Functional Diversity Measures Research Articles

Primer and Database Choice Affect Fungal Functional but Not Biological Diversity Findings in a National Soil Survey

The internal transcribed spacer (ITS) region is the accepted DNA barcode of fungi. Its use has led to a step-change in the assessment and characterisation of fungal communities from environmental samples by precluding the need to isolate, culture, and identify individuals. However, certain functionally important groups, such as the arbuscular mycorrhizas (Glomeromycetes), are better characterised by alternative markers such as the 18S rRNA region. Previous use of an ITS primer set in a nationwide metabarcoding soil biodiversity survey revealed that fungal richness declined along a gradient of productivity and management intensity. Here, we wanted to discern whether this trend was also present in data generated from universal 18S primers. Furthermore, we wanted to extend this comparison to include measures of functional diversity and establish trends with soil types and soil organic matter (SOM) content. Over the 413 individual sites examined (arable, grassland, woodland, moorland, heathland), we found congruent trends of total fungal richness and β-diversity across land uses, SOM class and soil type with both ITS and 18S primer sets. A total of 24 fungal classes were shared between datasets, in addition to 15 unique to ITS1 and 12 unique to 18S. However, using FUNGUILD, divergent trends of functional group richness became apparent, especially for symbiotrophic fungi, likely driven by an increased detection rate of Glomeromycetes in the 18S dataset. The disparate trends were also apparent when richness and β-diversity were compared to soil properties. Additionally, we found SOM class to be a more meaningful variable than soil type biodiversity analyses because organic matter was calculated for each sample whereas soil type was assigned from a national soil map. We advocate that a combination of fungal primers should be used in large-scale soil biodiversity surveys to capture important groups that can be underrepresented by universal barcodes. Utilising such an approach can prevent the oversight of ubiquitous but poorly described species as well as critically important functional groups.

Insight into tidal disturbance on colonization surveys for marine bioassessment using periphytic ciliates based on biological trait analysis

Abstract To understand tidal disturbance on the colonization dynamics in community functioning of the ciliates in marine ecosystems, a 1-month survey was conducted using the conventional slide system (CS) and the polyurethane foam enveloped slide system (PFES) in Korean coastal waters. The results showed considerable differences were detected in community functioning parameters between the two systems. The vagile, flattened forms feeding on periphytic microalgae showed a higher community-weighted mean (CWM) value, and the solitary-colonial pattern represented a more stable temporal variability during the colonization in the PFES system than the CS system. The temporal shift in community functioning of the ciliates showed different ways in both systems. The functional diversity measures generally levelled off at more stable values in the communities with ages of 13–15 days in the PFES system than the CS system. These results imply that the PFES system may be a workable method for bioassessment in marine ecosystems.

Inferring plant functional diversity from space: the potential of Sentinel-2

Plant functional diversity (FD) is an important component of biodiversity that characterizes the variability of functional traits within a community, landscape, or even large spatial scales. It can influence ecosystem processes and stability. Hence, it is important to understand how and why FD varies within and between ecosystems, along resources availability gradients and climate gradients, and across vegetation successional stages. Usually, FD is assessed through labor-intensive field measurements, while assessing FD from space may provide a way to monitor global FD changes in a consistent, time and resource efficient way. The potential of operational satellites for inferring FD, however, remains to be demonstrated. Here we studied the relationships between FD and spectral reflectance measurements taken by ESA's Sentinel-2 satellite over 117 field plots located in 6 European countries, with 46 plots having in-situ sampled leaf traits and the other 71 using traits from the TRY database. These field plots represent major European forest types, from boreal forests in Finland to Mediterranean mixed forests in Spain. Based on in-situ data collected in 2013 we computed functional dispersion (FDis), a measure of FD, using foliar and whole-plant traits of known ecological significance. These included five foliar traits: leaf nitrogen concentration (N%), leaf carbon concentration (%C), specific leaf area (SLA), leaf dry matter content (LDMC), leaf area (LA). In addition they included three whole-plant traits: tree height (H), crown cross-sectional area (CCSA), and diameter-at-breast-height (DBH). We applied partial least squares regression using Sentinel-2 surface reflectance measured in 2015 as predictive variables to model in-situ FDis measurements. We predicted, in cross-validation, 55% of the variation in the observed FDis. We also showed that the red-edge, near infrared and shortwave infrared regions of Sentinel-2 are more important than the visible region for predicting FDis. An initial 30-m resolution mapping of FDis revealed large local FDis variation within each forest type. The novelty of this study is the effective integration of spaceborne and in-situ measurements at a continental scale, and hence represents a key step towards achieving rapid global biodiversity monitoring schemes.

