Geographical Patterns Of Species Richness Research Articles

Community-level predictions in a megadiverse hotspot: comparison of stacked species distribution models to forest inventory data

AbstractGiven the current scenario of climate change and anthropogenic impacts, spatial predictions of biodiversity are fundamental to support conservation and restoration actions. Here, we compared different stacked species distribution models (S-SDMs) to forest inventories to assess if S-SDMs capture emerging properties and geographic patterns of species richness and composition of local communities in a biodiversity hotspot. We generated SDMs for 1499 tree species sampled in 151 sites across the Atlantic Forest. We applied four model stacking approaches to reconstruct the plant communities: binary SDMs (bS-SDMs), binary SDMs cropped by minimum convex polygons (bS-SDMs-CROP), stacked SDMs constrained by the observed species richness (cS-SDMs) and minimum convex polygons of species occurrences (MCPs). We compared the stacking methods with local communities in terms of species richness, composition, community prediction metrics and components of beta diversity—nestedness and turnover. S-SDMs captured general patterns, with bS-SDMs-CROP being the most parsimonious approach. Species composition differed between local communities and all stacking methods, in which bS-SDMs, bS-SDMs-CROP and MCPs followed a nested pattern, whereas species turnover was most important in cS-SDMs. S-SDMs varied in terms of performance, omission and commission errors, leading to a misprediction of some vulnerable, endangered and critically endangered species. Despite differing from forest inventory data, S-SDMs captured part of the variation from local communities, representing the potential species pool. Our results support the use of S-SDMs to endorse biodiversity synthesis and conservation planning at coarse scales and warn of potential misprediction at local scales in megadiverse regions.

The origins of climate-diversity relationships and richness patterns in Chinese plants.

A major goal of ecology and evolutionary biology is to explain geographic patterns of species richness. Richness is often correlated with climatic variables. However, the processes underlying these climate-diversity relationships remain poorly understood. Two potential hypotheses to explain these relationships involve: (i) faster diversification rates (speciation minus extinction) in high-richness climates and (ii) earlier colonization of high-richness climates, allowing more time for speciation to build up richness. Few studies have tested these hypotheses directly, and most focused on animal clades with limited richness. In this study, we test these hypotheses in Chinese angiosperms, encompassing ~10% of Earth's plant species, using large-scale phylogenetic, climatic, and distributional data including 26,977 species. We find that climatic zones that were colonized earlier have higher species richness. By contrast, relationships between diversification rates and richness of climatic zones are often nonsignificant or negative. Our study reveals that even when richness is strongly correlated with climate, the underlying explanation may still be rooted in phylogenetic history. Thus, climate may not be a competing explanation for richness patterns relative to colonization times and diversification rates. We also show that the timing of colonization can be crucial for explaining richness patterns. Yet, many recent studies have ignored this explanation and instead have focused solely on rates of speciation and diversification as drivers of diversity gradients.

Plant species richness on the Tibetan Plateau: patterns and determinants

Whether current hypotheses for geographic patterns of species richness (SR) have a strong explanatory power for the Tibetan Plateau (TP) with extreme climatic conditions remains unclear. In comparison with the classic ‘water–energy dynamics hypothesis', the unique climate factors (e.g. extreme low temperature and low oxygen partial pressure) on the TP likely significantly affect the spatial variation of SR. Here, we investigate geographic patterns and determinants of SR on the TP through a systematic field investigation. We systematically analyzed a total of 2013 plant communities covering 11 different vegetation types on the TP. To compare this SR with that of other sites across the globe, we compiled a global database containing information on 87 forest and 3660 grassland plots. The SR per 400 m2in the forests and shrubs and that per 1 m2in alpine grasslands and deserts was 62.76 (± 1.80 SE), 44.53 (± 7.57 SE), 16.84 (± 0.39 SE) and 3.62 (± 0.55 SE), respectively. The SR of forests and shrubs decreased with latitude and altitude, whereas that of alpine grasslands and deserts showed a unimodal pattern along the altitudinal gradient. Unique climate factors, such as extreme low temperature, mean diurnal temperature and oxygen partial pressure, act synergistically with water–energy dynamics and influence the spatial pattern of SR on the TP. Furthermore, the tree SR on the TP was lower than that of global tropical and subtropical broadleaf forests but higher than that of temperate conifer forests. Alpine meadows had a higher SR than other sites; however, the SR in alpine desert grasslands and alpine deserts was lower. Our findings provide novel insights into the mechanisms underlying the spatial variation in plant diversity, especially on plateaus and in high‐latitude regions. Our findings and the SR map with 1 km resolution provide important benchmarks for biodiversity conservation and may help to improve predictions of the effect of climate change on biodiversity.

