Different Facets Of Biodiversity Research Articles

Acoustic indices fail to represent different facets of biodiversity

Acoustic indices are cost-efficient tools for monitoring acoustically active taxa. Despite their increasing popularity, their suitability as biodiversity proxies remains debated due to theoretical and practical issues. Existing research has predominantly focused on assessing their capacity to capture species richness and abundance of sounds, with limited attention given to other biodiversity facets like phylogenetic and functional diversity. Yet, phylogenetic distance and trait diversity may influence acoustic communication, so acoustic indices may be better suited to capture their changes than changes in the mere number of species. Here, we investigated the ability of acoustic indices to represent the species, phylogenetic, and functional diversity of acoustically active avian species across three habitat types in Italy: urban, riparian forest and deciduous woodland.Recordings were collected at dawn by a trained ornithologist, who also identified acoustically active species captured, first in the field and secondarily from recordings. We then applied eleven widely used acoustic indices for each recording and tested their ability to capture differences in species, functional and phylogenetic diversity across sites (i.e., listening points) within each habitat type using a linear mixed effect model. We then reduced the acoustic indices dimensionality to a few axes and repeated the analysis to test if compound indices delivered comparable information.Species richness and phylogenetic diversity correlated with at least one acoustic index across the three habitat types, while functional diversity correlated with an index only in the urban habitat. However, the nature of the relationships identified was often opposite to what expected by the indices’ formulation. Furthermore, across the three habitat types the interrelations among indices varied, as well as the observed relationships with diversity indices. Compound indices also exhibited inconsistent relationships across sites and contrary to what expected based on their correlation with acoustic indices.Our results cast doubts on the suitability of acoustic indices as proxies for biodiversity for biodiversity monitoring. Additionally, the inconsistent relationship among indices across the three areas suggests they are unsuitable for geographic comparisons. Temporal comparisons are possible but require local validation and may need adjustments over time of the community composition changes. Despite the attractiveness of acoustic indices as easy and cheap tools for biodiversity monitoring, we urge caution on their application.

Connectivity and climate influence diversity–stability relationships across spatial scales in European butterfly metacommunities

AbstractAimAnthropogenic‐driven biodiversity loss can impact ecosystem stability. However, most studies have only evaluated the diversity–stability relationship at the local scale and we do not fully understand which factors stabilize animal populations and communities across scales. Here, we investigate the role of species dispersal ability, climate, spatial distance and different facets of biodiversity on the stability of butterfly populations and communities across multiple spatial scales.LocationPrimarily Western Europe.Time Period2005–2016.Major Taxa StudiedButterflies (Rhopalocera) of Europe.MethodsWe assembled a continent‐wide database of European butterflies' abundance and used Structural Equation Modelling to evaluate the direct and indirect effects of multiple stabilizing mechanisms. In parallel, we tested the effect of dispersal ability on the stability at multiple spatial scales, using a butterfly mobility index as an indicator of dispersal capacity.ResultsRegional stability strongly reflected local stability, which in turn was driven by both taxonomic and functional α‐diversity. Spatial asynchrony was also important for regional stability and it was driven by both functional β‐diversity and metapopulation asynchrony, which in turn increased with spatial distance among communities. We observed a positive effect of temperature on functional α‐diversity and on local stability, whereas precipitation negatively influenced local diversity. Finally, spatial asynchrony contributed more to the regional stability of less mobile species compared to highly mobile ones, indicating that both extrinsic and intrinsic determinants of connectivity impact regional stability indirectly.Main ConclusionsOur results demonstrate the importance of local and regional processes for regional stability. However, the relative contribution of spatial asynchrony and metapopulation asynchrony increases with connectivity loss, especially for less mobile species, indicating that landscape management should be tailored depending on the dispersal capacity of organisms. Both local biodiversity loss and regional biotic homogenization destabilize metacommunities, with potential implications for the reliable provision of ecosystem functions.