Do traits and phylogeny support congruent community diversity patterns and assembly inferences?

AbstractIt is now commonplace in community ecology to assess patterns of phylogenetic or functional diversity in order to inform our understanding of the assembly mechanisms that structure communities. While both phylogenetic and functional approaches have been used in conceptually similar ways, it is not clear if they both in fact reveal similar community diversity patterns or support similar inferences. We review studies that use both measures to determine the degree to which they support congruent patterns and inferences about communities.We performed a literature review with 188 analyses from 79 published papers that compared some facet of phylogenetic (PD) and functional diversity (FD) in community ecology. These studies generally report four main cases in which phylogenetic and functional information are used together in community analyses, to determine if: (a) there were phylogenetic signals in the measured traits in communities; (b) PD and FD were correlated with one another; (c) standardized PD and FD measures similarly revealed patterns of community over‐ or under‐dispersion; and (d) PD and FD were both related to other explanatory variables (e.g. elevation) similarly.We found that the vast majority of studies found both strong phylogenetic signals in their traits and positive correlations of PD and FD measures across sites. However, and surprisingly, we found substantial incongruencies for the other tests. Phylogenetic and functional dispersion patterns were congruent only about half the time. Specifically, when communities were phylogenetically over‐dispersed, these same communities were more likely to be functionally under‐dispersed. Similarly, we found that phylogenetic and functional relationships with independent predictors were incongruent in about half of the analyses.Synthesis. Phylogenetic signal tests and PD–FD correlations appear to strongly support the congruence between traits and phylogeny. It is surprising that strong phylogenetic signals appeared so ubiquitous given that ecological studies often analyse phylogenetically incomplete sets of species that have undergone ecological sorting. Despite the largely congruent findings based on phylogenetic signal tests and PD‐FD correlations, we found substantial incongruencies when researchers assessed either dispersion patterns or relationships with independent predictors. We discuss a number of potential ecological, evolutionary and methodological reasons for these incongruencies. Phylogenetic and functional information might reflect species ecological differences unequally with phylogenies better reflecting multivariate conserved elements of ecological similarity, and single traits better able to capture recent divergence, and both elements influence ecological patterns.

The functional trait space of tree species is influenced by the species richness of the canopy and the type of forest

Analysing how species modify their trait expression along a diversity gradient brings insight about the role that intraspecific variability plays over species interactions, e.g. competition versus complementarity. Here, we evaluated the functional trait space of nine tree species dominant in three types of European forests (a continental‐Mediterranean, a mountainous mixed temperate and a boreal) growing in communities with different species richness in the canopy, including pure stands. We compiled whole‐plant and leaf traits in 1719 individuals, and used them to quantify species trait hypervolumes in communities with different tree species richness. We investigated changes along the species richness gradient to disentangle species responses to the neighbouring environment, in terms of hypervolume size (trait variance), shape (trait relative importance) and centroid translation (shifts of mean trait values) using null models. Our main results showed differences in trait variance and shifts of mean values along the tree diversity gradient, with shorter trees but with larger crowns in mixed stands. We found constrained functional spaces (trait convergence) in pure stands, suggesting an important intraspecific competition, and expanded functional spaces (trait divergence) in two‐species admixtures, suggesting competition release due to interspecific complementarity. Nevertheless, further responses to increasing species richness were different for each forest type, waning species complementarity in sites with limiting conditions for growth. Our results demonstrate that tree species phenotypes respond to the species richness in the canopy in European forests, boosting species complementarity at low level of canopy diversity and with a site‐specific pattern at greater level of species richness. These outcomes evidence the limitation of functional diversity measures based only on traits from pure stands or general trait database values.

