Predictors of elevational biodiversity gradients change from single taxa to the multi-taxa community level

Song determined by phylogeny and body mass in two differently constrained groups of birds: manakins and cardinals

The songs of birds are complex signals that may have several functions and vary widely among species. Different ecological, behavioural and morphological factors, as well as phylogeny, have been associated as predictors of the evolution of song structure. However, the importance of differences in development, despite their relevance, has seldom been considered. Here, we analysed the evolution of song in two families of songbirds that differ in song development, manakins (suboscines) and cardinals (oscines), with their phylogeny, morphology, and ecology. Our results show that song characteristics had higher phylogenetic signal in cardinals than in manakins, suggesting higher evolutionary lability in the suboscines. Body mass was the main predictor of song parameters in manakins, and together with habitat type, had a major effect on cardinals' song structure. Precipitation and altitude were also associated with some song characteristics in cardinals. Our results bring unexpected insights into birdsong evolution, in which non-learners (manakins) revealed greater evolutionary lability than song learners (cardinals).

Phylogenetic structure of moth communities (Geometridae, Lepidoptera) along a complete rainforest elevational gradient in Papua New Guinea

We use community phylogenetics to elucidate the community assembly mechanisms for Geometridae moths (Lepidoptera) collected along a complete rainforest elevational gradient (200-3700 m a.s.l) on Mount Wilhelm in Papua New Guinea. A constrained phylogeny based on COI barcodes for 604 species was used to analyse 1390 species x elevation occurrences at eight elevational sites separated by 500 m elevation increments. We obtained Nearest Relatedness Index (NRI), Nearest Taxon Index (NTI) and Standardised Effect Size of Faith's Phylogenetic Diversity (SES.PD) and regressed these on temperature, plant species richness and predator abundance as key abiotic and biotic predictors. We also quantified beta diversity in the moth communities between elevations using the Phylogenetic Sorensen index. Overall, geometrid communities exhibited phylogenetic clustering, suggesting environmental filters, particularly at higher elevations at and above 2200 m a.s.l and no evidence of overdispersion. NRI, NTI and SES.PD showed no consistent trends with elevation or the studied biotic and abiotic variables. Change in community structure was driven by turnover of phylogenetic beta-diversity, except for the highest 2700-3200 m elevations, which were characterised by nested subsets of lower elevation communities. Overall, the elevational signal of geometrid phylogeny was weak-moderate. Additional insect community phylogeny studies are needed to understand this pattern.

Taxon-dependent diversity response along a temperate elevation gradient covered by grassland

Elevational gradients constitute excellent systems for understanding the mechanisms that generate and maintain global biodiversity patterns. Climatic gradients associated with elevation show strong influence on species distribution in mountains. The study of mountains covered by the same habitat type is an ideal scenario to compare alternatives to the energy hypotheses. Our aim was to investigate how changes in climatic conditions along the elevational gradient drive α- and β-diversity of four taxa in a mountain system located within a grassland biome. We sampled ants, spiders, birds and plants, and measured climatic variables at six elevational bands (with 10 sampling sites each) established between 470 and 1,000 masl on a mountain from the Ventania Mountain System, Argentina. Species richness per site and β-diversity (turnover and nestedness) between the lowest band and upper sites were estimated. For most taxa, species richness declined at high elevations and energy, through temperature, was the major driver of species richness for ants, plants and birds, prevailing over productivity and water availability. The major β-diversity component was turnover for plants, spiders and birds, and nestedness for ants. The unique environmental conditions of the upper bands could favour the occurrence of specialist and endemic species.

Optimizing efficiency and resilience of no-take marine protected areas for fish conservation under climate change along the coastlines of China Seas

Climate change is one of the major threats to coastal fish biodiversity, and optimization of no-take marine protected areas (MPAs) is imminent. We predicted fish redistribution under climate change in coastal China Seas with joint species distribution modeling and prioritized areas for conservation with Zonation, for which we used core area zonation (CAZ) and additive benefit function (ABF). Based on our results, we devised an expansion plan of no-take MPAs. Under climate change, fish were redistributed northward along the coast. These redistributions were segmented by the Yangtze River estuary and its adjacent waters, indicating a possible biogeographical barrier. Under CAZ and ABF, significantly more fish habitat was conserved than under random prioritization (p < 0.001, Cohen's d = -0.36 and -0.62, respectively). The ABF better represented areas with higher species richness, whereas CAZ better represented core habitats for species with narrow distributions. Without accounting for species redistribution, the expanded MPAs were mainly distributed in the northwest of the South China Sea, the East China Sea, the north of the Yellow Sea, and the west of the Bohai Sea. When accounting for species redistribution, the proposed MPAs were mainly distributed in the north of the Bohai Sea and southwest of the Yellow Sea, corresponding to the northern species redistributions. These MPAs conserved less habitat for fishes at present but protected more and better quality habitat for fishes in 2050 and 2100 than those MPAs that did not account for species redistribution, indicating improved fish conservation under climate change. Incorporating species redistribution and trade-offs between areas with high species richness and areas that contain habitats for rare species are suggested to address coastal fish conservation under climate change. This work provides valuable information for fish conservation and is a precursor to systematic conservation planning along the coastlines of China Seas.

Effects of microhabitat features on the intraspecific variability of the distribution and functional traits in a highest elevational distributed lizard

Exploring the microhabitat determinants of organisms distribution and functional traits differences can help us better understand the importance of intraspecific variations in ecological niches. Investigations on animals functional niche primarily focused on differences among species and tended to neglect the potential variability within species, despite the fact that the ecological and evolutionary importance of intraspecific variations was widely recognized. In this study, we examined the influence of microhabitat features on the intraspecific variability of the distribution and functional traits of a highest elevational distributed lizard species Phrynocephalus erythrurus. To do so, field work was conducted between July and August, 2020 and August and September, 2021 in Namtso watershed in central Xizang, China. Specifically, 11 transects were sampled for P. erythrurus individuals, which were measured for a set of 10 morphological traits. Moreover, 11 microhabitat variables that potentially affect the distribution of lizards were also measured for each transect. Our results indicated that juveniles, males, and females exhibited different functional traits, allowing them to occupy distinct functional space. The distribution of juveniles, males, and females was determined by different microhabitat variables such as illuminance and air temperature. More importantly, these variables also determined the intraspecific functional traits variability in this lizard species. All of these results supported previous claims that intraspecific traits variation should be incorporated into functional ecological studies, and diverse microhabitat features should be conserved to maintain high intraspecific diversity. Future studies can focus on the food analysis to explore the linkage between functional traits and resources utilization within animal populations.

