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Species under milder climates (e.g., warm and wet) tend to experience lower variability in temperature and rainfall regimes and might occur in narrower climatic ranges than species that tolerate harsher conditions (e.g., cold or dry climates). Thus, tree species that occur under harsh conditions should have a broader climatic range, being a small subset of the flora. Here, we assess the influence of climate on species distribution of 1138 tree species from the Atlantic Forest biodiversity hotspot. We investigate their range (or niche breadth), and the "center of gravity" index (or niche optima), along with gradients of mean annual temperature and climatic water deficit (CWD). We further identified those species associated with conditions on different ends of temperature and moisture gradients. We found a small subset of species occurring under colder temperatures or under drier conditions, and these species had a wider niche breadth. The warm or wet‐affiliated species had narrower ranges along with the temperature and the CWD gradients, respectively. Moreover, species affiliated to warm and those to moister conditions had greater densities near their occurrence limits, thus they may be more susceptible to climate changes. We conclude that global climate changes will affect the incidence and abundance distribution patterns of tree species along this threatened biodiversity hotspot, mainly those with narrow niches and within the limit of its distribution. Abstract in Portuguese is available with online material [ABSTRACT FROM AUTHOR]

Prior studies on Hemiculter leucisculus, which is a widespread native fish in China, mainly focused on its growth, feeding habits, and individual fecundity, but few have investigated the brain. In this research, we explored the developmental patterns of the Hemiculter leucisculus brain and found the brain showed allometry through sample time points and three age groups. At the same time, we found that the brain varied along climatic gradients. The volumes of the olfactory bulbs, telencephalic lobes, optic tectum, corpus cerebelli, and total brain in the south were larger than those in the north, while the volume of the hypothalamus in the north was larger than in the south. This study provides a view for the in‐depth study of the acclimatized mechanism of the teleost brain, lays a foundation for the further study of evolutionary ecology, and provides a reference for the phenotypic plasticity of the teleost brain. [ABSTRACT FROM AUTHOR]

Aim: Worldwide distribution patterns of living animals are structured in multiple zoogeographical regions, characterized by faunas with homogeneous composition that are separated by sharp boundaries. These zoogeographical regions can differ depending on the considered animal group, probably because they have distinct characteristics such as dispersal, metabolism, or evolutionary history, and thus divergent responses to major biogeographical drivers, such as tectonic movements, abrupt climate transitions and orographic barriers. Here, we tested if the drivers of biogeographical boundaries are different between vertebrate classes with strongly divergent traits and evolutionary history. Location: Global. Time period: Present. Major taxa studied: Amphibians, birds and mammals. Methods: We focused on terrestrial biogeographical boundaries, considering multiple potential drivers: spatial heterogeneity of present‐day climate, altitudinal variation, long‐term tectonic movements and past climate change (temperature). We used spatially explicit regression models and geographically weighted regressions to select and quantify the factors explaining the position of the biogeographical boundaries between vertebrate classes. Results: For mammals, tectonic movements, abrupt climatic transitions and orographic barriers jointly determined extant biogeographical boundaries, with tectonic movements being the most important. For birds, abrupt climatic transitions played the strongest role, while the effect of orographic barriers was weak. For amphibians, biogeographical boundaries mostly corresponded to areas with abrupt climatic transitions. The strongest transitions of amphibian faunas occur in areas with abrupt shifts of temperature and precipitation regimes. Main conclusions: Our analyses confirmed that different drivers have jointly shaped the global vertebrate biogeographical regions, and highlight that taxa with different features show heterogeneous responses across the globe. Eco‐physiological constraints likely increase the importance of spatial heterogeneity of climate, while dispersal limitations magnify the relevance of physical barriers (mountain chains and long‐term tectonic instability). Integrating among‐taxa heterogeneity into analyses thus provides a more complete view of how different processes determine biodiversity variation across the globe. [ABSTRACT FROM AUTHOR]

This study examines the distribution patterns of grass subfamilies and their diagnostic silica phytoliths along a transect running approximately at latitude 28° S in South Africa. The transect encompasses 77 surface samples collected along moisture and temperature gradients, across 6 biomes and 39 ecozones, and spanning elevations between near-sea level and over 2253 m. This study tests the relation between the distribution and density of grass subfamilies and the proportions of their diagnostic grass silica short cell phytoliths (GSSCP) representing them, and how these proportions correlate with five climatic variables (mean temperature of the wettest quarter, annual precipitation, precipitation of the wettest quarter, precipitation variability, and the aridity index). The results suggest that C 3 -grass diagnostic GSSCP morphotypes increase with a decline in temperature in the wettest quarter, occurring in areas receiving mostly winter rain or at high elevations in areas of summer rain. Of the C 4 grass subfamilies, the Panicoideae increase with summer precipitation and low precipitation variability, while the Aristidoideae- Stipagrostis the opposite. The distribution of Chloridoideae depends on complex changes in all climatic variables, suggesting aridity gradients only in the eastern half of the transect. In view of the data, this study reviews the usefulness of the phytolith humidity-aridity index (Iph) and the water stress index (Fs) and proposes the Panicoideae index (PI) and Stipagrostis index (SI) as indicator of aridity and high precipitation variability in southern Africa. • Modern surface grasses and their phytoliths vary across bioclimatic gradients. • Stipagrostis phytoliths are indicators of aridity and high precipitation variability. • Panicoideae phytoliths are good indicators of abundant summer precipitation. • The C 3 :C 4 ratio, the Panicoideae index, and the Stipagrostis index are proposed. [ABSTRACT FROM AUTHOR]

