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Climatic extremes are becoming more frequent and intense across much of the globe, potentially transforming the biodiversity and functioning of affected ecosystems. In freshwaters, hydrological extremes such as drought can regulate beta diversity, acting as powerful environmental filters to dictate the complement of species and functional traits found at local and landscape scales. New methods that enable beta diversity and its functional equivalent to be partitioned into turnover (replacement of species/functions) and nestedness-resultant (gain/loss of species/functions) components may offer novel insights into the parallel impacts of drought on ecosystem structure and function. Using a series of artificial channels (mesocosms) designed to mimic perennial headwater streams, we experimentally manipulated streamflows to simulate a gradient of drought intensity. We then modelled taxonomic and functional turnover and nestedness of macroinvertebrate communities along this gradient, validating direct gradient approaches (bootstrapping, Mantel tests) against null models of nestedness. Drought intensification produced significant environmental distance decay trends (i.e. communities became increasingly taxonomically and functionally dissimilar the more differentially disturbed by drought they were). Taxonomic distance decay was primarily driven by turnover, while the functional trend reflected a combination of richness differences and turnover at different points along the gradient. Taxonomic and functional distance decay slopes were not significantly different, implying that communities were functionally vulnerable to drying. The increased frequency and intensity of droughts predicted under most climate change scenarios could thus profoundly modify not only the structure of running water invertebrate communities, but also the ecosystem functions they underpin.

1. Logging is a major driver of tropical forest degradation, with severe impacts on plant richness and composition. Rarely have these effects been considered in terms of their impact on the functional and phylogenetic diversity of understorey plant communities, despite the direct relevance to community reassembly trajectories. Here, we test the effects of logging on functional traits and evolutionary relatedness, over and above effects that can be explained by changes in species richness alone. We hypothesised that strong environmental filtering will result in more clustered (under-dispersed) functional and phylogenetic structures within communities as logging intensity increases. 2. We surveyed understorey plant communities at 180 locations across a logging intensity gradient from primary to repeatedly logged tropical lowland rain forest in Sabah, Malaysia. For the 691 recorded plant taxa, we generated a phylogeny to assess plot-level phylogenetic relatedness. We quantified 10 plant traits known to respond to disturbance and affect ecosystem functioning, and tested the influence of logging on functional and phylogenetic structure. 3. We found no significant effect of forest canopy loss or road configuration on species richness. By contrast, both functional dispersion and phylogenetic dispersion (net relatedness index) showed strong gradients from clustered towards more randomly assembled communities at higher logging intensity, independent of variation in species richness. Moreover, there was a significant nonlinear shift in the trait dispersion relationship above a logging intensity threshold of 65% canopy loss (±17% CL). All functional traits showed significant phylogenetic signals, suggesting broad concordance between functional and phylogenetic dispersion, at least below the logging intensity threshold. 4. Synthesis. We found a strong logging signal in the functional and phylogenetic structure of understorey plant communities, over and above species richness, but this effect was opposite to that predicted. Logging increased, rather than decreased, functional and phylogenetic dispersion in understorey plant communities. This effect was particularly pronounced for functional response traits, which directly link disturbance with plant community reassembly. Our study provides novel insights into the way logging affects understorey plant communities in tropical rain forest and highlights the importance of trait-based approaches to improve our understanding of the broad range of logging-associated impacts.