Climate and site-specific factors shape chironomid taxonomic and functional diversity patterns in northern Patagonia

Functional richness patterns of lake chironomid assemblages have been increasingly studied in the Northern Hemisphere, but so far there are no studies in Southern Hemisphere lakes. Present-day chironomid assemblages were studied from 40 lakes in NW Patagonia to investigate functional and taxonomic diversity and its relationships with the environment. Using multiple regression analysis involving climate-related and site-specific variables, we found that water temperature and terrestrial vegetation cover were the main drivers affecting chironomid taxonomic richness and diversity. Functional richness was explained only by vegetation cover variation, and functional diversity was not explained by any of the predictor variables. Our results contrast with previous findings in the Northern Hemisphere showing that taxonomic and functional diversity measures provide similar information on community and ecosystem function. In Patagonian lakes, taxonomical diversity analysis is still more helpful to understand the relationships between chironomid assemblages and environment, which remarks the needs for further ecological studies on Chironomidae in the area. Regardless, this is the first study to investigate chironomid functional groups in relation to the environment and their distribution in austral lakes.

Promoting functional connectivity of anthropogenically-fragmented forest patches for multiple taxa across a critically endangered biome

Connectivity, the degree to which the landscape structure allows movement between resource and habitat patches, is vital for facilitating a wide range of ecological processes across transformed and anthropogenic landscapes. Connectivity is critical for dispersal of individuals from natal sites, colonisation of patches across a landscape by populations, the structuring of populations, and their persistence across metacommunities. Here, we present a replicable methodology for conservation and land-management practitioners to promote maximal functional connectivity for multiple taxa across a mixed land-use mosaic containing natural habitat patches. We used the maximal functional diversity present in three key taxa (trees, birds, and mammals) responsible for the persistence of forests and the provisioning of ecosystem function and services, in a mosaic landscape of natural, agricultural, and urban land-use practices to map probabilistic connectivity corridors. We used a hybrid of Circuit Theory, least-cost resistance pathways and pinch-points based on the traits and ecological parameters of a surrogate taxon to map functional connectivity across an anthropogenically-fragmented and critically endangered forest biome, the Indian Ocean Coastal Belt Forest of South Africa. By using functional diversity measures, rather than taxonomic species richness, we ensured that maximal ecosystem services were safeguarded, concurrently achieving high-priority conservation goals of protecting specialist, endangered, and range-restricted species and traits that may otherwise be lost through high turnover of generalists at the expense of specialist species. Mapping circuit/least-cost corridors and critical pinch-points in remnant natural, yet unprotected forested patches, highlighted priority habitat to be conserved for promoting maximal functional connectivity, cognisant of the restricted budgets available for conservation planning and landscape-level protection. Our approach simultaneously protects ecosystem services, threatened specialist species and traits, and range-restricted and endangered habitats, linking current Protected Areas while prioritising landscape features of connectivity importance to be conserved for land-management practitioners with limited budgets.

Spatio-temporal variability in structure and diversity in a semi-natural mixed oak-hornbeam floodplain forest