Despite their recognized importance in promoting crop yields and soil health, little is known about earthworm species composition and density within the cereal production region of the Inland Pacific Northwest (IPNW). The overall goal of this work was to understand the influence of climatic factors and soil properties on the presence/absence and density of earthworm species found in the region. The IPNW cereal production region includes a steep climatic gradient and can be divided into four agroecological classes (annual cropping, transition crop-fallow, crop-fallow and irrigated) (AECs) according to the dominant cropping systems present. Replicate sites were selected within the annual cropping, transition and crop-fallow AECs and earthworm density, diversity and soil properties were measured. Earthworm diversity was extremely low. Only two of the sampled sites had more than a single species, and these sites were both in the wettest AEC. Aporrectodea trapezoides was the predominant species sampled, and this species was present at every site where earthworms were found. Earthworms were present at all sites within the annual cropping and transition classes, while only 13.3% of sites within the crop-fallow AEC had earthworms. When only sites with earthworms were considered, earthworm metrics were greater in the driest crop-fallow AEC (density = 151.2 individuals m −2 ) compared to 113.8 individuals m −2 in the transition and 86.4 individuals m −2 in annual cropping fields and a significant negative correlation was found with precipitation. The data suggest that while earthworms are largely absent from the driest sites, they can achieve relatively high density and biomass values when local conditions (soil properties and management) are favorable. A clear minimum threshold of mean annual precipitation (MAP) between 330 and 370 mm was observed, with earthworms absent from all fields with MAP values below 330. This value is lower than those previous reported for A. trapezoides and demonstrates the species’ ability to deal with warm, dry conditions. Biomass values (mean of 94.3 g m −2 ) for sites with earthworms were generally above those reported to be necessary to significantly influence crop yields, suggesting that further research focusing on quantification of the impact of earthworm on crop yields in this important agricultural region is warranted. [ABSTRACT FROM AUTHOR]

Aims Understanding how tree growth is influenced by climate is vital for predicting how forests will respond to climate change, yet there have been few studies of tree growth spanning macroclimatic gradients. The aim of this study is to correlate growth of a single lineage of broadleaf evergreen trees with continental-scale variability in climate. Location Australia's temperate mesic eucalypt forests, spanning latitudes from 23 to 43° S and longitudes from 115 to 153° E. Methods We compiled and analysed a dataset containing around half a million measurements of growth in eucalypt tree diameter, collected from 2409 permanent forestry plots. These plots spanned a range of 558-2105 mm mean annual precipitation and 6-22 °C mean annual temperature. Generalized additive models were used to study the relationship between growth in tree diameter and several temperature and water availability variables. Results Tree growth increased with precipitation, but with a diminishing response above a mean annual precipitation of 1400 mm. There was a peaked response to temperature, with maximum growth occurring at a mean annual temperature of 11 °C and maximum temperature of the warmest month of 25-27 °C. Lower temperatures directly constrain growth. High temperatures primarily reduced growth by reducing water availability, but they also appeared to exert a direct negative effect. Our best model, which included maximum temperature of the warmest month and the ratio of precipitation to evaporation, explained 28% of the deviance. Main conclusions The productivity of Australia's temperate eucalypt forests could decline substantially as the climate warms, given that 87% of these forests currently experience a mean annual temperature above 11 °C, where the highest growth rates were observed. This will reduce carbon sequestration and slow recovery after catastrophic disturbances such as wildfire. [ABSTRACT FROM AUTHOR]

