Metacommunity Structure Research Articles

Functional zeta diversity can better reveal fish metacommunity assembly process in a transitional floodplain

Comprehending the mechanisms governing metacommunity assembly holds pivotal importance for effective conservation strategies. Amidst diverse theories in explaining metacommunity assembly processes, ecologists are progressively delving into the interplay between ecological stochasticity and determinism in shaping species assemblages. Given the ease of measurement, three null model-based methodologies have been widely employed to measure the stochastic and deterministic process, i.e., dispersal-niche continuum index (DNCI), elements of metacommunity structure (EMS), and zeta diversity calculations. However, it is still in doubt which approach can better detect the dominant ecological process governing metacommunity assembly. In this study, we concurrently utilized these three approaches to reveal the fish metacommunity assembly processes in a transitional floodplain among different habitats between high- and low-water levels. In general, our results recognized functional zeta diversity as indicative measurement in this study case since it uniquely unveiled the significant assembly transitions from stochasticity to determinism in response to water receding. Specifically, fish metacommunity in high-water periods was governed by stochastic processes, which can be ascribed to connectivity and easier dispersal in the flooding period. In contrast, the deterministic process shaped fish metacommunity in low-water phase since the stringent environmental loading enhance environmental filtering. This phenomenon is more pronounced in lotic habitats due to the more intricate environments there. It is worth noting that EMS and DNCI approaches showed blind response to this shift. In consequence, our findings advocate for favoring zeta diversity in resolving stochastic and deterministic contributions in governing metacommunity assembly. In addition, our findings also highlight the superiority of functional diversity over traditional taxonomic diversity, since we recorded a more reasonable metacommunity assembly process revealed by the functional group approach, which emphasizes the significance of incorporating functional traits in community ecology.

Spatial structure of phytoplankton metacommunities and their functional groups in a neotropical floodplain

Spatial structure of phytoplankton metacommunities and their functional groups in a neotropical floodplain

Spatiotemporal metacommunity structures and beta diversity of macroinvertebrates in stream and lake systems

Spatiotemporal metacommunity structures and beta diversity of macroinvertebrates in stream and lake systems

Understanding temporal variability across trophic levels and spatial scales in freshwater ecosystems.

A tenet of ecology is that temporal variability in ecological structure and processes tends to decrease with increasing spatial scales (from locales to regions) and levels of biological organization (from populations to communities). However, patterns in temporal variability across trophic levels and the mechanisms that produce them remain poorly understood. Here we analyzed the abundance time series of spatially structured communities (i.e., metacommunities) spanning basal resources to top predators from 355 freshwater sites across three continents. Specifically, we used a hierarchical partitioning method to disentangle the propagation of temporal variability in abundance across spatial scales and trophic levels. We then used structural equation modeling to determine if the strength and direction of relationships between temporal variability, synchrony, biodiversity, and environmental and spatial settings depended on trophic level and spatial scale. We found that temporal variability in abundance decreased from producers to tertiary consumers but did so mainly at the local scale. Species population synchrony within sites increased with trophic level, whereas synchrony among communities decreased. At the local scale, temporal variability in precipitation and species diversity were associated with population variability (linear partial coefficient, β = 0.23) and population synchrony (β = -0.39) similarly across trophic levels, respectively. At the regional scale, community synchrony was not related to climatic or spatial predictors, but the strength of relationships between metacommunity variability and community synchrony decreased systematically from top predators (β = 0.73) to secondary consumers (β = 0.54), to primary consumers (β = 0.30) to producers (β = 0). Our results suggest that mobile predators may often stabilize metacommunities by buffering variability that originates at the base of food webs. This finding illustrates that the trophic structure of metacommunities, which integrates variation in organismal body size and its correlates, should be considered when investigating ecological stability in natural systems. More broadly, our work advances the notion that temporal stability is an emergent property of ecosystems that may be threatened in complex ways by biodiversity loss and habitat fragmentation.

Dispersal mediates trophic interactions and habitat connectivity to alter metacommunity composition.