Abstract Mixed forests are particularly interesting for forest structure and diversity analyses, as higher complexity and diversity can be expected in these forests compared to pure ones. Integrating different approaches in the analyses of structure and diversity in these forests can provide complementary information on non-spatial, spatial and functional diversity patterns. The study aimed at evaluating the spatio-temporal dynamics in forest structure and diversity in a semi-natural mixed oak-hornbeam floodplain forest. All standing trees were mapped and inventoried in 1995, 2005 and 2016 in three 1-ha mixed forest stands, with different soil moisture regime (xeric, mesic, moist conditions). Traditional, non-spatial structure and diversity measures were coupled with spatially-explicit and functional diversity measures. Results indicated that the three stands showed limited variation in stand structure and similar non-spatial diversity attributes, despite the different species composition. Only the extension to spatial and functional analyses was able to reveal more pronounced differences of diversity patterns, as higher complexity, species mingling, and functional tree complementarity was observed in the moister stand. These findings support use of spatially-explicit measurements in traditional inventory measurement protocols to allow more refined analysis of diversity patterns. On the other hand, functional diversity can be easily implemented in diversity analyses, as it requires species abundance information (which is traditionally collected in forest inventory) and species-specific tree traits which can be inferred from literature.

Response of bird functional diversity to forest product harvesting in the Eastern Cape, South Africa

The ecological impact of forest product harvesting is poorly understood despite the reliance of millions of impoverished households on forest resources. As birds are indicators of environmental change and essential for the function and regeneration of forest ecosystems, this study aimed to assess the response of bird species richness and functional diversity to unregulated forest product harvesting, to illuminate the impact of harvest disturbances on forest biodiversity. Five forest ecotypes in the Eastern Cape Province, South Africa were sampled by means of circular plots in which bird communities, habitat structure and harvest intensities of sub-canopy trees harvested for poles, canopy trees harvested for timber, and bark harvested for medicinal use, were recorded. Generalized linear models (GLMs) were used to assess the response of bird diversity to harvesting activities measured on a continuous scale, and forest ecotype. Correlations between feeding traits and environmental variables relating to habitat structure and harvest disturbances were investigated using RLQ and fourth-corner analysis to better understand which traits were sensitive to harvest disturbances. Results indicated that forest ecotype was an important driver of variation in species richness and functional diversity. Additionally, harvesting disturbances negatively affected two measures of functional diversity, while species richness and functional richness were unaffected by harvesting. Specifically, functional evenness was negatively affected by timber harvesting, while functional dispersion declined in response to pole and bark harvesting. Bird traits relating to feeding ecology (i.e. primary diet and foraging strategy) were associated with habitat structure and harvest disturbances, indicating that harvest activities affected community structure. Specifically, frugivores and granivores were negatively affected by pole and bark harvesting respectively, while omnivorous species were positively affected by these harvest activities. Conversely, timber harvesting negatively affected omnivores, and positively affected nectarivores. Bark and timber harvesting, which resulted in canopy gaps, negatively affected species which forage in the understory or on the forest floor, while pole harvesting, which reduced tree abundance but not canopy cover, negatively affected canopy-foraging species. These results suggest that current unregulated forest product harvesting in the Eastern Cape may negatively affect forest productivity and ecosystem functioning. Specifically, this is the first study to measure the effects of harvesting of poles and medicinal bark on the functional diversity of avian forest communities.

Tropical forest subjected to intensive post-logging silviculture maintains functionally diverse dung beetle communities

Commercially logged tropical forests hold high conservation value but are rapidly being converted to lucrative low-diversity plantations. Post-logging interventions that accelerate forest timber and carbon recovery—such as enrichment planting and cutting of woody vines—may reduce both the spatial extent of logging and economic pressures to convert forests, delivering considerable conservation benefits. However, they could also seriously undermine logged forest biodiversity, simplifying forest structure and removing important wildlife microhabitats. To date, no study has investigated the impact of post-logging interventions on invertebrates. Focusing on dung beetles, we explore the effects of intensive vine-cutting and enrichment planting within a largescale post-logging silvicultural project in northern Borneo. We find that for four measures of functional diversity (the facet of diversity that accounts for species traits and functions) and for species richness, treated forest communities are similar to those in unlogged and naturally regenerating forest. Moreover, although community composition in treated forest remains distinct from old-growth forest, it is no different than that in naturally regenerating forest and in fact more closely resembles old-growth than naturally regenerating forest in terms of effective diversity. Our results indicate that logged forests continue to host diverse and functioning dung beetle communities even after silvicultural intensification. Post-logging interventions could therefore play an important role in forest and biodiversity conservation via their incorporation into emerging agendas including REDD+ and the Bonn Challenge.

