characteristics, or using the mean or median, did not change the consistency between estimates. Overall, GBIF occurrence data and IUCN range maps produced similar patterns of body mass—climate correlations. Main conclusions At the large spatial and taxonomic scale employed in this study, there does not seem to be any considerable differences in the average environmental data estimates derived from IUCN versus GBIF geographic range data. This result indicates that both sources of geographic range data could be used independently or in concert for macroecological inferences that involve summarizing species’ niches by a single estimate of the average of their used environments.

Beschreibung: Abstract Aim We use publicly available data to assess the influence of ocean basin, various biological traits and sea surface temperature on biogeographic range extent for temperate, continental shelf fish species spanning 141 families. Location Coastal waters of the temperate Northern Hemisphere. Taxon Teleost Fishes (Infraclass Teleostei). Methods We assess the relationship between species range extent and depth range, maximum body length, schooling behaviour and use of multiple habitats for 1,251 species of northern, temperate, continental shelf fishes in different basins (Atlantic vs. Pacific) and margins (east vs. west) using linear mixed‐effect models with family and genus as nested random effects. We further assess the relationship between species range endpoint distribution and latitudinal temperature gradient using generalized linear models. Results We found strong positive relationships between the number of species northern range endpoints and the steepness of the latitudinal sea surface temperature gradient on the western margins of the Atlantic and Pacific Oceans, but no relationship on the eastern margins of these ocean basins. The strongest predictors of range extent in our global model are ocean basin/margin and depth range. Maximum body length, schooling behaviour and use of multiple habitats are also significant predictors of range extent in the global model. The factors influencing range extent differ by basin and margin. Main conclusions There are broad differences in patterns of species range extent and distribution of species ranges among basins/margins. These differences appear to be driven in part by variation in latitudinal water temperature gradient between basin margins. Our data suggest that sharp latitudinal temperature gradients may pose a barrier to dispersal and range expansion along the western margins of the Atlantic and Pacific Oceans, but not necessarily on the eastern margins. Our work also suggests that several post‐settlement traits may be associated with range extent either globally or in some temperate basins.

Beschreibung: Abstract Aim Biogeographic barriers emerged in the tropical oceans as continental masses moved with plate tectonics, and as the tropics contracted to lower latitudes from the late Eocene. These barriers have shaped tropical marine biodiversity. We characterize large‐scale diversity patterns for tropical brittle stars and investigate the effect of biogeographic barriers on these in space and time. Location Shallow‐water (〈200 m) tropical oceans. Taxon Tropical shallow‐water brittle stars (class Ophiuroidea). Methods We integrate phylogenetic and biogeographic modelling to test and quantify the biogeographic structuring across the major ocean basins for five families of brittle stars. These are well‐sampled in our phylogenies (173 species) and represent an important component of the brittle star fauna of tropical shallow waters. We define major bioregions based on patterns of compositional and phylogenetic beta diversity. Results We find congruence between patterns of shared ancestry of regions and inferred biogeographic histories. Biogeographic reconstructions show that faunal patterns reflect the emergence of biogeographic barriers in the tropical world, with evidence of vicariant events driven by the opening of the Atlantic Ocean, the narrowing of the Tethyan Seaway and the rise of the Isthmus of Panama. Main conclusions Biogeographic barriers almost completely isolated regional faunas. However, divergence age estimates predate the onset of the different barriers, suggesting that changes associated with the gradual emergence of the barriers had a strong effect on the evolutionary history of tropical shallow‐water brittle stars. Limited, very recent, bi‐directional dispersal was detected across the East Pacific Barrier, which is otherwise an important barrier for dispersal of brittle stars.

Beschreibung: Abstract Aim The expansion of open habitats during the mid‐Miocene has been hypothesized as a driver of allopatric speciation for many African taxa. This habitat‐dependent mode of diversification has been implicated in the shift from C3 (e.g. forest/woodland) to C4 dominated systems (i.e. open savanna, grasslands) in a number of African squamates. We examined this hypothesis using a genus of African viperid snakes (Bitis) with both open habitat and forest‐dwelling representatives. Location Africa. Methods A comprehensive multilocus dataset was used to generate a calibrated species tree using a multispecies coalescent model. Individual gene trees and patterns of nuclear allele sharing were used to assess species monophyly and isolation. To test the habitat‐dependent evolution hypothesis, we generated an ancestral character state reconstruction for open and closed habitats using the dated phylogeny. This was related to the timing of open habitat expansion and forest/woodland contraction in Africa. Results The genus Bitis originated in the Oligocene, with species level diversification in the late Miocene/Pliocene. Four well‐supported clades correspond to the recognized subgenera Bitis, Keniabitis, Macrocerastes and Calechidna. Several previously unrecognized lineages potentially represent cryptic species. Main conclusions Habitat‐dependent evolution does not appear to have been a main driver for generic level viperine diversification: the ancestral state for Bitis was open habitat and at least one clade moved into forest in the Miocene, long after forest had contracted and fragmented. Forest‐dependent species diversified only in the late Miocene, presumably as forest became further reduced in extent, fitting an allopatric model of speciation. Although our results do not favour a general pattern of habitat‐dependent diversification in Bitis, cladogenesis within the subgenus Calechidna for “arenicolous” species (Bitis caudalis complex) and “rupicolous” species (B. atropos‐cornuta complex), corresponds to the aridification of southwest Africa. This suggests there are subtleties not captured in the broad open habitat category, which are relevant for understanding the role of habitat‐dependent evolution.