The different facets of biodiversity

The different facets of biodiversity Professor F. Guillaume Blanchet from Université de Sherbrooke explores the various aspects of biodiversity and the challenge involved in monitoring it. During the 2022 United Nations Biodiversity Conference of the Parties (COP15), the Kunming-Montréal Global Biodiversity Framework was adopted. This framework has given prized mediatic attention to biodiversity as a topic that needs to be given the same importance as climate change. Arguably, the most publicized part of the Kunming-Montréal Global Biodiversity Framework was defined by media from around the world as the 30 by 30 target.

Integrating different facets of diversity into food web models: how adaptation among and within functional groups shape ecosystem functioning

Adaptation of communities to environmental fluctuations can emerge from different facets of biodiversity, which may impact ecosystem functioning differently. Previous work in the field of biodiversity–ecosystem functioning (BEF) examined how ecosystem functions can be influenced by two sources of adaptive potential: sorting – i.e. changes in community composition due to fitness differences – can occur when multiple species or groups are present (richness), and trait adaptability – i.e. trait adjustments within species or functional groups – can emerge from genetic or phenotypic diversity. However, their effect is typically studied separately, and often in the context of only one trophic level. Therefore, we used a trait‐based, multispecies predator–prey model to investigate how sorting and trait adaptability, at one or two trophic levels, separately or jointly shape ecosystem functions and properties, such as total biomass, production, biomass‐weighted mean trait, relative top–down control and synchrony. We found that the adaptive potential emerging from any facet of diversity induced changes in trophic interactions, in turn affecting biomass distributions within and across trophic levels, dynamical behaviour, and synchrony of biomass dynamics within a trophic level. Particularly, sorting and trait adaptability could contribute to a similar degree and at a similar time to temporal changes in ecosystem functions, but their respective contribution depended on the speed of trait adaptation, the trait range between similar functional groups and trophic interactions. We thus suggest to consider multiple facets of diversity and their corresponding sources of adaptive potential to deepen our mechanistic understanding of BEF relationships, especially in the context of rapid biodiversity change.

Untangling the roles of centrality and environmental contribution in diversity patterns across spatial scales

AbstractThe application of graph theory to metacommunity ecology allows a deeper analysis of the effect of network structure on diversity patterns. Here, we set out to test the role of network centrality metrics and environmental characteristics in diversity patterns of pond macroinvertebrate metacommunities. We tested two approaches to construct the networks: one used the percolation distance, whereas the other was based on a community‐contingent distance. The role of each patch within the network was then analyzed using its centrality value. Later, we analyzed the relationships between the macroinvertebrate diversity and centrality metrics for four study sites. The calculated diversity metrics cover different facets of biodiversity at two scales: pond and pondscape. Environmental characteristics of the studied ponds were also included. All relationships were tested considering the entire macroinvertebrate dataset, but also differentiated by dispersal mode (i.e., active vs. passive) and considering the two types of network approaches analyzed. The results were mostly consistent when comparing the network approaches used. Centrality metrics tended to be positively related to alpha and negatively to beta diversity. Environmental uniqueness showed a positive effect on beta diversity metrics, regardless of the dispersal mode. We only observed a weak negative relationship between eutrophication and species richness of active dispersers. Pond size showed a positive effect on both alpha and beta diversity, but was detected more frequently on alpha diversity metrics. We could not find evidence for a clear negative effect of habitat degradation on diversity. We found a greater importance of environmental characteristics versus the centrality metrics for both alpha and beta diversity of active dispersers, while a combination of their contributions for passive dispersers. An unexpected importance of centrality was observed for alpha diversity of passive dispersers. Using empirical data, we demonstrate that the centrality of a patch in an undirected network affects diversity regardless of the approach used to construct the networks, with a higher influence at local scale regardless of the dispersal mode. This study broadens knowledge of the relationships between environmental features and network centrality, demonstrating the important role of centrality as a determinant of diversity in metacommunities.

