Effects of warming and nitrogen deposition on species and functional diversity of plant communities in the alpine meadow of Qinghai-Tibet Plateau

Plant species and functional diversity play an important role in the stability and sustainability of grassland ecosystems. However, the changes and mechanisms of plant species and functional diversity under warming and nitrogen deposition are still unclear. In this study, we investigated the plant and soil characteristics of alpine meadows on the Qinghai-Tibet Plateau to explore the changes in species and functional diversity of plant communities under warming and nitrogen deposition, as well as their interrelationships and key determinants. The results showed that warming, nitrogen deposition, and their interactions had significant effects on plant species diversity (plant Shannon-Wiener index) and functional diversity (functional richness index, functional differentiation index, functional dispersion, and Rao's quadratic entropy index). With the increase of warming and nitrogen deposition, the Shannon-Wiener index of plants increased first and then decreased. The plant functional richness index, functional diversity index, functional dispersion index, and Rao's quadratic entropy index showed a decreasing trend. At the same time, with the increase in temperature and nitrogen deposition, the relationship between plant species diversity index and functional diversity index in the alpine meadow of Qinghai-Tibet Plateau gradually weakened. Redundancy analysis and structural equation modeling showed that both warming and nitrogen deposition had significant negative effects on the plant species diversity index and plant functional diversity index. Plant factors (Grasses importance value, leaf nitrogen weighted mean, specific leaf area-weighted mean, leaf area-weighted mean, and leaf weight weighted mean) and soil environmental factors (soil total nitrogen and soil carbon-nitrogen ratio) directly or indirectly affect plant community diversity under warming and nitrogen deposition.

Diversity, functionality, and stability: shaping ecosystem multifunctionality in the successional sequences of alpine meadows and alpine steppes on the Qinghai-Tibet Plateau

Recent investigations on the Tibetan Plateau have harnessed advancements in digital ground vegetation surveys, high temporal resolution remote sensing data, and sophisticated cloud computing technologies to delineate successional dynamics between alpine meadows and alpine steppes. However, these efforts have not thoroughly explored how different successional stages affect key ecological parameters, such as species and functional diversity, stability, and ecosystem multifunctionality, which are fundamental to ecosystem resilience and adaptability. Given this gap, we systematically investigate variations in vegetation diversity, functional diversity, and the often-overlooked dimension of community stability across the successional gradient from alpine meadows to alpine steppes. We further identify the primary environmental drivers of these changes and evaluate their collective impact on ecosystem multifunctionality. Our analysis reveals that, as vegetation communities progress from alpine meadows toward alpine steppes, multi-year average precipitation and temperature decline significantly, accompanied by reductions in soil nutrients. These environmental shifts led to decreased species diversity, driven by lower precipitation and reduced soil nitrate-nitrogen levels, as well as community differentiation influenced by declining soil pH and precipitation. Consequently, as species loss and community differentiation intensified, these changes diminished functional diversity and eroded community resilience and resistance, ultimately reducing grassland ecosystem multifunctionality. Using linear mixed-effects model and structural equation modeling, we found that functional diversity is the foremost determinant of ecosystem multifunctionality, followed by species diversity. Surprisingly, community stability also significantly influences ecosystem multifunctionality-a factor rarely highlighted in previous studies. These findings deepen our understanding of the interplay among diversity, functionality, stability, and ecosystem multifunctionality, and support the development of an integrated feedback model linking environmental drivers with ecological attributes in alpine grassland ecosystems.

Characterising functional redundancy in microbiome communities via relative entropy

Functional redundancy has been hypothesised to be at the core of the well-evidenced relation between high ecological microbiome diversity and human health. Here, we conceptualise and operationalise functional redundancy on a single-trait level for functionally annotated microbial communities, utilising an information-theoretic approach based on relative entropy that also allows for the quantification of functional interdependency across species. Via constraint-based microbiome community modelling of a public faecal metagenomic dataset, we demonstrate that the strength of the relation between species diversity and functional redundancy is dependent on specific attributes of the function under consideration such as the rarity and the occurring functional interdependencies. Moreover, by integrating faecal metabolome data, we highlight that measures of functional redundancy have correlates in the host's metabolome. We further demonstrate that microbiomes sampled from colorectal cancer patients display higher levels of species-species functional interdependencies than those of healthy controls. By analysing microbiome community models from an inflammatory bowel disease (IBD) study, we show that although species diversity decreased in IBD subjects, functional redundancy increased for certain metabolites, notably hydrogen sulphide. This finding highlights their potential to provide valuable insights beyond species diversity. Here, we formalise the concept of functional redundancy in microbial communities and demonstrate its usefulness in real microbiome data, providing a foundation for a deeper understanding of how microbiome diversity shapes the functional capacities of a microbiome.

