ALBERT

Description: Strong regional differences exist in how hot temperature extremes increase under global warming. Using an ensemble of coupled climate models, we examine the regional warming rates of hot extremes relative to annual average warming rates in the same regions. We identify hotspots of accelerated warming of model-simulated hot extremes in Europe, North America, South America and Southeast China. These hotspots indicate where the warm tail of a distribution of temperatures increases faster than the average and are robust across most CMIP5 models. Exploring the conditions on the specific day the hot extreme occurs demonstrates the hotspots are explained by changes in the surface energy fluxes consistent with drying soils. However, the model-simulated accelerated warming of hot extremes appears inconsistent with observations, except over Europe. The simulated acceleration of hot extremes may therefore be unreliable, a result that necessitates a re-evaluation of how climate models resolve the relevant terrestrial processes.

Description: Using complementary metrics to evaluate phylogenetic diversity can facilitate the delimitation of floristic units and conservation priority areas. In this study, we describe the spatial patterns of phylogenetic alpha and beta diversity, phylogenetic endemism, and evolutionary distinctiveness of the hyperdiverse Ecuador Amazon forests and define priority areas for conservation. We established a network of 62 one-hectare plots in terra firme forests of Ecuadorian Amazon. In these plots, we tagged, collected, and identified every single adult tree with dbh ≥10 cm. These data were combined with a regional community phylogenetic tree to calculate different phylogenetic diversity (PD) metrics in order to create spatial models. We used Loess regression to estimate the spatial variation of taxonomic and phylogenetic beta diversity as well as phylogenetic endemism and evolutionary distinctiveness. We found evidence for the definition of three floristic districts in the Ecuadorian Amazon, supported by both taxonomic and phylogenetic diversity data. Areas with high levels of phylogenetic endemism and evolutionary distinctiveness in Ecuadorian Amazon forests are unprotected. Furthermore, these areas are severely threatened by proposed plans of oil and mining extraction at large scales and should be prioritized in conservation planning for this region. Using complementary metrics to evaluate phylogenetic diversity can facilitate the delimitation of floristic units and conservation priority areas. In this study, we describe the spatial patterns of phylogenetic beta diversity, phylogenetic endemism, and evolutionary distinctiveness of the hyperdiverse Ecuador Amazon forests and define priority areas for conservation. We found evidence for the definition of three floristic districts in the Ecuadorian Amazon, supported by both taxonomic and phylogenetic diversity data. Areas with high levels of phylogenetic endemism and evolutionary distinctiveness in Ecuadorian Amazon forests are unprotected. Furthermore, these areas are severely threatened by proposed plans of oil and mining extraction at large scales and should be prioritized in conservation planning for this region.

Description: The influence of two El Niño types on the frequency of summer heatwave days in Australia is investigated using both observations and an atmospheric climate model. The two basic spatial variants of El Niño are the traditional warming in the eastern equatorial Pacific (EP), and the Modoki variant that has its largest warming in the central equatorial Pacific. While impacts of Modoki El Niño on Australian precipitation can be quite distinct from EP El Niño, the impact on heatwaves is still unknown. Using a set of ensemble simulations, we compare the influence of Modoki and EP sea surface temperature forcing on Australian heatwaves. We find that there is minimal difference between the impact of Modoki and EP El Niños on heatwaves over Australia, which implies that future studies on heatwave variability need not differentiate the two.

Description: With many sophisticated methods available for estimating migration, ecologists face the difficult decision of choosing for their specific line of work. Here we test and compare several methods, performing sanity and robustness tests, applying to large-scale data and discussing the results and interpretation. Five methods were selected to compare for their ability to estimate migration from spatially implicit and semi-explicit simulations based on three large-scale field datasets from South America (Guyana, Suriname, French Guiana and Ecuador). Space was incorporated semi-explicitly by a discrete probability mass function for local recruitment, migration from adjacent plots or from a metacommunity. Most methods were able to accurately estimate migration from spatially implicit simulations. For spatially semi-explicit simulations, estimation was shown to be the additive effect of migration from adjacent plots and the metacommunity. It was only accurate when migration from the metacommunity outweighed that of adjacent plots, discrimination, however, proved to be impossible. We show that migration should be considered more an approximation of the resemblance between communities and the summed regional species pool. Application of migration estimates to simulate field datasets did show reasonably good fits and indicated consistent differences between sets in comparison with earlier studies. We conclude that estimates of migration using these methods are more an approximation of the homogenization among local communities over time rather than a direct measurement of migration and hence have a direct relationship with beta diversity. As betadiversity is the result of many (non)-neutral processes, we have to admit that migration as estimated in a spatial explicit world encompasses not only direct migration but is an ecological aggregate of these processes. The parameter m of neutral models then appears more as an emerging property revealed by neutral theory instead of being an effective mechanistic parameter and spatially implicit models should be rejected as an approximation of forest dynamics. Given joint migration probability with either migration predominantly coming from the metacommunity (left) or from adjacent plots (right) plotted against the estimated joint migration by both the Inference method (blue) and Gst statistic (red). Broken lines indicate the estimation plus or minus the standard deviation of the average over all plots used in the simulation. It is clear that when migration mostly comes from the metacommunity, both estimation methods are very accurate, and when migration from adjacent plots is dominant, both estimation methods are underestimations.