Community metabarcoding reveals the relative role of environmental filtering and spatial processes in metacommunity dynamics of soil microarthropods across a mosaic of montane forests

Disentangling the relative role of environmental filtering and spatial processes in driving metacommunity structure across mountainous regions remains challenging, as the way we quantify spatial connectivity in topographically and environmentally heterogeneous landscapes can influence our perception of which process predominates. More empirical data sets are required to account for taxon- and context-dependency, but relevant research in understudied areas is often compromised by the taxonomic impediment. Here we used haplotype-level community DNA metabarcoding, enabled by stringent filtering of amplicon sequence variants (ASVs), to characterize metacommunity structure of soil microarthropod assemblages across a mosaic of five forest habitats on the Troodos mountain range in Cyprus. We found similar β diversity patterns at ASV and species (OTU, operational taxonomic unit) levels, which pointed to a primary role of habitat filtering resulting in the existence of largely distinct metacommunities linked to different forest types. Within-habitat turnover was correlated to topoclimatic heterogeneity, again emphasizing the role of environmental filtering. However, when integrating landscape matrix information for the highly fragmented Quercus alnifolia habitat, we also detected a major role of spatial isolation determined by patch connectivity, indicating that stochastic and niche-based processes synergistically govern community assembly. Alpha diversity patterns varied between ASV and OTU levels, with OTU richness decreasing with elevation and ASV richness following a longitudinal gradient, potentially reflecting a decline of genetic diversity eastwards due to historical pressures. Our study demonstrates the utility of haplotype-level community metabarcoding for characterizing metacommunity structure of complex assemblages and improving our understanding of biodiversity dynamics across mountainous landscapes worldwide.

Temperature and predators as interactive drivers of community properties

The effects of warming on ecological communities emerge from a range of potentially asymmetric impacts on individual physiology and development. Understanding these responses, however, is limited by our ability to connect mechanisms or emergent patterns across the many processes that drive variation in demography. Further complicating this understanding is the gain or loss of predators to many communities, which may interact with changes in temperature to drive community change. Here we conducted a factorial warming and predation experiment to test generalized predictions about responses to warming. We used microcosms with a range of protists, rotifers, and a gastrotrich, with and without the predator Actinosphaerium, to assess changes in diversity, body size, function, and composition in response to warming. We find that community respiration and predator:prey biovolume ratios peak at intermediate temperatures, while species richness declined with temperature. We also found that overall biomass increased with species richness, driven by the effect of temperature on richness. There was little evidence of an interaction between predation and temperature change, likely because the predator was mostly limited to the intermediate temperatures. Overall, our results suggest that general predictions about community change are still challenging to make but may benefit by considering multiple dimensions of community patterns in an integrated way.

The declines of heterogeneity and stability in diatom communities are associated with human activity

Anthropogenic forcing caused the biodiversity loss and stability decline of communities. There is still controversy over whether the decline in biodiversity will lead to a decrease in community stability. The stability of biological communities is related to both biodiversity and structure, and this paper aims to reveal the human impacts on diatom communities' biodiversity and structure. We studied the richness, β-diversity and network distance of diatom communities in Qinghai-Xizang, Yunnan-Sichuan and Lower Yangtze River Basin, China through empirical dataset and simulation method. The results showed that the diatoms richness in the Qinghai-Xizang and the Yunnan-Sichuan region was lower and the network distance was higher than that of the Lower Yangtze River Basin. β-diversity in the Lower Yangtze River Basin was the lowest and the diatom network distance responds negatively to human population densities in China. The simulation showed that the network distance kept constant during random species loss, and declined while specialist species were lost or replaced by generalist species. The results suggested diatom communities' homogeneity and stability decline were associated with human activities. Human impacts may cause biodiversity loss targeted to specialist species or no biodiversity loss while generalist species replace those specialist species. This study showed that how diversity changes determined ecological stability depends on the type of species changes.

Seasonal and elevational changes of plant-pollinator interaction networks in East African mountains

Across an elevation gradient, several biotic and abiotic factors influence community assemblages of interacting species leading to a shift in species distribution, functioning, and ultimately topologies of species interaction networks. However, empirical studies of climate-driven seasonal and elevational changes in plant-pollinator networks are rare, particularly in tropical ecosystems. Eastern Afromontane Biodiversity Hotspots in Kenya, East Africa. We recorded plant-bee interactions at 50 study sites between 515 and 2600 m asl for a full year, following all four major seasons in this region. We analysed elevational and seasonal network patterns using generalised additive models (GAMs) and quantified the influence of climate, floral resource availability, and bee diversity on network structures using a multimodel inference framework. We recorded 16,741 interactions among 186 bee and 314 plant species of which a majority involved interactions with honeybees. We found that nestedness and bee species specialisation of plant-bee interaction networks increased with elevation and that the relationships were consistent in the cold-dry and warm-wet seasons respectively. Link rewiring increased in the warm-wet season with elevation but remained indifferent in the cold-dry seasons. Conversely, network modularity and plant species were more specialised at lower elevations during both the cold-dry and warm-wet seasons, with higher values observed during the warm-wet seasons. We found flower and bee species diversity and abundance rather than direct effects of climate variables to best predict modularity, specialisation, and link rewiring in plant-bee-interaction networks. This study highlights changes in network architectures with elevation suggesting a potential sensitivity of plant-bee interactions with climate warming and changes in rainfall patterns along the elevation gradients of the Eastern Afromontane Biodiversity Hotspot.

Patterns and drivers of soil surface-dwelling Oribatida diversity along an altitudinal gradient on the Changbai Mountain, China

Distribution patterns of biodiversity and environmental interactions are dominant themes in ecology. In montane ecosystems, biodiversity is closely associated with altitudinal gradients. However, studies of biodiversity in montane ecosystems are focused on plants and vertebrates, with relatively less on invertebrates. Here, the present study used a Vortis arthropod suction sampler to explore the biodiversity patterns of soil surface-dwelling Oribatida and their drivers along an altitudinal gradient (600, 800, 1600, 2000, and 2300 m) from typical temperate forests, evergreen coniferous forests, subalpine birch forests to alpine tundra on the north slope of Changbai Mountain, Northeast China. Trichoribates berlesei, Platynothrus peltifer, and Oribatula tibialis were the dominant soil surface-dwelling species on Changbai Mountain. Generally, alpha diversity and beta diversity of soil surface-dwelling Oribatida decreased with the rising altitude, with a peaking density value at 2000 m. The result of beta diversity showed that the structures of community were more influenced by the species turnover component than the nestedness component. Nonmetric multidimensional scaling (NMDS) ordination showed that the community structure of soil surface-dwelling Oribatida varied significantly along the altitudinal gradient. The variance partitioning showed that the elevation and climatic conditions determined the soil surface-dwelling Oribatida community. Spatial filtering represented by geographic and elevation distances was particularly associated with soil surface-dwelling Oribatida community variation between altitudes on Changbai Mountain. However, the variation of the Oribatida community between adjacent altitudes was only associated with geographic distance. Our study provides supportive evidence for the biodiversity analyzing of soil surface-dwelling Oribatida in montane ecosystems along an altitudinal gradient.

