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While there is increasing recognition that social processes in cities like gentrification have ecological consequences, we lack nuanced understanding of the ways gentrification affects urban biodiversity. We analyzed a large camera trap dataset of mammals (>500 g) to evaluate how gentrification impacts species richness and community composition across 23 US cities. After controlling for the negative effect of impervious cover, gentrified parts of cities had the highest mammal species richness. Change in community composition was associated with gentrification in a few cities, which were mostly located along the West Coast. At the species level, roughly half (11 of 21 mammals) had higher occupancy in gentrified parts of a city, especially when impervious cover was low. Our results indicate that the impacts of gentrification extend to nonhuman animals, which provides further evidence that some aspects of nature in cities, such as wildlife, are chronically inaccessible to marginalized human populations.

The loss of biodiversity and biotic homogenization are on the rise in ecosystems around the world as a result of species invasions, habitat degradation, and the effects of climate change. In the Sacramento–San Joaquin Delta, non-native species make up the majority of the fish community, and declines in native species have been well documented; however, little is known about whether these trends have resulted in biotic homogenization. In this study, we used data from a long-term beach seine survey to analyze regional beta diversity trends of nearshore fish assemblages in the Delta from 1995 to 2019. Overall, we found no evidence of regional biotic homogenization occurring over the study period. Regional beta diversity increased moderately over time and was significantly influenced by the high interannual variability of freshwater inflow. These beta diversity patterns were driven by the non-native Mississippi Silverside that has proliferated in the system in recent years, but also by a handful of native fish species such as the Sacramento Sucker, Tule Perch, and Splittail. Overall, our results offer a contrast to other highly invaded ecosystems around the world and suggest that despite the near extinction of some native fish species, there remain pockets of suitable habitat in the Delta that may play a key role in the conservation of remnant native fish diversity.

ABSTRACT Grassland afforestation poses a threat to biodiversity beyond land‐use conversion. Diversity patterns are shaped by temporal dynamics, particularly, time since afforestation can decline beta diversity and lead to biotic homogenisation. Our study examines the effect of grassland afforestation on soil prokaryotic and fungal beta diversity. We evaluate the contributions of colonisation and extinction processes to beta diversity, as well as the replacement of endemic species by ubiquitous ones. Along a 200 km climatic gradient in Argentina's Pampas region, we analysed grasslands and mature eucalypt plantations at different times since afforestation. Soil samples were collected at each site and analysed using 16S (V3–V4) and ITS2 amplicon sequencing to identify prokaryotic and fungal communities, respectively. The analyses revealed biotic homogenisation at the transition from grassland to newly planted stands, evidenced by a decrease in intratreatment beta diversity. Increasing time since afforestation did not exacerbate this decline. However, our findings indicate that there are different responses between prokaryotes and fungi. The homogenisation of prokaryotes in young stands is due to the low heterogeneity in colonising communities. On the other hand, the decline in fungal beta diversity is likely caused by other mechanisms beyond extinction or replacement. The study highlights the impacts of the afforestation process on the beta diversity of soil microbial communities of grasslands, affecting taxonomic groups in different ways. Although microbial diversity may be partially restored in time in eucalypt plantations, it is important to investigate its underlying mechanisms and the ecological implications for microbial diversity and its spatial distribution. [ABSTRACT FROM AUTHOR]

β‐diversity quantifies the change in taxonomic and phylogenetic composition between areas. It can be partitioned into two additive components (turnover and nestedness). Geographic distance, which reflects dispersal limitation, and climatic distance, which reflects environmental filtering, are major drivers of β‐diversity, but few studies have assessed their relative importance to β‐diversity at a global scale.Here, we investigate the relationship of β‐diversity of angiosperm genera in regional floras worldwide to climatic conditions within regions and to geographic and climatic distances between regions.We found that (1) current climate has a stronger effect on phylogenetic turnover than does Quaternary climate change; (2) of the current climate variables examined, mean annual temperature is the strongest driver of phylogenetic turnover, followed by precipitation seasonality; (3) regions with high precipitation seasonality have high phylogenetic β‐diversity and phylogenetic turnover; and (4) at a global scale, the variation in phylogenetic turnover explained jointly by geographic and climatic distances is, on average, much larger than that explained uniquely by either distance, but that geographic distance explains more variation in phylogenetic turnover than climatic distance.Synthesis. These results reveal the synergistic role of geographic isolation and climatic filtering in determining the composition of floras worldwide, with less influence of Quaternary climate changes. [ABSTRACT FROM AUTHOR]

Our understanding of how human activities impact biodiversity comes largely from space‐for‐time substitutions. However, spatial gradients are a poor surrogate for changes through time as they do not account for dynamic processes such as delayed extinction debts. Here we contribute towards filling this research gap by assessing the trajectories of local avian assemblages over 40+ years of climate and land‐use change. Using four decades of volunteer observations in Denmark we investigated long‐term trends of local bird richness, community structure, function, abundance, and biomass to better understand their anthropogenic drivers. Between 1976 and 2020, volunteers recorded ~ 2.4 million birds at 378 routes spanning a median of 15 years (range: 10–44). At the local level, we found a restructuring of bird communities over time (6% change per decade) and declines in abundance (−7% per decade), but stability in biomass, functional diversity, and spatial turnover. Local species richness showed a shallow decline on average. These results provide evidence that temporal turnover and loss of individuals are the most prominent features of recent ecological change in these communities. We found that the rate of local warming was positively associated with trends of species richness and functional diversity, suggesting a potential redistribution of warm‐adapted species. Meanwhile, communities that were becoming more spatially homogenous were associated with urban and farmland areas. In space, environmental changes are often distinct and recognisable, e.g. between forest and farmland. Through time, however, changes can be infrequent, gradual, and non‐linear. Despite these challenges, our results illustrate the power of spatially replicated, long‐term biodiversity monitoring programs for detecting the trends and attributing drivers of local biodiversity change. [ABSTRACT FROM AUTHOR]

Artificial ponds can be important reproductive sites for anurans in human-disturbed habitats. However, this capacity depends on the configuration of the habitat where they are inserted. We evaluated how anuran beta diversity was influenced by the configuration of the surrounding habitat and water parameters in artificial ponds in southern Brazil. Physicochemical parameters of water and the configuration of the surrounding habitat were the elements that best explained the variation in beta diversity. However, the surrounding habitat had a predominant role in the differences between communities. The level of exposed soil was the component that best acted on the turnover component of beta diversity followed by urbanization, which highlights the impact of human presence on anuran diversity. In other words, we observed that anthropogenic changes caused changes in species composition in the evaluated ponds. Among water parameters, only phosphate was relevant for the configuration of communities. Phosphate peaks may result from sewage or fertilizer contamination, not infrequent in the region despite the low human density and the small-scale agriculture economy. Even though they are anthropogenic environments, artificial ponds can help maintain the anuran communities, but their effectiveness will depend on the presence of forest remnants and water quality. [ABSTRACT FROM AUTHOR]