Population divergence associated with spatial asynchrony in precipitation in Neotropical frogs

AbstractAimThe role that geography plays in promoting speciation by spatially isolating populations has been studied extensively, but less attention has been devoted to assessing the role of isolation by time mediated by spatial variation in climate as a mechanism promoting population divergence. Gene flow between populations differing in their reproductive schedules might be reduced relative to that between populations with overlapping breeding seasons, potentially leading to genetic divergence. Assuming that precipitation influences reproductive schedules, we explored the effect of asynchronous precipitation regimes on intraspecific genetic divergence. In addition, we examined whether microevolutionary processes are reflected in macroevolutionary patterns by assessing whether regions with more asynchronous precipitation across space have higher frog species richness and have experienced greater speciation rates than regions with more spatially synchronous precipitation regimes.LocationCentral and South America.TaxonAnurans: across 38 species of Neotropical frogs.MethodsFor microevolutionary analyses, we assessed the relationship between spatial asynchrony in precipitation and mitochondrial DNA genetic divergence accounting for ecological connectivity using multiple regression and phylogenetic meta‐analyses. For macroevolutionary analyses, we assessed the relationship between species richness, speciation rates estimated from a comprehensive molecular phylogeny, and the degree of spatial asynchrony in precipitation using generalized linear models.ResultsWe found that spatial asynchrony in precipitation is positively associated with genetic differentiation in 39% of the species tested, resulting in a weak cross‐species effect. However, the effect of asynchrony in precipitation on population divergence seems not to scale to macroevolutionary patterns because spatial asynchrony in precipitation was not associated with geographical patterns of species richness nor speciation rates.Main ConclusionsOur results indicate that asynchronous breeding may promote genetic divergence even in the absence of geographical barriers in species where breeding is associated with water availability, but such effects may not be stable enough through time to influence macroevolutionary patterns.

中国蔷薇属植物物种丰富度分布格局及其与环境因子的关系

物种丰富度的大尺度地理格局及其成因是宏观生态学及生物地理学的中心议题之一。蔷薇属（Rosa L.）植物具有很高的经济价值和生态价值，探讨中国蔷薇属植物的丰富度分布格局及其影响因素可为该属植物资源的保护和合理开发利用乃至其系统进化研究提供重要依据。基于蔷薇属植物在中国的15451条分布数据和11种地理、气候等环境因子进行了物种丰富度分析和相关性分析，研究结果显示：（1）蔷薇属植物在中国分布不均匀。在水平方向上，蔷薇属植物于26.19°-34.29°N带内有较高的物种丰富度，之后随着纬度的增加而降低，且随着经度的增加表现为先增加后减少，于99.10°-108.47°E间存在明显的峰值；在垂直方向上，蔷薇属植物的物种丰富度随海拔的增加表现为先增加后减少，956.46-3518.60m范围内的丰富度最高。西南横断山区为蔷薇属物种分布的中心地区，新疆北部及东北长白山周边地区为局部聚集区。（2）蔷薇属物种丰富度与各能量、水分和生境异质性因子均呈正相关关系，与气候稳定性因子呈负相关关系。表明中国蔷薇属植物在水分和热量条件好、气候季节性变化小且生境异质性程度高的地方，有着更高的物种丰富度。（3）蔷薇属植物丰富度与各因子的关系基本支持了生产力假说、环境稳定性假说和生境异质性假说。但蔷薇属的物种丰富度格局并非完全由这些假说解释，历史环境、地形、土壤、人类活动等其他因子可能也有一定的影响作用。（4）水分因子的单独解释率占34.6%（R²；P<0.001），是影响蔷薇属物种丰富度格局的主导因子，这可能是由该类群的进化历史、生理适应等原因共同决定的。本研究可以为蔷薇属植物的分类、进化、以及野生资源的保护和开发利用提供参考。;Understanding macro-scale spatial patterns in species richness and their underlying mechanisms is an important issue to macroecology and biogeography. Rosa species have a high economic and ecological value. Exploring the geographic patterns of species richness and their environmental determinants of Rosa in China will facilitate the resources protection and rational utilization, as well as systematic and evolutionary research of the genus. In this study, datasets of 15451 distributional records and 11 environmental factors were used to conduct species richness and correlation analyses. The results show that (1) Rosa is unevenly distributed in China. The species richness is the highest at latitudes ranging from 26.19°N to 34.29°N, and decreases as the latitude increase. The richness of Rosa is the highest at longitudes ranging from 99.10°E to 108.47°E, and decreased from this optimal range to the west and the east. The species richness shows unimodal pattern that increases first and then decreases with the increase of altitude, with the maximum value between 956.46 m and 3518.60 m. The central aggregation areas are located in the mountain areas around Sichuan Basin as well as Hengduan Mountains, and Chang Bai Mountains region and northern Xinjiang are the local aggregation areas. (2) The energy, water and habitat heterogeneity are positively associated with species richness. In addition, there are negative correlations between species richness and environmental stability. The Rosa has higher species richness in regions with the suitable hydrothermal conditions, the steady climate, and the great habitat heterogeneity. (3) The relationship between the species richness and the environment factors basically supports the productivity hypothesis, the environmental stability hypothesis and the habitat heterogeneity hypothesis. However, the hypotheses cannot fully explain the species richness pattern of Rosa, which indicates that other factors such as historical environment, terrain, soil properties or human activity probably have played a role in shaping the richness pattern of Rosa species. (4) Water factors account for 34.6% (P<0.001) of the species richness patterns of Rosa, so water is the dominant factor, which might be determined by the evolutionary history, physiological adaptation and other reasons. Our results can provide valuable information for the classification, evolution, protection and exploitation of wild resources of the Rosa species.