Dispersal contributes vitally to metacommunity structure. However, interactions between dispersal and other key processes have rarely been explored, particularly in the context of multitrophic metacommunities. We investigated such a metacommunity in naturally fragmented habitats populated by butterfly species (whose dispersal capacities were previously assessed), flowering plants, and butterfly predators. Using data on butterfly species abundance, floral abundance, and predation (on experimentally placed clay butterfly models), we asked how dispersal ability mediates interactions with predators, mutualists, and the landscape matrix. In contrast to expectations, high densities of strong dispersers were found in more isolated sites and sites with low floral resource density, while intermediate dispersers maintained similar densities across isolation and floral gradients, and higher densities of poor dispersers were found in more connected sites and sites with higher floral density. These findings raise questions about how strong dispersers experience the landscape matrix and the quality of isolated and low-resource sites. Strong dispersers were able to escape habitat patches with high predation, while intermediate dispersers maintained similar densities along a predation gradient, and poor dispersers occurred at high densities in these patches, exposing them to interactions with predators. This work demonstrates that species that vary in dispersal capacities interact differently with predators and mutualist partners in a landscape context, shaping metacommunity composition.

How pondscapes function: connectivity matters for biodiversity even across small spatial scales in aquatic metacommunities

Habitat loss and fragmentation are growing global threats to natural habitats and their networks, posing significant challenges to biodiversity conservation. Globally, ponds are sharply declining in number because their small size makes them highly vulnerable to land use changes. While it is generally agreed that connectivity in habitat networks is crucial for sustaining biodiversity, the effect of connectivity on biodiversity patterns over small‐scaled habitat networks has so far received less attention given the general assumption that metacommunities lack spatial structuring on small scales. In this study, we tested whether this holds for multiple passively and actively dispersing organism groups in a well‐delineated pond metacommunity of 54 bomb crater ponds situated within 1 km. We investigated the influence of space and environment on species richness and metacommunity structure in these ponds, which share similar age, size, and shape and are subject to strong environmental gradients, making it an ideal study system. We specifically examined the impact of network centrality on taxonomic richness and eigenvector‐based spatial arrangement on metacommunity structure across different organism groups, including prokaryotes, microeukaryotes, zooplankton, macroinvertebrates, and amphibians. We found that while environmental filtering is the primary driver of community dynamics, there is also a significant spatial signal, particularly for passively dispersing groups, demonstrating the role of the central‐peripheral connectivity gradient. These findings highlight the importance of studying and protecting ponds as parts of a network rather than focusing on individual ponds.

Functional traits predict species co‐occurrence patterns in a North American Odonata metacommunity

AbstractThe probability of occurrence of a given species in a target locality and assemblage is conditioned not only by environmental/climatic variables but also by the presence of other species (i.e., species co‐occurrence). This framework, already complex in nature, becomes even more complicated if one considers the functional traits of species that, in turn, might influence the structure of metacommunities in various ways. Depending on the ecological and environmental setting, functional similarity (i.e., convergence in morphological and ecological traits) between species might either reduce their co‐occurrence due to high niche overlap driving negative interactions or promote it if the similar traits are associated with local habitat suitability. Similarly, functional divergence might either promote species co‐occurrence by limiting negative interactions through niche separation or reduce it through trait mediated environmental filtering. Therefore, discriminating between these alternative scenarios—predicting whether two species will tend to co‐occur or not based on their traits—is extremely challenging. Here, we develop a novel protocol to tackle the challenge, and we demonstrate its effectiveness by showing that ecological species traits can predict species co‐occurrence in a large dataset of North American Odonata. To this end, we first used the Hierarchical Modeling of Species Communities framework to quantify the pairwise species co‐occurrence after controlling for environmental and climatic factors. Then, we used machine learning to generate models which proved capable of predict accurately the observed co‐occurrence patterns from species functional traits. Our approach offers a generalizable analytical framework with the potential to clarify long‐standing ecological questions.

When Do Traits Tell More Than Species about a Metacommunity? A Synthesis across Ecosystems and Scales.

AbstractLinking species traits with the variation in species assemblages across habitats has often proved useful for developing a more mechanistic understanding of species distributions in metacommunities. However, summarizing the rich tapestry of a species in all of its nuance with a few key ecological traits can also lead to an abstraction that provides less predictability than when using taxonomy alone. As a further complication, taxonomic and functional diversities can be inequitably compared, either by integrating taxonomic-level information into the calculation of how functional aspects of communities vary or by detecting spurious trait-environment relationships. To remedy this, we here synthesize analyses of 80 datasets on different taxa, ecosystems, and spatial scales that include information on abundance or presence/absence of species across sites with variable environmental conditions and the species' traits. By developing analyses that treat functional and taxonomic diversity equitably, we ask when functional diversity helps to explain metacommunity structure. We found that patterns of functional diversity explained metacommunity structure and response to environmental variation in only 25% of the datasets using a multitrait approach but up to 59% using a single-trait approach. Nevertheless, an average of only 19% (interquartile range = 0%-29%) of the traits showed a significant signal across environmental gradients. Species-level traits, as typically collected and analyzed through functional diversity patterns, often do not bring predictive advantages over what the taxonomic information already holds. While our assessment of a limited advantage of using traits to explain variation in species assemblages was largely true across ecosystems, traits played a more useful role in explaining variation when many traits were used and when trait constructs were more related to species' status, life history, and mobility. We propose future research directions to make trait-based approaches and data more helpful for inference in metacommunity ecology.