Beschreibung: Abstract Aim Elevated biodiversity is the result of the cradle, museum or sink functions. The contributions of these three functions to species accumulation and their changes through time remain unknown for glacial refugia. Additionally, our understanding of the role these functions played during pre‐glacial periods is limited. We test for changes in contributions of functions through time leading to the current diversity patterns using a model refugium and taxon. Location Anatolia, Western Palaearctic. Taxon Freshwater neritid snails (genus Theodoxus). Methods Assessments were made to define molecular operational taxonomic units (MOTUs) for Theodoxus and reaffirm the genus as a suitable model taxon with elevated interspecific diversity in noted glacial refugia. Thereafter, we constructed a time‐calibrated multilocus Bayesian phylogeny of mtDNA and nDNA by using both fossil data and published substitution rates. Ancestral area estimation was performed on the phylogeny to define the contribution of the functions through time. Results Accumulation of Theodoxus diversity in Anatolia over the Miocene–Pliocene transition is attributed to the museum function, but its contribution was small as only few divergence events occurred. The cradle function dominated during the Pliocene and Early Pleistocene, when most interspecific diversity built up and extant lineages in Anatolia were established. The sink function acted from the Middle Pleistocene to present‐day, but with only a small contribution to the total extant Anatolian interspecific diversity. Main conclusion Our results do not entirely mitigate the role glacial cycles played in species accumulation, but highlight Ice Ages may have been less effective in forcing temperate aquatic interspecific diversity into more opportune areas. The elevated diversity in refugia may rather be the result of earlier in situ diversification. Elevated interspecific diversity attributed to the legacy of glacially forced retreats may need to be re‐evaluated in cases where refugia have long and complex geological histories such as Anatolia. These results highlight the importance of considering species accumulation through a temporal perspective to adequately explain present‐day biodiversity patterns.

Beschreibung: Abstract Aim The taxon cycle concept provides a geographically explicit and testable set of hypotheses for exploring the evolutionary processes underlying the distribution of species in space and time. Here, we test taxon cycle predictions within a large avian island radiation, the core Campephagidae and explicitly integrate the concepts of ‘supertramps’, ‘great speciators’ and relictualization. Location The Indo‐Pacific, Australia, Asia and Africa. Taxon Corvoid passerine birds. Methods We constructed a new time‐calibrated molecular phylogeny of the core Campephagidae (cuckooshrikes, cicadabirds and trillers) using Bayesian phylogenetic methods. Ancestral range estimation methods and diversification rate analyses were used to explore the dispersal and diversification history of the group. We used an extensive dataset on wing morphology and range distributions to test for correlations between evolutionary age of species and dispersal capacity, diversification and distribution, while accounting for phylogenetic non‐independence. Results The core Campephagidae represents an ecologically homogeneous radiation distributed across the Indo‐Pacific, Australia, Southeast Asia and Africa. Its members represent a continuum of dispersal abilities; some species are widespread and undifferentiated (‘supertramps’) or show strong differentiation of local populations (‘great speciators’), and a few are endemic to single islands (relicts). We show that older species relative to younger species inhabit fewer and larger islands at higher elevations. The level of intraspecific variation measured as the number of subspecies also decreases with species age, and is highest in ‘great speciators’ with intermediate levels of dispersal abilities (as per hand‐wing index). Main conclusions Based on trait correlations with species age, we infer phases of range expansion and contraction over millions of years (taxon cycles), within a single monophyletic group of birds. These observations demonstrate reconciliation of the concepts of ‘supertramps’, ‘great speciators’ and relictual palaeoendemics within the temporal stages of the taxon cycle.

Beschreibung: Abstract Aim To investigate how changing grid size can alter model predictions of the distribution of mesophotic taxa and how it affects different modelling methods. Location Ningaloo Marine Park, Western Australia. Taxon Benthic mesophotic taxa: corals, macroalgae and sponges. Methods We determined the distributions of the major benthic taxonomic groups: corals, macroalgae and sponges, using a number of modelling techniques and an ensemble using the ‘sdm’ R package. A range of grid sizes were used (10, 50, 100 and 250 m) to identify how model predictions were altered. Models were evaluated using the area under the curve of a receiver operator characteristic plot (AUC) and the true skill statistic (TSS) using a spatially independent dataset. Results Grid size had a large effect on model performance across the taxonomic groups. Model outputs were compared to null surfaces and 88.8% of models performed significantly better than null. Distribution of corals was best predicted using the finest grid size (10 m) regardless of modelling method, although a model ensemble produced the best results (AUC = 0.80, TSS = 0.52). Macroalgae and sponges were better predicted at coaster grids sizes (250 m). Again, ensembles performed well for both macroalgae (AUC = 0.83, TSS = 0.63) and sponges (AUC = 0.88, TSS = 0.66). Model ensembles maintained high accuracy across grid sizes and were consistently the best, or second‐best, performing method. Main conclusions This study has shown how grid size should be considered when producing distribution models. Identifying the most relevant grid size and being aware of the influence it may have will provide more accurate predictions of the distributions of taxa. Ensemble methods maintained good performance across scenarios and thus provide a useful tool for conservation and management especially where single modelling methods showed high levels of variability.