Conservation of woody species in China under future climate and land‐cover changes

Abstract 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.

Geographical variation of multiplex ecological networks in marine intertidal communities.

Understanding the drivers of geographical variation in species distributions, and the resulting community structure, constitutes one of the grandest challenges in ecology. Geographical patterns of species richness and composition have been relatively well studied. Less is known about how the entire set of trophic and non-trophic ecological interactions, and the complex networks that they create by gluing species together in complex communities, change across geographical extents. Here, we compiled data of species composition and three types of ecological interactions occurring between species in rocky intertidal communities across a large spatial extent (~970km of shoreline) of central Chile, and analyzed the geographical variability in these multiplex networks (i.e., comprising several interaction types) of ecological interactions. We calculated nine network summary statistics common across interaction types, and additional network attributes specific to each of the different types of interactions. We then investigated potential environmental drivers of this multivariate network organization. These included variation in sea surface temperature and coastal upwelling, the main drivers of productivity in nearshore waters. Our results suggest that structural properties of multiplex ecological networks are affected by local species richness and modulated by factors influencing productivity and environmental predictability. Our results show that non-trophic negative interactions are more sensitive to spatially structured temporal environmental variation than feeding relationships, with non-trophic positive interactions being the least labile to it. We also show that environmental effects are partly mediated through changes in species richness and partly through direct influences on species interactions, probably associated to changes in environmental predictability and to bottom-up nutrient availability. Our findings highlight the need for a comprehensive picture of ecological interactions and their geographical variability if we are to predict potential effects of environmental changes on ecological communities.

Discovery of widely available abyssal rock patches reveals overlooked habitat type and prompts rethinking deep-sea biodiversity

Habitat heterogeneity and species diversity are often linked. On the deep seafloor, sediment variability and hard-substrate availability influence geographic patterns of species richness and turnover. The assumption of a generally homogeneous, sedimented abyssal seafloor is at odds with the fact that the faunal diversity in some abyssal regions exceeds that of shallow-water environments. Here we show, using a ground-truthed analysis of multibeam sonar data, that the deep seafloor may be much rockier than previously assumed. A combination of bathymetry data, ruggedness, and backscatter from a trans-Atlantic corridor along the Vema Fracture Zone, covering crustal ages from 0 to 100 Ma, show rock exposures occurring at all crustal ages. Extrapolating to the whole Atlantic, over 260,000 km2 of rock habitats potentially occur along Atlantic fracture zones alone, significantly increasing our knowledge about abyssal habitat heterogeneity. This implies that sampling campaigns need to be considerably more sophisticated than at present to capture the full deep-sea habitat heterogeneity and biodiversity.

Geographic patterns of insect diversity across China's nature reserves: The roles of niche conservatism and range overlapping.

