Water availability drives gradients of tree diversity,structure and functional traits in the Atlantic–Cerrado–Caatinga transition,Brazil

Aims Climate and soil are among the most important factors determining variation in tree communities, but their effects have not been thoroughly elucidated to date for many vegetation features. In this study, we evaluate how climate and soil gradients affect gradients of vegetation composition, species diversity and dominance, structure and functional traits (seed mass and wood density) using over 327 000 trees in 158 sites distributed along environmental gradients in the transitions among the Atlantic forest, Cerrado and Caatinga in Minas Gerais State (MG), Brazil (nearly 600 000 km2).     

Environmental correlates of anuran beta diversity in the Brazilian Cerrado

Evolutionary processes are known to influence contemporary patterns of biological diversity, yet disentangling the effects of current and historical drivers of biodiversity patterns remain challenging. We use spatial analyses of community dissimilarity to generate hypotheses about the current and historical processes underlying patterns of beta diversity in anuran species in the Brazilian Cerrado. Specifically, we use a generalized dissimilarity modeling (GDM) approach to model compositional dissimilarity of anuran species and endemics as a function of geographic separation and local (within‐Cerrado) environmental conditions. To gain insight about potential historical processes, we incorporate information from biomes adjacent to the Cerrado to investigate whether environmental conditions in neighboring areas can help explain patterns of beta diversity within the Cerrado. Patterns of anuran beta diversity of both endemics and all species in the Cerrado appear to be strongly influenced by local environmental gradients, with elevation as one of the most important variables in all models. However, in models using endemic species only, environmental conditions of adjacent biomes were related to beta‐diversity patterns, and more strongly so, than to total species models. These results suggest that phylogenetic niche conservatism within species groups that invaded the Cerrado from adjacent biomes may cause these species to be restricted to environmental conditions within the Cerrado that are most similar to the conditions in the adjacent biome where they originated. Time‐calibrated phylogenies of Cerrado endemics and studies of ancestral and current ranges of Cerrado species are needed to test this hypothesis.     

Longitudinal Distribution of the Functional Feeding Groups of Aquatic Insects in Streams of the Brazilian Cerrado Savanna

We demonstrate that the distribution of the functional feeding groups of aquatic insects is related to hierarchical patch dynamics. Patches are sites with unique environmental and functional characteristics that are discontinuously distributed in time and space within a lotic system. This distribution predicts that the occurrence of species will be based predominantly on their environmental requirements. We sampled three streams within the same drainage basin in the Brazilian Cerrado savanna, focusing on waterfalls and associated habitats (upstream, downstream), representing different functional zones. We collected 2,636 specimens representing six functional feeding groups (FFGs): brushers, collector–gatherers, collector–filterers, shredders, predators, and scrapers. The frequency of occurrence of these groups varied significantly among environments. This variation appeared to be related to the distinct characteristics of the different habitat patches, which led us to infer that the hierarchical patch dynamics model can best explain the distribution of functional feeding groups in minor lotic environments, such as waterfalls.     

Water availability determines physiognomic gradient in an area of low-fertility soils under Cerrado vegetation

Soil is one of the environmental elements to influence Cerrado vegetation. Aluminum toxicity of Cerrado soils is well known, but the importance of water availability is still to be understood, especially in Cerrado under wetter climates. We studied the association between Cerrado physiognomies (cerrado sensu stricto and cerradão) and morphological, chemical, physical, and physical–hydrical soil attributes at southwestern São Paulo State, Brazil. Characterization of soil morphology, classification and sample collection for particle-size distribution, and chemical and water-retention analyses were carried out in 15 permanent plots, where vegetation was characterized floristically and structurally. Simple correlation and canonical correspondence analyses were performed with soil data. Classification of soils (U.S. Soil Taxonomy) with very low clay contents was not able to separate soils under cerradão—forestry physiognomy—from those under cerrado sensu stricto—savannic physiognomy, even though it tends to distinguish soils under greater biomass from those under lower biomass physiognomies. High soil acidity of all studied soils and increased at the sites with greater contents of organic matter, mainly with the cerradão physiognomy, precluded Al toxicity as a cause of the physiognomic gradient within Cerrado. Clay content, microporosity, and residual and saturation moisture were the most significant soil attributes to correlate directly with the cerradão physiognomy, indicating that water availability is the main factor explaining the physiognomic gradient of Cerrado vegetation in a local scale, where climate and soil fertility do not vary spatially.     