Beschreibung: Abstract Aim Distribution‐wide trends in climate variability significantly influence the genetic diversity, differentiation and population structure of tree species. This study investigates the effects of disturbances such as fire, fragmentation and climate on modern‐day genetic patterns and clonal structures of trembling aspen at the transcontinental scale. Location North American boreal zone. Taxon Trembling aspen (Populus tremuloides Michx.). Methods One thousand two hundred individuals in a 30‐site network (40 trees per location) were genotyped with neutral genetic markers and studied in relation to regional differences in climate and surrounding site conditions (aridity, fire cycle, fragmentation). Multiple linear regression models and variance analysis were used to test relationships between genetic indices, structural parameters and the surrounding site factors. Results Overall, a high percentage of single ramet clones (SRC) and clonal diversity was detected and assumed to be the consequence of multiple sexual reproduction events that took place at all sites, together with suckering, which shapes the clonal structure of populations. Neutral genetic diversity and clonal structure suggested no substantial differences among sites, which were categorized into climate moisture index (CMI) classes; aspen stands across Canada were highly similar from a genetic point of view. Allelic richness (AR) and the average number of alleles (Na) varied significantly among clonal organization groups, and landscape fragmentation and a higher frequency of fires showed a negative influence on the levels of genetic diversity. Main conclusions Our results are inconsistent with the idea that the genotypic diversity of trembling aspen is related to the intensity of disturbance within the boreal forest. It appears that species‐specific disturbance responses and post‐fire recruitment mechanisms are more important than dominant ecological factors, such as climate and fire regimes, in shaping distribution‐wide patterns of neutral genetic variation and clonal structure.

Beschreibung: Journal of Biogeography, Volume 46, Issue 6, Page i-iv, June 2019.

Beschreibung: Abstract Aim Riparian ecosystems are regarded as vulnerable to the effects of climate change. Because of their reliance on passive dispersal to migrate from areas where conditions have become unfavourable, plants are particularly susceptible. On dryland river floodplains, the species diversity of herbaceous annuals is often high while that of structurally dominant woody perennials is low. We examined gene flow genetic structure and dispersal in Acacia stenophylla, a small perennial tree widely distributed throughout river systems of inland Australia. The role of the river corridor in shaping patterns of gene flow and genetic structure is also investigated. Location Murray‐Darling Basin, south eastern Australia Methods A total of 127 individuals, from 12 subpopulations located on seven rivers were genotyped at 13 microsatellite loci. Several population and landscape genetic tools were applied to the microsatellite data to evaluate spatial patterns of gene flow and genetic structure and make inferences regarding possible modes of dispersal. Results High gene flow and weak genetic structure was identified for the 12 subpopulations of A. stenophylla sampled, a surprising result given large distances between subpopulations. Pairwise genetic distance between subpopulations was low to moderate and could largely be explained (R2 = 0.68) by two variables: distance along the river and the proportion of no flow days. structure analysis revealed two genetic clusters. Subpopulations located on the Darling and Lower Balonne rivers were dominated by cluster one while subpopulations from the Warrego and Paroo rivers showed largely mixed ancestry with individuals descending from both clusters one and two. Main Conclusions These results indicate that the river corridor facilitates extensive gene flow between subpopulations of A. stenophylla in this system. Hydrochory appears to be the dominant process; however, upstream movements of propagules most probably via animal movement are sufficient to negate effects expected under unidirectional dispersal.

Beschreibung: Abstract Aim Vicariance events have been proposed as a major source of lineage divergence on continental islands, whereas dispersal events followed by isolation have been proposed as the major cause on oceanic islands. However, organisms on continental islands may include taxa with characteristics similar to those on oceanic islands. Lineage divergence unassociated with the geological events that separated islands may also have occurred. This study addresses these possibilities through morphological and molecular phylogeographic analyses of land snails (Bradybaena) on continental islands. Location Samples were mainly collected on the Ryukyu and Izu Islands in Japan. Methods Molecular phylogenetic analyses using mtDNA (16S rRNA+COI) and nDNA (18S rRNA+ITS1+5.8S rRNA+ITS2+28S rRNA) were conducted for 225 individuals comprising B. circulus, B. phaeogramma and four of its subspecies endemic to the Ryukyu Islands. Shell and genital morphologies were also examined using qualitative and statistical methods. Results The Bradybaena populations examined were phylogenetically classified into six major clades whose divergence occurred during either Miocene‐Pliocene or Pliocene‐Pleistocene. Although phylogeographic patterns estimated on the basis of the 16S rRNA gene support the vicariance hypothesis for the origin of the major clades of Bradybaena, the phylogeographic patterns estimated by COI showed that these major clades resulted from diversification before the archipelagos separated from the continent. Both of these phylogeographic patterns suggest that genetic divergence occurred by dispersal from the southern to northern islands after divergence of major clades. The inferred phylogenies document parallel morphological evolution, yielding phylogenetic, morphological and taxonomic incongruences that created mosaic geographical patterns in the distribution of nominal taxa. Main conclusions Lineage diversification in endemic species on continental islands can occur before archipelago separation or subsequently via dispersal, as is seen in species on oceanic islands. Mechanisms other than vicariance should also be considered when estimating processes that created geographical patterns of genetic variations on continental islands.

Beschreibung: Abstract Aim We investigate the Plio‐Pleistocene evolutionary history of one of the most abundant rodents in Afrotropical forests. Specifically, we ask how their diversification was influenced by climate change, topography and major rivers. Location Tropical Africa: Lower Guinea (including Cameroon volcanic line; CVL), Congolia, Albertine Rift (AR), Kenyan highlands (KH). Taxon Murine rodents of the Praomys jacksoni complex. Methods We used 849 genotyped individuals to describe the overall diversity and spatial genetic structure across a majority of their known distribution area. The combination of one mitochondrial and three nuclear markers was used to infer dated phylogenies using Bayesian and maximum likelihood approaches. Genetic structure was further assessed by multispecies coalescent species delimitation. Current and past distributions of particular taxa were predicted using environmental niche modelling. Results The complex is composed of five major genetic clades (proposed species). Two of them are restricted to specific habitat types (either montane forests of AR or wetlands in lowland forests along the Congo River), three others have wide geographic distributions and lower levels of ecological specialization. The earliest divergence is dated to the Plio‐Pleistocene boundary and is in accordance with the separation of AR forests and Guineo‐Congolian forests. Further diversification of the complex is associated with Pleistocene climate changes. Relatively stable refugia of suitable climatic conditions were identified in lowland Congolia (for two species currently distributed only in lowland forests) as well as in montane forests of CVL, AR, KH (playing the role of reservoirs of diversity). Large rivers, especially the Congo River, are important barriers to gene flow for most taxa, but probably were not the primary cause of differentiation. Main conclusions The evolutionary history of the complex was primarily affected by Pleistocene climate changes and diversification in forest refugia. There is little support for ecological parapatric speciation or the riverine barrier hypothesis.