Spatial and temporal effects of heat waves on the diversity of European stream invertebrate communities

The frequency and magnitude of extreme events, such as heat waves, are predicted to increase with climate change. However, assessments of the response of biological communities to heat waves are often inconclusive. We aimed to assess the responses in abundance, taxonomic and functional diversity indices of stream invertebrate communities to heat waves using long-term monitoring data collected across Europe. We quantified the heat waves' magnitude, analyzed the spatial (i.e., long-term mean) and temporal (anomaly around the long-term mean) components of variation in the magnitude of heat waves, and their interaction with anthropogenic stressors (ecological quality and land cover). For the spatial component of variation, we found a negative association of the community indices to the increasing magnitude of heat waves. Sites undergoing heat waves of higher magnitude showed fewer species and lower trait diversity compared with sites experiencing lower magnitude heat waves. However, we could not detect an immediate temporal response of the communities to heat waves (i.e., the temporal component). Furthermore, we found that the effects of heat waves interacted with the ecological quality of the streams and their surrounding land cover. Diversity declined with increasing heat waves' magnitude in streams with higher ecological quality or surrounded by forest, which may be due to a higher proportion of sensitive species in the community. Heat waves' impacts on diversity were also exacerbated by increasing urban cover. The interaction between heat waves' magnitude and anthropogenic stressors suggests that the effects of extreme events can compromise the recovery of communities. Further, the predicted increase in heat waves will likely have long-term effects on stream invertebrate communities that are currently undetected.

Assessment of habitat features modulated carbon sequestration strategies for drought management in tropical dry forest fragments

Habitat features, such as species diversity, functional diversity, tree size, disturbances and fragment sizes have differential impacts on carbon (C) storage and C-sequestration in forest ecosystems. Present study attempted to understand the tree strategies for modulating C-sequestration capacity across tropical dry forest fragments with variable edge distances. We evaluated the differences between drought strategies (i.e., drought avoiding and drought tolerant) for variations in stem density, relative growth rate (RGR), C-storage and C-sequestration, species diversity, functional diversity, tree size and disturbance indicators along edge distance gradient, besides analyzed the differences between drought strategies for responses of C-storage and C-sequestration to variations in species diversity, functional diversity, tree size and disturbance indicators. Various traits and functional indices were analyzed using standard statistical techniques. For total trees and for the two drought strategies, generalized linear modeling results showed a significant decline in stem density, RGR, C-stock, C-sequestration, species diversity, functional diversity and tree size indicators, while a considerable increase in disturbance indicators, along decreasing edge distance across the fragments. The drought strategies exhibited a high degree of variation in the slope of associations for above variables with edge distance across fragments. For predicting C-sequestration, structural equation modeling results showed highly significant influence of functional diversity indicators for drought avoiding strategy, while species diversity indicators were strongly significant for drought tolerant strategy. Moreover, fire index and drought index were critical predictors for C-sequestration for drought avoiding and drought tolerant strategies, respectively. This study provide inputs to understand the largely ignored processes of C-storage and C-sequestration in fragmented forests, which are currently prevalent due to heavy anthropogenic pressures. Our findings are useful for forest managers to understand vegetation responses to interactions of species diversity, functional diversity, tree size and disturbance indicators, for predicting the stability of larger fragments and for planning restoration of smaller fragments.

Adaptive forest management improves stand-level resilience of temperate forests under multiple stressors

Forests are expected to be strongly affected by modifications in climate and disturbance regimes, threatening their ability to sustain the provision of essential services. Promoting drought-tolerant species or functionally diverse stands have recently emerged as management options to cope with global change. Our study aimed at evaluating the impact of contrasting stand-level management scenarios on the resilience of temperate forests in eastern North America and central-western Europe using the individual process-based model HETEROFOR. We simulated the evolution of eight stands over 100 years under a future extreme climate according to four management scenarios (business as usual - BAU; climate change adaptation - CC; functional diversity approach - FD; no management - NM) while facing multiple disturbances, resulting in a total of 160 simulations. We found that FD demonstrated the greatest resilience regarding transpiration and tree biomass, followed by CC and then BAU, while these three scenarios were equivalent concerning the net primary production. These results were however dependent on forest type: increasing functional diversity was a powerful option to increase the resilience of coniferous plantations whereas no clear differences between BAU and adaptive management scenarios were detected in broadleaved and mixed stands. The FD promoted a higher level of tree species diversity than any other scenario, and all scenarios of management were similar regarding the amount of harvested wood. The NM always showed the lowest resilience, demonstrating that forest management could be an important tool to mitigate adverse effects of global change. Our study highlighted that tree-level process-based models are a relevant tool to identify suitable management options for adapting forests to global change provided that model limitations are considered, and that alternative management options, particularly those based on functional diversity, are promising and should be promoted from now on.