Effects of landscape and patch attributes on the functional diversity of medium and large-sized mammals in the Brazilian Cerrado

The Cerrado ecoregion, although threatened, holds an important diversity of medium- and large-sized mammals, which play considerable ecological functions. However, the functional diversity of medium- and large-sized mammals is considerably affected by landscape characteristics. Thus, we inventoried medium- and large-sized mammals in nine patches (natural forest remnants) in the Cerrado ecoregion of central Brazil and investigated the influence of patch and landscape attributes (buffer with 5 km around patch) on their functional diversity. We surveyed these species from August 2016 to January 2017 through camera trapping and active search techniques (tracks, vocalizations, and burrows). Functional diversity was calculated based on body mass, behavior (presence or absence of social behavior), type of locomotion, dietary habits, and environmental sensitivity. For analysis, we divided species into two groups: forest dependent mammals (FDM) and forest non-dependent mammals (NDM). We used Akaike’s information criterion corrected for small sample size to select the models that best explain the functional diversity at the local (patch) and landscape scales. The FDM species were influenced by Normalized Difference Vegetation Index (NDVI) and patch size at the patch scale and by mean patch size and edge density at the landscape scale. The NDM were not influenced by patch and landscape scale attributes. Our results indicated that analyses at two scales with the mammal species grouped considering their differences in dependence of forest remnants is a valid approach for evaluating diversity patterns of medium-and large-sized mammals in the Brazilian Cerrado ecoregion.

     

Precipitation gradients,plant biogeography,and the incidence of drip-tips in Cerrado plant species

Examining how both climate and species distribution patterns correlate with leaf morphology can give insights into the ecological and evolutionary patterns that drive adaptive selection of leaf form and function. Drip-tips are a common feature of leaves in rain forest tree species; they are thought to be an adaptation that aids leaf drying and maximizes photosynthesis in areas with high-rainfall climates. We tested whether this macroecological pattern holds true across the precipitation gradients in a non-rain forest region—the woodland savannas of Brazil known as the Cerrado—and compared our results with previous studies from Amazonia. Drip-tips were, as expected, less common overall in the drier Cerrado than in Amazonia. In addition, within the Cerrado, drip-tips were more prevalent in areas with higher rainfall as well as in Cerrado sites that were closer to Amazonia. Moreover, species that occurred across both the Cerrado and Amazonia had drip-tips more often than species that were found only in the Cerrado. These findings support the hypothesis that drip-tips are adaptive and that either the cost of retaining drip-tips is low or that in drier regions they have other benefits.     

The roles of environment,space, and phylogeny in determining functional dispersion of rodents (Rodentia) in the Hengduan Mountains,China

The recently described trait‐based approach is becoming widely popular for a mechanistic understanding of species coexistence. However, the greatest challenge in functional analyses is decomposing the contributions of different ecological and evolutionary processes (e.g., niche‐based process, neutral process, and evolutionary process) in determining trait structure. Taking rodents (Rodentia) in the Hengduan Mountains as our study model, we aim to (1) quantify the vertical patterns of functional structure for head–body length (HL), tail/body ratio (TR), animal component in diet (ACD), and all traits; (2) disentangle the relative importance of different assembly processes (environment, space, and phylogeny) in structuring trait dispersion; and (3) assess the feasibility of Bergmann's rule and Allen's rule along elevational gradient. Our results have suggested that the vertical functional structure pattern varied across these three traits, indicating distinct functional roles in the community assembly process. These nonrandom vertical patterns of HL, TR, and terminal ACD have demonstrated these traits were dominated by different ecological process along environmental gradient. In variance partitioning, high proportion of the spatial variations in trait dispersion was explained by environmental and spatial models, which have provided supporting strong evidence for niche‐based and neutral processes in leading species coexistence. Although the three traits all exhibited apparent phylogenetic signals, phylogenetic relationship within community failed to predict the spatial variations of functional dispersion, confirming the enormous inference of phylogenetic signals in predicting trait structure. By assessing the vertical patterns of HL and TR at order and family levels, we argued that functional adaptation along an environmental gradient is a surrogate of series of complex processes (e.g., environmental filtering, interspecific interaction, and neutral dispersal) acting on multiple functional axes, which results in inconsistence with the empirical rules along elevational gradient.     