Effects of Environmental Factors on the Spatial Distribution Pattern and Diversity of Insect Communities along Altitude Gradients in Guandi Mountain, China

Understanding the distribution patterns and underlying maintenance mechanisms of insect species is a core issue in the field of insect ecology. However, research gaps remain regarding the environmental factors that determine the distribution of insect species along altitudinal gradients in Guandi Mountain, China. Here, we explored these determinants based on the distribution pattern and diversity of insect species from 1600 m to 2800 m in the Guandi Mountain, which covers all typical vegetation ecosystems in this area. Our results showed that the insect community showed certain differentiation characteristics with the altitude gradient. The results of RDA and correlation analysis also support the above speculation and indicate that soil physicochemical properties are closely related to the distribution and diversity of insect taxa orders along the altitude gradient. In addition, the soil temperature showed an obvious decreasing trend with increasing altitude, and temperature was also the most significant environmental factor affecting the insect community structure and diversity on the altitude gradient. These findings provide a reference for exploring the maintenance mechanisms affecting the structure, distribution pattern, and diversity of insect communities in mountain ecosystems, and the effects of global warming on insect communities.

Biodiversity patterns diverge along geographic temperature gradients

Models applying space-for-time substitution, including those projecting ecological responses to climate change, generally assume an elevational and latitudinal equivalence that is rarely tested. However, a mismatch may lead to different capacities for providing climatic refuge to dispersing species. We compiled community data on zooplankton, ectothermic animals that form the consumer basis of most aquatic food webs, from over 1200 mountain lakes and ponds across western North America to assess biodiversity along geographic temperature gradients spanning nearly 3750 m elevation and 30° latitude. Species richness, phylogenetic relationships, and functional diversity all showed contrasting responses across gradients, with richness metrics plateauing at low elevations but exhibiting intermediate latitudinal maxima. The nonmonotonic/hump-shaped diversity trends with latitude emerged from geographic interactions, including weaker latitudinal relationships at higher elevations (i.e. in alpine lakes) linked to different underlying drivers. Here, divergent patterns of phylogenetic and functional trait dispersion indicate shifting roles of environmental filters and limiting similarity in the assembly of communities with increasing elevation and latitude. We further tested whether gradients showed common responses to warmer temperatures and found that mean annual (but not seasonal) temperatures predicted elevational richness patterns but failed to capture consistent trends with latitude, meaning that predictions of how climate change will influence diversity also differ between gradients. Contrasting responses to elevation- and latitude-driven warming suggest different limits on climatic refugia and likely greater barriers to northward range expansion.

Climatic and Non-Climatic Drivers of Plant Diversity along an Altitudinal Gradient in the Taihang Mountains of Northern China

Climate is critical for plant altitudinal distribution patterns. Non-climatic factors also have important effects on vegetation altitudinal distribution in mountain regions. The purpose of this study was to explore the current distribution of plant diversity along the altitudinal gradient in the Taihang Mountain range of northern China and to estimate the effects of climatic and non-climatic factors on the elevational pattern. Through a field survey, a total of 480 sampling plots were established in the central Taihang Mountain range. Alpha diversities (the Shannon–Weiner index and Simpson index) and beta diversities (the Jaccard index and Cody index) were measured based on the survey data. Plant community structure change based on the altitudinal gradient was explored by measuring the diversity indices. Canonical correspondence analysis was carried out to determine the factors influencing plant altitudinal distribution. The contributions of climatic and non-climatic factors on plant distribution were determined by partial methods. The results showed that the plant diversity of the elevational gradient complied with a “hump-shaped” pattern, in which communities in the medium altitude area with higher plant diversity had a higher species turnover rate, and non-climatic factors, particularly the anthropogenic factors, had an important influence on the plant altitudinal pattern. In conclusion, climatic and non-climatic factors both had important effects on the plant altitudinal pattern. It is strongly recommended to reduce human interference in mountain vegetation protection and management.

Decomposing niche components reveals simultaneous effects of opposite deterministic processes structuring alpine small mammal assembly

Introduction

Species distribution in alpine areas is constrained by multiple abiotic and biotic stressors. This leads to discrepant assembly patterns between different locations and study objects as opposite niche-based processes—limiting similarity and habitat filtering—simultaneously structure communities, masking overall patterns. We aimed to address how these processes structure small mammal communities in the alpine tree line transition zone, one of the most distinct vegetation transitions between alpine and montane habitats.

Methods

We compiled a dataset of species checklist, phylogeny, and functional traits from field collection and published sources spanning 18 mountains in southwest China. We first examined hypothetical niche-based processes with frequently used phylogenetic and trait approaches using this dataset. The species traits were decomposed into different niche components to explore the respective effects of specific stressors. Indices representing evolutionary history, trait space, and pairwise species distance were estimated and compared with null model expectations. Linear mixed-effect models were used to assess the association patterns between diversity indices and elevation.

Results

The results indicated that phylogenetic and functional richness were positively correlated with species richness. In contrast, distance-based indices were either negatively or weakly positively correlated with species richness. Null model analyses suggested no evidence of non-random phylogenetic or overall trait patterns. However, the resource acquisition niche tended to be more overdispersed (positive slopes), while the habitat affinity niche tended to be more clustered (negative slopes) beyond the high elevation tree line.

Discussion

These findings show that opposite niche-based processes simultaneously structure small mammal communities in alpine areas. Overall, the present study provides vital insights into the complexity of assembly processes in these habitats. It also highlights the importance of relating relevant traits to distinguish the influences of specific abiotic and biotic stressors.

Humboldt's legacy: explaining the influence of environmental factors on the taxonomic and phylogenetic diversity of angiosperms along a Neotropical elevational gradient

The scientific work of Alexander von Humboldt was influenced by his interaction with the diversity and natural wealth of the Neotropics. He proposed that climate determines plant diversity along elevational gradients based on his observations. Here, we evaluated the most prominent climate-based hypotheses in explaining plant diversity along an elevational gradient that Humboldt himself visited during his journey across Mexico. Specifically, we examined how climatic variables and forest-use intensity affected species richness and phylogenetic structure of major angiosperm life forms (trees, shrubs, epiphytes, herbs and lianas) along the Cofre de Perote mountain, Veracruz, Mexico. We analysed species richness and phylogenetic structure of angiosperms at eight sites between 30 to 3500 m a.s.l. We estimated the phylogenetic structure using a mega-phylogeny of angiosperms and the abundance-weighted net relatedness index. We considered multiple environmental factors' direct and indirect effects by applying a piecewise structural equation modelling approach. Each life form responds differently to the environmental variables included in our model; however, it is observed that temperature is the main predictor of the taxonomic and phylogenetic diversity of the angiosperms studied, both when the different life forms are grouped and separated. Potential evapotranspiration and precipitation are variables that also influence some life forms' diversity, especially taxonomic diversity. The forest-use intensity negatively affected only the taxonomic diversity of trees. These results highlight the influence of studying the different life forms of angiosperms in diversity gradient models and show the great influence that temperature has in conjunction with other environmental variables to promote the taxonomic and phylogenetic diversity of plant communities. Given the current global environmental crisis, an integrative biogeographically oriented vision based on Humboldt's method is necessary. Honouring the work of Humboldt and continuing his legacy demands more research to understand the causes behind elevational diversity gradients.