AimInsects are the most species‐rich clade in the world, but the broad‐scale diversity pattern and the potential drivers have not been well documented for the clade as a whole. We aimed to examine the relative roles of contemporary and historical climate, niche conservatism, range overlapping, and other environmental factors on geographic patterns of species richness and phylogenetic structure, for insects across China.LocationChina.MethodsWe collected insect data from 184 nature reserves and examined geographic patterns of species richness and mean root distance (MRD, a metric of the evolutionary development of assemblages) for different biogeographic affinities (Palearctic, Oriental, and widespread species) and for clades originated during the warm and cold geohistorical periods (“warm clades” and “cold clades,” respectively). We related richness and MRD to contemporary and historical climate, area, habitat heterogeneity, and human disturbance to evaluate their relative importance.ResultsTotal species richness revealed a hump‐shaped latitudinal pattern, peaking between 30°~35°N. Richness patterns differed markedly among evolutionary groups: Oriental species richness decreased significantly with higher latitude but Palearctic species increased, while other groups again peaked between 30°~35°N. The range overlapping of different biogeographic groups in midlatitudes may be an important contributor to humped latitudinal richness patterns. MRD was positively related to latitude and increased more rapidly for “warm clades” than “cold clades.” Historical climate factors (especially winter coldness) were among the strongest predictors for both richness and phylogenetic patterns, for each evolutionary group, suggesting the strong influence of niche conservatism.ConclusionsThe hump‐shaped latitudinal pattern of insect richness in China is mainly shaped by niche conservatism and range overlapping, supplemented by habitat heterogeneity and contemporary climate. The role of niche conservatism and range overlapping may have been overlooked if only total species richness was analyzed, suggesting the importance of examining different evolutionary groups separately.

Spatial patterns of plant functional types and environmental proxies of plant richness in alpine region of Western Himalaya, India

The geographical patterns of species richness and underlying mechanisms are among the central issues of ecology. The Himalaya, a global biodiversity hotspot, lacks spatially explicit representation of plant richness patterns and predictor environmental covariates. The rugged Himalayan terrain limits large-scale field surveys, we, therefore, disentangle the role of remotely sensed environmental proxies for characterization of Plant Functional Types (PFTs) and prediction of plant richness in an alpine area in Western Himalaya. Alpine plant richness was recorded in cluster plots (10 random quadrants of 1 m2 in approximately 1-ha area) across 97 sites in Pithoragarh district in part of the Western Himalaya (India). The dominant PFTs were mapped based on support vector machine classification of Landsat 8 image. The satellite-derived climate, landscape, and topographic variables were correlated to plant richness using generalized linear model (GLM) with poisson distribution to unravel species richness-environment linkages in the study area. The dominant PFTs mapped were herbaceous meadow, Danthonia grassland, Kobresia sedge meadow, moist scrub, and dry scrub. The GLM based plant richness model explained 70% variation in alpine plant richness. The environmental factors such as vegetation vigor, elevation, landscape diversity and moisture were observed to influence alpine plant richness of the study area. The study presents a valuable baseline spatial database for judicious management of alpine plant resources and climate change studies.

Tree species richness predicted using a spatial environmental model including forest area and frost frequency, eastern USA.

Assessing geographic patterns of species richness is essential to develop biological conservation as well as to understand the processes that shape these patterns. We aim to improve geographic prediction of tree species richness (TSR) across eastern USA by using: 1) gridded point-sample data rather than spatially generalized range maps for the TSR outcome variable, 2) new predictor variables (forest area FA; mean frost day frequency MFDF) and 3) regression models that account for spatial autocorrelation. TSR was estimated in 50 km by 50 km grids using Forest Inventory and Analysis (FIA) point-sample data. Eighteen environmental predictor variables were employed, with the most effective set selected by a LASSO that reduced multicollinearity. Those predictors were then employed in Generalized linear models (GLMs), and in Eigenvector spatial filtering (ESF) models that accounted for spatial autocorrelation. Models were evaluated by model fit statistics, spatial patterns of TSR predictions, and spatial autocorrelation. Our results showed gridded TSR was best-predicted by the ESF model that used, in descending order of influence: precipitation seasonality, mean precipitation in the driest quarter, FA, and MFDF. ESF models, by accounting for spatial autocorrelation, outperformed GLMs regardless of the predictors employed, as indicated by percent deviance explained and spatial autocorrelation of residuals. Small regions with low TSR, such as the Midwest prairie peninsula, were successfully predicted by ESF models, but not by GLMs or other studies. Gridded TSR in Florida was only correctly predicted by the ESF model with FA and MFDF, and was over-predicted by all other models.