Plant species diversity and functional diversity relations in the degradation process of desert steppe in an arid area of northwest China

Species and functional diversity play a major role in the stability and sustainability of grassland ecosystems. However, changes in species and functional diversity during grassland degradation in arid areas as well as the underlying mechanisms remain unclear. In this study, we surveyed the vegetation and soil properties of arid regions across a degradation gradient to explore the shifts in species and functional diversity in plant communities, their relationships and key determinants during desert steppe degradation. Our results found significant variability in species diversity and functional diversity across degradation stages. Species diversity (Shannon-Wiener index (H), and Pielou index) and functional diversity (functional evenness (FEve) index, and Rao's quadratic entropy (RaoQ) index) tended to increase initially and then decrease with increasing grassland degradation. The Patrick index, Simpson index, functional richness (FRic) index, functional divergence (FDiv) index, and functional dispersion (FDis) index declined as grassland degradation increased. The relationships between species diversity and functional diversity indices at different stages of degradation in the desert steppe were inconsistent. From no to heavy degradation grasslands, the correlation between species diversity and functional diversity gradually weakened. Specifically, there was a significant correlation between Patrick (R) and FRic indices (R2 > 0.7) on both non-degraded and light degraded grasslands, but there was no significant correlation between R and FRic indices in moderately and heavily degraded grasslands (R2 < 0.7), and R2 gradually decreased. Redundancy analysis and partial least squares path modeling showed that grassland degradation has a significant direct effect on the species diversity and functional diversity. In addition grassland degradation has direct and indirect effects on the species diversity through soil available nitrogen, organic matter and total nitrogen. Functional diversity is directly or indirectly affected by species diversity, soil available nitrogen, organic matter and total nitrogen, soil moisture content, soil bulk density, and pH value. In summary, the relationship between species and functional diversity indices gradually weakened from areas with no degradation to heavy degradation in arid desert grasslands. Our study reveals the patterns and relationships between species diversity and functional diversity throughout the process of grassland degradation, demonstrating a gradual decrease in ecosystem stability and sustainability as degradation advances. Our results have significant implications for the restoration of grassland degradation and the management of ecosystem services in arid steppe regions.

Biodiversity drives ecosystem multifunctionality in sandy grasslands?

Plant communities and soil microbiomes play a crucial role in regulating ecosystem multifunctionality (EMF). However, whether and how aboveground plant diversity, belowground soil microbial diversity and interactions with environmental factors affect EMF in sandy grasslands under climate change conditions is unclear. Here, we selected 15 typical grassland communities from the Horqin sandy grassland along temperature and precipitation gradients, using the mean annual temperature (AMT), mean annual precipitation (AP), soil temperature (ST), soil water content (SW) and pH as abiotic factors, and plant diversity (PD) and soil microbial diversity (SD) as biodiversity indicators. The effects of biodiversity and abiotic factors on individual ecosystem functions and EMF were studied. We found that PD and its components, plant species richness (SR), species diversity (PR) and genetic diversity (GD), had significant effects on aboveground biomass (AGB) and major factors involved in ecosystem nitrogen cycling (plant leaf nitrogen content (PLN) and soil total nitrogen content (STN)) (P < 0.05). Soil fungal diversity (FR) has a greater impact on ecosystem function than soil bacteria (BR) and archaea (ABR) in sandy grasslands and mainly promotes the accumulation of soil microbial carbon and nitrogen (MBC, MBN) (P < 0.05), STC and STN (P < 0.01). PD and two types of SD (FR and ABR) significantly regulated EMF (P < 0.01). Among the abiotic factors, soil pH and SW regulated EMF (P < 0.05), and SW and ST directly drove EMF (P < 0.05). PD drove EMF significantly and indirectly (positively) through soil pH and ST (P < 0.001), while SD drove EMF weakly and indirectly (negatively) through AP and PD (P > 0.05). PD was a stronger driving force on EMF than SD. These results improve our understanding of the drivers of multifunctionality in sandy grassland ecosystems.