The presence or absence of species in a specific area and their distribution in geographic space are consequences of various factors, including geographic barriers. This study analyzes the change in species composition of two crane fly communities separated by a geographic barrier in the state of Veracruz, Mexico. Crane flies were collected using Malaise traps in 10 sites across two transects along the Misantla river (MT) and Actopan river (AT) basins, divided by the Chiconquiaco mountain range, through quarterly samplings over three years. A total of 559 specimens belonging to 60 species were collected, with 45 in MT (23 exclusive) and 37 species in AT (15 exclusive). The species composition differed by more than 60% between transects, primarily due to turnover; with higher values and a similar pattern among the sites along the transects, it is suggested that geographic barrier could be a factor in the change in composition. Additionally, three new and 41 potential new records for Mexico and 10 new records for Veracruz are reported, increasing the species records in Veracruz to 90 and in the country to 376. This study represents the first assessment of crane flies species composition at a specific site in Mexico. [ABSTRACT FROM AUTHOR]

Aim: We address the relative importance of biogeographic regions (areas of endemism), regional climate and spatial factors on taxonomic, functional and phylogenetic beta diversity of bird assemblages in upland terra‐firme forests in the Amazon. Location: Amazon biome. Taxon: Birds. Methods: We gathered 27,498 occurrence records of 873 bird species for 115 bird assemblages distributed in all nine biogeographic regions delimited by the major Amazonian rivers. Only data from studies surveying whole communities with standard sampling methods and exhaustive sampling effort were included. We partitioned the fractions of taxonomic, functional and phylogenetic beta diversity explained by climate, biogeographic regions, spatial factors and the variation shared between them. Results: Across the entire Amazon, we found higher total taxonomic (0.68 ± 0.10) than phylogenetic (0.46 ± 0.08) β‐diversity, and low functional β‐diversity (0.34 ± 0.08). Biogeographic regions showed the highest unique contributions explaining taxonomic and phylogenetic β‐total (7% and 5%, respectively) and turnover components (7% of β‐jtu taxonomic, 7% of β‐jtu phylogenetic), but accounted for only 2% of total functional β‐diversity and trait turnover. Climatic variables explained slightly more trait nestedness (5%) compared with species and lineage turnover (3% each). Species composition was clearly distinct between biogeographical regions limited by the Amazon River, but support for the effect of other rivers was mixed. Main Conclusions: Our study highlights the significant influence of biogeographic regions and climate on species composition in the Amazon. However, our findings also suggest that the Amazon River exerts a more pronounced impact on species distribution compared with other major Amazonian rivers. Species turnover across biogeographical regions is particularly evident at the species level, with minor effects observed in functional traits, suggesting that taxonomic turnover is driven mainly by functionally redundant species. In addition, recent diversification events, occurring predominantly at the tips of the phylogeny without substantial turnover at deeper nodes, are likely responsible for the patchy distribution of species across Amazonia. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the patterns of stream diatom beta diversity in islands versus continents across scales, to relate community similarities with spatial and environmental distances and to investigate the role of island characteristics in shaping insular diatom beta diversity. Location: Africa, America, Europe and the Pacific. Time Period: Present. Major Taxa Studied: Stream diatoms. Methods: We compared diatom beta diversity between islands and continents at large scales (within biogeographic regions) in two study regions (America and Europe) and at small scales (within islands/equivalent areas in continents) in three regions (Africa, America and Europe) partitioning beta diversity into turnover and nestedness components. We used a partial Mantel test and distance–decay curves to assess how diatom beta diversity on islands and continents is affected by spatial and environmental distances. Finally, using island data from all four regions, we evaluated the relationship between island beta diversity and island latitude, area, age and isolation using linear models. Results: At large scales, mean dissimilarities were higher on islands than in continents in Europe but lower in America. At smaller scales, the differences varied mostly depending on island isolation. Beta diversity was mainly caused by species turnover. Partial Mantel test and distance–decay curves revealed that spatial and environmental distances shaped diatom beta diversity at large, but not at small scales. Moreover, diatom beta diversity on islands was affected by island latitude, age and isolation, but not by island area. Main Conclusions: Diatom beta diversity on islands versus continents and its responses to spatial and environmental factors are scale and region dependent. Incomplete colonisation, evolutionary processes and environmental filtering likely contribute to insular beta diversity, which further varies with island latitude, age and isolation. This study sheds new light on beta diversity of microorganisms on islands and suggests that beta diversity should be explicitly considered in island biogeographical research. [ABSTRACT FROM AUTHOR]

Aim: To describe worldwide distribution of mammalian cradles and museums using the rates of phylogenetic lineage turnover as a surrogate. Additionally, we investigated the influences of current water–energy dynamics, climate instability, past climate changes and elevational ranges on the distribution of these evolutionary zones. Location: Global. Time Period: Current. Major Taxa Studied: Terrestrial mammals. Methods: We developed a new methodology that consists of calculating the spatial phylogenetic turnover for non‐overlapping temporal segments of phylogenetic trees. By calculating the relative turnover in each tree segment, we quantified the rate of accumulation of phylogenetic turnover through time. We depicted cold and hotspots of rates of lineage turnover using bivariate maps and examined the effects of environmental factors using a path model. Results: The distributions of cradles and museums of biodiversity are primarily driven by water–energy dynamics. Environments with higher water availability than energetic demand predominantly act as cradles, as seen in tropical rainforests, while xeric‐like environments predominantly serve as museums. Conversely, regions undergoing higher historical climate changes become cradles, such as in higher northern latitudes, while climatically stable areas function as museums. Mountains play a dual role, acting as both cradles and museums by generating new lineages along their elevation bands while simultaneously providing climate refuges for ancient mammal lineages. Main Conclusions: Our findings demonstrate that cradles and museums are not merely a dichotomy but exist along an evolutionary continuum. Furthermore, they reveal how spatial patterns of mammalian cradles and museums are intricately shaped by biogeographical processes governed by environmental forces. Uncovering these hidden effects provides insights into the ecological mechanisms by which ongoing climate changes continually shape evolutionary assemblages over time. [ABSTRACT FROM AUTHOR]