The influence of spatial processes on fish community structure: using a metacommunity framework for freshwater bioassessment.

The use of biological indicators in a bioassessment approach is important for inferences of anthropogenic stress in routine monitoring programs. One of the primary assumptions of bioassessment is that biological indicators observed at specific sampling sites will allow for inferences of local environmental quality; however, this assumption requires a reliable understanding of dispersal processes, which is particularly relevant in river systems due to their dendritic network. Inter-stream dispersal between different points of the river network could bias bioassessment, especially for highly mobile organisms like fish. Here, we examine standard biological metrics used in routine biomonitoring to determine how spatial variables, including dispersal, influence inferences between fish populations and environmental gradients. Using redundancy analysis (RDA) and variation partitioning, we tested the relative influence of both environmental and spatial variables on fish community structure and related community metrics. Fish were collected from 99 sampling sites distributed across 44 rivers and streams of the Great Morava River Basin, Serbia. Electroconductivity, the percentage of agricultural areas, dissolved oxygen, ammonia, and nitrate-nitrogen were found to be significant environmental variables, while ten spatial predictors from broad- to small-scales were found to influence fish community structure and community metrics. Our results suggest that contemporary dispersal among streams influences fish community composition, but that trait-based metrics are less sensitive than basic measures of diversity to spatial processes. Our results highlight the need for spatially independent sampling, as well as the need to consider dispersal-based processes in routine biomonitoring.

Impacts of habitat connectivity on grassland arthropod metacommunity structure: A field-based experimental test of theory.

Metacommunity theory has advanced scientific understanding of how species interactions and spatial processes influence patterns of biodiversity and community structure across landscapes. While the central tenets of metacommunity theory have been promoted as pivotal considerations for conservation management, few field experiments have tested the validity of metacommunity predictions. Here, we tested one key prediction of metacommunity theory-that decreasing habitat connectivity should erode metacommunity structure by hindering species movement between patches. For 2 years, we manipulated an experimental old-field grassland ecosystem via mowing to represent four levels of habitat connectivity: (1) open control, (2) full connectivity, (3) partial connectivity, and (4) no connectivity. Within each treatment plot (10 × 10 m, n = 4 replicates), we measured the abundance and diversity (i.e., alpha and beta) of both flying and ground arthropods using sticky and pitfall traps, respectively. We found that the abundance and diversity of highly mobile flying arthropods were unaffected by habitat connectivity, whereas less mobile ground arthropods were highly impacted. The mean total abundance of ground arthropods was 2.5× and 2× higher in the control and partially connected plots compared to isolated patches, respectively. We also reveal that habitat connectivity affected the trophic interactions of ground arthropods, with predators (e.g., wolf spiders, ground spiders) being highly positively correlated with micro-detritivores (springtails, mites) but not macro-detritivores (millipedes, isopods) as habitat connectivity increased. Together these findings indicate that changes in habitat connectivity can alter the metacommunity structure for less mobile organisms such as ground arthropods. Because of their essential roles in terrestrial ecosystem functioning and services, we recommend that conservationists, restoration practitioners, and land managers include principles of habitat connectivity for ground arthropods when designing biodiversity management programs.

Temporally robust occupancy frequency distributions in riverine metacommunities explained by local biodiversity regulation

AbstractAimThe mechanisms determining the distribution of the number of sites species occupy, the occupancy frequency distribution (OFD), remain incompletely understood despite decades of research. To explore the dominant mechanisms responsible for the shape and temporal dynamics of empirical OFD, we develop a simple patch occupancy framework with intrinsically regulated local richness and fit the model to a highly replicated dataset describing macroinvertebrate, macrophyte and diatom occupancy.LocationEngland.Time periodUp to years between 1990 and 2020.Major taxa studiedMacroinvertebrates, macrophytes and diatoms.MethodsWe study the OFD in a highly replicated dataset of freshwater metacommunities in England across time. We consider temporal change in species richness, composition, and in the shape of the OFD. Goodness‐of‐fit of the steady state of a simple patch occupancy model—which predicts a log‐series OFD—to the empirical observations is assessed. Additionally, we test the capacity of the model to predict metacommunity‐scale processes.ResultsOur model provides a consistently good fit to empirical OFDs. It can additionally be used to predict metacommunity‐scale species turnover.Main conclusionsOur results support the view that metacommunity structure reflects a dynamic steady state controlled by local limits to coexistence.