Planktonic functional diversity changes in synchrony with lake ecosystem state

Managing ecosystems to effectively preserve function and services requires reliable tools that can infer changes in the stability and dynamics of a system. Conceptually, functional diversity (FD) appears as a sensitive and viable monitoring metric stemming from suggestions that FD is a universally important measure of biodiversity and has a mechanistic influence on ecological processes. It is however unclear whether changes in FD consistently occur prior to state responses or vice versa, with no current work on the temporal relationship between FD and state to support a transition towards trait-based indicators. There is consequently a knowledge gap regarding when functioning changes relative to biodiversity change and where FD change falls in that sequence. We therefore examine the lagged relationship between planktonic FD and abundance-based metrics of system state (e.g. biomass) across five highly monitored lake communities using both correlation and cutting edge non-linear empirical dynamic modelling approaches. Overall, phytoplankton and zooplankton FD display synchrony with lake state but each lake is idiosyncratic in the strength of relationship. It is therefore unlikely that changes in plankton FD are identifiable before changes in more easily collected abundance metrics. These results highlight the power of empirical dynamic modelling in disentangling time lagged relationships in complex multivariate ecosystems, but suggest that FD cannot be generically viable as an early indicator. Individual lakes therefore require consideration of their specific context and any interpretation of FD across systems requires caution. However, FD still retains value as an alternative state measure or a trait representation of biodiversity when considered at the system level.

Changing plant functional diversity over the last 12,000 years provides perspectives for tracking future changes in vegetation communities

Plant communities are largely reshaped by climate and the environment over millennia, providing a powerful tool for understanding their response to future climates. Using a globally applicable functional palaeocological approach, we provide a deeper understanding of fossil pollen-inferred long-term response of vegetation to past climatic disturbances based on changes in functional trait composition. Specifically, we show how and why the ecological strategies exhibited by vegetation have changed through time by linking observations of plant traits to multiple pollen records from southeast Australia to reconstruct past functional diversity (FD, the value and the range of species traits that influence ecosystem functioning). The drivers of FD changes were assessed quantitatively by comparing FD reconstructions to independent records of past climates. During the last 12,000 years, peaks in FD were associated with both dry and wet climates in southeast Australia, with shifts in leaf traits particularly pronounced under wet conditions. Continentality determined the degree of stability maintained by high FD, with the greatest seen on the mainland. We expect projected frequent drier conditions in southeast Australia over coming decades to drive changes in vegetation community functioning and productivity mirroring the functional palaeocological record, particularly in western Tasmania and western southeast mainland.

Understanding the taxonomic homogenization of road-influenced plant assemblages in the Qionglai mountain range: A functional and phylogenetic perspective

As an increasingly prevalent form of human activity, roads drive the taxonomic homogenization of mountain plant assemblages, threatening global biodiversity. However, little is known about how mountain roads impact functional and phylogenetic beta diversity and how these effects are related to taxonomic homogenization. To understand the mechanism of taxonomic homogenization triggered by mountain roads, we used species absence/presence data from 76 plots (2 m*50 m) and values for 12 traits measured on 978 species from the interior and roadside communities in the Qionglai mountain range, one of the temperate regions with the highest plant species richness in the world. We used a structural equation modeling approach (SEM) to consider several surrogates of road disturbance (changes in soil physicochemical properties and the presence or absence of roads) and the causal relationship between three facets of beta diversity (taxonomic beta diversity, TBD; functional beta diversity, FBD and phylogenetic beta diversity, PBD). The results suggest that TBD, FBD and PBD respond inconsistently to mountain roads, despite strong positive correlations between the three facets of plant beta diversity in the study area. Compared with the interior community, the βtotal.tax and βtotal.func of the roadside community decreased by 2.54% and 2.22%, respectively, which were related to the reduction of species and trait richness differences and replacements; however, we did not find the same results when assessing the changes in βtotal.phy, which represents tip-weighted PBD (twPBD). Furthermore, the largest effect of roads on beta diversity was reflected in basal-weighted PBD (bwPBD), which decreased by 9.97%, indicating that those species with fewer extant relatives and longer evolutionary histories are more sensitive to mountain roads. Therefore, it is necessary to take targeted protection measures for ancient species in roadside communities. In addition, we believe that it is still necessary to take measures to prevent the further dispersal of nonnative species, although the presence of non-native species in roadside plots has led to small changes in three facets of beta diversity. There were causal relationships between the three facets of beta diversity, but their intensity and sign different in the SEM of different components of beta diversity (i.e., richness difference and replacement). Our findings suggest that the homogenization of community species composition at the landscape scale arises by a combination of adaptive responses of the functional traits of organisms to environmental consistency (e.g., reduced the differences in soil variables) caused by roads and resorting or reassembly of community clades composition due to environmental filtering. These results contribute to our comprehensive understanding of the impact of mountain roads on plant diversity, which highlights the complex relationship between human pressure and biodiversity loss.