Understanding how forest structure and species composition respond to anthropogenic pressure is essential for sustainable forest management in tropical protected landscapes. This study assessed variations in forest structure and plant species composition along disturbance gradients in the Lagonoy Natural Biotic area (LNBA), a multiple-use natural biotic area characterized by long-term human occupation. Vegetation data were collected from systematically established plots across upland and riparian forest zones, documenting species identity, abundance, and community composition. Anthropogenic pressure gradients were represented using indirect but robust proxies, including spatial accessibility, altitude, proximity to settlements and markets, forest resource dependence, and length of community residency. Results showed pronounced compositional and structural differentiation across pressure gradients. Forest areas characterized by higher accessibility and stronger livelihood dependence exhibited lower species diversity, reduced community heterogeneity, and a greater dominance of disturbance-tolerant and early-successional taxa. Multivariate ordination analyses revealed clear separation of plant communities along anthropogenic pressure gradients, indicating consistent ecosystem responses to cumulative human use. Cluster analysis further identified distinct forest condition classes corresponding to low-, moderate-, and high-pressure environments. Indicator species analysis demonstrated that late-successional and native species were strongly associated with less disturbed forest segments, whereas generalist and pioneer species dominated highly accessible areas. These findings indicate that anthropogenic pressure drives measurable simplification of forest structure and reorganization of species composition within protected landscapes. The study demonstrates the utility of integrating vegetation data with socio-spatial disturbance proxies to detect forest degradation patterns in data-limited tropical contexts. This approach provides a practical and scalable framework for informing adaptive forest management and conservation planning in human-inhabited tropical forests.

Aim: Our aims were to determine whether cross-taxon congruence of species composition patterns varies across regions and human disturbance levels and to infer whether these patterns relate to the size of the regional species pool and the sorting of species along a gradient of human disturbance. Location: Alberta's Boreal and Grassland Natural Regions, Canada. Method: We compiled presence-absence data of four biological groups (birds, vascular plants, bryophytes and mites) from low and high disturbance sites in upland habitat. The cross-taxon congruence across ecoregion and disturbance levels was analysed using Mantel and Procrustes tests. We applied resampling without replacement to generate confidence intervals to test for significant differences in strength of congruency between disturbance levels and ecoregions. We performed indicator species analysis to highlight how the species-level response to high and low disturbance influences the pattern in communitylevel cross-taxon congruence. Results: Cross-taxon congruence was stronger when all sites were considered than when high and low disturbance sites were considered separately. Congruency was relatively stronger in high than low disturbance sites in the Boreal ecoregion, but the pattern was reversed in the Grassland ecoregion. More species were indicators of undisturbed habitat than of highly disturbed habitats for all biological groups except for birds. Overall, biological groups that were poorly represented in a region and/or with few characteristic indicator species showed weak congruence in those sites. Main conclusions: We conclude that a longer disturbance gradient can promote cross-taxon congruence by increasing the species pool characteristic of low or high disturbance levels. Moreover, regional context can influence (or even reverse) the relative strength of cross-taxon congruence in high and low disturbance sites, which may explain the inconsistent strength of cross-taxon congruence along the disturbance gradient. To use biodiversity surrogates across biogeographical regions, it is therefore important to account for the regional and disturbance-level dependence of cross-taxon congruence.

The United States Clean Water Act (CWA; 1972, and as amended, U.S. Code title 33, sections 1251-1387) provides the long-term, national objective to \"restore and maintain the ... biological integrity of the Nation's waters\" (section 1251). However, the Act does not define the ecological components, or attributes, that constitute biological integrity nor does it recommend scientific methods to measure the condition of aquatic biota. One way to define biological integrity was described over 25 years ago as a balanced, integrated, adaptive system. Since then a variety of different methods and indices have been designed and applied by each state to quantify the biological condition of their waters. Because states in the United States use different methods to determine biological condition, it is currently difficult to determine if conditions vary across states or to combine state assessments to develop regional or national assessments. A nationally applicable model that allows biological condition to be interpreted independently of assessment methods will greatly assist the efforts of environmental practitioners in the United States to (1) assess aquatic resources more uniformly and directly and (2) communicate more clearly to the public both the current status of aquatic resources and their potential for restoration. To address this need, we propose a descriptive model, the Biological Condition Gradient (BCG) that describes how 10 ecological attributes change in response to increasing levels of stressors. We divide this gradient of biological condition into six tiers useful to water quality scientists and managers. The model was tested by determining how consistently a regionally diverse group of biologists assigned samples of macroinvertebrates or fish to the six tiers. Thirty-three macroinvertebrate biologists concurred in 81% of their 54 assignments. Eleven fish biologists concurred in 74% of their 58 assignments. These results support our contention that the BCG represents aspects of biological condition common to existing assessment methods. We believe the model is consistent with ecological theory and will provide a means to make more consistent, ecologically relevant interpretations of the response of aquatic biota to stressors and to better communicate this information to the public.