Varying congruence among spatial patterns of vascular plants and vertebrates based on habitat groups.

Proxies are adopted to represent biodiversity patterns due to inadequate information for all taxa. Despite the wide use of proxies, their efficacy remains unclear. Previous analyses focused on overall species richness for fewer groups, affecting the generality and depth of inference. Biological taxa often exhibit very different habitat preferences. Habitat groupings may be an appropriate approach to advancing the study of richness patterns. Diverse geographical patterns of species richness and their potential mechanisms were then examined for habitat groups. We used a database of the spatial distribution of 32,824 species of mammals, birds, reptiles, amphibians and plants from 2,376 counties across China, divided the five taxa into 30 habitat groups, calculated Spearman correlations of species richness among taxa and habitat groups, and tested five hypotheses about richness patterns using multivariate models. We identified one major group [i.e., forest‐ and shrub‐dependent (FS) groups], and some minor groups such as grassland‐dependent vertebrates and desert‐dependent vertebrates. There were mostly high or moderate correlations among FS groups, but mostly low or moderate correlations among other habitat groups. The prominent variables differed among habitat groups of the same taxon, such as birds and reptiles. The sets of predictors were also different within the same habitat, such as forests, grasslands, and deserts. Average correlations among the same habitat groups of vertebrates and among habitat groups of a single taxon were low or moderate, except correlations among FS groups. The sets of prominent variables of species richness differed strongly among habitat groups, although elevation range was the most important variable for most FS groups. The ecological and evolutionary processes that underpin richness patterns might be disparate among different habitat groups. Appropriate groupings based on habitats could reveal important patterns of richness gradients and valuable biodiversity components.

Quaternary refugia are associated with higher speciation rates in mammalian faunas of the Western Palaearctic

Quaternary climate changes have contributed to shape the biogeographic distribution of extant species. The combination of climatic niche conservatism and glacial‐interglacial cycles forced many species to retract their range limits for surviving under the advance of Pleistocene ice‐sheets. Refugia offered geographical opportunities for species to retreat, persist and, later on, begin recolonization processes under favourable environmental conditions. Here we explore the hypothesis that refugia have been not only crucial for the survival of multiple species but also acted as speciation centres for Western Palaearctic mammals. We define ‘recurrent massive refugia’ as those geographical regions that have historically accumulated the highest levels of co‐occurring species for several Quaternary cycles. Our assemblage‐level analyses identify the existence of refugia within the Iberian Peninsula and the Atlantic French margin that were recurrently selected by most mammals. The topographic heterogeneity, climatic stability and microhabitat availability of these refugial areas may have offered suitable habitat conditions for multiple species during different climatic events over time. Using a Bayesian analysis of macroevolutionary mixtures we detected that the higher level of divergence and accumulative evolutionary changes in mammals of the Western Palaearctic are found in refugia. The continuous retractions and expansions of species’ ranges during the Pleistocene promoted temporal changes in the composition and richness of communities in this biogeographic region. The reorganization of ecological composition driven by cyclical climatic events may have favoured the emergence of biotic interactions and ecological responses conducive to novel selective pressures. Our findings suggest, first, that multiple climatic changes in the form of glacial‐interglacial transitions during the Quaternary have left a detectable imprint on the observed geographical patterns of species richness in mammalian faunas of the Western Palaearctic, and second, highlight the importance of refugia for the preservation of species (‘museums’) and as centers of speciation and endemism (‘cradles’) as well.