Analyzing the temporal dynamics of ecological communities can shed light on coexistence mechanisms and help understand how populations and communities will behave in the face of climate change. However, little is known about how frog communities respond to climate in urban ecosystems, especially in tropical countries. Here, we analyzed how frog species richness and abundance are influenced by weather variables both intra‐ and inter‐annually. We surveyed a peri‐urban area in central Brazil, monthly for 3 years. To test the effect of weather variables on species richness and abundance, we used Generalized Additive Mixed‐effects Models. We assessed seasonality using circular statistics. We also tested for differences in temporal beta diversity within and among years by estimating species disappearance and temporal rank shift, in addition to a multivariate model‐based method to test the effect of year on species composition. Finally, we tested how taxonomic and phylogenetic alpha diversity changed through time using a novel approach based on Hill numbers. We found that species richness varied little among years and was affected only by photoperiod, while species abundance was more variable both between and within years, being mostly affected by humidity, temperature, and photoperiod. Species composition varied little between years, mostly between the first and subsequent years. Conversely, beta diversity was highest within years. Only the effective number of species changed significantly through time. Our results help not only understand temporal mechanisms that allow species coexistence, but also allow to make inferences about the impact of urbanization on biodiversity in recently urbanized landscapes, showing that species composition in peri‐urban sites remains unaltered in a mid‐timescale, especially when climate conditions change little across years. [ABSTRACT FROM AUTHOR]

Ishikawaella is an obligate gut bacterium in stinkbugs that belong to Plataspidae family (Hemiptera: Heteroptera). It is vertically transmitted to newborn nymphs through capsules laid on eggs by maternal stinkbugs. Previous research has established a pattern of strict cospeciation between Plataspidae stinkbugs and Ishikawaella. However, the possibility of host–symbiont coevolution at the population level within Plataspidae stinkbugs has not been thoroughly explored. This study analyzed the samples of Megacopta cribraria from three phylogenetic clades to investigate host–symbiont coevolution in this insect species. We compared data from third‐generation sequencing (PacBio), next‐generation sequencing (Illumina), and first‐generation sequencing (Sanger), and the results indicated that Illumina sequencing most accurately represents the composition of gut bacterial communities. All stinkbug individuals shared a dominant amplicon sequence variant (ASV), which accounted for an average of 65.99% of Ishikawaella sequences (ranging from 58.68% to 87.01%). The top five ASVs (ASV0–ASV4) represented 99.82% of all Ishikawaella sequences. Among these, the number of base substitutions between any two ASVs ranged from 1 to 3, significantly lower than the number of substitutions between the main and minor ASVs. This finding suggests that closely related strains are likely to coexist in the same host. Beta diversity analyses revealed significant differences in Ishikawaella composition among the three phylogenetic clades, providing evidence for host–symbiont coevolution at the population level in Plataspidae stinkbugs. [ABSTRACT FROM AUTHOR]

Understanding variation in assemblage composition (i.e., beta diversity) along geographic and environmental gradients is a central topic in biogeography and ecology.We compared relationships between hemipteran beta diversity (overall dissimilarity: βtotal, Sorensen dissimilarity; turnover component: βsim, the replacement of species between assemblages; nestedness‐resultant component: βsne, the nested difference in richness between assemblages) and geographic, climatic and land cover distances among four ecoregions (Northeast Ecoregion; Northern Ecoregion; Tibet Ecoregion; Southern Ecoregion) across China.The hemipteran assemblage composition differed markedly among ecoregions. In general, βtotal and βsim both significantly increased with increasing geographic, climatic and land cover distances.Intercepts and slopes of dissimilarity‐distance relationships all varied significantly among different ecoregions, suggesting different levels of within‐ecoregion assemblage heterogeneity and change rate in assemblage composition. Moreover, the slopes of βtotal and βsim were highest in Northeast Ecoregion but lowest in Northern Ecoregion, exhibiting latitudinal and longitudinal dissimilarity pattern.According to variation partitioning analysis, although the overall explained variance was relatively low, spatial variables explained a much greater proportion of variance compared to climate and land cover variables.To conclude, our results showed significant regional differences in assemblage composition and biodiversity among ecoregions. Both dispersal‐related and niche‐related processes affect hemipteran assemblage structure, while the low overall explained variance indicates that high dissimilarity in hemipteran composition is affected by multiple factors and processes that remained undetected in this study.Our results may be relevant for wider insect groups because hemipterans constitute a highly diverse group in terms of phylogenetic origins and functional significance. [ABSTRACT FROM AUTHOR]

Deterministic factors including homogeneous and heterogeneous selection and stochastic factors jointly shape ecological communities. However, a quantitative synthesis of the factors underlying the balance among different assembly processes is lacking. Here, we synthesized data from 149 datasets covering major biotic groups and ecosystem types globally. We used a null model approach based on Raup–Crick dissimilarities and Bayesian meta‐regression to analyze the data. We found that communities were more under homogeneous selection than heterogeneous selection across biotic taxa and ecosystems. Environment selected species homogeneously more often at small scales while heterogeneously more often at large scales. Stochasticity also showed scale‐dependence as stochastic community assembly increased with study scale. Homogeneous and heterogeneous selection were strongest at high latitudes while stochastic factors were strongest in tropics. Marine systems had the highest degree of homogeneous selection and the lowest stochasticity. We provide the first analysis of community assembly across taxa and ecosystems which should be important for a better understanding of how communities respond to environmental change. [ABSTRACT FROM AUTHOR]

The combined impacts of anthropogenic activities and global climate changes threaten native fish communities. Such threats are particularly critical in biodiversity hot spot areas with many endemic species, as exemplified by the isolated Yun‐Gui Plateau, China. The risk of biotic homogenization is also expected to be high in such areas, but this risk and its underlying drivers remain poorly studied.Here, we established a database of fish distributions and used environmental filtering for spatial clusters (n = 3759) in river basins located at Yun‐Gui Plateau. This database was based on public data sources and a comprehensive review of relevant literature (n = 481) covering the period from 1950 to 2021. We divided the plateau into nine subbasins for spatial comparison and into two periods for temporal comparison—before and after the start of rapid economic growth development in 1978.We found: (a) a marginal increase in replacement (species exchange in different subbasins) and similarity index but a decrease in richness difference index, indicating homogenization and the loss of natural barriers across the entire plateau; (b) an increase in species richness accompanied by a discernible decline in phylogenetic diversity, also indicating homogenization; (c) the increase in species richness by species loss‐gain analyses was associated with climatic variables (temperature and precipitation), elevation and human activities in all subbasins.Temporal and spatial comparisons indicated that homogenization of fish assemblages in the Yun‐Gui Plateau was exacerbated by climatic and anthropogenic pressures.The observed homogenization of fish species is of great concern, and we call for systematic assessments and precautionary mitigation actions to maintain the uniqueness of biodiversity in the Yun‐Gui Plateau region. [ABSTRACT FROM AUTHOR]