Beschreibung: Abstract Aims Rising temperature and declining summer precipitation due to the 1970s‐climate shift in southern South America have reduced forest productivity at dry sites. Here, we worked with the most widespread Southern Hemisphere tree line species, Nothofagus pumilio, across contrasting climatic conditions and determined whether rising atmospheric CO2 concentrations as well as warmer and drier climatic conditions provoked by the 70s‐climatic shift have been causing systematic changes in tree line growth rates and intrinsic water‐use efficiency (iWUE). Location 36–54°S, southern Andes. Time period 1950–2010. Major taxa studied Nothofagus pumilio. Methods We worked at five disparate climatic tree line locations, spanning 18 degrees of latitude; at each location, we sampled trees at four different elevations, including tree line elevation. We quantified the variation in annual tree‐ring width (TRW) as a function of climate, elevation, tree age, size, annual CO2 concentrations and location, using linear mixed‐effects models and interpreted TRW trends in relation to iWUE and isotope (δ13C and δ18O) signalling. Results Across locations, the patterns of tree line growth occurring in the 1980–2010 period exhibited a clear and significant negative trend, in contrast to the previous 1950–1980 period. We found an increase in iWUE and δ18O across time and locations. Given that an increase in δ18O indicates a decrease in stomatal conductance, we assert that drought‐induced stomatal closure appears to be causing the reduction in growth. Main conclusions We show unequivocal evidence that warmer and drier summer conditions translated into a decrease in growth rates along the elevational tree line of the southern Andes, reverting previous growth improvements linked to climate warming. An improvement in iWUE at all locations is most likely explained by decreased stomatal conductance given the rising δ18O signal. An iWUE–growth decoupling may act as an ecological strategy to respond to drought.

Beschreibung: Abstract Aim The relationship size–environment has been continuously debated for ectotherms. Surface‐to‐volume ratios are recurrently suggested as the cause of body size responses to climate, but most inferences on organismal size clines stem from single linear measurements of body length. Here, we illustrate how new photogrammetric techniques can be applied to characterize amphibian morphologies with 3D models. Using the natterjack toad (Epidalea calamita) as model organism, we compared the performance of climatic models in accounting for body size (measured as snout‐to vent length, SVL) and body geometry (surface area‐to‐volume ratios) variation across macroclimatic gradients. Location Palaearctic. Taxon Epidalea calamita (former genus Bufo). Methods We used photogrammetry techniques to reconstruct 104 museum specimens of Epidalea calamita into 3D models and to collect geometric data (volume and surface area) to calculate surface area‐to‐volume ratios (SA:V). We then apply spatial and non‐spatial regression to examine the relationships between SA:V, SVL and a set of bioclimatic variables. Results In accordance with the water conservation hypothesis, SA:V decreased towards more arid environments, a pattern that remained consistent after accounting for spatial autocorrelation effects. Only mean annual temperature was significant correlated with SVL. The contrast between both sets of models indicates that more traditional body size metrics (SVL) and body geometry (SA:V) do not operate the same constraints. Main conclusions We show that the variation in SA:V can be explained by the geographical variation in aridity. Evaporative water loss in wet‐skinned ectotherms is highly dependent on the surface area of the skin exposed to the air. In contrast, SVL models detected that body length was more associated with mean annual temperature. This finding stresses the importance of selecting different metrics of body geometry and body size when examining variation across climatic gradients.

Beschreibung: Abstract Aim We analysed elevational and microclimatic drivers of thermal tolerance diversity in a tropical mountain frog clade to test three macrophysiological predictions: less spatial variation in upper than lower thermal limits (Bretts’ heat‐invariant hypothesis); narrower thermal tolerance ranges in habitats with less variation in temperature (Janzen's climatic variability hypothesis); and higher level of heat impacts at lower elevations. Location Forest and open habitats through a 4,230‐m elevational gradient across the tropical Andes of Ecuador. Method We examined variability in critical thermal limits (CTmax and CTmin) and thermal breadth (TB; CTmax–CTmin) in 21 species of Pristimantis frogs. Additionally, we monitored maximum and minimum temperatures at the local scale (tmax, tmin) and estimated vulnerability to acute thermal stress from heat (CTmax–tmax) and cold (tmin–CTmin), by partitioning thermal diversity into elevational and microclimatic variation. Results Our results were consistent with Brett's hypothesis: elevation promotes more variation in CTmin and tmin than in CTmax and tmax. Frogs inhabiting thermally variable open habitats have higher CTmax and tmax and greater TBs than species restricted to forest habitats, which show less climatic overlap across the elevational gradient (Janzen's hypothesis). Vulnerability to heat stress was higher in open than forest habitats and did not vary with elevation. Main conclusions We suggest a mechanistic explanation of thermal tolerance diversity in elevational gradients by including microclimatic thermal variation. We propose that the unfeasibility to buffer minimum temperatures locally may explain the rapid increase in cold tolerance (lower CTmin) with elevation. In contrast, the relative invariability in heat tolerance (CTmax) with elevation may revolve around the organisms’ habitat selection of open‐ and canopy‐buffered habitats. Secondly, on the basis of microclimatic estimates, lowland and upland species may be equally vulnerable to temperature increase, which is contrary to the pattern inferred from regional interpolated climate estimators.