Taxonomic and Functional Diversity of Benthic Macroinvertebrate Assemblages in Reservoirs of South Korea

Numerous community indices have been developed to quantify the various aspects of communities. However, indices including functional aspects have been less focused on. Here, we examined how community composition varies in response to the environment and discovered the relationship between taxonomic diversity and functional diversity while considering the environment. Macroinvertebrate communities were collected from 20 reservoirs in South Korea. To characterize functional diversity, functional traits in four categories were considered: generation per year, adult lifespan, adult size, and functional feeding groups. Based on their community composition, we classified the reservoirs using hierarchical cluster analysis. Physicochemical and land use variables varied considerably between clusters. Non-metric multidimensional scaling indicated differences between reservoirs and clusters in terms of structure, functional diversity, and environmental variables. A self-organizing map was used to categorize functional traits, and network association analysis was used to unravel relationships between functional traits. Our results support the characteristics of species' survival strategies such as r- and K-selection. Functional richness exhibited a relationship with taxonomic diversity. Our findings suggest that different types of diversity could play complementary roles in identifying biodiversity. Our findings should prove useful in developing new criteria for assessing freshwater ecosystem health, as well as in evaluating and predicting future alteration of benthic macroinvertebrate communities facing anthropogenic disturbances.

Variations in Avian Species and Functional Diversity in Different Habitat Types in a Vulnerable Savannah Ecosystem in Ghana

Most research on avian functional diversity in the tropics is focused on forest and agroecosystems, leaving a gap in knowledge about the effects of habitat types on functional diversity in savannah landscapes. Savanna ecosystems are fragile and are under threat of anthropogenic destruction, particularly in developing Sub-Saharan Africa and could be eliminated in the face of the ever-increasing human population exacerbated by the changing climate. This study investigated the influence of the three major habitat types (grassland, riparian forest, woodland) on bird species and functional diversity in the Mole National Park (MNP) in Ghana. We used the line transect method to survey birds along 39 transects, each 1 km in length, and collected data on environmental variables along the same transects. Data from these surveys was used to estimate species and functional diversity indicators. We found significant variations in species and functional diversity measures between the three habitat types in the MNP. These variations were significantly influenced by species abundance and environmental covariates. Diversity measures were particularly higher in the riparian forest habitats compared to the woodland and grassland, with the latter being the least diverse habitat both functionally and species wise. The results of this study suggest that the avifauna assemblages in MNP are largely influenced by the riparian forest and are important for ecosystem function and stability. We recommend management efforts to intensify the protection of such vital habitats of the Mole National Park from illegal human activities, especially the rising removal and export of rosewoods (Dalbergia nigra) around the park. Further research on the avian community composition and structure in the MNP is recommended.

Functional diversity regulates the effects of habitat degradation on biocrust phylogenetic and taxonomic diversities

Biocrusts are major contributors to dryland diversity, functioning, and services. However, little is known about how habitat degradation will impact multiple facets of biocrust diversity and measurable functional traits. We evaluated changes in taxonomic, functional, and phylogenetic diversity of biocrust-forming lichens along a habitat degradation gradient related to the presence of linear infrastructure (i.e., a road) and a profound agricultural driven transformation. To do so, we selected 50 remnants of a Mediterranean shrubland. We considered several surrogates of habitat quality and causal disturbance on the various diversity facets of biocrusts by using structural equation modeling, hypothesizing that habitat degradation primarily affects functional diversity, which in turn regulates changes in taxonomic and phylogenetic diversities, and also that taxonomic and phylogenetic diversities are coupled. Fragment connectivity, distance to linear infrastructure (i.e., a road) and, particularly, soil fertility (i.e., soil P concentration), had mostly negative effects on biocrust functional diversity, which in turn affected both taxonomic and phylogenetic diversities. However, we found no direct effects of habitat degradation variables on the taxonomic and phylogenetic diversities. We also found that increases in phylogenetic diversity had a positive effect on taxonomic diversity along the habitat degradation gradient. Our results indicate that functional diversity of biocrusts is strongly affected by habitat degradation, which may profoundly alter their contribution to ecosystem functioning and services. Furthermore, functional diversity regulates the response of biocrust taxonomic and phylogenetic diversity to habitat degradation. These findings indicate that habitat degradation alters and simplifies the diversity of functional traits of biocrust-forming lichens, leading to biodiversity loss, with important consequences for the conservation of global drylands biodiversity.