Aggregate patterns of macrofaunal diversity: An interocean comparison

AbstractAimWhile geographical patterns of species richness are reasonably well explored for single well‐studied taxa, less is known about aggregate patterns of total richness for major biomes and their environmental correlates. Here we analyse continental‐scale aggregate patterns of macrofaunal diversity for sandy beaches, a dominant habitat along the Atlantic and Pacific coasts of South America.LocationSouth American coastlines.Time periodPresent day (data amassed from studies performed since 1971).Major taxa studiedBenthic macrofauna, including crustaceans, polychaetes and molluscs.MethodsWe compiled richness information for all macrofaunal groups on 263 sandy beaches in South America using standard criteria. We further matched these data with environmental variables including sea surface temperature (SST), chlorophyll a, grain size, beach slope, tide range and various morphometrics. We used generalized linear mixed models to relate environmental factors to observed variation in total macrofaunal richness across all beaches, testing competing hypotheses about environmental correlates and possible drivers of latitudinal diversity.ResultsMacrofaunal richness decreased from tropical to temperate beaches in the Pacific and followed a parabolic trend in the Atlantic, with the highest biodiversity found at tropical and mid‐latitudinal bands. Beach slope, tidal range and chlorophyll a mostly explained latitudinal trends in macrofaunal richness, followed by grain size, SST and ocean basin.Main conclusionsThis study indicates that richness of macrofaunal species at a given beach is most closely related to characteristics of the physical habitat, such as beach slope, area and grain size. At this scale, planktonic food supply also appeared to be more important than temperature, which is a dominant explanatory variable of global‐scale variation in species richness.

Asymmetric constraints on limits to species ranges influence consumer‐resource richness over an environmental gradient

AbstractAimThere is little consensus about the relative roles of biotic versus abiotic factors in setting limits to species distributions or in generating geographical patterns of species richness. However, despite the probable importance of host availability in governing the distribution and diversity of consumers, few studies have simultaneously tested the effects of resource distribution and diversity on consumer ranges and richness patterns.LocationSierra de Guadarrama, central Spain.MethodsWe examined the effects of biotic resources, consumer attributes and climate on the ranges and species richness patterns of 43 specialist butterflies at 40 sites over a 1800‐m elevational gradient. Evidence for resource use was based on comprehensive field records of oviposition and larval feeding on host plants.ResultsWe show that limitation by either biotic interactions with resources (the distributions and parts eaten of the larval host plants) or intrinsic dispersal ability was stronger at upper than lower elevational range limits for butterflies. Both resource and consumer richness followed a unimodal, humped pattern over the elevational gradient, but host plant richness peaked 300 m lower than butterfly richness. In addition, whereas changes in butterfly species richness were roughly symmetrical around peak richness over the gradient studied, the host plants showed markedly lower species richness at high elevations (&gt; 1750 m). Butterfly species richness increased with host plant resource diversity and relative humidity, with a steeper response to host plant richness in cooler sites (at higher elevations).Main conclusionsThe results demonstrate the role of bottom‐up control by resource availability in limiting consumer distributions and richness. Importantly, resource limitation had increasing relevance towards the coolest parts of environmental gradients and those poorest in resource species, with potential consequences for ecological responses to environmental change.

Relationship between climate and geographical variation of local woody species richness within the Mediterranean-type region of Chile

Latitudinal and altitudinal patterns of plant species richness have frequently been related to different climate variables such as precipitation, temperature and evapotranspiration. However, studies assessing this relationship have mostly compared different regions and used regional scales of richness (in quadrants of several km2). It is less known the relationship between climate and geographical patterns of species richness in local scales (richness in < 1 ha plots). For central Chile some studies have described geographical patterns of plant species richness, but only using regional scales to quantify richness. It is not known how local richness of plant species varies geographically and if climate variables are related to this variation. In this paper I evaluated latitudinal and altitudinal trends of local richness of woody species within forest ecosystems of the Mediterranean-type climate region in central Chile, and explored if these patterns are related to climatic variables. We used data collected in the field as well as published data of composition of woody species in plots of 100 m2 collected in different localities within this region. Climatic variables were obtained for each locality from isoclimate curves published for the whole region. Local woody species richness was positively related to latitude and negatively related to elevation. Also, it was positively related to annual precipitation and atmospheric relative moisture, and negatively to mean minimal temperature of winter. In addition, precipitation increased with latitude, and minimal temperature of winter decreased with elevation. These results suggest that climate may be an important driver of altitudinal and latitudinal patterns of local species richness of woody species in central Chile.

