Search

Summary: Anthropogenetic climate change has caused range shifts among many species. Species distribution models (SDMs) are used to predict how species ranges may change in the future. However, most SDMs rarely consider how climate‐sensitive traits, such as phenology, which affect individuals' demography and fitness, may influence species' ranges.Using > 120 000 herbarium specimens representing 360 plant species distributed across the eastern United States, we developed a novel 'phenology‐informed' SDM that integrates phenological responses to changing climates. We compared the ranges of each species forecast by the phenology‐informed SDM with those from conventional SDMs. We further validated the modeling approach using hindcasting.When examining the range changes of all species, our phenology‐informed SDMs forecast less species loss and turnover under climate change than conventional SDMs. These results suggest that dynamic phenological responses of species may help them adjust their ecological niches and persist in their habitats as the climate changes.Plant phenology can modulate species' responses to climate change, mitigating its negative effects on species persistence. Further application of our framework will contribute to a generalized understanding of how traits affect species distributions along environmental gradients and facilitate the use of trait‐based SDMs across spatial and taxonomic scales. [ABSTRACT FROM AUTHOR]

Climate and land‐cover changes are major threats to biodiversity, and their impacts are expected to intensify in the future. Protected areas (PAs) are crucial for biodiversity conservation. However, their effectiveness under future climate and land‐cover changes remains to be evaluated. Moreover, the impacts of climate and land‐cover changes on multi‐dimensions of biodiversity are rarely considered when expanding PAs.Using distributions of 8,732 woody species in China and species distribution models, we identified species that will be threatened by future climate and land‐cover changes (i.e. species with significant projected loss of suitable habitats by the 2070s) under different dispersal scenarios. We then estimated the geographical patterns in species richness (SR) and phylogenetic diversity (PD) of threatened species, evaluated the effectiveness (i.e. the changes in SR and PD) of Chinese PAs and identified conservation priorities for future PA expansion.Approximately 12%–38% of woody species will be threatened under different scenarios. These species tend to be clustered in the tree of life, and their SR and PD show consistent spatial patterns, being highest at low latitudes. PAs currently protect 90% of threatened species. However, their SR and PD of threatened species within PAs will decrease by 30%–40% by the 2070s, which reduces the PA effectiveness, especially for PAs at low elevations and those with low topographic heterogeneity and high natural vegetation loss.The conservation priorities identified from the SR and PD of the threatened species are mainly in mountains in southern China, the Yunnan‐Guizhou Plateau and Taiwan Island. PA expansion and ecological corridors in these regions are needed to conserve threatened species.Synthesis and applications. We present a systematic study of the impacts of future climate and land‐cover changes on the conservation status of woody species and PA effectiveness in China. Our results suggest that future climate and land‐cover changes will reduce PA effectiveness, and the spatial prioritization of biodiversity conservation should consider the influences of future global changes on biodiversity. These results shed new light on the conservation priorities for the post‐2020 expansion of PAs in China. [ABSTRACT FROM AUTHOR]

Predicting spatial patterns in thermal tolerance and vulnerability of species under climate warming remains a challenge. Current knowledge is mainly from experiment‐based thermal physiology of limited numbers of ectotherms, yet large‐scale evaluations on plants remain elusive. Here, using distribution maps with spatial resolutions of 20 × 20 km for 5628 woody species in China, we propose a novel approach, i.e. thermal distribution curves, to describe species' realized thermal niches and then estimate their thermal tolerance and warming risks under projected climate warming in 2050s and 2070s. We find that species' vulnerability and potential local extinction risks within grid cells decrease with latitude and increase with aridity due to narrow thermal tolerance of species located at low latitudes and arid regions. Over 90% of species could still tolerate future warming in most areas, indicating relatively optimistic expectation of potential local extinctions. Our study presents a new framework to quantify climate warming impacts on a large number of species without sufficient physiological information and provides fundamental references for conservation planning under climate change. [ABSTRACT FROM AUTHOR]

Aim Stratospheric ozone depletion and simultaneous increases in UVB radiation due to human activities have the potential to affect freshwater biota. The goal of our study is to summarize the impacts of UVB on freshwater biota by comparing the differences in the general patterns, including the directions and the magnitudes of the impacts of UVB on four major freshwater taxa (phytoplankton, zooplankton, fish and amphibians). The potential driving forces for these differences are also explored. Location Global. Methods We performed a meta-analysis on a database consisting of 146 studies including 127 species from four taxonomic groups. We tested for the effects of taxonomic group, experimental venue, developmental stage, UVB dosage and the latitude of organism provenance. Results UVB had significant negative effects on freshwater biota from the molecular-cellular to individual-population levels. However, these effects were highly variable among the taxonomic groups. In general, zooplankton was the most negatively affected group, whereas fish and amphibians were less affected. As direct fitness components, survival and reproduction were the two responses most affected by UVB. The sensitivities of individuals to UVB at different developmental stages were different for the same taxon, while the stage-dependent sensitivity patterns also differed among different taxa. Additionally, effects of different experimental venues, UVB dosages and latitudes of organism provenance on the effects of UVB were detected. Main conclusions Our results suggest that UVB has significant negative effects on freshwater biota. We found that the effects of UVB varied among taxonomic groups, developmental stages, experimental venues, UVB dosages and latitudes of organism provenance. The variation in sensitivity among the different taxa has important implications for ecosystem responses. Given that stratospheric ozone is unlikely to recover to the levels of the 1980s in the upcoming decades, more conservation efforts should be taken to protect freshwater habitats from further damage by UVB. [ABSTRACT FROM AUTHOR]