Mixed-species bird flocks re-assemble interspecific associations across an elevational gradient

Understanding how non-trophic social systems respond to environmental gradients is still a challenge in animal ecology, particularly in comparing changes in species composition to changes in interspecific interactions. Here, we combined long-term monitoring of mixed-species bird flocks, data on participating species' evolutionary history and traits, to test how elevation affected community assemblages and interspecific interactions in flock social networks. Elevation primarily affected flocks through reassembling interspecific associations rather than modifying community assemblages. Specifically, flock networks at higher elevations (compared to low elevations) had stronger interspecific associations (larger average weighted degree), network connectivity (enhanced network density) and fewer subnetworks. A phylogenetic and functional perspective revealed that associations between similar species weakened, whereas connections between dissimilar and/or random species were unchanged or strengthened with elevation. Likewise, network assortativity for the traits of vertical stratum and breeding period declined with elevation. The overall pattern is a change from modular networks in the lowlands, where species join flocks with other species that have matching traits, to a more open, random system at high elevations. Collectively, this rewiring of interspecific networks across elevational gradients imparts network stability and resiliency and makes mixed-species flocks less sensitive to local extinctions caused by harsh environments.

A multi-level exploration of the relationship between temperature and species diversity: Two cases of marine phytoplankton

The relationship between temperature (T) and diversity is one of the most important issues in ecology. It provides a key direction not only for exploring the determinants of diversity's patterns, but also for understanding diversity's responses to climate change. Previous studies suggested that T-diversity relationships could be positive, negative, or unimodal. Although these studies accumulated many informative achievements, they might be unsatisfied due to (1) investigating inadequate range of T, (2) selecting incomplete diversity metrics, and (3) making insufficiently detailed analysis of correlation. In this study, species diversity is estimated by four most commonly used diversity metrics and three parameters of species abundance distribution (SAD), and two global datasets of marine phytoplankton (covering a wider range of T) are used to evaluate the T-diversity relationships according to a piecewise model. Results show that all aspects of diversity (except evenness) have the similar relationship with T in the range of lower T, noting that diversity significantly increases as T increases. However, in the range of higher T, diversity may significantly decrease or nearly constant, which indicates that their relationships may be the unimodal or asymptotic. The asymptotic relationship found by this study is assumed that increasing diversity with T will gradually approach the Zipf's law (1:1/2:1/3…). If such assumption can be verified by future investigations, the intrinsic mechanism of the asymptotic relationship is likely to be crucial in understanding the T-diversity relationships.

Temperature and Precipitation Drive Elevational Patterns of Microbial Beta Diversity in Alpine Grasslands

Understanding the mechanisms underlying biodiversity patterns is a central issue in ecology, while how temperature and precipitation jointly control the elevational patterns of microbes is understudied. Here, we studied the effects of temperature, precipitation and their interactions on the alpha and beta diversity of soil archaea and bacteria in alpine grasslands along an elevational gradient of 4300-5200 m on the Tibetan Plateau. Alpha diversity was examined on the basis of species richness and evenness, and beta diversity was quantified with the recently developed metric of local contributions to beta diversity (LCBD). Typical alpine steppe and meadow ecosystems were distributed below and above 4850 m, respectively, which was consistent with the two main constraints of mean annual temperature (MAT) and mean annual precipitation (MAP). Species richness and evenness showed decreasing elevational patterns in archaea and nonsignificant or U-shaped patterns in bacteria. The LCBD of both groups exhibited significant U-shaped elevational patterns, with the lowest values occurring at 4800 m. For the three diversity metrics, soil pH was the primary explanatory variable in archaea, explaining over 20.1% of the observed variation, whereas vegetation richness, total nitrogen and the K/Al ratio presented the strongest effects on bacteria, with relative importance values of 16.1%, 12.5% and 11.6%, respectively. For the microbial community composition of both archaea and bacteria, the moisture index showed the dominant effect, explaining 17.6% of the observed variation, followed by MAT and MAP. Taken together, temperature and precipitation exerted considerable indirect effects on microbial richness and evenness through local environmental and energy supply-related variables, such as vegetation richness, whereas temperature exerted a larger direct influence on LCBD and the community composition. Our findings highlighted the profound influence of temperature and precipitation interactions on microbial beta diversity in alpine grasslands on the Tibetan Plateau.

Moth Diversity Increases along a Continent-Wide Gradient of Environmental Productivity in South African Savannahs

Environmental productivity, i.e., the amount of biomass produced by primary producers, belongs among the key factors for the biodiversity patterns. Although the relationship of diversity to environmental productivity differs among studied taxa, detailed data are largely missing for most groups, including insects. Here, we present a study of moth diversity patterns at local and regional scales along a continent-wide gradient of environmental productivity in southern African savannah ecosystems. We sampled diversity of moths (Lepidoptera: Heterocera) at 120 local plots along a gradient of normalized difference vegetation index (NDVI) from the Namib Desert to woodland savannahs along the Zambezi River. By standardized light trapping, we collected 12,372 specimens belonging to 487 moth species. The relationship between species richness for most analyzed moth groups and environmental productivity was significantly positively linear at the local and regional scales. The absence of a significant relationship of most moth groups' abundance to environmental productivity did not support the role of the number of individuals in the diversity-productivity relationship for south African moths. We hypothesize the effects of water availability, habitat complexity, and plant diversity drive the observed moth diversity patterns.