Metacommunity structure preserves genome diversity in the presence of gene-specific selective sweeps under moderate rates of horizontal gene transfer.

The horizontal transfer of genes is fundamental for the eco-evolutionary dynamics of microbial communities, such as oceanic plankton, soil, and the human microbiome. In the case of an acquired beneficial gene, classic population genetics would predict a genome-wide selective sweep, whereby the genome spreads clonally within the community and together with the beneficial gene, removing genome diversity. Instead, several sources of metagenomic data show the existence of "gene-specific sweeps", whereby a beneficial gene spreads across a bacterial community, maintaining genome diversity. Several hypotheses have been proposed to explain this process, including the decreasing gene flow between ecologically distant populations, frequency-dependent selection from linked deleterious allelles, and very high rates of horizontal gene transfer. Here, we propose an additional possible scenario grounded in eco-evolutionary principles. Specifically, we show by a mathematical model and simulations that a metacommunity where species can occupy multiple patches, acting together with a realistic (moderate) HGT rate, helps maintain genome diversity. Assuming a scenario of patches dominated by single species, our model predicts that diversity only decreases moderately upon the arrival of a new beneficial gene, and that losses in diversity can be quickly restored. We explore the generic behaviour of diversity as a function of three key parameters, frequency of insertion of new beneficial genes, migration rates and horizontal transfer rates.Our results provides a testable explanation for how diversity can be maintained by gene-specific sweeps even in the absence of high horizontal gene transfer rates.

Metacommunity organisation of Amazonian stream fish assemblages: The importance of spatial and environmental factors

AbstractMetacommunity theory seeks to explain how local and regional processes contribute to the organisation of biological communities. Recent conceptual frameworks of this theory indicate that the dynamics of populations and communities are jointly established by dispersal, species responses to environmental conditions and biotic interactions dependent on species density. Here, we use hierarchical joint species distribution modelling to verify the effects of environmental factors (at multiple spatial scales), drainage network configuration, spatial autocorrelation and interspecific interactions on the structure of fish assemblages in terra‐firme streams in the Eastern Brazilian Amazon. Thirty streams were sampled in two field surveys, and 89 species were collected in total. Our results confirm the effects of limited dispersal, environmental conditions (at multiple scales) and the configuration of the drainage network on the dynamics of these assemblages. Furthermore, our results suggest that interspecific interactions are less relevant for the structuring of fish metacommunities in small Amazonian headwater streams. Abiotic factors like drainage networks and environmental heterogeneity were better predictors of species distributions than co‐occurrence patterns with potential competitors or predators.

The effects of longitudinal fragmentation on riverine beta diversity are modulated by fragmentation intensity

The loss of longitudinal connectivity affects river systems globally, being one of the leading causes of the freshwater biodiversity crisis. Barriers alter the dispersal of aquatic organisms and limit the exchange of species between local communities, disrupting metacommunity dynamics. However, the interplay between connectivity losses due to dams and other drivers of metacommunity structure, such as the configuration of the river network, needs to be explored. In this paper, we analyzed the response of fish communities to the network position and the fragmentation induced by dams while controlling for human pressures and environmental gradients. We studied three large European catchments covering a fragmentation gradient: Upper Danube (Austrian section), Ebro (Spain), and Odra/Oder (Poland). We quantified fragmentation through reach-scaled connectivity indices that account for the position of barriers along the dendritic network and the dispersal capacity of the organisms. We used generalized linear models to explain species richness and Local Contributions to Beta Diversity (LCBD) and multilinear regressions on the distance matrix to describe Beta Diversity and its Replacement and Richness Difference components. Results show that species richness was not affected by fragmentation. Network centrality metrics were relevant drivers of beta diversity for catchments with lower fragmentation (Ebro, Odra), and fragmentation indices were strong beta diversity predictors for the catchment with higher fragmentation (Danube). We conclude that in highly fragmented catchments, the effects of network centrality/isolation on biodiversity could be masked by the effects of dam fragmentation. In such catchments, metapopulation and metacommunity dynamics can be strongly altered by barriers, and the restoration of longitudinal connectivity (i.e. the natural centrality/isolation gradient) is urgent to prevent local extinctions.