Biodiversity, mental health and well-being: psychological mechanisms and moderators of a complex relationship (BIOWELL)

Human activities and their consequences, such as environmental pollution, the exploitation of resources or deforestation, are major causes of biodiversity loss. However, humans depend on a biologically diverse and healthy environment in many ways, as it provides access to clean water, air and food. The loss of biodiversity is an ecological crisis that threatens human health, and ultimately their very existence. At the same time, there is an unwavering interest in the positive effects of "nature" on mental health. Although these examples point to a connection between biodiversity and health, little is known about the causal effects of different facets of biodiversity on mental health. Exploring these relationships and the underlying psychological mechanisms is a major goal of this project. We will build on the expertise of an interdisciplinary team involving scholars from psychology, biodiversity research, human geography, and behavioural economics and combine this expertise with a variety of methods, with a focus on quantitative research, experimental and intervention designs, and investigate participants from different age groups to understand the causal effects of different environments with varying degrees of biological diversity on mental health, and to identify the physical, social, and psychological boundary conditions of these causal effects.

Contrasting impacts of non-native and threatened species on morphological, life history, and phylogenetic diversity in bird assemblages.

Human activities have altered the species composition of assemblages through introductions and extinctions, but it remains unclear how those changes can affect the different facets of biodiversity. Here we assessed the impact of changes in species composition on taxonomic, functional, and phylogenetic diversity across 281 bird assemblages worldwide. To provide a more nuanced understanding of functional diversity, we distinguished morphological from life-history traits. We showed that shifts in species composition could trigger a global decline in avian biodiversity due to the high number of potential extinctions. Moreover, these extinctions were not random but unique in terms of function and phylogeny at the regional level. Our findings demonstrated that non-native species cannot compensate for these losses, as they are both morphologically and phylogenetically close to the native fauna. In the context of the ongoing biodiversity crisis, such alterations in the functional and phylogenetic structure of bird assemblages could heighten ecosystem vulnerability.

Chronic anthropogenic disturbance mediates the biodiversity‐productivity relationship across stand ages in a large temperate forest region

Abstract Temperate forests, especially those in the densely populated regions of the world, are experiencing increasing levels of habitat degradation and biological impoverishment due to subtle but pervasive chronic anthropogenic disturbances including frequent and continuous grazing and extraction of non‐timber forest products. However, the effects of these subtle, chronic disturbances on the biodiversity‐productivity relationship have rarely been examined especially in forests at different development stages. Accordingly, this study explores how chronic anthropogenic disturbance affects the relationship between tree species diversity and forest productivity at different stand development stages in a large temperate forest region. We used the human footprint index as a proxy for chronic human disturbance. Hierarchical Bayesian models were employed to assess the effects of chronic human disturbance on the relationship between tree diversity and forest productivity across different stand age. Several measures of diversity were employed, including taxonomic, functional and phylogenetic diversity. Forest productivity consistently increased with taxonomic, functional and phylogenetic biodiversity; these biodiversity facets were the main drivers of forest productivity compared to stand age, chronic human disturbance and climate. However, the magnitude at which productivity increases with the increments of taxonomic and functional diversity diminishes with the increasing chronic disturbance, especially in younger stands. The effects of phylogenetic diversity on productivity did not vary with chronic disturbance, regardless of stand age. Synthesis and applications: Chronic human disturbance in a large temperate forest region reduces the increase in community productivity due to different facets of biodiversity, especially in young forests. The evidence suggests that the mitigation of chronic human disturbance and the conservation of biodiversity will be effective in sustaining essential ecosystem functions.

Multifaceted patterns of diversity and co-occurrence along an extensive survey of shrubland communities across China