Ectomycorrhizal (EM) networks are hypothesized to facilitate regeneration under abiotic stress. We tested the role of networks in interactions between P. menziesii var. glauca trees and conspecific seedlings along a climatic moisture gradient to: (1) determine the effects of climatic factors on network facilitation of Pseudotsuga menziesii (Mirb.) Franco var. glauca (Mayr) seedling establishment, (2) infer the changing importance of P. menziesii var. glauca parent trees in conspecific regeneration with climate, and (3) parse the competitive from facilitative effects of P. menziesii var. glauca trees on seedlings. When drought conditions were greatest, seedling growth increased when seedlings could form a network with trees in the absence of root competition, but was reduced when unable to form a network. Survival was maximized when seedlings were able to form a network in the absence of root competition. Seedling stem natural abundance δC increased with drought due to increasing water use efficiency, but was unaffected by distance from tree or network potential. We conclude that P. menziesii seedlings may benefit from the presence of established P. menziesii trees when growing under climatic drought, but that this benefit is contingent upon the establishment of an EM network prior to the onset of summer drought. These results suggest that networks are an important mechanism for EM plants establishing in a pattern consistent with the stress-gradient hypothesis, and therefore the importance of EM networks to facilitation in regeneration of EM trees is expected to increase with drought. [ABSTRACT FROM AUTHOR]

Aim To identify the reasons behind differing geographical species richness patterns of range-restricted and widespread species. Location The Western Hemisphere. Methods We used regression to determine the strongest environmental predictors of richness for widespread and range-restricted mammal species in 10,000 km2 quadrats in the continental Americas. We then used range-placement models to predict the expected correlation between range-restricted and widespread species richness were they to be determined by identical, random, or contrasting environmental factors. Finally, to determine the reasons underlying deviations from these predictions, we divided the Americas into 5% quantiles based on temperature and topographic heterogeneity and correlated richness of these two assemblages across quantiles – an approach that avoids constraints on statistical testing imposed by low potential for range overlap among range-restricted species. Results Minimum annual temperature was the strongest predictor of widespread species richness while topographic heterogeneity was the best, although weak, predictor of range-restricted species richness in conventional regression analysis. Our models revealed that the observed correlation between range-restricted and widespread species richness was similar to what would be observed if both range-restricted and widespread species richness were determined by temperature. Patterns of range-restricted and widespread species richness were highly correlated across temperature quantiles, but range-restricted species uniquely showed an increasing pattern across heterogeneity quantiles. Main conclusions Species richness gradients among range-restricted species differ from those of widespread species, but not as extensively or for the reasons reported previously. Instead, these assemblages appear to share some but not all underlying environmental determinants of species richness. Our new approach to examining species richness patterns reveals that range-restricted and widespread species richnesses share a common response to temperature that conventional analyses have not previously revealed. However, topographic heterogeneity has assemblage-specific effects on range-restricted species. [ABSTRACT FROM AUTHOR]

We tested whether local abundance of rain forest trees in the medium elevation wet forests of the southern Western Ghats (WG) was related to environmental tolerance, life form, and geographical range. We selected trees in medium elevation wet forests (750–1700 m asl) of the southern WG, using two data bases: a small plot (30 × 30 m) data base of 288 species of trees (≥ 3 cm dbh) in 33 plots totaling 2.97 ha, and a data base of 135 species of tree (≥ 10 cm dbh) in larger plots of 1 ha each, totaling 4.84 ha. The species density per hectare and number of records in the plot network was used in a factor analysis to give a measure of the local abundance of each species. The altitude and seasonality ranges of these species in the WG was assessed from independent data bases and used to generate an environmental tolerance score. Results indicated that as a species became locally more abundant, it occurred across a wider range of environmental gradients, but regional distribution was not related to geographical distribution. Understory species tended to be rarer with smaller range sizes and lower environmental tolerances than overstory species. Climate change is predicted to have drastic effects on restricted range species with limited environmental tolerances. [ABSTRACT FROM AUTHOR]

Anonychomyrma is a dolichoderine ant genus of cool-temperate Gondwanan origin with a current distribution that extends from the north of southern Australia into the Australasian tropics. Despite its abundance and ecological dominance, little is known of its species diversity and distribution throughout its range. Here, we describe the diversity and distribution of Anonychomyrma in the Australian Wet Tropics bioregion, where only two of the many putative species are described. We hypothesise that the genus in tropical Australia retains a preference for cool wet rainforests reminiscent of the Gondwanan forests that once dominated Australia, but now only exist in upland habitats of the Wet Tropics. Our study was based on extensive recent surveys across five subregions and along elevation and vertical (arboreal) gradients. We integrated genetic (CO1) data with morphology to recognise 22 species among our samples, 20 of which appeared to be undescribed. As predicted, diversity and endemism were concentrated in uplands above 900 m a.s.l. Distribution modelling of the nine commonest species identified maximum temperature of the warmest month, rainfall seasonality, and rainfall of the wettest month as correlates of distributional patterns across subregions. Our study supported the notion that Anonychomyrma radiated from a southern temperate origin into the tropical zone, with a preference for areas of montane rainforest that were stably cool and wet over the late quaternary. [ABSTRACT FROM AUTHOR]