Linking Taxonomic, Phylogenetic and Functional Plant Diversity with Ecosystem Services of Cliffs and Screes in Greece

Sparsely vegetated habitats of cliffs and screes act as refugia for many regional and local endemic specialized plant taxa most of which have evolved precisely for that type of habitat. The interplay between taxonomic, phylogenetic, and functional plant diversity on rock and scree habitats of extreme environmental conditions, enlightens the relations of plant communities and ecosystems and facilitates management planning for the conservation of biodiversity and ecosystem services. The identification of biodiversity patterns and hotspots (taxonomic, phylogenetic, and functional) contributes to the integration of the ecosystem services (ES) approach for the mapping and assessment of ecosystems and their services (MAES) implementation in Greece and the creation of thematic maps based on the MAES reporting format. The overlap among the protected areas’ network revealed that almost all areas of cliffs and screes of medium, high, and very high taxonomic and phylogenetic plant endemism are included in the Natura 2000 area network. The results of this study provide the baseline information for ES assessments at sparsely vegetated land of cliffs and screes. Our results contribute to the implementation of certain indicators of the national set of MAES indicators in Greece such as (a) floristic diversity and (b) microrefugia of endemic diversity and support of decision-making.

Multi-biologic group analysis for an ecosystem response to longitudinal river regulation gradients

This work assesses the effects of river regulation on the diversity of different instream and riparian biological communities along a relieve gradient of disturbance in regulated rivers. Two case studies in Portugal were used, with different river regulation typology (downstream of run-of-river and reservoir dams), where regulated and free-flowing river stretches were surveyed for riparian vegetation, macrophytes, bryophytes, macroalgae, diatoms and macroinvertebrates. The assessment of the regulation effects on biological communities was approached by both biological and functional diversity analysis. Results of this investigation endorse river regulation as a major factor differentiating fluvial biological communities through an artificial environmental filtering that governs species assemblages by accentuating species traits related to river regulation tolerance. Communities' response to regulation gradient seem to be similar and insensitive to river regulation typology. Biological communities respond to this regulation gradient with different sensibilities and rates of response, with riparian vegetation and macroinvertebrates being the most responsive to river regulation and its gradient. Richness appears to be the best indicator for general fluvial ecological quality facing river regulation. Nevertheless, there are high correlations between the biological and functional diversity indices of different biological groups, which denotes biological connections indicative of a cascade of effects leading to an indirect influence of river regulation even on non-responsive facets of communities' biological and functional diversities. These results highlight the necessary holistic perspective of the fluvial system when assessing the effects of river regulation and the proposal of restoration measures.

Disentangling effects of disturbance severity and frequency: Does bioindication really work?

Ecological disturbances are recognized as a crucial factor influencing the attributes of ecological communities. Depending on the specific adaptation or life cycle, plant species show different responses to disturbances of different magnitudes. Herben et al. (Journal of Vegetation Science, 27, 628-636) proposed six disturbance indicator values (DIVs) that describe the niches of Central-European plant species along gradients of disturbance frequency and severity. Here, we ask if the DIVs can be used in community ecology for bioindication of disturbance regime? We used a dataset of riparian forests sampled within mountain catchments (the Sudetes, SW Poland). As the regime of disturbance is driven by changes in floods from the spring toward the mouth, we calculated the position of every plot along longitudinal (upstream-downstream) gradient and used it as a proxy for the disturbance severity and frequency. We then calculated the community-weighted means (CWMs) for each of the six indices for each plot and analyzed whether these indices reflected the position of the plots along the rivers. We expected an increase in the severity indices and a decrease in the frequency indices downstream along the rivers. Moreover, we analyzed relationships between disturbance indices and species optima along longitudinal gradient. Surprisingly, means for all analyzed indices increased along the rivers. Severity indices showed the strongest association with the longitudinal gradient. The disturbance severity index for herbs was the only index that differed significantly among species with different responses along longitudinal gradient. On these results, we identified a strong correlation between the severity and frequency indices as the main problem. We conclude that the DIVs have considerable applicative potential; however, the determination of ecological niches separately for disturbance severity and frequency is difficult because different components interact to shape the realized niche of each species. All analyzed indices encompass different attributes of the disturbance regime including both severity and frequency.