The gut microbiome is essential for the health of carnivorous mammals, including the endangered Siberian tiger (Panthera tigris altaica). However, limited research exists on the gut microbiome of captive Siberian tigers, especially regarding how diet and health status influence microbial diversity. This study addresses this gap by investigating the gut microbiome diversity and composition of six captive-born Siberian tigers housed at the Baekdudaegan National Arboretum in South Korea, using 16S rRNA gene sequencing. The study aimed to examine how diet and health status influence microbial communities, providing baseline data for managing captive tigers. Alpha diversity analysis revealed significant variation in microbial richness and evenness, with Tigers 2 and 6 exhibiting the highest microbial diversity and Tiger 3 the lowest, likely due to its surgical history and limited diet. Beta diversity analysis showed distinct microbial community structures influenced by diet and health. Taxonomic profiling identified Firmicutes and Bacteroidota as the dominant phyla, with Clostridium sensu stricto more prevalent in healthier tigers, while Escherichia-Shigella and Proteobacteria were abundant in tigers with lower diversity, suggesting dysbiosis. Comparisons with other tiger species confirm that diet, health, and captivity significantly shape the gut microbiome. These findings highlight the need for personalized health management in captive environments. [ABSTRACT FROM AUTHOR]

Tropical dry forests (TDFs) are unique ecosystems with high biodiversity, including a rich variety of lichen species. Lichens are sensitive to environmental changes and can serve as bioindicators of ecosystem health. This study examined the diversity of lichen communities at four TDF sites in the Atlántico Department of Colombia. More than 700 tree lichen specimens were collected and identified at the four sites. A total of 135 species of lichens were identified, of which 19 are possibly undescribed. The most diverse sites were Usiacurí and Repelón, both protected areas with relatively well-preserved forests. The findings of this study demonstrate that the Atlántico TDFs host a large diversity of lichens, with a significant number of records of new species. The observed differences in species composition between sites highlight the importance of habitat heterogeneity and anthropogenic pressures on lichen communities. The results emphasize the need for conservation strategies to protect these ecologically valuable lichen communities within the Atlántico TDFs. [ABSTRACT FROM AUTHOR]

Understanding biodiversity changes, along with its driving factors and mechanisms, is crucial in biogeography and community ecology. Beta diversity is an indicator for discerning the compositional variations among communities and is essential role in fostering a comprehensive understanding of the ecological processes shaping biodiversity distribution patterns. This study quantitatively evaluated the beta diversity of macroinvertebrates in the Wei River Basin, focusing on: (i) contributions of turnover and nestedness to taxonomic, functional, and phylogenetic total beta diversity, (ii) correlations between these beta diversity dimensions, and (iii) the influences of local, climatic, and spatial factors on beta diversity. We analyzed macroinvertebrate data from 51 sampling locations in the Wei River Basin and explored the relationships between different beta diversity dimensions using the Mantel test. Additionally, we assessed the relative influence of local, climatic, and spatial factors on beta diversity through distance-based redundancy analysis and variance partitioning methods. The results indicated that turnover predominantly affects taxonomic and phylogenetic beta diversity, while nestedness mainly drives functional beta diversity. Functional beta diversity was more weakly associated with the other dimensions. Local environmental factors significantly influenced taxonomic and phylogenetic beta diversity, whereas spatial factors had a stronger influence on functional beta diversity. Our findings highlight the need for conservation strategies to integrate taxonomic, functional, and phylogenetic dimensions, transcending traditional species-level approaches. [ABSTRACT FROM AUTHOR]

Phylogenetic indexes summarize the evolutionary information within a given assemblage pool based on the topology and branch lengths of a hypothesized phylogenetic tree. However, different historical contingencies experienced by these assemblages can unevenly distribute evolutionary information through time and over the phylogeny. ‘treesliceR' is an R package containing tools to flexibly cut phylogenies at different depths, and also has built‐in functions to assess spatially explicit phylogenetic patterns over time. ‘treesliceR' can slice phylogenies in any temporal orientation (‘rootwardly' or ‘tipwardly'), using different criteria (million years or phylogenetic diversity). Moreover, ‘treesliceR' contains functions to assess the rates of accumulation of any phylogenetic information (e.g. α and β diversities) through time. These functions are unique to the package and provide outputs that are ready‐to‐use in graphing functions. We demonstrated the main uses of ‘treesliceR' by investigating areas of paleo‐endemism and neo‐endemism of Passeriformes in Australia. Finally, we mapped rates of accumulation of phylogenetic β‐diversity (Cpβrate) across Australia. ‘treesliceR' is an open‐source R package under continuous progress, designed to decompose temporally any phylogenetic information. [ABSTRACT FROM AUTHOR]

Riparian forests are crucial for biodiversity, but dam construction for hydroelectric power disrupts these ecosystems, causing habitat loss and altering river dynamics. Our study investigates the impacts of dams on tree diversity in the southern Brazilian Atlantic Forest. We sampled trees along riverbanks and uplands across 15 dam-affected fragments, analysing the relationship between habitat loss (i.e. loss of riparian zones by permanent flooding due to dam filling), elevation difference, fragment size, and dam implementation time with alpha and beta diversity using mixed models and redundancy analyses. Habitat loss had a more significant impact on beta diversity, leading to shifts in species composition and reduced uniqueness of communities as the impact's intensity, spatial extent, and duration increased. Alpha diversity only increased in response to local elevation differences between plots located on uplands and riverbanks. Our sampling design can be applied to other inadequately monitored systems to provide insights into beta diversity, a component often neglected in dam licensing and mitigation processes. Our findings reveal a transient local heterogenisation, transitioning into regional homogenisation due to dam-induced habitat loss in riparian forests of the Brazilian Atlantic Forest. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim Location Taxon Methods Results Main Conclusions Variation in community composition along environmental gradients provides crucial information for identifying zones where species turnover is rapid and to ascertain whether compositional changes occur gradually or rather abruptly. We examined changes in bird community composition along three bioclimatic transects in Australia to test whether drivers of species turnover are consistent, rather than spatially contingent, across biologically contrasting ecosystems. We also detected potential transition zones associated with environmental thresholds and determined whether certain abiotic conditions promote a higher rate of community compositional turnover.Mainland Australia.Terrestrial birds.We applied multivariate community analysis, generalised dissimilarity modelling (GDM) and threshold indicator taxa analysis (TITAN).We observed that environmental variables are better predictors of community composition than spatial distance, which indicates that species sorting, rather than dispersal, plays a key role in structuring Australian avian communities. Annual precipitation constitutes a key driver of species turnover regardless of the analysed transect. The most humid landscapes and those with a higher tree canopy show lower spatial heterogeneity in community composition compared to those with less benign environmental conditions (e.g., dryer environments). TITAN detected significant transition points and supported the results obtained using GDM, which suggests that bird composition change along the gradients is not monotonic.Our results suggest that avian beta diversity increases with increasing environmental harshness, presumably through changes in the relative importance of stochastic versus deterministic processes. The obtained findings show that open forests and woodlands are extremely important ecosystems on this continent and deserve special attention in terms of conservation due to their vulnerability to global change. Lastly, this study exemplifies the value of combining community‐ and taxon‐based analyses to identify and interpret community thresholds, which can serve to pinpoint targets for preserving biodiversity. [ABSTRACT FROM AUTHOR]