Can Saturniidae moths be bioindicators? Spatial and temporal distribution in the Brazilian savannah

Some moths species are considered good indicators of habitat quality because they are very responsive to human disturbance, vegetation type, and successional processes. However, Saturniidae moths have not yet been considered as indicators of environmental quality. Little is known on the distribution of moth species in different vegetation types and the moths’ seasonal variations in the Brazilian savannah. Therefore, this study aims to describe the spatial distribution and temporal patterns of moths belonging to the Saturniidae family in two vegetation types—Cerrado sensu stricto on rocky outcrops and semi-deciduous forest—in both the rainy and dry seasons. It addresses the influence of the climatic seasons and vegetation types on abundance, richness, and species composition to describe the temporal and spatial distribution patterns and the relationship between the ecological aspects and the life history of these moths. This study was conducted in the Cerrado phytogeographical domain, in Pireneus State Park, Goiás, Brazil. The results revealed that most Saturniidae species sampled are present during the rainy season and typically found in forest habitats. Furthermore, a clear positive connection was found between the abundance pattern and rainfall seasonality and humid habitats; this is apparently related to the physiological tolerance of these moths, due to rudimentary mouthparts during their adulthood. Thus, rainfall and a forest habitat are important to and fundamental requirements for the persistence of the Saturniidae species in the Cerrado domain. Based on the results of this study, we suggest the use of saturniid species as indicators of changes in vegetation and climatic conditions.     

Frugivory and seed dispersal in the Cerrado: Network structure and defaunation effects

Seed dispersal is a fundamental process that is highly threatened by the rapid decline of large-bodied frugivores worldwide. The Brazilian Cerrado, the largest savanna in the world, represents an ideal site for investigating seed dispersal because of its biodiversity, environmental challenges, and knowledge shortfalls. We performed a systematic literature review to analyze the seed dispersal network in the Cerrado and the potential impacts of the defaunation of large-bodied frugivores on it. We considered network metrics, calculated the defaunation index of the frugivore assemblage, and compared traits among different fruit-sized plants and their respective dispersers in the network. We retrieved 1565 interactions involving 193 plant species and 270 animal species. Results show that the Cerrado seed dispersal network is slightly nested and considerably modular, dominated by small- to medium-sized generalist species, such as passerines, marsupials, and mesocarnivores. Nonetheless, large-bodied frugivores like the lowland tapir have a key role in the network due to their great foraging and network integration capacity. The Cerrado frugivore assemblage is moderately defaunated, with possible effects in its interactions with large-fruited plants. The Cerrado's defaunation and functional loss of large vertebrates deserve urgent attention to further understand the impacts on seed dispersal mechanisms and ecosystem functioning.     

克隆植物芦苇叶片功能性状对异质环境的响应

芦苇叶片功能性状的空间变化反映克隆植物的资源分配格局,而其与土壤环境因子的耦合关系体现了克隆植物对异质环境的生态适应策略。本研究以中国西北内陆湿地克隆植物芦苇为对象,分析了湿生生境、盐沼生境、荒漠生境条件下芦苇叶片功能性状及其对土壤环境因子的响应。结果表明: 从湿生生境到荒漠生境,芦苇叶片C、N、P含量分别下降7.2%、40.0%、64.1%,N、P利用效率增加,芦苇叶长、叶宽、叶面积、叶干重、比叶面积和叶厚度均表现出减小趋势。芦苇叶片功能性状间存在协同变化的特征,比叶面积与叶片营养元素表现出显著相关关系。土壤容重、盐分和水分分别是驱动湿生生境、盐沼生境和荒漠生境芦苇叶片功能性状变异的最重要的环境因子。     

Assessment of the nursery species pool for restoring landscapes in southeastern Brazil

Brazil has committed to fulfilling international restoration goals and to enforcing environmental legislation that will require private landowners to undertake ecological restoration of 21 million hectares of degraded and deforested landscapes. To support a broad range of restoration practices, a well‐established supply chain capable of representing regional plant diversity is essential. This study investigated the restoration species pool in native plant nurseries in São Paulo state, located in southeastern Brazil, and evaluated their geographic distribution, similarity of their plant stocks, and the proportion of species represented from regional floras. Despite a lack of technical assistance and a significant presence of nonnative species (126 species, average 7.5 species/nursery), we found an impressive native species richness in plant nurseries (561 species, average 86.4 species/nursery) from both the Atlantic Forest and Cerrado domains, representing 38–44% of regional floras. There was a huge bias toward tree and shrub species (96.6%) and an absence or underrepresentation of other growth forms, as well as of savanna specialists, animal‐dispersed, and threatened species. The dissimilarity of species observed among the different nurseries surveyed highlights their role in representing regional diversity, which reflects their regional seed collection practices. Effective assistance and training are essential to address issues related to misidentification of species, underrepresentation of most functional plant groups, and the presence of nonnative species, as well as to support the supply chain, which is currently undergoing a market downturn.     