Interpreting biodiversity patterns and the underlying processes is crucial for evaluating the mechanisms of community assembly, but the view of multifaceted diversity patterns spanning broad spatial extents is less strengthened. We implemented an inventory of 1260 vegetation plots from shrublands across China with standardized methods and analyzed patterns of taxonomic and phylogenetic diversity with differential weighting of common and rare species, as well as phylogenetic co-occurrence structures. Taxonomic and phylogenetic diversity were linearly correlated when common and rare species were weighted equally, but had a logarithmic correlation when species were weighted with their relative abundances. While most shrubland communities were phylogenetically unstructured, the correlation between taxonomic and phylogenetic diversity covaried with phylogenetic relatedness when incorporating relative abundance, but only weakly so in phylogenetically over-dispersed communities. When we correlated patterns of taxonomic and phylogenetic diversity with different weightings for common versus rare species, we found an important role for geographic (e.g., longitude, altitude), climatic (temperature, precipitation) and soil factors. The importance of underlying variables varied between facets of diversity. We found a strong role for altitude in taxonomic, but less so for phylogenetic diversity. Furthermore, the importance of several environmental drivers varied depending on whether diversity metrics were strongly influenced by rare species or put more weight on common and/or dominant species. Overall, our assessment highlights the importance of synthetic analyses of patterns and processes of different facets of biodiversity to capture the full complexity of diversity in conservation studies.

Increasing human environmental footprint does not lead to biotic homogenization of forest bird communities in northern USA.

Studies have shown negative impacts of increased human pressures on biodiversity at local (alpha-diversity) and regional (gamma-diversity) scales. However, the diversity between local sites (beta-diversity) has received less attention. This is an important shortcoming since beta-diversity acts as a linkage between the local and regional scales. Decreased beta-diversity means that local sites lose their distinctiveness, becoming more similar to each other. This process is known as biotic homogenization. However, the mechanisms causing biotic homogenization have not been fully studied nor its impacts on different facets of biodiversity. We examined if land-use change due to human actions causes biotic homogenization of taxonomic, functional, and phylogenetic diversity in bird communities of forested habitats in the state of Minnesota, USA. We address if forest loss and increased human domination in a region were associated with decreased beta-diversity. Our results showed that elevated human pressure was not related to increased biotic homogenization in this study region. Effects of landscape change were incongruent among taxonomic, functional, and phylogenetic diversity. At all spatial scales, taxonomic diversity was unrelated to forest loss or human domination. Interestingly, increased human domination appeared to increase the functional beta-diversity of bird communities. This association was driven by a decrease in local diversity. Forest habitat loss was associated with decreasing functional and phylogenetic diversity in local communities (alpha-diversity) and in regional species pool (gamma-diversity), but not in beta-diversity. We highlight the importance of considering multiple facets of biodiversity as their responses to human land-use is varied. Conservation significance of beta-diversity hinges on local and regional diversity responses to human land-use intensification, and organization of biodiversity should therefore be analyzed at multiple spatial scales.

Patterns of functional diversity along latitudinal gradients of species richness in eleven fish families

AbstractAimAs we enter an era of major biodiversity shifts, understanding large‐scale biodiversity patterns has become crucial for ecological and conservation purposes. Often, conservation priorities are based on concepts derived largely from species richness, yet recent work shows that different facets of biodiversity are also crucial for proper ecosystem continuity, function and services. One facet of biodiversity increasingly relevant to conservation is functional diversity. Here, we aim to improve our understanding of large‐scale patterns of biodiversity by testing the hypothesis that species richness can also accurately estimate functional diversity along the latitudinal gradient of species richness in fish.LocationMarine environments.Time periodContemporary.Major taxa studiedEight hundred and forty‐two species within 11 fish families: Acanthuridae, Blenniidae, Chaetodontidae, Gobiidae, Labridae, Lutjanidae, Pleuronectidae, Pomacanthidae, Pomacentridae, Scombridae and Sparidae.MethodsUsing geometric morphometrics to calculate morphological diversity, a proxy for functional diversity, we estimated the expected functional diversity for a given number of species and compared it with the observed functional diversity in fish families along latitudes. We then fitted a broken‐stick regression model with estimates of functional diversity over absolute degree of latitudes to locate latitudes where significant shifts in functional diversity occur.ResultsWe found that species richness typically over‐ or underestimated functional diversity along the latitudinal gradient of species richness in the evaluated fishes. We also showed that for most families investigated, there was a pattern of stable functional diversity from the equator through the tropics that shifted, with a mean inflection point occurring at absolute latitude 31.7 ± 10.1°. We suggest that this pattern might be linked to changes in environmental factors such as global temperature and/or habitat availability beyond tropical latitudes; however, these concepts require more study.Main conclusionsThis analysis shows the importance of considering functional diversity further, in combination with other biodiversity metrics, when developing conservation priorities and policies.