Understanding the driving mechanisms of diversity across multiple dimensions is a fundamental task in biodiversity conservation. Here, we examined the alpha and beta diversity of macroinvertebrates in the taxonomic, functional, and phylogenetic dimensions in mountain streams of northwestern Hubei Province, China. We also assessed how much local environmental, land use, climatic, and spatial variables affected these diversities. We found that (1) there were generally weak or no correlations of alpha and beta diversity between taxonomic, functional, and phylogenetic dimensions; (2) compared to both functional and phylogenetic beta diversity, which was mainly determined by nestedness, taxonomic beta diversity was mostly molded by turnover and was much higher; and (3) local environmental variables predominantly influenced taxonomic and functional dimensions of alpha and beta diversity, while spatial factors primarily drove phylogenetic dimension. These results suggest that regulating local habitats is crucial for lotic biodiversity conservation efforts, though spatial processes cannot be overlooked. Furthermore, our findings verify the supplemental role of functional and phylogenetic data in enriching insights provided by taxonomic data alone. This underscores the importance of a multidimensional approach for a more nuanced understanding of community assembly mechanisms, which is crucial for efficient ecosystem management and biodiversity conservation. [ABSTRACT FROM AUTHOR]

The services provided by the world's coral reefs are threatened by increasingly frequent and severe marine heatwaves. Heatwave-induced degradation of reefs has often been inferred from the extent of the decline in total coral cover, which overlooks extreme variation among coral taxa in their susceptibility and responses to thermal stress. Here, we provide a continental-scale assessment of coral cover changes at 262 shallow tropical reef sites around Australia, using ecological survey data on 404 coral taxa before and after the 2016 mass bleaching event. A strong spatial structure in coral community composition along large-scale environmental gradients largely dictated how coral communities responded to heat stress. While heat stress variables were the best predictors of change in total coral cover, the pre-heatwave community composition best predicted the temporal beta-diversity index (an indicator of change in community composition over time). Indicator taxa in each coral community differed before and after the heatwave, highlighting potential winners and losers of climate-driven coral bleaching. Our results demonstrate how assessment of change in total cover alone may conceal very different responses in community structure, some of which showed strong regional consistency, and may provide a telling outlook of how coral reefs may reorganize in a warmer future. [ABSTRACT FROM AUTHOR]

Background: Studies indicate that gut microbiota is related to neurodevelopmental and behavioral outcomes. Accordingly, early gut microbiota composition (GMC) has been linked to child temperament, but research is still scarce. The aim of this study was to examine how early GMC at 2.5 months is associated with child negative and fear reactivity at 8 and 12 months since they are potentially important intermediate phenotypes of later child psychiatric disorders. Methods: Our study population was 330 infants enrolled in the longitudinal FinnBrain Birth Cohort Study. Gut microbiota composition was analyzed using stool sample 16s rRNA sequencing. Negative and fear reactivity were assessed using the Laboratory Temperament Assessment Battery (Lab-TAB) at child's age of 8 months (n =150) and the Infant Behavior Questionnaire-Revised Short Form (IBQ-R SF) at child's age of 12 months (n = 276). Conclusions: We found a positive association between alpha diversity and reported fear reactivity and differing microbial community composition based on negative reactivity for boys. Isobutyric acid correlated with observed negative reactivity, however, this association attenuated in the linear model. Several genera were associated with the selected infant temperament traits. This study adds to the growing literature on links between infant gut microbiota and temperament informing future mechanistic studies. [ABSTRACT FROM AUTHOR]

Assemblages in seasonal ecosystems undergo striking changes in species composition and diversity across the annual cycle. Despite a long‐standing recognition that seasonality structures biogeographic gradients in taxonomic diversity (e.g., species richness), our understanding of how seasonality structures other aspects of biodiversity (e.g., functional diversity) has lagged. Integrating seasonal species distributions with comprehensive data on key morphological traits for bird assemblages across North America, we find that seasonal turnover in functional diversity increases with the magnitude and predictability of seasonality. Furthermore, seasonal increases in bird species richness led to a denser packing of functional trait space, but functional expansion was important, especially in regions with higher seasonality. Our results suggest that the magnitude and predictability of seasonality and total productivity can explain the geography of changes in functional diversity with broader implications for understanding species redistribution, community assembly and ecosystem functioning. [ABSTRACT FROM AUTHOR]

The oligotrophic tropical western Pacific region is characterized by a high density of seamounts, with the Kyushu‐Palau Ridge (KPR) being the longest seamount chain here. Effective spatial management plans for seamount ecosystems necessitate an understanding of distribution patterns and key environmental factors influencing benthic communities. However, knowledge regarding deep‐sea biodiversity patterns over intricate topography remains limited. In this study, we investigated a seamount with a water depth of 522 m at the summit located in the southern section of KPR. Survey transects were conducted from 522 m to 4059 m. By analyzing video‐recorded data obtained by a human‐occupied vehicle (HOV) during dives and environmental variables derived from bathymetry, distinct assemblages were identified through noise clustering. α‐ and β‐diversity patterns within the seamount megabenthic community were analyzed across the depth gradient, along with investigation of their environmental drivers. A total of 10,596 megafauna individuals were documented, categorized into 88 morphospecies and statistically separated into six distinct community clusters using noise clustering analysis. Species abundance and richness were highest within the 700–800 m water depth range, declining notably beyond 2100 m, indicating a critical threshold for habitat classification in this region. The β‐diversity of megabenthic communities was high (0.836). Although β‐diversity patterns along the depth gradient were mostly dominated by differences in species richness, the contribution of species replacement increased with depth, becoming dominant at depths greater than 3000 m. Depth emerged as the primary driver of spatial variation in community structure, while near‐bottom current velocity, topographic parameters (bathymetric position index, slope), and substrate type also influenced the formation of microhabitats. The study highlights the depth gradients, thresholds, and other intricate environmental factors shaping the spatial heterogeneity of these communities. It provides valuable insights for the future development of effective survey and conservation strategies for benthic biodiversity on the KPR. We conducted a detailed study of a seamount in the Philippine Sea and analyzed the patterns of variation and factors controlling the beta diversity of the benthic community. [ABSTRACT FROM AUTHOR]