Mechanisms underlying large‐scale spatial patterns of species richness are one of the central issues in ecology. Although contemporary climate, evolutionary history, and historical climate change have been proposed as drivers of species richness patterns, variation in the relative importance of different factors remains a major challenge. Here, using newly compiled distribution data with a spatial resolution of 100 × 100 km for 43 023 angiosperms plant species in east Eurasia, we mapped species richness patterns for plants with different growth forms (i.e. woody versus herbaceous) and range sizes (i.e. wide‐ranged versus narrow‐ranged species), and compared the relative importance of the four hypotheses in explaining these patterns, i.e. freezing tolerance hypothesis, historical climate change hypothesis, Janzen's hypothesis (predicting that climate seasonality and topography determine species richness patterns), and diversification rate hypothesis. We found that species richness of all angiosperm plants presented a clear latitudinal gradient and was highest in southwestern China and Central Asian mountains. Notably, species richness patterns and their dominant drivers differed between species groups. Historical climate change was the dominant driver for richness patterns of all and herbaceous species. The freezing tolerance hypothesis dominated the drivers for all woody species, while Janzen's hypothesis dominated narrow‐ranged woody and herbaceous species. Our study suggests that different hypotheses contribute to large‐scale plant richness patterns via their effects on different plant groups. Our results did not support the diversification rate hypothesis, but demonstrated the high importance of historical climate change to plant diversity in east Eurasia, providing new perspectives on the mechanisms of plant diversity patterns in this continent. [ABSTRACT FROM AUTHOR]

Support for the "biotic resistance hypothesis," that species‐rich communities are more successful at resisting invasion by exotic species than are species‐poor communities, has long been debated. It has been argued that native–exotic richness relationships (NERR) are negative at small spatial scales and positive at large scales, but evidence for the role of spatial scale on NERR has been contradictory. However, no formal quantitative synthesis has previously examined whether NERR is scale‐dependent across multiple studies, and previous studies on NERR have not distinguished spatial grain and extent, which may drive very different ecological processes. We used a global systematic review and hierarchical mixed‐effects meta‐analysis to provide a comprehensive quantitative assessment of the patterns of NERR over a range of spatial grain sizes and spatial extents, based on 204 individual cases of observational (non‐experimental) NERRs from 101 publications. We show that NERR was indeed highly scale dependent across studies and increased with the log of grain size. However, mean NERR was not negative at any grain size, although there was high heterogeneity at small grain sizes. We found no clear patterns of NERR across different spatial extents, suggesting that extent plays a less important role in determining NERR than does grain, although there was a complex interaction between extent and grain size. Almost all studies on NERR were conducted in North America, western Europe, and a few other regions, with little information on tropical or Arctic regions. We did find that NERR increased northward in temperate regions and also varied with longitude. We discuss possible explanations for the patterns we found, and caution that our results do not show that invasive species are benign or have no negative consequences for biodiversity preservation. This study represents the first global quantitative analysis of scale‐based NERR, and casts doubt on the existence of an "invasion paradox" of negative NERR at small scales and positive correlations at large scales in non‐experimental studies. [ABSTRACT FROM AUTHOR]

Aim: Woody and herbaceous habits represent one of the most distinct contrasts among angiosperms, and the proportion of woody species in floras (i.e., "woodiness" hereafter) represents a fundamental structural element of plant diversity. Despite its core influence on ecosystem processes, spatio‐temporal patterns in woodiness remain poorly understood. Here, we aim to demonstrate the global spatio‐temporal patterns in angiosperm woodiness and their relationship with environmental factors. Location: Global. Time period: Cenozoic, 66 Ma to present. Major taxa studied: Angiosperms. Methods: Using newly compiled data on the growth forms and distributions of c. 300,000 angiosperm species and an angiosperm phylogeny, we mapped the current global geographical patterns in angiosperm woodiness, reconstructed ancestral states of growth forms through the angiosperm phylogeny and demonstrated the Cenozoic evolutionary dynamics of woodiness. We evaluated the relationships between woodiness and current climate and palaeoclimate. Results: We found that c. 42.7% of angiosperms are woody. Woodiness decreased spatially from the equator towards high latitudes, temporally since the early Cenozoic. Temperature was the best predictor of the spatio‐temporal decline in woodiness and was positively correlated with woodiness. Despite the temporal decline in woodiness, macroevolutionary herbaceous‐to‐woody transitions increased through time and contributed to the evolution of woody floras in temperate drylands, whereas the opposite transitions decreased through time and contributed to herbaceous floras in tropical and subtropical drylands. Main conclusions: Our study improves understanding of the spatio‐temporal dynamics of angiosperm woodiness. Our findings suggest that temperature is likely to be a determinant of spatio‐temporal variations in woodiness, highlighting the role of temperature in maintaining the growth form composition of ecosystems. Our study also calls for attention to growth form transitions (e.g., secondary woodiness) in temperate drylands that have been neglected before. [ABSTRACT FROM AUTHOR]