Biodiversity buffers the impact of eutrophication on ecosystem functioning of submerged macrophytes on the Yunnan-Guizhou Plateau, Southwest China

Increasing eutrophication poses a considerable threat to freshwater ecosystems, which are closely associated with human well-being. As important functional entities for freshwater ecosystems, submerged macrophytes have suffered rapidly decline with eutrophication. However, it is unclear whether and how submerged macrophytes maintain their ecological functions under increasing eutrophication stress and the underlying patterns in the process. In the current study, we conducted an extensive survey of submerged macrophytes in 49 lakes and reservoirs (67% of them are eutrophic) on the Yunnan-Guizhou Plateau of southwestern China to reveal the relationship between submerged macrophyte biodiversity and ecosystem functioning (BEF) under eutrophication stress. Results showed that submerged macrophytes species richness, functional diversity (FD), and β diversity had positive effects on ecosystem functioning, even under eutrophication. Functional diversity was a stronger predictor of community biomass than species richness and β diversity, while species richness explained higher coverage variability than FD and β diversity. This suggests that species richness was a reliable indicator when valid functional traits cannot be collected in considering specific ecological process. With increasing eutrophication in water bodies, the mechanisms underlying biodiversity-ecosystem functioning evolved from “niche complementarity” to “selection effects”, as evidenced by decreased species turnover and increased nestedness. Furthermore, the relative growth rate, specific leaf area, and ramet size in trade-off of community functional composition became smaller along eutrophication while flowering duration and shoot height became longer.This study contributes to a better understanding of positive BEF in freshwater ecosystems, despite increasing anthropogenic impacts. Protecting the environment remained the effective way to protect biodiversity and corresponding ecological functions and services. It will be important to consider different facets of biodiversity on ecosystem functioning in future studies to improve effective management plans.

Spatial decoupling of α and β diversity suggest different management needs for coral reef fish along an extensive mid-oceanic ridge

Understanding the underlying drivers of biodiversity is essential for conservation planning of large, connected seascapes. We tested how patterns in α and β components of species and functional diversity of coral reef fish (214, species, 23 families) varied along the extensive Chagos-Lakshadweep oceanic ridge (the largest chain of mid-oceanic atolls in the Indian Ocean) and evaluated geomorphological, environmental, and anthropogenic predictors of diversity patterns. α and β diversity (species and functional) showed contrasting patterns along the ridge; richness and α diversity decreased towards the north and were influenced by anthropogenic pressures, while β diversity increased towards the north, along environmental gradients and with geographic distance. Species β diversity was dominated by turnover (> 80%), while functional β diversity was dominated by nestedness (> 60%). Geographically distant reefs (> 2000 km apart) with high structural complexity were functionally similar, illustrating a ridge-wide capacity for reefs to maintain ecological structure and function despite significant differences in biodiversity. Low spatial congruence in different facets of biodiversity suggest differentiated management needs for reef fish communities along the Chagos-Lakshadweep ridge. Specifically, while a single large marine reserve may be effective for biodiversity conservation in the Chagos archipelago in the south, a network of several smaller conservation areas may be needed to confer resilience to densely populated and biologically differentiated reefs further north.