Six groups of ground-dwelling arthropods show different diversity responses along elevational gradients in the Swiss Alps

Elevational gradients along mountain slopes offer opportunities to study key factors shaping species diversity patterns. Several environmental factors change over short distances along the elevational gradient in predictable ways. However, different taxa respond to these factors differently resulting in various proposed models for biodiversity patterns along elevational transects. Using a multi-taxa approach, we investigated the effects of elevation, area, habitat and soil characteristics on species richness, individual abundance and species composition of six groups of ground-dwelling arthropods along four transect lines in the Swiss National Park and its surroundings (Eastern Alps). Spiders, millipedes, centipedes, ants, ground beetles and rove beetles were sampled using standardized methods (pitfall traps, cardboard traps, visual search) in 65 sites spanning an elevational range from 1800 to 2750 m a.s.l.. A total of 14,782 individuals comprising 248 species were collected (86 spider, 74 rove beetle, 34 ground beetle, 21 millipede, 19 centipede and 14 ant species). Linear mixed model-analysis revealed that rarefied species richness in five out of the six arthropod groups was affected by elevation (the quadratic term of elevation provided the best fit in most cases). We found three different patterns (linear decrease in centipedes, low elevation plateau followed by a decrease in ants and rove beetles, and midpoint peak in spiders and millipedes). These patterns were only partially mirrored when considering individual abundance. Elevation influenced species composition in all groups examined. Overall, elevation was the most important factor explaining the diversity patterns, while most local habitat and soil characteristics have little influence on these patterns. Our study supports the importance of using multi-taxa approaches when examining effects of elevational gradients. Considering only a single group may result in misleading findings for overall biodiversity.

Pattern of β-Diversity and Plant Species Richness along Vertical Gradient in Northwest Himalaya, India

Simple Summary

Elevation has a significant impact on the distribution of plant species. However, the structure and distribution patterns of Himalayan vegetation are poorly explored, and research on species composition along an elevation gradient in these mountain ranges is still deficient. Plant species richness is supposed to diminish with altitude, although numerous scientists have found a peak in species richness at mid-elevation, yielding a humped relationship. Many studies along the Himalayan altitudinal gradients have been conducted in order to better understand large-scale biogeographical patterns as well as what drives them, but no clear pattern has emerged. In order to understand how elevation affects plant species, we focused on species diversity, species composition and β-diversity, which allow for the interpreting of different patterns along the elevations. It was found that all these components of diversity vary significantly with the change in altitude.

Abstract

The structure and distribution patterns of Himalayan vegetation are poorly explored, and research on species composition along the elevation gradient in these mountain ranges is still deficient. The current study was undertaken to analyze the variation and pattern of plant species composition along a vertical gradient in northwestern Himalaya, India. A total of 18 sites were selected along an elevation gradient ranging from 2200 to 3900 m asl positioned at an interval of 100 m. The Renyi diversity profile, non-metric multidimensional scaling based on the Bray–Curtis dissimilarity metric and beta diversity components among the elevation belts were calculated. Furthermore, to study the influence of altitude on species richness and diversity, a generalized additive model was created. Two hundred and ten plant species representing 66 families and 147 genera were recorded. The Renyi diversity profiles show that the lower and mid-altitudes had rich species diversity. The results of the non-metric multidimensional scaling analysis show a considerable variation in the total plant species composition among the studied elevation belts. The observed multiple-site Sorensen dissimilarity index across the studied elevation belts was very high. The contribution of species replacement or the turnover component to the observed dissimilarity was much higher than the nestedness component. Furthermore, the herbaceous and tree richness showed a significant decrease with increase in elevation; however, the richness of shrubs showed a bimodal pattern. The present study increases our understanding of the trends and patterns of species richness along the vertical gradient in the Himalayan region.

Functional and phylogenetic diversity of an agricultural matrix avifauna: The role of habitat heterogeneity in Afrotropical farmland

Varied strategies to alleviate the loss of farmland biodiversity have been tested, yet there is still insufficient evidence supporting their effectiveness, especially when considering phylogenetic and functional diversity alongside traditional taxonomic diversity metrics. This conservation challenge is accentuated in the Afrotropics by the rapid agricultural expansion and intensification for the production of cash crops and by a comparative lack of research. In this study, we assessed how farming practices influence avian phylogenetic and functional diversity. We conducted point-count surveys to assess avian diversity in monocultures of tea and mixed crop farming systems surrounding the Nyungwe rainforest in south-west Rwanda, allowing us to investigate the drivers of avian diversity at farm level. Species composition was found to be moderately different between farm types, with mixed crop farms supporting higher phylogenetic diversity than tea plantations. There were no significant seasonal differences in species composition, functional or phylogenetic diversity. Overall, functional diversity did not differ between farm types, but the dispersion of trophic-related traits was significantly higher in mixed crop farms. Both functional and phylogenetic diversity were influenced by floristic diversity, vegetation height, tree number, and elevation to varying degrees. Our results also (i) highlight the role of farmland heterogeneity (e.g., crop species composition, height, and tree cover extent) in encouraging avian functional and phylogenetic diversity in the Afrotropics and (ii) indicate that the generally negative biodiversity impacts of monoculture agriculture can be partially alleviated by extensive agroforestry with an emphasis on indigenous tree species.

Phylogenetic relatedness of food plants reveals highest insect herbivore specialization at intermediate temperatures along a broad climatic gradient

The composition and richness of herbivore and plant assemblages change along climatic gradients, but knowledge about associated shifts in specialization is scarce and lacks controlling for the abundance and phylogeny of interaction partners. Thus, we aimed to test whether the specialization of phytophagous insects in insect-plant interaction networks decreases toward cold habitats as predicted by the 'altitude niche-breadth hypothesis' to forecast possible consequences of interaction rewiring under climate change. We used a non-invasive, standardized metabarcoding approach to reconstruct dietary relationships of Orthoptera species as a major insect herbivore taxon along a broad temperature gradient (~12°C) in Southern Germany. Based on Orthoptera surveys, feeding observations, collection of fecal pellets from >3,000 individuals of 54 species, and parallel vegetation surveys on 41 grassland sites, we quantified plant resource availability and its use by herbivores. Herbivore assemblages were richer in species and individuals at sites with high summer temperatures, while plant richness peaked at intermediate temperatures. Corresponding interaction networks were most specialized in warm habitats. Considering phylogenetic relationships of plant resources, however, the specialization pattern was not linear but peaked at intermediate temperatures, mediated by herbivores feeding on a narrow range of phylogenetically related resources. Our study provides empirical evidence of resource specialization of insect herbivores along a climatic gradient, demonstrating that resource phylogeny, availability, and temperature interactively shape the specialization of herbivore assemblages. Instead of low specialization levels only in cold, harsh habitats, our results suggest increased generalist feeding due to intraspecific changes and compositional differences at both ends of the microclimatic gradient. We conclude that this nonlinear change of phylogeny-based resource specialization questions predictions derived from the 'altitude-niche breadth hypothesis' and highlights the currently limited understanding of how plant-herbivore interactions will change under future climatic conditions.

A framework for near-real time monitoring of diversity patterns based on indirect remote sensing, with an application in the Brazilian Atlantic rainforest

Monitoring biodiversity change is key to effective conservation policy. While it is difficult to establish in situ biodiversity monitoring programs at broad geographical scales, remote sensing advances allow for near-real time Earth observations that may help with this goal. We combine periodical and freely available remote sensing information describing temperature and precipitation with curated biological information from several groups of animals and plants in the Brazilian Atlantic rainforest to design an indirect remote sensing framework that monitors potential loss and gain of biodiversity in near-real time. Using data from biological collections and information from repeated field inventories, we demonstrate that this framework has the potential to accurately predict trends of biodiversity change for both taxonomic and phylogenetic diversity. The framework identifies areas of potential diversity loss more accurately than areas of species gain, and performs best when applied to broadly distributed groups of animals and plants.