Riparian forests as dispersal corridors for adult European mayflies, stoneflies and caddisflies (EPTs)

Metacommunity theory connects the diversity patterns of the community across the landscape with the effects of ecological processes. As dispersal is one of the main factors driving the metacommunity structure, it is important to understand the interaction between landscape and dispersal to apply metacommunity theory. Herein, we summarize the main challenges of applying metacommunity theory to the mayfly, stonefly and caddisfly community (Ephemeroptera, Plecoptera and Trichoptera, or EPTs). Then, we attempt to solve some of the open questions regarding EPT dispersal and its relation with riparian forests. First, we investigate the diversity of functional dispersal traits of the European EPT species, analysing the existing empirical data and selecting a suitable functional index. Second, we assess the effect of riparian forest in landscape connectivity for EPTs, concluding that deciduous riparian forest can enhance dispersal. Third, we extend the study to four European regions, concluding that the role of native riparian forest as dispersal corridor differs between regions. We achieved three goals: First, we produced a theoretical and methodological framework to include dispersal in the study of EPT metacommunity, highlighting the role of riparian forest as a dispersal corridor. Second, we identify several aspects that require further investigation such as empirical dispersal studies or interactions between ecological stressors and dispersal. Third, we provide a new perspective for riverine and riparian ecosystems management, highlighting the need to consider riparian buffers as an integral part of the riverine ecosystems.

Hydrological changes regulate fish metacommunity structures and β-diversity patterns in the floodplain lake, China

The metacommunity structures are continuously dynamic, and understanding the temporal species distribution patterns and biodiversity variations will elucidate the metacommunity theory. To examine whether the idealized metacommunity structuring, diversity patterns, and potential driving mechanisms vary among different seasons, we assessed seasonal fish data (i.e., normal, wet, and dry seasons) in the Poyang Lake, the largest freshwater lake in China, by incorporating the Elements of Metacommunity Structure (EMS), β-diversity partitioning, and variance partitioning. The results suggested fish metacommunity displayed quasi-structures, with the quasi-Clemensian paradigm in the normal season and the quasi-Gleasonian paradigm in the wet and dry seasons, indicating the unity of species groups and individualistic species responded weakly to latent environmental gradients, respectively. The highest fish β-diversity occurred in the normal season and the lowest in the wet season with a humped trend. The species abundance replacement process contributed more to the total β-diversity than the nestedness-resultant component among seasons. The variation of the highest Local Contribution to Beta Diversity (LCBD) across seasons indicated the significance of protecting unique habitats. The relative importance of environment and spatial factors on fish metacommunity structure depended on discharge alternation, with a more significant role of spatial structuring occurring in the wet season, whereas predominant environmental filtering in the normal and dry seasons. The seasonal shifts in EMS patterns, β-diversity, and metacommunity assembly rules result from the change in hydrological conditions in the Poyang Lake. This work helps understand seasonal metacommunity dynamics and provides essential information for systematic biodiversity conservation planning in freshwater lakes.

Trait‐based and multi‐scale approach provides insight on responses of freshwater mussels to environmental heterogeneity

AbstractOur understanding of the factors driving the distribution of metacommunities at different scales can be obscured by high variation in species composition between sites and a lack of fine‐scale distribution data. Trait‐based approaches have long been used to better identify and examine ecological patterns. Most recent studies of riverine metacommunities examining trait‐based patterns have focused on shorter lived organisms. Here we focused on a group of longer lived, sedentary riverine organisms, unionid freshwater mussels. The objective of this study was to examine how (1) the distribution of mussels with different life history strategies (trait‐based approach) and (2) the relative importance of environmental and spatial factors (as a proxy for dispersal) would differ with spatial scale and position in the river; and to (3) further compare this with patterns derived from a taxonomic approach. Fine‐scale distribution data of mussels and environmental factors were collected every 100 m in spatially extensive surveys in an upstream and downstream segment (200 sites/20‐km segment) of a semiarid river, making them some of the most spatially intensive surveys documented to date. A combination of redundancy analysis, asymmetric eigenvector mapping, and variation partitioning analyses revealed that more variation was explained by environmental factors where more environmental differences occur between sites. Where environmental heterogeneity was lower, the amount of variation explained by smaller scale spatial factors was higher, likely mostly associated with stochastic rather than dispersal processes. A higher amount of unexplained variation at the taxonomic level suggests that stochasticity may also play an important role in determining species composition. In contrast, different life history groups had a highly predictable distribution pattern driven by environmental heterogeneity, especially between river segments and mesohabitat, which was associated with different flow conditions. The role we predict for environmental heterogeneity and stochasticity in shaping the distribution of mussels in our study river likely also applies to other taxa and ecosystems at a spatial scale at which neither dispersal limitation nor mass effects occur. Thus, understanding the magnitude and extent of dispersal relative to the amount of environmental heterogeneity may be key for predicting metacommunity structure and dynamics for different organisms.