Beschreibung: Abstract Aim Mutualisms are often disrupted for plants introduced to new ranges, yet many of these plants have managed to obtain effective mutualistic associations in their new ranges. There are two potential pathways for non‐native plants to reassemble mutualisms: cointroduction (i.e. familiar associations with cointroduced mutualists) or ecological fitting (i.e. forming or adapting novel associations with resident native mutualists). We assessed the importance of each pathway for mutualist reassembly in four Australian Acacia species (A. baileyana, A. dealbata, A. decurrens and A. melanoxylon) and their associated nitrogen‐fixing rhizobial symbionts in two non‐native locations. Location Native ranges of acacias in south‐eastern Australia and two non‐native ranges in New Zealand and South Africa. Methods Rhizobia associated with each acacia species in each country were isolated and identified based on DNA sequencing of the housekeeping recA gene and the symbiotic nodA gene. Separate phylogenies were reconstructed for each gene region to infer biogeographic histories of acacia‐associated rhizobia. Selected rhizobial strains for each acacia species by country combination were used as inocula in a glasshouse experiment and early growth kinetics and nitrogen fixation efficiency of acacia seedlings were compared between inoculum treatments to determine symbiotic effectiveness. Results All isolated rhizobial strains belonged to the genus Bradyrhizobium. Phylogenetic analyses revealed almost no country‐ or species‐specific clusters of these strains for either gene region and indicated that most acacia‐associated bradyrhizobia in New Zealand and South Africa were cointroduced from Australia. These results were supported by little variation in the growth performances of acacia seedlings, irrespective of inoculum treatment. Main conclusions This study revealed that cointroduction of Australian acacias and their rhizobia may be more prevalent than previously thought. Additionally, a single rhizobium cointroduction event may be sufficient to facilitate the establishment of effective mutualisms in numerous Acacia species, potentially leading to an invasion meltdown.

Beschreibung: Abstract Aim Research on plant–herbivore interactions has shown that islands typically have low abundances and diversity of herbivores because of barriers to dispersal, isolation and reduced land area. Islands commonly have lower levels of herbivory relative to mainland regions, and, as a consequence, insular plants should exhibit lower levels of defences than their mainland counterparts. Despite these predictions, there are significant gaps in our understanding of insularity effects on plant–herbivore interactions. For instance, most work addressing the effects of insularity on plant–herbivore interactions have compared one or a few islands with a single mainland site. In addition, studies have measured herbivory or plant defences but not both, and the influence of abiotic factors has been neglected. Location Mediterranean Basin (from Spain to Greece). Taxon Quercus ilex L. Methods We conducted a large‐scale study to investigate whether insect leaf herbivory and plant chemical defences in holm oak (Quercus ilex L.) differ between insular versus mainland populations. We further investigated mechanisms by which insularity effects on herbivory may take place by assessing the influence of defences and climatic variables on herbivory. Results We found that insular populations exhibited lower herbivory and higher defences (condensed tannins) than their mainland counterparts. Our analyses, however, suggest that these concomitant patterns of insect herbivory and plant defences were seemingly unrelated as island versus mainland differences in defences did not account for the observed pattern in herbivory. Furthermore, climatic factors did not explain insularity effects on either herbivory or plant defences. Main conclusions Overall, this study provides one of the most robust assessments to date on insularity effects on herbivory and builds towards a better understanding of the ecology and evolution of plant–insect interactions in insular ecosystems.

Beschreibung: Abstract Aim Abiotic factors such as global temperature or continental fragmentation may favour speciation through the ecological and geographical isolation of lineages, but macroevolutionary quantifications of such effect with both fossil and phylogenetic data are rarely performed. Here, we propose to use biogeographical estimations and palaeo‐environmental diversification models to estimate whether and how palaeotemperature and the sequential break‐ups of Pangaea, Gondwana and Laurasia have affected the diversification of amphibians through time. Location Global. Methods Using a time‐calibrated phylogeny for 3,309 amphibian species and a genus‐level fossil record, we estimated the diversification rates of the group with birth–death models allowing rates to depend on the temporal variations of the environment. We used estimates of global palaeotemperature and an index of continental fragmentation through time to test the association between speciation and/or extinction rates and past temperature and fragmentation. We also estimated the biogeographical history based on a time‐stratified parametric model informed by the global palaeogeography. We inferred whether vicariance or dispersal events explained the ancient and current geographical distribution of amphibians. Results The diversification analyses on the whole amphibians showed that temperature‐dependent models are better supported than tectonic‐dependent, time‐dependent and constant‐rate models for both the fossil and phylogenetic data. The best‐fitting temperature‐dependent model indicated a positive dependence of both speciation and extinction rates with the temperature through time. Biogeographical analyses indicated a Pangaean origin for amphibians and also showed that allopatric speciation (vicariance) explained important phases of the evolution of geographical ranges in the Mesozoic. Main conclusions Our results support that palaeotemperatures have positively impacted amphibian diversification. Our study provides additional insights into how to quantify the effect of the landmass fragmentation on the diversification processes and shows with biogeographical reconstruction that continental fragmentation is linked to allopatric speciation in the early history of the clade.