Geographic patterns of species richness of diurnal raptors in Venezuela

Knowledge of a species’ geographic distribution is crucial to assessing its vulnerability. It is also important to know if protected areas provide effective protection for raptor species. Here, we examine the species richness (S) patterns, factors predicting S and the effectiveness of protected areas (EPA) in the conservation of diurnal raptors in Venezuela. We modeled geographic distributions (SDM) of 64 raptor species using ecological niche models. Nine climatic and seven landscape metrics were used as environmental predictors. SDM were stacked to examine S and predictors of S were investigated using regression models. This study evaluated S patterns in the 13 bioregions defined for Venezuela. A gap analysis was performed to evaluate the EPA in the conservation of raptor diversity. Forty species showed a continuous distribution, whereas as disjunct distributions were observed in 24 species. Species richness differed among bioregions; six pairwise compared bioregions did not show differences. Guyana Massif and the mountains of northern Venezuela had the highest species richness. Landscape features, specifically canopy height, land cover and terrain slope explained most of the species richness. Environmental heterogeneity affected the distribution of S and is therefore important in conservation planning for Neotropical raptors. Responses from environmental variables used to predict S were scale dependent; it is necessary to standardize methods/experimental design to study the biogeography of raptors. Priority-setting for the conservation of raptors in Venezuela must consider restricted range species, even if they are not threatened. A new territorial ordering is urgent to improve the protection of this group of birds.

Distribution, congruence, and hotspots of higher plants in China.

Identifying biodiversity hotspots has become a central issue in setting up priority protection areas, especially as financial resources for biological diversity conservation are limited. Taking China’s Higher Plants Red List (CHPRL), including Bryophytes, Ferns, Gymnosperms, Angiosperms, as the data source, we analyzed the geographic patterns of species richness, endemism, and endangerment via data processing at a fine grid-scale with an average edge length of 30 km based on three aspects of richness information: species richness, endemic species richness, and threatened species richness. We sought to test the accuracy of hotspots used in identifying conservation priorities with regard to higher plants. Next, we tested the congruence of the three aspects and made a comparison of the similarities and differences between the hotspots described in this paper and those in previous studies. We found that over 90% of threatened species in China are concentrated. While a high spatial congruence is observed among the three measures, there is a low congruence between two different sets of hotspots. Our results suggest that biodiversity information should be considered when identifying biological hotspots. Other factors, such as scales, should be included as well to develop biodiversity conservation plans in accordance with the region’s specific conditions.

Geographical patterns of species richness and beta diversity of Larentiinae moths (Lepidoptera: Geometridae) in two temperate biodiversity hotspots

Biodiversity hotspots have been in the mainstream of studies and debates regarding conservation and biodiversity. Results, however, are skewed towards vertebrates and the tropics, and cannot simply be generalized to invertebrates and temperate biodiversity hotspot regions. In this first study of its kind, we explored the spatial patterns of Larentiinae moth (except genus Eupithecia Curtis, 1825) species richness and beta diversity in two neighbouring temperate biodiversity hotspots, the Caucasus and the Irano-Anatolian biodiversity hotspots, Middle Palearctic. We explored how spatial gradients contribute to the formation of moth species richness in these two biodiversity hotspots by disentangling beta diversity patterns to spatial turnover and nestedness components. Larentiinae moths showed a positive association with latitude and a unimodal relationship with elevation. The latitudinal gradient contributed more than the elevational gradient in formation of biodiversity. Both hotspots showed similar patterns of beta diversity partitioning, demonstrating a large contribution of spatial turnover to biodiversity formation. Constant high values of spatial turnover across 17° of latitudinal gradient may indicate that diversity has been formed by a consistent mechanism of horizontal species level diversification of larentine moths throughout mountains.

Downscaling the environmental associations and spatial patterns of species richness.

We introduce a method that enables the estimation of species richness environment association and prediction of geographic patterns of species richness at grains finer than the original grain of observation. The method is based on a hierarchical model that uses coarse-grain values of species richness and fine-grain environmental data as input. In the model, the (unobserved) fine-grain species richness is linked to the observed fine-grain environment and upscaled using a simple species-area relationship (SAR). The upscaled values are then stochastically linked to the observed coarse-grain species richness. We tested the method on Southern African Bird Atlas data by downscaling richness from 2 degrees to 0.25 degrees (-250 km to -30 km) resolution. When prior knowledge of the SAR slope (average species turnover within coarse-grain cells) was available, the method predicted the fine-grain relationship between richness and environment and provided fine-grain predictions of richness that closely resembled results from native fine-grain models. Without the SAR knowledge the method still accurately quantified the richness-environment relationship, but accurately predicted only relative (rank) values of richness. The approach can be easily extended and it is a powerful path for cross-scale statistical modeling of richness-environment relationships, and for the provision of high-resolution maps for basic science and conservation.