Functional diversity patterns of macrofauna in the adjacent waters of the Yangtze River Estuary

Functional diversity can reflect the overall differences in functional traits and indicate their response to environmental disturbance. Macrofaunal feeding functional groups and functional diversity were studied in the adjacent waters of the Yangtze River Estuary. The detritivorous group had the highest species number, abundance and secondary productivity while the canivorous group had the highest biomass. Pearson correlation analysis showed that functional evenness was negatively correlated with species number and Shannon-Wiener index. Functional divergence was negatively correlated with Simpson dominance index. Functional dispersion was positively correlated with species evenness, Shannon-Wiener index and Simpson dominance index. High values of functional diversity mainly cooccurred with high species diversity, uniform trait distribution and small niche overlap, indicating weak interspecific competition and high resources utilization. The dominant species were miniaturized and their biological traits analysis indicated that the study area has been disturbed for long time, resulting in the decline of the benthic ecosystem stability.

Avian functional responses to landscape recovery

Restoring native vegetation in agricultural landscapes can reverse biodiversity declines via species gains. Depending on whether the traits of colonizers are complementary or redundant to the assemblage, species gains can increase the efficiency or stability of ecological functions, yet detecting these processes is not straightforward. We propose a new conceptual model to identify potential changes to complementarity and redundancy in response to landscape change via relative changes in taxonomic and functional richness. We applied our model to a 14-year study of birds across an extensive agricultural region. We found compelling evidence that high levels of landscape-scale tree cover and patch-scale restoration were significant determinants of functional change in the overall bird assemblage. This was true for every one of the six traits investigated individually, indicating increased trait-specific functional complementarity and redundancy in the assemblage. Applying our conceptual model to species diversity data provided new insights into how the return of vertebrates to restored landscapes may affect ecological function.

Establishing causal links between aquatic biodiversity and ecosystem functioning: Status and research needs

Understanding how changes in biodiversity affects ecosystem functioning is imperative in allowing Ecosystem-Based Management (EBM), especially when addressing global change and environmental degradation. Research into the link between biodiversity and ecosystem functioning (BEF) has indeed increased considerably over the past decades. BEF research has focussed on terrestrial ecosystems and aquatic ecosystems have received considerably less attention. Due to differences in phylogenetic diversity, ecological processes and reported BEF relationships, however, it may at least be questionable whether BEF relationships are exchangeable between these ecosystems (i.e. terrestrial and aquatic). The aim of the present paper was therefore to pinpoint key areas and bottlenecks in establishing BEF relationships for aquatic ecosystems (freshwater, transitional, and marine). To this end, the available literature with special emphasis on the last 10 years was assessed to evaluate: i) reported mechanisms and shapes of aquatic BEF relationships; ii) to what extent BEF relations are interchangeable or ecosystem-specific; and iii) contemporary gaps and needs in aquatic BEF research. Based on our analysis, it may be concluded that despite considerable progress in BEF research over the past decades, several bottlenecks still need to be tackled, namely incorporating the multitude of functions supported by ecosystems, functional distinctiveness of rare species, multitrophic interactions and spatial-temporal scales, before BEF relationships can be used in ecosystem-based management.

Distribution of mammal functional diversity in the Neotropical realm: Influence of land-use and extinction risk

Functional diversity represents a measure of diversity that incorporates the role of species in an ecosystem, and therefore its dynamics and resilience. Assessing its drivers and spatial variation represents an important step forward in our understanding of functional ecosystem dynamics and it is also necessary to achieve a comprehensive conservation planning. In this paper, we assessed mammal functional diversity for the 218 ecoregions within the Neotropical realm. We evaluated the overall influence and spatial variation of species richness, ecoregion extent, intervention and species at risk on functional diversity. Using ordinary least squares and geographically weighted regression modeling approaches, we found that intervened areas and threatened and non-threatened species are the most influential overall drivers of functional diversity. However, we also detected that these variables do not operate equally across scales. Our local analyses indicated both that the variation explained and local coefficients vary spatially depending on the ecoregion and major habitat type. As estimates of functional diversity are based on current distribution of all mammals, negative influence of intervened areas and positive influence of non-threatened species may reflect a potential degradation of functional processes for some ecosystems. Most generally, the negative influence of intervention together with the influence of threatened species indicates that some areas are currently more susceptible to functional diversity loss. Our results help to pinpoint key areas requiring urgent conservation action to reduce natural land-cover loss and areas where threatened species play influential roles on ecosystem functioning.