Beschreibung: Abstract Aim Previous studies primarily based on the culture method have revealed that caves host a high fungal diversity and that exogenous carbon sources influence fungal communities. Here, we assess the fungal diversity and distribution patterns in karst caves in Southwest China and reveal the major factors that shape the fungal communities. Location Southwest China. Methods Samples of air, rock, sediment and water were collected from eight caves in Southwest China. Using high‐throughput sequencing of the internal transcribed spacer 1 region of fungal rDNA, we examined the cave fungal communities in Southwest China and studied their correlations with potentially influential factors, such as substrate, cave, location and environmental variables. Results Approximately 10,000 fungal operational taxonomic units (OTUs) spanning 15 phyla were obtained. The highest diversity genus was Penicillium, while Mortierella had the highest relative abundance. Compared with air and rock samples, sediment and water samples harboured higher diversity and distinct communities. Substrate and cave were revealed to be the key determinants of the fungal communities in caves. Sample location and sampling distance from the entrance had more significant impacts on rock and sediment communities than on air and water assemblages. The fungal assemblages in air and water samples from the cave and outside cave environments were similar, while those of rock and sediment samples were significantly different. Main conclusions Our results indicate that sediment and water harboured higher fungal diversity than air and rock, and substrate and spatial variables are key determinants of fungal communities in caves.

Beschreibung: Abstract Aim To analyse the diversity and distribution of oceanic pelagic cephalopods along the eastern Pacific Ocean assessing the existence of biogeographic structuring, and the role of physical variables in generating geographical patterns. We hypothesized that the control by environmental factors, and the effect of geometric constraints, determine the range size and limits of distribution of oceanic cephalopods along the eastern Pacific Ocean, generating a latitudinal gradient in species richness. Location Eastern Pacific Ocean (60°N – 60°S), from the Gulf of Alaska to the Southern Ocean. Methods Based on a literature review and 〉5,000 records obtained from collections, we constructed a presence–absence matrix including 61 latitudinal bands (2° each) along the Eastern Pacific, and estimated species richness and range endpoints at each band. Biogeographic units were determined by means of multivariate analyses. Species richness was compared with null model predictions in order to test for the existence of geometric constraints using the Mid‐Domain Null model. The effects on species richness of environmental variables (temperature, salinity and oxygen) were evaluated separately for surface and depth (0–1,000 m) data, by means of ordinary least squares regression and simultaneous autoregressive models. Rapoport's pattern was assessed by applying the Stevens’ method and the range midpoint method. Results Species richness was high across the tropics and decreased towards the both poles. We identified five biogeographic units, highlighting two major distribution breaks at 40°N and 42°S. Species richness was strongly related with environmental variables, although the combined variables accounted for a large fraction of the variance between 0 and 1,000 m (R2 = 0.99), while temperature was the best single predictor at the surface (R2 = 0.98). Species richness curves showed a mid‐domain effect (MDE), and the mean latitudinal range was higher in the tropics and at warm latitudes, generating an inverse Rapoport's pattern. Main conclusions Along the eastern Pacific Ocean oceanic cephalopods exhibit both a clear biogeographic patterning and an interhemispheric (poleward decreasing) diversity gradient, which appear strongly related with physical factors and external forcing, as well as with a MDE as a seemingly consequence of the naturally bounded domain of the Eastern Pacific.

Beschreibung: Abstract Aim To discover how biological traits, ecological preferences and taxonomic relatedness are associated with occupancy and abundance of diatom species across lakes and streams. Location Finland. Taxon Diatoms. Methods We studied 288 diatom species from 492 stream sites and 230 diatom species from 290 lake sites. For each species, we calculated logit‐transformed regional occupancy and log‐transformed mean local abundance, and further determined biological traits, ecological preferences and taxonomic levels for each species. Boosted regression tree (BRT) analysis was used to reveal the linear and nonlinear associations of biological, ecological and taxonomic predictors with occupancy or abundance of lake and stream diatoms. Results There were strong and positive interspecific occupancy–abundance relationships across both lakes and streams. The BRT models explained more deviances in variation in occupancy and abundance and their relationship for lakes than streams. Biological traits, especially cell size, but also life‐form and guild, were the strongest predictors of diatom occupancy and abundance in lakes and streams when controlling for ecological preferences and taxonomic relatedness. Main conclusions In general, biological traits were the strongest predictors of occupancy and abundance in both freshwater systems. Species with similar biological traits thus tended to show similar occupancies and abundances. As indicated by lower explained deviances, occupancy and abundance in streams seemed to be more complexly structured than in lakes, suggesting that these two freshwater system types differ in the formation of biodiversity patterns. This difference may be related to the differences in hydrological connectedness between lakes and streams. Understanding how variations in species’ occupancy and abundance are formed across various waterbodies is important for meaningful biodiversity conservation.

Beschreibung: Abstract Aim Ecological niche modelling requires robust estimation of model performance and significance, but common evaluation approaches often yield biased estimates. Null models provide a solution but are rarely used in this field. We implemented an important modification to existing null model tests, evaluating null models with the same withheld records that were used to evaluate the real model. We built and evaluated models across a range of modelling scenarios and for various performance measures using the algorithm Maxent and the monk parakeet (Myiopsitta monachus). Location Native range in Southern America and global invasions predominantly in North/Central America and Europe. Methods We tested the ability of models built under 15 scenarios (five sets of calibration records and three settings that varied the level of model complexity) to predict spatially independent evaluation data in the invaded range (in effect, testing the models under spatial transfer). We quantified performance with measures of discriminatory ability and overfitting based on area under the receiver operating characteristic curve (AUC) and the omission error rate. We estimated null distributions of these measures and calculated effect size and significance. We determined how these estimates varied across modelling scenarios, comparing with two tests existing in the literature. Results Performance varied starkly across modelling scenarios. As expected, the measures of overfitting agreed with each other and provided different information than that of discriminatory ability. However, high performance per se did not show strong association with high effect size and significance. Main Conclusions Ecological niche models should be assessed with measures of effect size and significance based on appropriate null distributions, in contrast to several approaches existing in the literature. The proposed approach using independent evaluation data, implemented with our accompanying code and R package, allows such estimates for either the same or a different region/time period, and it merits use and continued development.