Snailed It! Inside the Shell: Using Augmented Reality as a Window Into Biodiversity

Snails have occupied an important role in the ideology and religion of the ancient American peoples, who considered them to be magical and used them in ritual ceremonies as ornaments, musical instruments, and architectural elements. Today, they are a valuable study system for understanding biodiversity and evolution due to their remarkable ecological and morphological diversity. Given that many endemic snails are of conservation concern, and that most South American species are poorly studied, there is a need to engage the public through understandable and scientifically based language, conveying the importance of biodiversity. However, not all biodiversity can be seen with the naked eye. Herein, we describe how we utilize snails and their shells to engage citizens and train teachers to promote the many different facets of biodiversity. Through design-based research oriented toward educational innovation, we created a teaching–learning sequence with immersive technology through the following stages of work: (1) produce a teaching–learning sequence and accompanying mobile device application (for Android on GooglePlay), (2) evaluate the impact of the educational resource, and (3) conduct research through a pre- and posttest design on the learning outcomes of participants. In this work, we first present the field experience where scientists, teachers, and pre-service teachers worked together to find snails from northern Chile to Chiloé Island. Some results from this research stage are: criteria for designing a teaching–learning sequence (e.g., how to utilize place as an opportunity for learning science with developmentally appropriate technologies identified for every phase of the sequence), modeling relevant phenomena about biodiversity and ecosystems through snails, scaffolding for teachers implementing the sequence, and activities that enhance STEM education. A teaching–learning sequence that addresses snails as study objects for 4th grade is presented and validated, allowing us to continue the next phase of our research with schools. A second article will propose results from implementation, iterations, and their implications.

Changes in plant biodiversity facets of rocky outcrops and their surrounding rangelands across precipitation and soil gradients

Climate and soil factors induce substantial controls over plant biodiversity in stressful ecosystems. Despite of some studies on plant biodiversity in extreme ecosystems including rocky outcrops, simultaneous effects of climate and soil factors have rarely been studied on different facets of biodiversity including taxonomic and functional diversity in these ecosystems. In addition, we know little about plant biodiversity variations in such extreme ecosystems compared to natural environments. It seems that environmental factors acting in different spatial scales specifically influence some facets of plant biodiversity. Therefore, we studied changes in taxonomic and functional diversity along precipitation and soil gradients in both landscapes (i) rocky outcrops and (ii) their nearby rangeland sites in northeast of Iran. In this regard, we considered six sites across precipitation and soil gradients in each landscape, and established 90 1m2 quadrates in them (i.e. 15 quadrats in each site; 15 × 6 = 90 in each landscape). Then, taxonomic and functional diversity were measured using RaoQ index, FDis and CWM indices. Finally, we assessed impacts of precipitation and soil factors on biodiversity indices in both landscapes by performing regression models and variation partitioning procedure. The patterns of taxonomic diversity similarly showed nonlinear changes along the precipitation and soil factors in both landscapes (i.e. outcrop and rangeland). However, we found a more negative and significant trends of variation in functional diversity indices (except for CWMSLA) across precipitation and soil factors in outcrops than their surrounding rangelands. Variations of plant biodiversity were more explained by precipitation factors in surrounding rangelands, whereas soil factors including organic carbon had more consistent and significant effects on plant biodiversity in outcrops. Therefore, our results represent important impacts of soil factors in structuring plant biodiversity facets in stressful ecosystems. While, environmental factors acting in regional and broad scales such as precipitation generally shape vegetation and plant biodiversity patterns in natural ecosystems. We can conclude that rocky outcrops provide suitable microenvironments to present plant species with similar yields that are less able to be present in rangeland ecosystems.

When Imagery and Physical Sampling Work Together: Toward an Integrative Methodology of Deep-Sea Image-Based Megafauna Identification