Plant Traits Rather than Species Richness Explain Ecological Processes in Subtropical Forests

Functional traits and species richness have been used to assess variation in ecological functions in multiple ecosystems. However, biodiversity effects on ecosystem functioning could differ between ecosystem types and evaluating these associations could help assess ecosystem recovery in restoration sites. The objective of this study was to analyze the effect of species richness and plant functional traits on ecological processes related to nutrient cycling, productivity and regeneration in subtropical forest ecosystems. The study was performed in three sites (each site containing a reference forest and a forest undergoing restoration) located in the south of Brazil. We collected data on understory abundance, aboveground biomass, litter stock, decomposition, soil feeding activity, litter and soil quality and evaluated the association with tree species richness and plant traits (both community-weighted mean trait values—CWM, and functional diversity measures). Variables related to plant functional traits, especially CWM measures, were associated with most of the ecological processes analyzed. Leaf traits showed the strongest effect on the processes, especially for aboveground biomass, litter stock and understory abundance. Most relationships did not differ between reference and restoration sites. Our results support the mass-ratio theory, suggesting that dominant species traits are the ones that strongly affect ecosystem functioning, and suggest a secondary role of species number on the ecological processes analyzed. Our study provides evidence for the usefulness of functional traits to assess changes in ecological processes in forest ecosystems, with similar patterns in reference forests and forests undergoing restoration.

Can tidal events influence monitoring surveys using periphytic ciliates based on biological trait analysis in marine ecosystems?

To identify the influence of tidal events on community functioning of periphytic ciliates for monitoring program and community research using biological trait analysis, a 3-month baseline survey was conducted in Korean coastal waters using the polyurethane foam enveloped slide system (PFES) and conventional slide system (CS). Although the periphytic ciliate communities had similar biological trait categories, they represented considerable differences in community functioning and functional diversity measures within the PFES and CS systems. Multivariate analyses revealed different ways of the temporal shift in community functioning of the ciliates in both systems. The dispersion analysis demonstrated that the CS system was sensitive to the strong disturbance of tidal current and circulation compared to the PFES system. These findings suggest that the strong tidal event may significantly influence the output of analysis on community functioning of periphytic ciliates for bioassessment in marine ecosystems.

A functional perspective for breeding and wintering waterbird communities: temporal trends in species and trait diversity

Waterbird communities are prone to strong temporal changes both seasonally and annually, but little is known about how this affects their functional diversity and community assembly. Detecting temporal trends in taxonomic and functional diversity within (alpha diversity) and between (beta diversity) communities in breeding and wintering seasons could give insight into the ecological processes driving those trends. In this study, we investigated trends in wintering and breeding waterbirds within and between eleven wetlands in Mediterranean Spain, using a 28‐year time‐series up to 2017. We assessed the temporal trends in taxonomic and functional diversity measures, and compared observed functional diversity values with null expectations, in order to explore the mechanisms driving community assembly. We found increases over time in species richness and in the occupied functional space for both wintering and breeding communities, indicating that species with distinct functional roles were added in both seasons. However, the distribution of the abundances in the functional space was different for breeding and wintering communities. Dissimilarity of species and functional traits decreased among wetlands, suggesting that some of the same functional traits were added to the different wetlands, increasing regional homogenization through time. This is reflected in increases over time in mean body mass, diet plasticity and in the importance of fish in waterbird diets, plus declines in the dietary importance of invertebrates and in plasticity of feeding strata. Furthermore, species composition between wintering and breeding communities, but not trait composition, has become more similar through time. Our results highlight that annual changes, and especially seasonal changes, in the composition of waterbird communities have different effects on their functional diversity, and are influenced by opposing community assembly mechanisms.