生态梯度轴(EGA)用于林木生态遗传的研究——PCA方法估算EGAPC_r

n个群体的p维环境因子主成分分析（PCA）,Z＝U’X,恢复原始数据线性表达成X＝UZ,依据λ值,取前－1r个主成分,1≤r≤p,将P维环境因子降维成1元向量,建立前r个主成分的生态梯度轴（EGA（PCr)],估算误差为d(j)。对白榆全分布区20个群体的样点6维环境因子PCA求算的EGA（PCr),取r=1,2,3,建立3个生态梯度轴,累计贡献率依次为63．8％,84．3％和96．0％,都能较好的代表环境因子,EGA（PCr)在揭示群体7个性状的梯度变异中得到验证,并能用于判别种群变异模式。     

Effects of freshwater eutrophication on species and functional beta diversity of periphytic algae

Studies about beta diversity and environmental heterogeneity have shown that the strength of the environmental filtering effect may decrease with the increasing scale. These empirical results have related eutrophic aquatic environments to higher values of beta diversity, but never to dissimilarity of species and functional traits of periphytic algae. We tested the hypotheses that periphytic algae have higher dissimilarity of both species and functional traits in eutrophic environments, and that these dissimilarities are related to environmental dissimilarity. To this end, we used richness, density, and four functional traits of periphytic algae and local limnological data from wetlands in the Brazilian savanna (Cerrado). We analyzed the beta diversity and the relationship of species and functional dissimilarities with the environmental dissimilarity and geographic distances. Our hypothesis was confirmed for functional traits dissimilarity and for the importance of the environmental dissimilarity for both species and functional beta diversity. The cultural eutrophication led to a functional homogenization in urban wetlands, which indicates the establishment of species with similar ecological requirements, and consequently, similar ‘roles’ in the ecosystem, and also that sensitive species may have been replaced by tolerant species, leading to declining biodiversity.

     

Effects of abandoned Eucalyptus plantations on lizard communities in the Brazilian Cerrado

The rapid expansion of human altered landscapes affects biodiversity on every continent. A fundamental goal of conservation biologists is to understand why certain species are at risk of extinction while others are able to persist in human altered landscapes. Afforestation, the conversion of unforested lands to planted forest, is rapidly altering many natural landscapes worldwide. In the Cerrado (Brazilian savanna), a global biodiversity hotspot, a shortage of government incentives has the landscape riddled with abandoned plantation forests that are not subject to active restoration projects. Studies investigating the impacts of abandoned plantations on biodiversity are strikingly limited. We examine the effects of abandoned Eucalyptus plantations on the structure of Cerrado lizard communities. We assessed changes in lizard capture, richness and equitability along cerrado sensu stricto—Eucalyptus transects. Our results indicate abandoned Eucalyptus plantations have subsets of Cerrado species persisting with a great loss of endemic species. The cerrado sensu stricto—Eucalyptus linear transect analysis demonstrated distance from native habitat is positively correlated with loss of biodiversity. We performed correspondence analyses to summarize the variation in species captures across different sites, habitats and pitfall array positions. These analyses depicted strong species associations between habitats and their pitfall array positions. This study is the first to show the negative impacts of abandoned Eucalyptus plantations on Cerrado lizard communities, serving as a cautionary tale of Cerrado biodiversity non-resilience in abandoned Eucalyptus plantations. Mitigation requires that abandoned Eucalyptus plantations are made more suitable to Cerrado lizards by implementing targeted habitat heterogeneity restoration.     

Climatic drivers of leaf traits and genetic divergence in the tree Annona crassiflora: a broad spatial survey in the Brazilian savannas

The Cerrado is the largest South American savanna and encompasses substantial species diversity and environmental variation. Nevertheless, little is known regarding the influence of the environment on population divergence of Cerrado species. Here, we searched for climatic drivers of genetic (nuclear microsatellites) and leaf trait divergence in Annona crassiflora, a widespread tree in the Cerrado. The sampling encompassed all phytogeographic provinces of the continuous area of the Cerrado and included 397 individuals belonging to 21 populations. Populations showed substantial genetic and leaf trait divergence across the species' range. Our data revealed three spatially defined genetic groups (eastern, western and southern) and two morphologically distinct groups (eastern and western only). The east‐west split in both the morphological and genetic data closely mirrors previously described phylogeographic patterns of Cerrado species. Generalized linear mixed effects models and multiple regression analyses revealed several climatic factors associated with both genetic and leaf trait divergence among populations of A. crassiflora. Isolation by environment (IBE) was mainly due to temperature seasonality and precipitation of the warmest quarter. Populations that experienced lower precipitation summers and hotter winters had heavier leaves and lower specific leaf area. The southwestern area of the Cerrado had the highest genetic diversity of A. crassiflora, suggesting that this region may have been climatically stable. Overall, we demonstrate that a combination of current climate and past climatic changes have shaped the population divergence and spatial structure of A. crassiflora. However, the genetic structure of A. crassiflora reflects the biogeographic history of the species more strongly than leaf traits, which are more related to current climate.     