Hierarchical metacommunity structure of fungal endophytes.

The ecological and evolutionary processes shaping community structure and functions of microbial symbionts are known to be scale-dependent. Nonetheless, understanding how the relative importance of these processes changes across spatial scales, and deciphering the hierarchical metacommunity structure of fungal endophytes has proven challenging. We investigated metacommunities of endophytic fungi within leaves of an invasive plant (Alternanthera philoxeroides) across wide latitudinal transects both in its native (Argentina) and introduced (China) ranges to test whether metacommunities of fungal endophytes were structured by different drivers at different spatial scales. We found Clementsian structures with seven discrete compartments (distinctive groups of fungal species with coincident distribution ranges), which coincided with the distribution of major watersheds. Metacommunity compartments were explicitly demarcated at three spatial scales, that is, the between-continent, between-compartment, and within-compartment scales. At larger spatial scales, local environmental conditions (climate, soil, and host plant traits) were replaced by other geographical factors as principal determinants of metacommunity structure of fungal endophytes and community diversity-function relationships. Our results reveal novel insights into the scale dependency of diversity and functions of fungal endophytes, which are likely similar for plant symbionts. These findings can potentially improve our understanding of the global patterns of fungal diversity.

Dissecting biodiversity: assessing the taxonomic, functional and phylogenetic structure of an insect metacommunity in a river network using morphological and metabarcoding data

Most empirical metacommunity studies rely solely on morphological identification of taxa, precluding the species-level identification of several biotic groups, which can influence the characterization of metacommunities. DNA metabarcoding enables inference of species and even intraspecific diversity from community samples but has rarely been used to infer metacommunity structure. Here, we combined morphology and metabarcoding to improve the characterization of an insect metacommunity at different identification levels. We included measures of taxonomic, functional and phylogenetic richness, and we evaluated drivers affecting metacommunity structure (i.e., environmental filtering and dispersal). Communities were sampled from an area that included nine perennial, two near-perennial and two intermittent sites in a river network characterized by high hydrological variability. We identified organisms to a mixed (family to species) taxonomic level using morphology, and to operational taxonomic unit (OTU) and haplotype levels using metabarcoding of the mitochondrial cytochrome c oxidase gene. Diptera and Ephemeroptera showed the greatest increases in taxonomic and phylogenetic richness but not biological trait richness with increasing taxonomic resolution. The joint effect of environmental filtering and dispersal was more important than their individual effects in shaping metacommunity structure at all identification levels. Mixed-level and OTU-level identification were more effective than family and haplotype in characterizing the drivers of metacommunity structure. We demonstrate that the greater taxonomic resolution enabled by metabarcoding could improve understanding of metacommunities within river networks, thus enhancing our capacity to predict ecological responses in ecosystems adapting to global change.

Codistribution as an indicator of whole metacommunity response to environmental change

The landscape scale response of ecological communities to environmental drivers can be challenging to efficiently summarise and differentiate from expected background turnover through time. Metacommunity structure can be encapsulated by fitting joint species distribution models (JSDMs) and partitioning the variance explained into environmental, spatial and species‐codistribution components. Here we identify how these components respond through time with directed environmental change and propose these changes in metacommunity structure as an indicator of sustained directional pressure. Through simulations, we identify how declines in the variation explained by species codistribution could diagnose ecological disintegration, while increases in the explanatory power of environmental and spatial predictors may indicate losses in peripheral areas and dispersal limitations. We then test these results in two well‐studied systems. Butterflies are known to be strongly responding to climate change, and we show that over 21 years the codistribution component declines for butterfly communities in southern England. By contrast, birds in the same region are thought to be responding less strongly to climatic pressure and, despite high occupancy turnover, do not show clear changes in metacommunity structure as measured by this approach. Our results suggest that these approaches could have a high potential to summarise and compare the impacts of external drivers on whole communities.