Temporal Changes in Species, Phylogenetic, and Functional Diversity of Temperate Tree Communities: Insights From Assembly Patterns.

Species-based approaches to the analysis of changes in successional community assemblages are limited in the ability to reflect long-term evolutionary and functional trait responses of organisms to environment change. Recent advances in concepts and analyses of community phylogenetics and functional traits have improved the interpretation and understanding of community assembly processes. Here, we examined phylogenetic signals of four functional traits such as maximum height, leaf size, seed mass and wood density in woody plant species and temporal changes in species, phylogenetic, and functional diversity among forest strata (i.e., whole, overstory, and understory strata) at four forest long term ecological research sites in South Korea. A census of woody plant species was implemented in a 1-ha permanent plot of each study site every 5 years. We analyzed community structure and compositional turnover using twenty-five 20 × 20 m2 quadrat data converted from 1-ha plot data of each site. We found that phylogenetic signals for four functional traits were low but significant, indicating that phylogenetic diversity may be used as a crude surrogate measure of functional diversity. Temporal changes in alpha and beta components of the three diversity differed among forest strata and four study sites over time. This study also revealed that the temporal changes of phylogenetic and functional diversity for understory strata in a forest, which were consecutively damaged by typhoon, were more extreme and larger than those of understory strata in the other sites. Therefore, our study supports recent studies that plant community structures differ among forest strata and such differences of community structure among sites can be accelerated by disturbance. Although the role and relative importance of niche-based deterministic and neutral processes for the patterns of successional community structure differed among the study sites, we found niche-based deterministic processes are the dominant drivers in structuring plant community assembly regardless of forest age and disturbance in this study. From these results, our study suggests that contemporary forest ecosystems are composed of mosaics of plant communities that are formed by interactions among various processes.

An attribute‐diversity approach to functional diversity, functional beta diversity, and related (dis)similarity measures

AbstractBased on the framework of attribute diversity (a generalization of Hill numbers of order q), we develop a class of functional diversity measures sensitive not only to species abundances but also to trait‐based species‐pairwise functional distances. The new method refines and improves on the conventional species‐equivalent approach in three areas: (1) the conventional method often gives similar values (close to unity) to assemblages with contrasting levels of functional diversity; (2) when a distance metric is unbounded, the conventional functional diversity depends on the presence/absence of other assemblages in the study; (3) in partitioning functional gamma diversity into alpha and beta components, the conventional gamma is sometimes less than alpha. To resolve these issues, we add to the attribute‐diversity framework a novel concept: τ, the threshold of functional distinctiveness between any two species; here, τ can be chosen to be any positive value. Any two species with functional distance ≥ τ are treated as functionally equally distinct. Our functional diversity quantifies the effective number of functionally equally distinct species (or “virtual functional groups”) with all pairwise distances at least τ for different species pairs. We advocate the use of two complementary diversity profiles (τ profile and q profile), which depict functional diversity with varying levels of τ and q, respectively. Both the conventional species‐equivalent method (i.e., τ is the maximum of species‐pairwise distances) and classic taxonomic diversity (i.e., τ is the minimum of non‐zero species‐pairwise distances) are incorporated into our proposed τ profile for an assemblage. For any type of species‐pairwise distance matrices, our attribute‐diversity approach allows proper diversity partitioning, with the desired property gamma ≥ alpha and thus avoids all the restrictions that apply to the conventional diversity decomposition. Our functional alpha and gamma are interpreted as the effective numbers of functionally equally distinct species, respectively, in an assemblage and in the pooled assemblage, while beta is the effective number of equally large assemblages with no shared species and all species in the assemblages being equally distinct. The resulting beta diversity can be transformed to obtain abundance‐sensitive Sørensen‐ and Jaccard‐type functional (dis)similarity profiles. Hypothetical and real examples are used to illustrate the framework. Online software and R codes are available to facilitate computations.