Relative importance of abiotic, biotic, and disturbance drivers of plant community structure in the sagebrush steppe

Abiotic conditions, biotic factors, and disturbances can act as filters that control community structure and composition. Understanding the relative importance of these drivers would allow us to understand and predict the causes and consequences of changes in community structure. We used long-term data (1989-2002) from the sagebrush steppe in the state of Washington, USA, to ask three questions: (1) What are the key drivers of community-level metrics of community structure? (2) Do community-level metrics and functional groups differ in magnitude or direction of response to drivers of community structure? (3) What is the relative importance of drivers of community structure? The vegetation in 2002 was expressed as seven response variables: three community-level metrics (species richness, total cover, compositional change from 1989 to 2002) and the relative abundances of four functional groups. We used a multi-model inference framework to identify a set of top models for each response metric beginning from a global model that included two abiotic drivers, six disturbances, a biotic driver (initial plant community), and interactions between the disturbance and biotic drivers. We also used a permutational relative variable importance metric to rank the influence of drivers. Moisture availability was the most important driver of species richness and of native forb cover. Fire was the most important driver of shrub cover and training area usage was important for compositional change, but disturbances, including grazing, were of secondary importance for most other variables. Biotic drivers, as represented by the initial plant communities, were the most important driver for total cover and for the relative covers of exotics and native grasses. Our results indicate that the relative importance of drivers is dependent on the choice of metric, and that drivers such as disturbance and initial plant community can interact.

Land-use change promotes avian diversity at the expense of species with unique traits

Land‐use change may alter both species diversity and species functional diversity patterns. To test the idea that species diversity and functional diversity changes respond in differing ways to land‐use changes, we characterize the form of the change in bird assemblages and species functional traits along an intensifying gradient of land use in the savanna biome in a historically homogeneous vegetation type in Phalaborwa, South Africa. A section of this vegetation type has been untransformed, and the remainder is now mainly characterized by urban and subsistence agricultural areas. Using morphometric, foraging and breeding functional traits of birds, we estimate functional diversity changes. Bird species richness and abundance are generally higher in urban and subsistence agricultural land uses, as well as in the habitat matrix connecting these regions, than in the untransformed area, a pattern mainly driven through species replacement. Functionally unique species, particularly ground nesters of large body size, were, however, less abundant in more utilized land uses. For a previously homogenous vegetation type, declines in the seasonality of energy availability under land‐use change have led to an increase in local avian diversity, promoting the turnover of species, but reduced the abundance of functionally unique species. Although there is no simple relationship between land‐use and diversity change, land‐use change may suit some species, but such change may also involve functional homogenization.

N-dimensional hypervolumes to study stability of complex ecosystems

Although our knowledge on the stabilising role of biodiversity and on how it is affected by perturbations has greatly improved, we still lack a comprehensive view on ecosystem stability that is transversal to different habitats and perturbations. Hence, we propose a framework that takes advantage of the multiplicity of components of an ecosystem and their contribution to stability. Ecosystem components can range from species or functional groups, to different functional traits, or even the cover of different habitats in a landscape mosaic. We make use of n-dimensional hypervolumes to define ecosystem states and assess how much they shift after environmental changes have occurred. We demonstrate the value of this framework with a study case on the effects of environmental change on Alpine ecosystems. Our results highlight the importance of a multidimensional approach when studying ecosystem stability and show that our framework is flexible enough to be applied to different types of ecosystem components, which can have important implications for the study of ecosystem stability and transient dynamics.

The role of biogeochemical hotspots, landscape heterogeneity, and hydrological connectivity for minimizing forestry effects on water quality

Protecting water quality in forested regions is increasingly important as pressures from land-use, long-range transport of air pollutants, and climate change intensify. Maintaining forest industry without jeopardizing sustainability of surface water quality therefore requires new tools and approaches. Here, we show how forest management can be optimized by incorporating landscape sensitivity and hydrological connectivity into a framework that promotes the protection of water quality. We discuss how this approach can be operationalized into a hydromapping tool to support forestry operations that minimize water quality impacts. We specifically focus on how hydromapping can be used to support three fundamental aspects of land management planning including how to (i) locate areas where different forestry practices can be conducted with minimal water quality impact; (ii) guide the off-road driving of forestry machines to minimize soil damage; and (iii) optimize the design of riparian buffer zones. While this work has a boreal perspective, these concepts and approaches have broad-scale applicability.