Squamate richness in the Brazilian Cerrado and its environmental–climatic associations

We investigate patterns of species richness of squamates (lizards, snakes, and amphisbaenians) in the Brazilian Cerrado, identifying areas of particularly high richness, and testing predictions of large‐scale richness hypotheses by analysing the relationship between species richness and environmental climatic variables. We used point localities from museum collections to produce maps of the predicted distributions for 237 Cerrado squamate species, using niche‐modelling techniques. We superimposed distributions of all species on a composite map, depicting richness across the ecosystem. Then, we performed a multiple regression analysis using eigenvector‐based spatial filtering (Principal Coordinate of Neighbour Matrices) to assess environmental–climatic variables that are best predictors of species richness. We found that the environmental–climatic and spatial filters multiple regression model explained 78% of the variation in Cerrado squamate richness (r² = 0.78; F = 32.66; P < 0.01). Best predictors of species richness were: annual precipitation, precipitation seasonality, altitude, net primary productivity, and precipitation during the driest quarter. A model selection approach revealed that several mechanisms related to the different diversity hypothesis might work together to explain richness variation in the Cerrado. Areas of higher species richness in Cerrado were located mainly in the south‐west, north, extreme east, and scattered areas in the north‐west portions of the biome. Partitioning of energy among species, habitat differentiation, and tolerance to variable environments may be the primary ecological factors determining variation in squamate richness across the Cerrado. High richness areas in northern Cerrado, predicted by our models, are still poorly sampled, and biological surveys are warranted in that region. The south‐western region of the Cerrado exhibits high species richness and is also undergoing high levels of deforestation. Therefore, maintenance of existing reserves, establishment of ecological corridors among reserves, and creation of new reserves are urgently needed to ensure conservation of species in these areas.     

生态梯度轴(EGA)用于林木生态遗传的研究——CA方法估算EGA(CA_1)和EGA(r~2)

应用典型相关的原理和技术,将多元地理坐标和生态因子降维成1元,研究提出2个生态梯度轴(EGA);EGA(CA_1)和EGA(r~2)。通过白榆20个种源的2个EGA估算,它们与6个环境因子平均相关系数为0.8551和0.8804,复相关系数0.9998和0.9985,很好地综合了诸环境因子在对群体7个性状分析结果,EGA能很好描述梯度变异,证明了白榆种群属于连续变异模式。     

Soil properties and geomorphic processes influence vegetation composition,structure, and function in the Cerrado Domain

Plant and Soil - The Cerrado of central Brazil—the world’s largest Neotropical savanna – is comprised of a mosaic of highly heterogeneous vegetation growing on an extremely...     

Integrating phylogenetic and functional biodiversity facets to guide conservation: a case study using anurans in a global biodiversity hotspot

The Cerrado is one of the most threatened biomes in Brazil, with little spatial representation within the Protected Area network. Recently, proposed conservation plans worldwide have advocated for the use of multiple biodiversity facets to protect unique evolutionary and functional processes. Our aim was to identify areas with high biodiversity representativeness applying this multifaceted perspective, and propose conservation plans based on the joint analysis of taxonomic, functional and phylogenetic diversity. We used a database of the Brazilian National Program for Research in Biodiversity, which employs a standard protocol for sampling tadpoles. The Cerrado database includes samples from 165 water bodies spread over 15 localities, covering most of the Central Brazilian Cerrado. We selected four morphological traits to calculate functional diversity and used a dated phylogeny available in the literature to compute phylogenetic diversity. Our approach selected five priority areas for conservation, one of which is already protected. Our results highlighted the importance of four new areas which show high values of diversity, including original lineages and traits, and urgently need conservation prioritization. Furthermore, unlike the current protected network, our approach performs significantly better than random at protecting sites with high phylogenetic and functional diversity. We therefore discuss how the multifaceted indices considered can help protect key ecosystem functions and evolutionary legacy in anuran communities of the Brazilian Cerrado.