Island and Mountain Ecosystems as Testbeds for Biological Control in the Anthropocene

For centuries, islands and mountains have incited the interest of naturalists, evolutionary biologists and ecologists. Islands have been the cradle for biogeography and speciation theories, while mountain ranges have informed how population adaptation to thermal floors shapes the distribution of species globally. Islands of varying size and mountains’ altitudinal ranges constitute unique “natural laboratories” where one can investigate the effects of species loss or global warming on ecosystem service delivery. Although invertebrate pollination or seed dispersal processes are steadily being examined, biological control research is lagging. While observations of a wider niche breadth among insect pollinators in small (i.e., species-poor) islands or at high (i.e., colder) altitudes likely also hold for biological control agents, such remains to be examined. In this Perspective piece, we draw on published datasets to show that island size alone does not explain biological control outcomes. Instead, one needs to account for species’ functional traits, habitat heterogeneity, host community make-up, phenology, site history or even anthropogenic forces. Meanwhile, data from mountain ranges show how parasitism rates of Noctuid moths and Tephritid fruit flies exhibit species- and context-dependent shifts with altitude. Nevertheless, future empirical work in mountain settings could clarify the thermal niche space of individual natural enemy taxa and overall thermal resilience of biological control. We further discuss how global databases can be screened, while ecological theories can be tested, and simulation models defined based upon observational or manipulative assays in either system. Doing so can yield unprecedented insights into the fate of biological control in the Anthropocene and inform ways to reinforce this vital ecosystem service under global environmental change scenarios.

Elevational Gradients Impose Dispersal Limitation on Streptomyces

Dispersal governs microbial biogeography, but the rates and mechanisms of dispersal remain poorly characterized for most microbial taxa. Dispersal limitation is driven by limits on dissemination and establishment, respectively. Elevation gradients create striking patterns of biogeography because they produce steep environmental gradients at small spatial scales, and these gradients offer a powerful tool to examine mechanisms of dispersal limitation. We focus on Streptomyces, a bacterial genus common to soil, by using a taxon-specific phylogenetic marker, the RNA polymerase-encoding rpoB gene. By targeting Streptomyces, we assess dispersal limitation at finer phylogenetic resolution than is possible using whole community analyses. We characterized Streptomyces diversity at local spatial scales (100 to 3,000 m) in two temperate forest sites located in the Adirondacks region of New York State: Woods Lake (<100 m elevation change), and Whiteface Mountain (>1,000 m elevation change). Beta diversity varied considerably at both locations, indicative of dispersal limitation acting at local spatial scales, but beta diversity was significantly higher at Whiteface Mountain. Beta diversity varied across elevation at Whiteface Mountain, being lowest at the mountain’s base. We show that Streptomyces taxa exhibit elevational preferences, and these preferences are phylogenetically conserved. These results indicate that habitat preferences influence Streptomyces biogeography and suggest that barriers to establishment structure Streptomyces communities at higher elevations. These data illustrate that Streptomyces biogeography is governed by dispersal limitation resulting from a complex mixture of stochastic and deterministic processes.

Biodiversity responses to restoration across the Brazilian Atlantic Forest

The UN Decade on Ecosystem Restoration is focussing attention and resources on restoration globally. Nowhere is this more crucial than in tropical forests that harbor immense biodiversity, but have also undergone widespread deforestation over the past few decades. We performed a meta-analysis to investigate how biodiversity features respond to forest restoration across the Brazilian Atlantic Forest (BAF), one of the most threatened biodiversity hotspots in the world. We assembled biodiversity in different metrics of structure and diversity features of three taxonomic groups (vascular plants, soil microorganisms, and invertebrates), generating a dataset with 2370 observations from 76 primary studies. We quantified the incomplete recovery of biodiversity (i.e., the rate of recovery to a pre-disturbance state) occurring during the restoration process, which we called the 'recovery gap'. Our results revealed that forests undergoing restoration in the BAF show a recovery gap of 34% for structure features and 22% for diversity features in comparison to reference reforests, considering all taxonomic groups investigated. For vascular plants, soil microorganisms, and invertebrates the recovery gap ranged between 46 and 47%, 16-26%, and 4-7%, respectively. Overall, the recovery gap was influenced by the interaction of restoration actions (i.e., the past land use, restoration age and restoration approach - active and passive restoration), however, structure features responded more sensitively to the time elapsed since restoration started, while the recovery gap for diversity features depended more on the past land-use. Our study can help guide the prioritization of the aforenamed taxonomic groups in restoration, the regulation of potential biodiversity offsetting policies in the BAF, and understanding how coupled biodiversity features respond to the interaction of environmental conditions and restoration actions in a high fragmented tropical landscape.

Unravelling insect declines: can space replace time?

Temporal trends in insect numbers vary across studies and habitats, but drivers are poorly understood. Suitable long-term data are scant and biased, and interpretations of trends remain controversial. By contrast, there is substantial quantitative evidence for drivers of spatial variation. From observational and experimental studies, we have gained a profound understanding of where insect abundance and diversity is higher-and identified underlying environmental conditions, resource change and disturbances. We thus propose an increased consideration of spatial evidence in studying the causes of insect decline. This is because for most time series available today, the number of sites and thus statistical power strongly exceed the number of years studied. Comparisons across sites allow quantifying insect population risks, impacts of land use, habitat destruction, restoration or management, and stressors such as chemical and light pollution, pesticides, mowing or harvesting, climatic extremes or biological invasions. Notably, drivers may not have to change in intensity to have long-term effects on populations, e.g. annually repeated disturbances or mortality risks such as those arising from agricultural practices. Space-for-time substitution has been controversially debated. However, evidence from well-replicated spatial data can inform on urgent actions required to halt or reverse declines-to be implemented in space.