Home gardening is an indigenous practice of cultivation that has effectively adapted to local ecological conditions over generations. This study examined the effects of disturbance and garden size on biodiversity to develop a better understanding of vegetation cover and its role in livelihood and provision of forest management in the Vindhyan highlands. Data were collected from 60 gardens which were classified into large (> 650 m 2 ), medium (400–650 m 2 ), and small (< 400 m 2 ), based on size and disturbance gradients viz., high, medium, and low. A total of 133 species from 50 families were recorded, in which trees (47.4%) were dominant followed by shrubs (18%) and herbs (16.5%). With respect to disturbance, the highest number of tree species (39) were found at low disturbance (LD) followed by 33 species in medium disturbance (MD) and 32 species in high disturbhance (HD). The total mean richness of species was greater at LD (20.3 ± 2.3) and lowest at HD (18.5 ± 2.2). Tree density was significantly ( P ≤ 0.05) higher at LD (293.75 ± 16.1 individual ha –1 ) as compared to MD (221 ± 11.5 individual ha –1 ) and HD (210 ± 10.3 individual ha –1 ). However, the results for shrubs and herbs density were considerably different, where shrubs density was highest at HD (70 ± 6.9 individual per 1,000 m 2 ) and lowest at LD (62.5 ± 5.8 individual per 1,000 m 2 ), while the maximum density of herbs was recorded at MD (466.25 ± 29.8 individual per 100 m 2 ) and minimum at LD (370 ± 21.4 individual per 100 m 2 ). The summed dominance ratio indicated frequent use of garden plants in bio-fencing, vegetables, ornamental, and ethnomedicine. Diversity ( P < 0.01) and species richness ( P < 0.05) showed a significant positive correlation with garden size. The Principal Component Analysis (PCA) showed that the first component (PC1) accounted for 28.6% of variance, whereas the second explained 21.9% of variance in both disturbance and garden size with a cumulative variance of 50.5%. These components depicted the positive association with HD (14.34), SDiv (13.91), TCD (12.47), and HDiv (12.09). We concluded that the diversity of home gardens changed with disturbance, which crucially served as a refuge for native tree species in a degraded landscape. This pattern highlighted the importance of home gardens for plant biodiversity conservation and local livelihood, which must be a viable option for regeneration of deforested dry tropics, while also reducing the burden on dry tropical forest regions.

Chronic disturbance is widely recognized as one of main triggers of diversity loss in seasonally dry tropical forests (SDTFs). However, the pathways through which diffuse disturbance is acting on the forest are little understood. This information is especially demanded in the case of vanishing Neotropical seasonally dry forests such as the Tumbesian ones. We proposed a conceptual model to analyze the factors behind the loss of woody species richness along a forest disturbance gradient, explicitly considering the existence of direct and indirect causal pathways of biodiversity loss. We hypothesized that the chronic disturbance can act on the woody species richness directly, either by selective extraction of resources or by browsing of palatable species for livestock, or indirectly, by modifying characteristics of the forest structure and productivity. To test our model, we sampled forest remnants in a very extensive area submitted to long standing chronic pressure. Our forests cells (200 × 200 m) were characterized both in terms of woody species composition, structure, and human pressure. Our structural equation models (SEMs) showed that chronic disturbance is driving a loss of species richness. This was done mainly by indirect effects through the reduction of large trees density. We assume that changes in tree density modify the environmental conditions, thus increasing the stress and finally filtering some specific species. The analysis of both, direct and indirect, allows us to gain a better understanding of the processes behind plant species loss in this SDTF.