Simple Summary: Understanding the distribution of plants and animals is a major focus of ecologists and is of increasing importance as temperatures rise and the world's climate becomes more unpredictable. One large-scale pattern that has often been observed is for the number of species in a group of interest to be greater in the tropics than towards the poles. Species also tend to decline in number at higher elevations. We examined the distribution of mayfly species, insects commonly found in streams, at multiple sites throughout New Zealand to see whether the numbers and identities of species were related to latitude and altitude. We found that the number of mayfly species declined from north to south, i.e., towards higher latitudes, and less strongly as elevation increased. Furthermore, the species composition of communities became increasingly different with distance along the latitudinal gradient. Our findings suggest that the species gradient has historical origins, with the north of North Island and the South Island mountains likely to have been important regions of speciation 1.5–0.5 million years ago. The distribution of species in relation to latitude and altitude is of fundamental interest to ecologists and is expected to attain increasing importance as the Earth's climate continues to change. Species diversity is commonly greater at lower than higher latitudes on a global scale, and the similarity of communities frequently decreases with distance. Nevertheless, reasons for such patterns are not well understood. We investigated species richness and changes in community composition of mayflies (Ephemeroptera) over 13 degrees of latitude at 81 locations throughout New Zealand by light-trapping and the benthic sampling of streams. Mayflies were also sampled along an altitudinal gradient on a prominent inactive volcano in the east of North Island. Sampled streams were predominantly in the native forest, at a wide range of altitudes from sea level to c. 1000 m a. s. l. A total of 47 of the 59 described New Zealand mayflies were recorded during the study, along with five undescribed morphospecies. Species richness declined and the degree of dissimilarity (beta diversity) of mayfly communities increased significantly from north to south but less strongly with increasing altitude. Our results suggest that the southward decline in species richness has historical origins with the north of the country having acted as a major refuge and region of speciation during the Pleistocene. The increasing dissimilarity of the northern and southern communities may reflect an increasingly harsh climate, variable amounts of subsequent southward dispersal of northern species and, in the South Island, the presence of species which may have evolved in the newly uplifted mountains during the Miocene–Pliocene. [ABSTRACT FROM AUTHOR]

The proliferation of alien species that can suppress resident species via biotic interactions represents a growing concern worldwide. Yet, how above‐ and below‐ground communities simultaneously respond to plant invasion, particularly across large spatial scales, remains poorly explored. We hypothesized plant invasion has a greater impact on recipient above‐ and below‐ground communities at lower than higher latitudes given that biotic interactions play a more significant role in shaping communities in more favourable, lower latitude environments.To test this hypothesis, we conducted a comprehensive field survey of 124 sites spanning a 1700‐km latitudinal gradient in China, to explore the effects of invasion of Alternanthera philoxeroides, a globally widespread invasive plant, on plant, soil fungal and above‐ground arthropod communities.Invasion of A. philoxeroides had divergent effects on beta diversity (i.e. variation in taxa composition among sites) of plants, above‐ground arthropods and soil saprotrophic fungi, with negative, neutral and positive responses, respectively. Notably, the compositional dissimilarity of plant and arthropod communities between adjacent invaded and non‐invaded sites remained constant across latitudes. In contrast, the compositional dissimilarity of the entire and pathogenic fungal communities between adjacent invaded and non‐invaded sites increased with latitude. This resulted in a decreasing difference in invasion effects on the composition of plant and fungal communities with increasing latitude.Synthesis. Our study provides novel insights into the complexities of invasion effects by revealing contrasting responses of above‐ and below‐ground communities to plant invasion across latitudes. The contrasting responses could weaken or reshape above‐ and below‐ground interactions, and, in turn, affect future species invasions and the functioning of terrestrial ecosystems. [ABSTRACT FROM AUTHOR]

Successional dynamics can vary because of a range of ecological and environmental factors, but our understanding of biogeographic variation in succession, and the processes contributing to community development across ecosystems, is limited. The pattern and rate of recruitment of dispersive propagules likely differs over large spatial scales and can be an important predictor of successional trajectory. Over a 20° tropical-temperate latitudinal gradient, we measured sessile invertebrates over 12 months of community development and successive 3-month recruitment windows to understand succession and how it is influenced by recruitment. Succession and recruitment patterns varied over latitude. In the tropics, fast temporal turnover, fluctuating abundances, and lack of successional progression suggest that the contribution of stochastic processes was high. As latitude increased, successional progression became more apparent, characterized by increasing species richness and community cover and a shift to more competitive taxa over time. At temperate locations, species identities were similar between older communities and recruiting assemblages; however, community composition became more variable across space over time. Such divergence suggests an important role of early colonizers and species interactions on community structure. These findings demonstrate differences in the processes contributing to community development and biodiversity patterns over latitude. Understanding such biogeographic variation in community dynamics and identifying the prevalence of different processes can provide insights into how communities assemble and persist in response to environmental variability. [ABSTRACT FROM AUTHOR]

The partitioning of overall beta diversity into local contributions (LCBD; compositional uniqueness) and species contributions (SCBD) has enhanced the understanding of the organization of metacommunities. Here, we evaluated LCBD and SCBD of aquatic macrophyte metacommunities from 29 subtropical coastal wetlands, covering an extension of 640 km, in Southern Brazil. Furthermore, we assessed the environmental uniqueness, considering both the physical and chemical variables of water in wetlands, as well as climatic variables. We assessed the environmental and spatial correlates of LCBD and the environmental correlates of SCBD. We expected that (i) communities with greater compositional uniqueness would be found in environmentally more unique wetlands, (ii) the compositional uniqueness would also be related to climatic variables that determine the hydrological changes in wetlands, and (iii) the contribution of emergent species to beta diversity would be lower than of floating and submerged species. The compositional uniqueness did not present a clear spatial structure, being positively related to uniqueness in water chemistry and negatively to the mean air temperature during the driest quarter. The species contribution to beta diversity was higher for floating species than for emergent ones. Moreover, SCBD correlated to climatic variables and presented a positive relationship with site occupation, suggesting that more frequent species in terms of site occurrence contribute most to beta diversity. Our results show the importance of local environmental and broader climatic predictors in determining the compositional uniqueness of macrophyte communities and species contributions to overall beta diversity in the coastal wetlands of Southern Brazil. [ABSTRACT FROM AUTHOR]