Spatial and seasonal group size variation of wild mammalian herbivores in multiple use landscapes of the Ngorongoro Conservation Area, Tanzania

Group sizes of wild herbivores can be indicators of ecosystem health and proxies for individual and population fitness, particularly in areas where human activities have become increasingly common. We recorded 176 single- and multi-species groups of wild herbivores in human-dominated landscapes of the Ngorongoro Conservation Area (NCA) during dry and wet seasons. We analyzed how wild herbivore group sizes were affected by: (1) season, (2) distance to fully protected area (NCA crater) and to streams, (3) distance to human settlements, and (4) numbers of livestock. Group sizes were generally larger during the wet season than during the dry season and varied seasonally with distance to NCA crater, streams, and human settlements. During the wet season, larger groups were observed further away from the NCA crater whereas the opposite pattern was apparent during the dry season. Average wild herbivore group sizes increased by about three-fold with increasing distance from the streams during the dry season but were invariant to streams during the wet season. Furthermore, during the dry season, group sizes were larger close to settlements but varied little with distance to settlements during the wet season. While livestock presence did not directly affect wild herbivore group size, distance to settlements, streams and distance to the Ngorongoro crater in interaction with rainfall seasonality did. We conclude that the NCA crater functions as a key resource area for wild herbivores such as wildebeest (Connochaetes taurinus) and zebra (Equus quagga burchelli) during the dry season, highlighting the need for its full protection status in this Man and Biosphere reserve.

Altitudinal patterns of species richness and flowering phenology in herbaceous community in Qilian Mountains of China

In montane systems, there are normally significant spatial differences in vegetation community structure and ecological processes due to the complex topography. The study of such topographic effect can provide scientific basis for the prediction of vegetation dynamics. In this work, the effects of altitude and slope aspect on species richness and flowering phenology of herbaceous communities were investigated in Qilian Mountains, a typical mountainous region in arid climate zones of China. Our monitoring of 102 plots in 34 sites revealed that there were significant topographic effects on species richness and flowering phenology. Specifically, the results showed a spatial pattern that the average number of species in plots was slightly higher at middle altitudes, and was higher on shady than sunny slopes. In flowering phenology, the flowering onsets of low-altitude and sunny-slope communities are generally earlier than that of high-altitude and shady-slope communities, respectively, while the ending dates of flowering between slope aspects and between altitudes are relatively small. This topographic effect revealed the influences of temperature and soil moisture on community structure and flowering phenology, which is reflected in the inverse responses of species richness to temperature and soil water content, and the high sensitivity of flowering phenology to temperature. It can be inferred that under the conditions of climate warming and wetting in the future, the species diversity of herbaceous community may increase at high altitudes, and the flowering duration is likely to be further prolonged in Qilian Mountains.

Contrasting patterns of richness, abundance, and turnover in mountain bumble bees and their floral hosts

Environmental gradients generate and maintain biodiversity on Earth. Mountain slopes are among the most pronounced terrestrial environmental gradients, and the elevational structure of species and their interactions can provide unique insight into the processes that govern community assembly and function in mountain ecosystems. We recorded bumble bee-flower interactions over three years along an 1400 m elevational gradient in the German Alps. Using nonlinear modeling techniques, we analyzed elevational patterns at the levels of abundance, species richness, species β-diversity, and interaction β-diversity. While floral richness exhibited a mid-elevation peak, bumble bee richness increased with elevation before leveling off at the highest sites, demonstrating the exceptional adaptation of these bees to cold temperatures and short growing seasons. In terms of abundance, though, bumble bees exhibited divergent species-level responses to elevation, with a clear separation between species preferring low vs. high elevations. Overall interaction β-diversity was mainly caused by strong turnover in the floral community, which exhibited a well-defined threshold of β-diversity rate at the tree line ecotone. Interaction β-diversity increased sharply at the upper extreme of the elevation gradient (1800-2000 m), an interval over which we also saw steep decline in floral richness and abundance. Turnover of bumble bees along the elevation gradient was modest, with the highest rate of β-diversity occurring over the interval from low- to mid-elevation sites. The contrast between the relative robustness bumble bee communities and sensitivity of plant communities to the elevational gradient in our study suggests that the strongest effects of climate change on mountain bumble bees may be indirect effects mediated by the responses of their floral hosts, though bumble bee species that specialize on high-elevation habitats may also experience significant direct effects of warming.

Different Distribution Patterns of Hoverflies (Diptera: Syrphidae) and Bees (Hymenoptera: Anthophila) Along Altitudinal Gradients in Dolomiti Bellunesi National Park (Italy)

Simple Summary

Hoverflies and bees play a key role in plant pollination. The increasing concern about pollinator reduction forces the planning of a sampling monitoring scheme to evaluate the change in the populations of these important insects. The present research provides baseline data about the distribution of hoverflies and bees in the Dolomiti Bellunesi National Park (Northeastern Italy). The hoverfly community shows a unimodal distribution with peak at middle elevation, while bees display a linear reduction in richness and abundance with increasing altitude. Both hoverfly and bee β-diversity at high altitude is dominated by species turnover more than by nestedness.

Abstract

Hoverflies (Diptera: Syrphidae) and bees (Hymenoptera: Anthophila) are two key taxa for plant pollination. In the present research, the altitudinal distribution of these taxa was studied along two gradients (elevation range: 780–2130 m) in the Dolomiti Bellunesi National Park (Northeastern Italy). Pan traps were used as a sampling device to collect both hoverflies and bees. Other than altitude, the effect of landscape complexity and plant diversity were considered as potential predictors of hoverfly and bee richness and abundance along the two gradients. A total of 68 species of hoverflies and 67 of bees were collected during one sampling year, confirming the efficacy of pan traps as a sampling device to study these taxa. Altitude was the main variable affecting both hoverfly and bee distribution. The two taxa show different distribution patterns: hoverflies have a unimodal distribution (richness and abundance) with peak at middle altitude (1500 m), while bees have a monotonic decline (richness and abundance) with increasing altitude. Both hoverfly and bee populations change with the increasing altitude, but the change in hoverflies is more pronounced than in bees. Species turnover dominates the β-diversity both for hoverflies and bees; therefore, the hoverfly and bee communities at higher altitudes are not subsamples of species at lower altitude but are characterized by different species. This poses important conservation consequences. Some rare species, typical of an alpine habitat were recorded; the present research represents important baseline data to plan a monitoring scheme aimed at evaluating the effect of climate change on pollinators in these fragile habitats.

Effect of human disturbances and hydrologic elements on the distribution of plant diversity within the Shamu watershed, Mt. Yuntai Nature Reserve, China

This paper explores how human disturbance and hydrologic elements affect the spatial distribution pattern of plant diversity in the watershed, taking Shamu watershed in the World Natural Heritage Site as a case study. Spatial analysis of multisource remote sensing and plant diversity plots data were conducted using linear mixed effects models and structural equation models. Results revealed that the distribution of plant diversity in the watershed is mainly affected by human disturbance. However, under similar human disturbance levels, hydrologic elements also affect the plant diversity within the watershed. The topographic undulation and surface runoff significantly promote plant diversity, while the river network density, the watershed shape factor, the river longitudinal gradient do not. The influence of topographic undulation is more obvious than that of runoff on plant diversity, but the effect of topographic undulation and runoff on plant diversity is getting weaker from upstream to downstream within the watershed. In addition, the impact of hydrologic elements on plant diversity is mainly regulated by environmental factors Pre and Tem. The findings clarify how human disturbance and hydrologic elements affect plant diversity distribution within the watershed, optimizing the conservation theory of plant diversity resources and scientifically guiding the region's sustainable development.