Description: Irrigation is known to influence regional climate but most studies forecast and simulate irrigation with offline (i.e. land only) models. Using south eastern Australia as a test bed, we demonstrate that irrigation demand is fundamentally different between land only and land–atmosphere simulations. While irrigation only has a small impact on maximum temperature, the semi-arid environment experiences near surface moistening in coupled simulations over the irrigated regions, a feedback that is prevented in offline simulations. In land only simulations that neglect the local feedbacks, the simulated irrigation demand is 25% higher and the standard deviation of the mean irrigation rate is 60% smaller. These local-scale irrigation-driven feedbacks are not resolved in coarse-resolution climate models implying that use of these tools will overestimate irrigation demand. Future studies of irrigation demand must therefore account for the local land–atmosphere interactions by using coupled...

Description: Two-wing flyingfish ( Exocoetus spp .) are widely distributed, epipelagic, mid-trophic organisms that feed on zooplankton and are preyed upon by numerous predators (e.g., tunas, dolphinfish, tropical seabirds), yet an understanding of their speciation and systematics is lacking. As a model of epipelagic fish speciation and to investigate mechanisms that increase biodiversity, we studied the phylogeny and biogeography of Exocoetus , a highly abundant holoepipelagic fish taxon of the tropical open ocean. Morphological and molecular data were used to evaluate the phylogenetic relationships, species boundaries, and biogeographic patterns of the five putative Exocoetus species. We show that the most widespread species ( E. volitans ) is sister to all other species, and we find no evidence for cryptic species in this taxon. Sister relationship between E. monocirrhus (Indo-Pacific) and E. obtusirostris (Atlantic) indicates the Isthmus of Panama and/or Benguela Barrier may have played a role in their divergence via allopatric speciation. The sister species E. peruvianus and E. gibbosus are found in different regions of the Pacific Ocean; however, our molecular results do not show a clear distinction between these species, indicating recent divergence or ongoing gene flow. Overall, our phylogeny reveals that the most spatially restricted species are more recently derived, suggesting that allopatric barriers may drive speciation, but subsequent dispersal and range expansion may affect the distributions of species. Morphological and molecular data of two-wing flyingfish species analyzed within a phylogenetic context revealed three clear species definitions and two others that were less obvious. Cryptic species were not detected, and biogeographic patterns of speciation associated with species range size. Two-wing flyingfish are abundant mid-trophic fishes representative of the tropical epipelagos, such that other taxa within the same habitat should be investigated for similar patterns of phylogenetic history and biogeography, as well as speciation.

Description: ABSTRACT We use the Weather Research and Forecast model and estimate anthropogenic heat (AH) fluxes based on fine-scale energy consumption data for Sydney, Australia, to investigate the effects of urbanization on temperature. We examine both the impact of urban canopy effects (UCE) and AH which in combination causes the urban heat island effect. Sydney's urban heat island (UHI) varies from −1 to 〉3.4 °C between day and night and between seasons. UHI intensity is highest at night and an urban cool island is often experienced during the day. UCE contributes 80% of the UHI during summer nights because of the release of stored heat from urban infrastructure that has been absorbed during the day. During the day for UCE, the reduced net radiation and greater heat storage by urban infrastructure combine to slightly cool. In contrast, AH contributes 90% of the UHI during winter nights because it does not dissipate into the higher levels of the boundary layer efficiently. The opposite applies during summer nights and during daytime in both summer and winter where heat mixes effectively into the atmosphere. Our results show contrasting impacts of UCE and AH by time of day and time of year and point to major simulation biases if only one of these phenomena is represented, or if their seasonal contributions are not accounted for separately.

Description: The sudden death of a friend or relative, particularly by suicide, is a risk factor for suicide. People who experience sudden bereavement report feeling highly stigmatised by the loss, potentially influencing access to support. We assessed whether perceived stigma following sudden bereavement is associated with suicidal thoughts and suicide attempt. We analysed cross-sectional survey data on 3387 young adults bereaved by the sudden death of a close contact. We tested the association of high versus low perceived stigma (on the stigma sub-scale of the Grief Experience Questionnaire) with post-bereavement suicidal ideation and suicide attempt, using random effects logistic regression, adjusting for socio-demographic factors, pre-bereavement psychopathology, and mode of sudden bereavement (natural causes/unnatural causes/suicide). Subjects with high perceived stigma scores were significantly more likely to report post-bereavement suicidal thoughts (adjusted odds ratio (AOR) = 2.74; 95% confidence interval (CI) = 1.93–3.89) and suicide attempt (AOR = 2.73; 95% CI = 2.33–3.18) than those with low stigma scores. People who feel highly stigmatised by a sudden bereavement are at increased risk of suicidal thoughts and suicide attempt, even taking into account prior suicidal behaviour. General practitioners, bereavement counsellors, and others who support people bereaved suddenly, should consider inquiring about perceived stigma, mental wellbeing, and suicidal thoughts, and directing them to appropriate sources of support.

Description: Australia allocates less than 0.1% of health funding to research on health and climate change. This Perspective highlights the country's strength in the individual disciplines of climate science and health research and calls for bringing these areas together. Nature Climate Change 7 103 doi: 10.1038/nclimate3182