Beschreibung: Abstract Aim According to palaeo‐biome reconstructions, the subtropical evergreen broadleaved forests (EBLF) in East Asia contracted to a narrow belt south of 24° N during the Last Glacial Maximum (LGM). Yet numerous phylogeographical studies of EBLF plants have inferred glacial refugia north of this area. Here, we aim to further elucidate the Quaternary dynamics of EBLFs using the widespread shrub Lindera aggregata as model. Location Subtropical China. Taxon Lindera aggregata (Sims) Kosterm (angiosperms). Methods Four chloroplast DNA (cpDNA) fragments and 15 low‐copy nuclear genes (LCGs) were sequenced in 19 populations. The time to the most recent common ancestor (TMRCA) was estimated using secondary calibrations. Bayesian algorithms were used to infer population clustering, phylogeny and divergence time. Historical gene flow was estimated using a maximum‐likelihood algorithm. Potential habitats at present and during the LGM were predicted using ecological niche modelling. Results The TMRCA estimate was 1.78 Myr. We observed a shallow cpDNA network organized around one dominant haplotype. The LCGs revealed three distinct genetic clusters that reflected contrasting historical population dynamics. The most ancient cluster was located south of the Nanling and Wuyi Mountains and indicated long‐term population persistence in multiple refugia. The area further north was occupied by two disjunct clusters that dated back to the LGM and showed signatures of a rapid northward expansion from two refugia. We detected noteworthy pollen‐mediated secondary admixture between all three clusters including somewhat preferential southward gene flow. Main conclusions Lindera aggregata represents a rare example of extensive post‐glacial range expansion across the EBLF biome (expansion‐contraction model) that contrasts with its generalized long‐term population stability in the southernmost range parts. Our findings also provide rare evidence for noteworthy post‐glacial gene flow into long‐term refugial populations. They correspond relatively well with palaeo‐biome reconstructions and support the hypothesis that the EBLF has undergone extensive post‐glacial community reshuffling.

Beschreibung: Abstract Aim Climate is an important factor controlling plant distributions. However, it is not yet fully understood how climate interacts with human impacts or whether the effects of these factors differ between native and alien species. Facing ongoing climate change and urbanization, we explore the effects of climate on plant species richness and composition across European cities. Location Sixty cities in Western, Central and Southern Europe. Taxon Vascular plants. Methods Species presence was recorded in seven habitats in each city. Large‐scale climatic gradients were derived from 22 climatic variables using a partial principal component analysis that controlled for the effects of human population size and gross domestic product. The effects of climate and habitat type on the numbers of native and alien species were tested using linear mixed‐effect models. The native and alien compositional variation across cities and habitats was analysed using principal component analysis with variation partitioning. Results The Mediterranean‐to‐temperate climatic gradient had a significant effect on species numbers across all habitats. The numbers of both native and alien species increased from the Mediterranean to temperate Europe. Within each city, the proportion of alien species decreased from highly urbanized to less urbanized habitats. Climate had a stronger effect on the composition of alien plants than on the composition of native plants. The native species composition especially changed from the Mediterranean to temperate cities and alien species composition also from oceanic to continental cities. Main conclusions Urban native and alien species richness follow the pattern found for the whole European flora. Based on this observation, we suggest that the future shift of warm and dry conditions from the Mediterranean to the north that is expected under global change scenarios could affect richness and change the composition of European urban floras. However, this shift would not necessarily alter the proportions of aliens.

Beschreibung: Abstract Since von Humboldt, recognizing and using elevational subdivisions is at the core of biogeographical and ecological studies in mountain ecosystems. However, despite the large use of vegetational belts, their conceptual definition and practical identification appear to be surprisingly loose and inconsistent. Many authors use variations in climatic conditions to identify elevational belts. These belts are useful to set a framework for ecological studies but cannot be considered a surrogate of vegetational belts, because factors different from climate play a major role in determining the distribution of plant assemblages. Vegetation physiognomy can be used to identify ‘biome‐type’ belts that are useful for comparisons across geographical areas with different floras. However, to properly reflect ecological conditions at local scale, vegetational belts should be based on species composition. One of the most effective statistical approaches for this purpose is the use spatially constrained cluster analysis. The use of indicator species analysis may be also recommended to identify the species that most characterize vegetational belts. This can help researchers to identify belts in the field. Since species identification can be difficult, some authors use plant functional types for belt delimitation. Plant functional types can be helpful to trace the adaptative responses of vegetation along elevational gradients, but cannot be recommended as a standard way to identify belts. In general, criteria to identify vegetational belts can be based on both vegetation structure (namely physiognomy and structural parameters) and/or species composition, depending on the scale and the aim of the analyses, and they should be clearly stated.