Streams and ponds provide several ecosystem services but are threatened by anthropic activities. Studies on species contribution and local uniqueness are ways of analyzing sites that need conservation or restoration due to anthropic activities. These metrics are especially important when evaluating Amazonian environments, which are complex and understudied. In this study, we investigated the relationships between the local contribution (LCBD) and the species contribution (SCBD) to beta diversity and community attributes for zooplankton in Amazonian streams and ponds, and those between the land use change and local environmental factors on the LCBD (total, replacement, and richness difference). Additionally, we investigated whether sites with ecological uniqueness should be considered for conservation or restoration. We sampled zooplankton, macrophytes, and physical–chemical variables in 42 streams and 26 ponds in 2022. We also determined land use and land cover through digital image processing and calculated the Catchment Disturbance Index (CDI). A total of 130 taxa, comprising 76 rotifers, 41 cladocerans, and 13 copepods, were recorded. The zooplankton SCBD was positively correlated with species occurrence and abundance of individuals, while the LCBD was negatively related to abundance and species richness. In streams, total-LCBD was positively related to CDI and negatively related to macrophyte cover; in ponds, no significant relationship was observed. Our results improve current understanding of the effects of land use changes on zooplankton beta diversity, showing that more altered sites have unique and poor species composition and need restoration. Our data also increase knowledge on zooplankton in Amazonian environments, especially in streams that are understudied. [ABSTRACT FROM AUTHOR]

A variety of stormwater infrastructure such as constructed wetlands, rain gardens, vegetated drainage channels and retention ponds are primarily used for managing water runoff, but these environments can also foster biodiversity. Despite extensive literature about certain taxa (e.g., amphibians, aquatic macroinvertebrates, etc.) found in these human-made environments, the terrestrial plants and invertebrates present there remain understudied. Here, we compared alpha and beta diversity of plant and terrestrial invertebrate communities and assessed the influence of landscape characteristics on their composition in different types of urban stormwater basins and ponds. Plants and terrestrial invertebrates were identified in the main body (excluding the aquatic section) and on the banks of 54 basins and ponds (dry basins, wet basins with and without a water channel and retention ponds) in Quebec City and Trois-Rivières, in Eastern Canada. Results showed poor and homogenous plant and invertebrate communities in dry basins. Wet basins had the highest plant alpha diversity, with more facultative wetland species than the two other types. Wet basins with and without a water channel had similar plant and invertebrate composition, and wet basins and retention ponds were the most heterogeneous. Retention ponds (with permanent water) had distinct communities with fewer plant species than wet basins. The presence of natural areas around the infrastructure significantly influenced communities within a 2000 m and 500 m radius for plant and invertebrate communities, respectively. Wetland plant species were generally found in infrastructure close to natural areas, whereas tolerant and opportunist species were associated with disturbed environments. Our results suggest that enhancing diversity of the stormwater basins and ponds at the regional and local (microhabitat) scales has the potential to maximize diversity of plants and terrestrial invertebrates. [ABSTRACT FROM AUTHOR]

Reptiles are one of the most diverse groups of vertebrates in the world that are distributed in almost all ecosystems. Many of these studies have focused on exploring their diversity patterns across different environments; and recent studies on reptile alpha and beta diversity have incorporated a multifaceted approach into their analysis to have more comprehensive evaluations. This study presents an assessment of the taxonomic diversity of reptile patterns using methods that incorporate the assessment of higher taxa. Likewise, the taxonomic dissimilarities between reptile communities in the physiographic regions of the state of Jalisco were analyzed. Evaluations for the groups of snakes and lizards independently are presented. We use the taxonomic distinctiveness index that assesses the complexity of the taxonomic structure of communities through hierarchical classification above the species level to measure the relationships between taxa. The dissimilarity of the taxonomic structure in each community was also analyzed. Beta diversity partitions were performed to identify the contribution of turnover and the differences in richness. We determined that alpha diversity of species and higher taxa maintain different patterns, indicating that Jalisco presents regions with overrepresentation of reptile families and genera, as well as regions with an opposite trend. The representation of higher taxa is higher in the lizard group, although in terms of species richness snakes are the most prominent group. The turnover is the most important component at species and higher taxa, with similar values for lizards and snakes. The findings presented show that incorporating phylogenetic information about species through taxonomic relationships provides complementary information that species diversity per se, especially at the level of alpha diversity. [ABSTRACT FROM AUTHOR]

Stormwater ponds (SP) are increasingly used for water management along roads and in urban environments. How these infrastructures compare to natural wetlands in terms of biodiversity remains unclear, however. Studies to date have evaluated the subject in general terms, without considering the different zones in SP and wetlands (from aquatic, at the pond edge, to terrestrial, at the upper bank) or other local and regional factors. In this project, we aimed to compare the taxonomic diversity and composition of plant communities established in four different zones of SP with that in either roadside or remote natural wetlands. We also evaluated the effect of various local and regional factors on those communities. Our results show that, globally, the species composition of the lower, wetter zones was similar between SP and natural wetlands, especially roadside wetlands, while higher, drier zones showed significant differentiation. Factors explaining observed differences between SP and both roadside and remote natural wetlands were water level fluctuations, road proximity, slope, and age of the SP. Stormwater ponds also exhibited lower beta diversity than both types of wetlands. Nonetheless, our study suggests that with some modifications in their design, SP have the potential to harbour more wetland plant communities. [ABSTRACT FROM AUTHOR]

Research on Mesophotic Coral Ecosystems (MCEs; 30–150 m) has grown exponentially in the last few decades, highlighting their rich diversity and extensive distribution. However, they are still largely underexplored compared to shallow-water coral reefs and frequently remain under-protected and under-represented in marine spatial planning. One reason for the imbalance between the high ecological value of MCEs and the limited levels of protection may be that baseline data on MCEs are largely missing to date, yet are crucial to provide evidence-based information for management actions. Here, we present data on the alpha and beta diversity of the benthic communities within MCEs in the Chagos Archipelago, Indian Ocean. Using imagery collected from Remotely Operated Vehicle surveys, benthic invertebrate megafauna were surveyed along the entire depth gradient from shallow to lower mesophotic depths (15–160 m). The diversity of the benthic communities decreased with increasing depth, from shallow water to the lower mesophotic zone. Nevertheless, the deepest parts of MCEs in the Archipelago displayed higher species richness values than several other shallow subtropical regions. In addition, the benthic communities showed high dissimilarity along the depth gradient, indicating that the key driver of community composition change with depth is species turnover (species replacement), revealing the uniqueness of MCEs. This study presents novel findings on MCEs in the central Indian Ocean, demonstrating that they host a high and unique benthic diversity, and highlighting the need to protect these ecosystems to preserve the overall biodiversity of coral reefs. [ABSTRACT FROM AUTHOR]