Direct and indirect effects of plant and frugivore diversity on structural and functional components of fruit removal by birds.

Seed dispersal is an important ecosystem function, but it is contentious how structural and functional diversity of plant and bird communities are associated with seed-dispersal functions. We used structural equation models to test how structural (i.e., abundance, species richness) and functional diversity (i.e., functional dispersion and community-weighted means of functional traits) of fruiting plants and frugivorous birds directly and indirectly influence the respective components of fruit removal. We recorded plant and bird diversity in point counts and observed plant-frugivore interactions in a tropical mountain forest in Ecuador. We also recorded plant and bird morphological traits to calculate measures of functional diversity. We found that fruit abundance had a positive direct effect on bird abundance, which directly and indirectly mediated the abundance of removed fruits. Plant and bird species richness were only directly related to the richness of the removed fruits. Functional dispersion of the plant community was positively associated to that of the bird community and to that of the removed fruits. Consistently, we found positive associations between community-weighted means of plant and bird traits and between community-weighted means of plant traits and that of plants with removed fruits. In contrast, community-weighted means of the bird community were unrelated to that of the removed fruits. Overall, our results suggest that plant abundance directly and indirectly influences fruit removal, likely because of avian fruit tracking. However, we did not find strong links between the functional diversity of the frugivore community and removed fruits, suggesting that other factors in addition to plant-animal trait matching might be important for the functional diversity of removed fruits. Our findings highlight the importance of frugivore abundance for maintaining seed dispersal by animals in tropical forests.

Plant Functional Diversity and the Biogeography of Biomes in North and South America

The concept of the biome has a long history dating back to Carl Ludwig Willdenow and Alexander von Humboldt. However, while the association between climate and the structure and diversity of vegetation has a long history, scientists have only recently begun to develop a more synthetic understanding of biomes based on the evolution of plant diversity, function, and community assembly. At the broadest scales, climate filters species based on their functional attributes, and the resulting functional differences in dominant vegetation among biomes are important to modeling the global carbon cycle and the functioning of the Earth system. Nevertheless, across biomes, plant species have been shown to occupy a common set of global functional “spectra”, reflecting variation in overall plant size, leaf economics, and hydraulics. Still, comprehensive measures of functional diversity and assessments of functional similarity have not been compared across biomes at continental to global scales. Here, we examine distributions of functional diversity of plant species across the biomes of North and South America, based on distributional information for > 80,000 vascular plant species and functional trait data for ca. 8,000 of those species. First, we show that despite progress in data integration and synthesis, significant knowledge shortfalls persist that limit our ability to quantify the functional biodiversity of biomes. Second, our analyses of the available data show that all the biomes in North and South America share a common pattern–most geographically common, widespread species in any biome tend to be functionally similar whereas the most functionally distinctive species are restricted in their distribution. Third, when only the widespread and functionally similar species in each biome are considered, biomes can be more readily distinguished functionally, and patterns of dissimilarity between biomes appear to reflect a correspondence between climate and functional niche space. Taken together, our results suggest that while the study of the functional diversity of biomes is still in its formative stages, further development of the field will yield insights linking evolution, biogeography, community assembly, and ecosystem function.

Goat grazing reduces diversity and leads to functional, taxonomic, and phylogenetic homogenization in an arid shrubland