Imagery has become a key tool for assessing deep-sea megafaunal biodiversity, historically based on physical sampling using fishing gears. Image datasets provide quantitative and repeatable estimates, small-scale spatial patterns and habitat descriptions. However, taxon identification from images is challenging and often relies on morphotypes without considering a taxonomic framework. Taxon identification is particularly challenging in regions where the fauna is poorly known and/or highly diverse. Furthermore, the efficiency of imagery and physical sampling may vary among habitat types. Here, we compared biodiversity metrics (alpha and gamma diversity, composition) based on physical sampling (dredging and trawling) and towed-camera still images (1) along the upper continental slope of Papua New Guinea (sedimented slope with wood-falls, a canyon and cold seeps), and (2) on the outer slopes of the volcanic islands of Mayotte, dominated by hard bottoms. The comparison was done on selected taxa (Pisces, Crustacea, Echinoidea, and Asteroidea), which are good candidates for identification from images. Taxonomic identification ranks obtained for the images varied among these taxa (e.g., family/order for fishes, genus for echinoderms). At these ranks, imagery provided a higher taxonomic richness for hard-bottom and complex habitats, partially explained by the poor performance of trawling on these rough substrates. For the same reason, the gamma diversity of Pisces and Crustacea was also higher from images, but no difference was observed for echinoderms. On soft bottoms, physical sampling provided higher alpha and gamma diversity for fishes and crustaceans, but these differences tended to decrease for crustaceans identified to the species/morphospecies level from images. Physical sampling and imagery were selective against some taxa (e.g., according to size or behavior), therefore providing different facets of biodiversity. In addition, specimens collected at a larger scale facilitated megafauna identification from images. Based on this complementary approach, we propose a robust methodology for image-based faunal identification relying on a taxonomic framework, from collaborative work with taxonomists. An original outcome of this collaborative work is the creation of identification keys dedicated specifically to in situ images and which take into account the state of the taxonomic knowledge for the explored sites.

Fish taxonomic, functional, and phylogenetic diversity and their vulnerabilities in the largest river in southeastern China.

Freshwater biodiversity is currently under multiple threats. Conservation of freshwater fish biodiversity needs to be prioritized because natural conservation resources are always limited.Samples were collected at 24 sites in the Min River, the largest basin in southeastern China. Taxonomic, functional, and phylogenetic diversity were analyzed. Biodiversity vulnerability was measured by removing one species each time out of the community with replacement.Results suggested that hotspots for taxonomic and phylogenetic diversity were located at two impounded sites, while for functional diversity were those sites with no upstream dams. Little congruence was observed between taxonomic, functional, and phylogenetic diversity. Fragmentation of river network connectivity caused by dams was a significant factor affecting the biodiversity patterns. Beta turnover was the driving component for beta diversity, indicating that biodiversity dissimilarity along the river was mostly explained by environmental sorting. Fifteen out of 16 species that contributed the most to different facets of biodiversity were mostly endemic, either they had distinctive functional traits or they were the most prevalent species. Sites with the highest diversity vulnerability were characterized by these distinctive species. Functional diversity was more vulnerable to species loss comparing with the other two biodiversity facets.Prioritizing those biodiversity hotspots, sites with extreme functional vulnerability, and those distinctive endemic species which contributed the most to biodiversity vulnerability is suggested in the Min River. The study found evidence that congruence among different facets of biodiversity is hard to achieve, and functional diversity is the most vulnerable in a freshwater system fragmented by intensive dam constructions. This work will help to develop systematic conservation planning from the perspective of different biodiversity facets.

Habitat loss-biodiversity relationships are influenced by assembly processes and the spatial configuration of area loss

Habitat loss greatly threatens biodiversity worldwide. However, how different facets of biodiversity (taxonomic, phylogenetic and functional diversity) decline with habitat loss is currently poorly understood. Habitat loss-biodiversity relationships, while important to understand in their own right, have the potential to reveal the underlying mechanisms that naturally structure plant communities and can further illuminate how spatial configurations of habitat loss affect biodiversity in a given amount of habitat. In this study, we used four spatial point process models to assess the relative importance of the processes of random placement of individuals, habitat filtering, dispersal limitation and the combined effects of habitat filtering and dispersal limitation in producing habitat loss-biodiversity relationships across different biodiversity facets for plant species in a subtropical forest. We assessed this using a 50 ha fully mapped subtropical forest in southern China by applying two simulated habitat destruction patterns, namely random and aggregated habitat removal to both real and simulated forest communities. We found that the combined effects of habitat filtering and dispersal limitation provided the best fit among the four competing assembly mechanisms, to the simulated habitat loss-biodiversity relationships applied to real forest data across all three biodiversity metrics. We also found that phylogenetic and functional diversity were less sensitive to the loss of habitat area than species richness and biodiversity declined more gradually under random habitat removal than for aggregated removal for both empirical forests and the simulated communities where assembly mechanisms generated intraspecific aggregation. Overall, our study examined how different assembly processes and the spatial configuration of habitat loss result in differing susceptibilities to diversity loss from habitat destruction and identified the potential mechanisms underlying the spatial patterns of diversity. This study also provides guidelines for the prioritization of the conservation of different facets of biodiversity under different spatial configurations of habitat loss.