Beschreibung: Abstract Aims Understanding how biodiversity emerges and how it varies in space and time requires integration of the underlying processes that affect biodiversity at different levels of ecological organization. We present BioGEEM (BioGeographical Eco‐Evolutionary Model), a spatially explicit model that integrates theories and processes understood to drive biodiversity dynamics. We investigated the necessary degree of mechanistic complexity by exploring simulation experiments to evaluate the relative roles of the underlying processes across spatio‐temporal scales and ecological levels (e.g. populations, species, communities). Location Hypothetical oceanic islands. Methods BioGEEM is stochastic and grid‐based, and it integrates ecological (metabolic constraints, demography, dispersal and competition), evolutionary (mutation and speciation) and environmental (geo‐climatic dynamics) processes. Plants on oceanic islands served as a model system. We ran the simulations both with all processes on and with selected processes switched off to assess the role of each process from the emergent patterns. Results The full model was able to generate patterns matching empirical evidence and theoretical expectations. Population sizes were largest on young islands, and species, particularly endemics, better filled their potential range on young and old islands due to limited area and reduced competition. Richness peaked at mid‐elevations. The proportion of endemics was highest in old, large and isolated environments within the islands. Species and trait richness showed unimodal temporal trends. Switching off selected processes led to several unrealistic patterns, including the evolution of super‐dominant species, extremely high richness and weakened spatial diversity gradients. Main conclusions The main predictions derived from BioGEEM are: Competition has cross‐scale effects on diversity. Hump‐shaped temporal dynamics can be obtained without speciation. Endemic species seem less susceptible to extinction than native non‐endemic species. Endemism reflects stronger geographical and environmental isolation. Finally, only the integration of all implemented processes generates realistic spatio‐temporal dynamics at population, species, community and assemblage levels.

Beschreibung: Abstract The discovery of new species of mammals in Europe is a rare event, but owing to recent progress in genetic methods used to survey current biodiversity, such discoveries have been accumulating during the last decades. The naming of these new taxa has important bearings in conservation, as this is the first step needed for them to be recognised by the scientific community but also legally. The naming of new animal species, however, needs to follow the strict rules of the International Code of Zoological Nomenclature in order to be available and to provide a stable basis for further taxonomic research. We report here a case where new names have been improperly proposed to designate distinctive lineages in the Natterer's bat species complex. As these new names do not follow several mandatory rules imposed by the Code, they are declared unavailable and are not to be used for further taxonomy studies.

Beschreibung: Abstract Aims Biotic interactions may be disrupted at the range boundary if the involved species are rare in the most distant sectors. This study assesses fruit tracking by seed‐dispersing birds wintering on the border of the Palaearctic, a region where many species become scarcer before reaching the limits of their distribution in the Sahara. As vagrancy improves fruit tracking, this study tests if vagrant birds track fruit resources better than non‐vagrant birds and if their tracking ability is reduced at the range edge. Location The Iberian Peninsula and the Maghreb. Methods Seed‐dispersing passerines (O. Passeriformes) were counted in 134 sampling sites along a 2000‐km‐long latitudinal belt. Relationships between bird numbers and latitude, temperature, shrub cover and fruit abundance were explored by multivariate analyses. In addition, the habitat matching rule was used to assess the ability of birds to track fruit changes along the latitudinal belt. Results Fruit abundance and temperature were the main drivers of the distribution of vagrant birds (all of them migratory species) while for non‐vagrant birds (most of them sedentary species) distribution was weakly correlated to the study variables. Vagrant birds tracked the spatial–temporal variations in fruit abundance but showed a reduced ability to fit numbers to fruit abundance changes in southern sectors. Main conclusions Vagrant are migratory birds responsible for large‐scale tracking of fruit outputs but seems to face some constraints on fruit tracking at the far edge of the Palaearctic. As the movements of these birds southwards are declining due to climate warming effects, these results suggest a future weakening of their role as seed dispersers in the most peripheral areas of the Palaearctic.

Beschreibung: Abstract Aim The aim of the study was to assess the diversity of algal symbionts of the family Symbiodiniaceae associated with the coral genus Porites in the Red Sea, and to test for host‐specificity and environmental variables driving biogeographical patterns of algal symbiont distribution. Location Saudi Arabian Red Sea. Taxon Endosymbiotic dinoflagellates of the family Symbiodiniaceae in association with the reef‐building coral genus Porites. Methods Eighty Porites coral specimens were collected along the Saudi Arabian Red Sea coast. Species boundaries were assessed morphologically and genetically (putative Control Region – mtCR; ITS region – ITS). Community composition of symbiotic dinoflagellates of the family Symbiodiniaceae was also assessed. Using the ITS2 marker with the SymPortal framework, Symbiodiniaceae data at the genus, majority ITS2 sequence and ITS2 type profile were used to assess symbiont diversity and distribution patterns. These were analysed in relation to coral host diversity, geographic location and environmental variables. Results Among the 80 Porites samples, 10 morphologies were identified. These corals were clustered into five lineages (clades I–V) by each of the markers independently. Clades I, II and III each comprised of a single Porites morphology, while clades IV and V contained up to five distinct morphologies. The diversity of Symbiodiniaceae associated with Porites was high and latitudinal differentiation was observed. In particular, a shift from a Cladocopium‐dominated to a Durusdinium‐dominated community was found along the north–south gradient. Symbiont diversity showed the patterns of geographic‐specific association at Symbiodiniaceae genus, majority ITS2 sequence and ITS2 type profile level. Specific associations with host genotypes (but not morphological species) were also recovered when considering Symbiodiniaceae majority ITS2 sequence and ITS2 type profiles. Main conclusions This study provides the first large‐scale molecular characterization of Symbiodiniaceae communities associated with Porites corals from the Saudi Arabian Red Sea. The use of intragenomic diversity data enabled the resolution of host‐symbiont specificity and biogeographical patterns of distribution, previously unachievable with the ITS2 marker alone. Finally, correlation among symbiont diversity and Red Sea environmental gradients was documented.