AbstractLivestock production is an important activity in drylands. However, lack of adequate regulation of ranching activities can lead to the degradation of plant communities, which in turn can impact ecosystem functioning. In the arid ecosystems of north‐central Chile, unregulated goat grazing is widespread. Because the vegetation has a relatively short evolutionary history of grazing, it is expected to be highly susceptible to this activity. In this study, we evaluated the effects of goat grazing on plant taxonomic, functional, and phylogenetic community structure by comparing 39‐year‐old grazing exclusion plots and unprotected plots in an arid shrubland in north‐central Chile. By integrating analyses of the impact of goat grazing on functional and phylogenetic diversity and dispersion, we studied the mechanisms behind goat impact and the potential consequences. Loss of functional and/or phylogenetic diversity can result in important losses in ecosystem function. As a measure of functional diversity, we recorded plant growth form, life span, and life form. We also reconstructed a phylogeny of all plant species found at the study site and determined the phylogenetic structure of the plant community in ungrazed and grazed areas. We found that goat grazing affected diversity and community composition, leading to taxonomic, functional, and phylogenetic biotic homogenization and causing overall community impoverishment. Goats acted as a habitat filter, increasing functional convergence and promoting the establishment of exotics plants, which can lead to further losses of biodiversity, decreased ecosystem function and overall lower ecosystem stability. Our results indicate that sustainable management strategies are necessary to prevent the further degradation of these ecosystems.

Evolutionary distinctiveness and conservation priorities in a large radiation of songbirds

AbstractHuman‐induced impacts such as climate change and habitat alterations, coupled with limits on funding, have forced conservation actions into a mode of triage. Although no current method has been agreed upon as the best approach to select species for conservation, many studies have demonstrated the utility of incorporating phylogenetic diversity into these decisions. In many cases, degree of phylogenetic relatedness is thought to provide a measure of functional diversity, and greater phylogenetic distinctiveness is likely linked to ecosystem stability. Despite recent debate over the validity of this notion, phylogenetic information remains an important factor to consider in evaluating species and regions for conservation attention. Emberizoidea is a large radiation of 830 species, representing roughly 17% of all songbirds and 8% of all birds. Species in this clade are found throughout the Americas and occur in all terrestrial biomes in the region. The large distribution of this clade, coupled with its morphological and ecological diversity, makes it an important radiation to study from an evolutionary and conservation perspective. This study provides conservation priorities for all species in Emberizoidea using evolutionary distinctiveness (ED) and Evolutionarily Distinct and Globally Endangered (EDGE) values from a pseudoposterior distribution of time‐calibrated supertrees. We found that threat level is not correlated with degree of ED, indicating that the most threatened species do not represent a disproportionate amount of ED. In addition, threatened species are slightly clustered across the phylogeny, indicating similar threats may be affecting groups of closely related species such as island radiations or geographically restricted radiations in highly disturbed regions.

Changes in multiple facets of macroinvertebrate alpha diversity are linked to afforestation in a subtropical riverine natural reserve.

Land use change is one of the major factors impacting freshwater biodiversity. Afforestation could convert new lands from agriculture or urban land uses to reduce erosion and lead to landscape alterations and biodiversity changes. Here, we examined the changes in the three facets of macroinvertebrate alpha diversity (i.e., taxonomic, functional, and phylogenetic diversity) and further explored possible mechanisms driving their variations before (2007) and after (2016) afforestation along the undammed Chishui River, the core of the National Nature Reserve of Rare and Endemic Fishes in the Upper Yangtze River. We found that taxonomic diversity measures (e.g., species richness, Shannon-Wiener index and Simpson index) increased but all measures of functional diversity (e.g., FRic, FEve, FDiv, and RaoQ) and phylogenetic diversity (e.g., indices of taxonomic distinctness) exhibited stability after the afforestation practice. We also found that only significant taxonomic diversity variation was detected and it showed a relationship to alterations of land use rather than local environmental condition changes across the 10-year afforestation practice. Moreover, hydrology and nutrients levels showed changes after afforestation, but these changes had no effect on the biodiversity changes based on multiple linear regression models. In each survey, the three facets of alpha diversity were significantly explained by natural physical factors and showed inconsistent responses to these underlying environmental variables. In addition, the biodiversity-environment relationships remained stable before and after afforestation, indicating that the inherent mechanisms that drive macroinvertebrate community variation have not changed. Our findings highlight that different alpha diversity measures of lotic macroinvertebrates provide different information about biodiversity and respond differently to various environmental variables. Thus, it is necessary to integrate them into one framework when applying routine monitoring, assessment, and conservation procedures based on lotic macroinvertebrates.