Effects of different types of land-use on taxonomic and functional diversity of benthic macroinvertebrates in a subtropical river network.

Expansion of agricultural and urban areas and intensification of catchment land-use increasingly affect different facets of biodiversity in aquatic communities. However, understanding the responses of taxonomic and functional diversity to specific conversion from natural forest to agriculture and urban land-use remains limited, especially in subtropical streams where biomonitoring programs and using functional traits are still under development. Here, we conducted research in a subtropical stream network to examine the responses of macroinvertebrate taxonomic and functional diversity to different types of land-use in central China. Our results showed that medium body size, univoltine, gill respiration, and slow seasonal development were much higher in natural forest sites, while certain traits related to strong resilience and resistance (e.g., small body size, fast seasonal development, bi-or multivoltine, abundant occurrence in drift, sprawler) dominated in high-intensity agriculture and urbanization sites. We further found that land-use compromised water quality (e.g., increases in total phosphate, conductivity and water temperature) and habitat conditions (e.g., high proportion of sand and silt, gravel, and channel width) accounted for the changes in trait composition based on a combination of RLQ and fourth-corner analysis. Moreover, natural forest sites presented relatively high values of functional richness than other land-use, demonstrating the importance of natural forest maintenance to promote high levels of functional diversity. However, taxonomic diversity indexes showed higher sensitivity to distinguish different types of land-use compared to functional diversity measures. Even so, given that certain trait categories showed significant relationships with specific local environmental stressors, trait-based approaches can provide reliable evidence to diagnose the cause of impairment and complement the results of the taxonomic-based approaches. Our findings support the idea that taxonomic and functional approaches should be integrated in river restoration and land-use management.

More diverse tree communities promote foliar fungal pathogen diversity, but decrease infestation rates per tree species, in a subtropical biodiversity experiment

Abstract Fungal pathogens have the potential to affect plant biogeography and ecosystem processes through their influence on the fitness and functioning of their plant hosts. Simultaneously, changes in plant communities can influence fungal pathogen communities. Exactly which host plant attributes determine the composition of fungal pathogen communities on the leaves remains poorly understood. Here, we characterized foliar fungal pathogen communities in subtropical tree communities along an experimental diversity gradient in Jiangxi, South‐East China. On 32 tree species, we identified all visible fungal structures and symptoms microscopically and studied fungi‐specific traits such as conidia or spores in detail. We asked how different facets of biodiversity, including taxonomic, phylogenetic and functional tree diversity, shape fungal diversity and fungal infestation at different scales. We found a positive relationship between tree richness and fungal richness at the plot level. At the level of individual trees of the same species, the relationship between tree species richness and fungal species richness was marginally significantly negative. Importantly, the fungal infestation rates decreased as tree species richness increased, suggesting that colonization of hosts by specialist fungi was impeded by dilution of the pool of available hosts. Moreover, we found evidence for similar topologies between phylogenetic topologies of trees and fungal genera which is a precondition for coevolution and we identified leaf traits, including leaf habit (deciduous/evergreen), leaf magnesium content and stomata size that predicted fungal richness and infestation. Synthesis. Our study indicates that host tree species harbour different foliar fungal pathogens, which sums up to the highest fungal pathogen richness in more diverse forest stands. At the same time, the foliar fungal pathogen infestation rate for each tree species decreased with increasing tree richness in forests. We identified leaf traits that can help to better predict fungal pathogen richness and infestation, and we show that phylogenetically closely related tree species harbour phylogenetically closely related foliar fungal pathogens. These new insights might be helpful to improve the pest resilience of future forests and plantations.