Wuling Mountains Function as a Corridor for Woody Plant Species Exchange Between Northern and Southern Central China

Aim

Wuling Mountains range from the northeast to southwest in Central China, a region with high habitat complexity and diversity that supports substantial plant species diversity. Connecting the northern subtropics to the mid-subtropics, Wuling Mountains also link the floras of Eastern and South-Western China. Despite a long-standing interest in how important role Wuling Mountains play in species exchange, patterns of plant species diversity in Wuling and their underlying drivers are still not well characterized. Here, the spatial distribution of woody plant species in this region is described and the role the Wuling Mountains play in structuring biodiversity in surrounding areas is explored.

Location

Wuling Mountains and adjacent regions, China.

Methods

Detailed distribution data for woody plant species in China were collected and mapped onto a raster grid of the Wuling Mountains and adjacent regions (a total of 820,000 km2) to analyze spatial patterns in species diversity, including α-diversity (species richness) and β-diversity (βsor). Unweighted pair-group method using arithmetic averages (UPGMA) clustering was used to divide the study region based on species composition. Canonical redundancy analysis was used to illustrate spatial patterns and species-environment relationships.

Results

Mountainous areas in the study region have high species richness as compared to other areas. Species exchanges occurred at a greater rate latitudinally vs. longitudinally, especially in Wuling Mountains. This suggests that Wuling Mountains may be an important ecological corridor for woody species, linking Northern and Southern Chinese floras. The study region was divided into six bioregions based on species composition: the Wuling Mountains Region, Nanling-Xuefengshan Mountains Region, Qinling-Dabashan Mountains Region, Sichuan Basin Region, Yangtze Plain Region and Yungui Plateau Region.

Main Conclusions

The Wuling Mountains Region acts as an ecological corridor for woody species, linking Northern and Southern China, and fostering biodiversity exchange and conservation in Central China.

Potential of Airborne LiDAR Derived Vegetation Structure for the Prediction of Animal Species Richness at Mount Kilimanjaro

The monitoring of species and functional diversity is of increasing relevance for the development of strategies for the conservation and management of biodiversity. Therefore, reliable estimates of the performance of monitoring techniques across taxa become important. Using a unique dataset, this study investigates the potential of airborne LiDAR-derived variables characterizing vegetation structure as predictors for animal species richness at the southern slopes of Mount Kilimanjaro. To disentangle the structural LiDAR information from co-factors related to elevational vegetation zones, LiDAR-based models were compared to the predictive power of elevation models. 17 taxa and 4 feeding guilds were modeled and the standardized study design allowed for a comparison across the assemblages. Results show that most taxa (14) and feeding guilds (3) can be predicted best by elevation with normalized RMSE values but only for three of those taxa and two of those feeding guilds the difference to other models is significant. Generally, modeling performances between different models vary only slightly for each assemblage. For the remaining, structural information at most showed little additional contribution to the performance. In summary, LiDAR observations can be used for animal species prediction. However, the effort and cost of aerial surveys are not always in proportion with the prediction quality, especially when the species distribution follows zonal patterns, and elevation information yields similar results.

Biological Aspects and Movements of Neotropical Fruit-Feeding Butterflies

The patterns of insect movement are the cumulate product of many individual decisions and can be shaped by the way morphology and behaviour interacts with landscape structure and composition. Hence, the ongoing process of habitat fragmentation increases the distance among suitable habitats and changes those in such a way that it may favour some movement behaviour. Our study described some biological traits (sex ratio, age structure and individual permanence in a population), as well as the movements of fruit-feeding butterflies along the horizontal dimension (among habitats: forest interior, natural forest transition - ecotone and anthropogenic forest transition - edge) and the vertical dimension (between canopy and understory). We sampled butterflies monthly over 1 year in the Atlantic rainforest, South-eastern Brazil, following a standardized design using bait traps. We found that sex ratio was male biased for five out of the six more abundant species and the age structure showed an increase in recruitment of new individuals in the dry season followed by a noticeable aging of the populations in the wet season. In general, our results revealed an aggregated spatial distribution, in which few individuals travelled long distances while most individuals were recaptured in the same trap, suggesting that all studied habitats currently provide the necessary conditions for the maintenance of butterfly populations, favouring fewer movements and narrow home ranges for both sexes and species. Conservation of a set of heterogeneous habitats it is especially important for the maintenance of sedentary butterflies and of those that move large distances.

Sculpting the soil microbiota

Soil is a living ecosystem, the health of which depends on fine interactions among its abiotic and biotic components. These form a delicate equilibrium maintained through a multilayer network that absorbs certain perturbations and guarantees soil functioning. Deciphering the principles governing the interactions within soils is of critical importance for their management and conservation. Here, we focus on soil microbiota and discuss the complexity of interactions that impact the composition and function of soil microbiota and their interaction with plants. We discuss how physical aspects of soils influence microbiota composition and how microbiota-plant interactions support plant growth and responses to nutrient deficiencies. We predict that understanding the principles determining the configuration and functioning of soil microbiota will contribute to the design of microbiota-based strategies to preserve natural resources and develop more environmentally friendly agricultural practices.

The ecological niche and terrestrial environment jointly influence the altitudinal pattern of aquatic biodiversity

The altitudinal distribution of biodiversity in alpine ecosystems has captured academic attention, especially in streams because of their sensitivity to climate change. In the past years, research mainly focused on understanding the role played by alpine streams' internal factors such as aquatic environmental variables, as well as physical and hydrological conditions, on the shaping of benthic macroinvertebrate communities. More recently, external factors such as terrestrial environments were included in analyses worldwide. In particular, the inherent properties constituting the ecological niche of specific species were considered as factors regulating dispersal and influencing community construction. The objective of this study was to reveal the distribution pattern and the driving factors regulating aquatic biodiversity in alpine streams. We hypothesized that the altitudinal distribution of aquatic macroinvertebrates could be explained by the interaction of the aquatic environment with both species' ecological niche and the terrestrial environment surrounding their habitat, and that rare species display a more pronounced pattern than widespread dominant species. To test these hypotheses, samples were collected from two alpine streams situated on opposite slopes of Biluo Snow Mountain in Yunnan Province, China. Results of statistical analyses showed poor explanatory power from aquatic environmental factors, while the differences in vegetation type and the ecological niche of the species played an important role in determining the distribution pattern of aquatic biodiversity. Furthermore, we found that the altitudinal distribution pattern of aquatic biodiversity exhibits a bimodal type, with rare species fitting the bimodal peaks. These findings call for a better inclusion and further investigation on the effects of the terrestrial environment on aquatic ecosystems.