Urbanization and biological invasions synergistically threaten global biodiversity. The COVID‐19 lockdowns created a unique quasi‐experimental reduction in human mobility. We leveraged this period to conduct paired field surveys during both suppressed and resurgent human activity across urbanization (urban/rural) and invasion (invaded/uninvaded) gradients in China's Yangtze Basin, assessing the invasion dynamics of the American bullfrog (Lithobates catesbeianus). Key findings reveal three core patterns: (1) Urbanization facilitates invasion—bullfrog densities averaged 1.69 times higher in urban than rural habitats, a pattern unexplained by measured habitat variables; (2) Invasion impacts are species‐specific: Bufo gargarizans abundance increased in invaded sites (with the stronger response in urban areas), while four native frog species (Pelophylax nigromaculatus, P. plancyi, Fejervarya multistriata, Microhyla fissipes) declined, with P. nigromaculatus, P. plancyi and Microhyla fissipes experiencing intensified suppression in urban landscapes; (3) The reopening and resumption of human activity drove a 12.1% greater increase in bullfrog densities in rural versus urban areas, suggesting that rural establishment is dispersal‐dependent. Mechanistically, urbanization accelerates invasions through anthropogenic dispersal networks and permanent water sources, while habitat fragmentation forces native species to aggregate, intensifying competition and disease transmission. These findings underscore the need for differentiated urban–rural conservation strategies to mitigate invasion impacts. This study investigates how urbanization amplifies the invasion of American bullfrogs and exacerbates declines in native amphibians in China's Yangtze Basin, using the COVID‐19 lockdown as a natural experiment. It finds that urban areas have higher bullfrog densities, likely due to human dispersal networks and permanent water sources, while native species face intensified competition and disease transmission. The research underscores the need for differentiated urban–rural conservation strategies to mitigate invasion impacts.

Alpine meadows on the Tibetan Plateau experience chronic, fine-scale disturbances from the plateau zokor (Eospalax baileyi), a subterranean rodent that alters soil and vegetation structure through persistent burrowing and mounding. While classical theory predicts that plant community stability peaks at intermediate disturbance levels, this may not apply under spatially heterogeneous disturbance regimes. We assessed community stability across a five-level zokor disturbance gradient using a multi-indicator framework integrating compositional variability (average variation degree, AVD), co-occurrence-based cohesion, indicator species analysis, and boosted regression tree (BRT) modeling. Stability (1−AVD) peaked under extreme disturbance, alongside reduced indicator species richness and the dominance of disturbance-tolerant taxa. Increased cohesion suggested stronger species associations. Drivers of stability shifted from plant attributes under low disturbance to soil constraints (bulk density and moisture) under high disturbance. These results challenge the intermediate disturbance–stability paradigm and suggest that abiotic filtering can promote compositional convergence and structural stability. Our findings highlight the importance of spatial disturbance patterns in shaping community resilience and provide early warning indicators and targeted guidance for managing alpine grasslands under subterranean disturbance.

Habitat disturbance driven by human activities poses a major threat to biodiversity and can disrupt ecological interactions. Butterfly–plant mutualisms represent an ideal model system to study such anthropogenic impacts, as butterflies exhibit intimate dependencies on larval host plants and adult nectar sources, rendering them highly sensitive to habitat changes affecting the availability of these floral resources. This study examined flower-visiting butterfly communities and their associations with flowering plants in a landscape altered by anthropogenic factors in central Mexico. The study area encompassed a mosaic of vegetation types, including native juniper forests, agricultural lands, and introduced eucalyptus plantations, representing different degrees of human-induced habitat modification. Monthly surveys were conducted over a single year, covering both rainy and dry seasons, to analyze butterfly and plant diversity, community composition, and interactions. Results showed the highest diversity in juniper forests, followed by eucalyptus and agricultural sites. Seasonal turnover was the primary driver of community changes, with habitat-based segregation persisting within seasons. Butterfly diversity strongly correlated with flower abundance, while plant richness played a secondary role. SIMPER and indicator species analyses identified key taxa contributing to compositional dissimilarities among habitats and associated with specific vegetation types and seasons. Our research provides insights into temporal dynamics structuring butterfly–plant interactions across this forest disturbance spectrum, highlighting how habitat changes and seasonality shape these mutualistic communities in changing landscapes.