Srivilliputhur Wildlife Sanctuary holds significant value being a part of Western Ghats, which remains unexplored in terms of vegetation. The current study is the first quantitative assessment of tree distribution along an elevation gradient combined with environmental variables. Sampling was conducted from December 2020 to April 2021 in six elevation zones (Z1 to Z6). A total of 135 plots of 20m × 20m size were established, and the stems were measured (>30 cm GBH). Across a 5.4 ha studied area, 2157 individuals representing 188 tree species and 48 families were documented. Tree density (348-473 ind. ha−1), basal area (21.71-36.59 m2 ha−1), and species richness (84-122) were highest at mid-elevations. One-way ANOVA result highlighted the significant influence of elevation on species richness (p

The Permanent Forest Reserve (PFR) is recognised as one of the Environmentally Sensitive Areas (ESAs) in Malaysia`s spatial planning. Incorporating biological factors alongside existing physical attributes is crucial to improve the classification of ESAs. It is important to attain biological diversity information to formulate biological factors, which include vertebrates such as bird communities. Birds are highly sensitive to changes within ecosystems; hence, they play a pivotal role in reflecting the overall ecological condition. Therefore, the study focused on assessing bird species’ richness in the Kluang Forest Reserve (Kluang FR) and compared its bird diversity amongst five PFRs ESAs in southern Peninsular Malaysia. Methods such as mist netting, point count observations and call recording were deployed to calculate the alpha and beta diversity of the bird community. A total of 68 species comprised of 36 families were recorded and the white-rumped shama (Copsychus malabaricus) was the most abundant species in all reserves studied. Principal Coordinates Analysis (PCoA) revealed that the bird diversity in Kluang FR is more similar to bird santuary Panti Forest Reserve compared to the other four forest reserves and indicates that diversification of species richness. However, the absence of published species information in forest reserves poses challenges for comparing bird assemblages amongst different reserves. More extensive studies are needed in Johor and throughout Malaysia to provide data that can effectively assist and support biodiversity conservation and management.

Abstract Riparian forests are crucial for biodiversity, but dam construction for hydroelectric power disrupts these ecosystems, causing habitat loss and altering river dynamics. Our study investigates the impacts of dams on tree diversity in the southern Brazilian Atlantic Forest. We sampled trees along riverbanks and uplands across 15 dam-affected fragments, analysing the relationship between habitat loss (i.e. loss of riparian zones by permanent flooding due to dam filling), elevation difference, fragment size, and dam implementation time with alpha and beta diversity using mixed models and redundancy analyses. Habitat loss had a more significant impact on beta diversity, leading to shifts in species composition and reduced uniqueness of communities as the impact’s intensity, spatial extent, and duration increased. Alpha diversity only increased in response to local elevation differences between plots located on uplands and riverbanks. Our sampling design can be applied to other inadequately monitored systems to provide insights into beta diversity, a component often neglected in dam licensing and mitigation processes. Our findings reveal a transient local heterogenisation, transitioning into regional homogenisation due to dam-induced habitat loss in riparian forests of the Brazilian Atlantic Forest.

There is a growing body of evidence suggesting that antidepressant drugs (ADs) alter the gut microbiome of persons with depressive disorders. Herein, we aim to investigate the gut microbial profile of AD-treated animal models of depression (MoD) and persons with major depressive disorder (MDD). We conducted a systematic review and meta-analysis investigating the gut microbiome community-level diversity and relative abundance of microbial taxa in AD-treated animal MoD and persons with MDD. 24 human studies (898 participants) and 48 animal studies (849 subjects) were identified. Nonsignificant differences in gut microbial richness were observed between AD-treated and nonmedicated animals and humans. Beta diversity analysis in animals shows that AD intake is linked to a distinct gut microbial profile, a result not observed in humans. Consistent depletion of the genera Faecalibacterium and Parasutterella , along with enrichment of Bifidobacterium , was observed in AD-treated persons with MDD. In AD-treated animals, AD intake was associated with depletion of Flavobacterium and Adlercreutzia , and enrichment of Parabacteroides. The studies in our review were heterogeneous in their participant population, dietary intake, type of ADs used, length and dosing of AD treatment, and frequency and time of fecal sample collection. ADs are associated with some changes to the gut microbiome. Future studies should evaluate the gut microbiome profiles between depressive disorder diagnoses that may reveal potential differences and predictors of AD response, as well as new combinatorial therapeutics with agents (e.g., specific-strain probiotic adjunctive treatment) that can ameliorate micro-composition gut dysbiosis. • Antidepressant use is not associated with gut microbial diversity changes • Antidepressant use is associated with some changes to gut microbial taxa • Some remitted and non-remitted MDD groups harbours distinct microbiome profiles • Basal microbial profile may predict antidepressant response and disease remittance [ABSTRACT FROM AUTHOR]

Abstract Elucidating biodiversity patterns and their background processes is critical in biodiversity science. Dissimilarity, which is calculated based on multivariate biological quantities, is a major component of biodiversity. As spatial and temporal biodiversity information availability increases, the scope of dissimilarity studies has been expanded to cover various levels and types of spatiotemporal biodiversity facets (e.g. gene, community and ecosystem function), and diverse pairwise dissimilarity indices have been developed. However, further development of the dissimilarity concept is required in comparative studies on spatiotemporal structures of biodiversity compositional patterns, such as those exploring commonalities of biogeographical boundaries among taxa, compared to the conventional ones to consider higher dimensions of dissimilarity: dissimilarity of dissimilarity structures. This study proposes a novel and general concept, higher‐order dissimilarity (HOD), for quantitatively evaluating the dissimilarities of spatial or temporal dissimilarity structures among different datasets, proposes specific implementations of HOD as operational indices, and illustrates the potential resolution of scientific and practical questions through HOD. We further demonstrate the advantages of the HOD concept by applying it to actual patterns, such as long‐term and/or large‐spatial hypothetical monitoring datasets. Our conceptual framework on HOD extends the existing framework of biodiversity science and is versatile, with many potential applications in acquiring more valuable information from ever‐increasing biodiversity data.

In the context of worldwide biodiversity and wild bee decline, it is increasingly important to better understand the effect of land-use changes on wild bee communities at a global scale. To do so, we studied the effect of city area and urban green spaces layout on wild bee species richness and community composition, as well as on wild bee species with an unfavorable UICN conservation status. This study was based on a large European dataset encompassing 20 cities from France, Belgium and Switzerland. We found a mean wild bee species richness in cities of 96 ± 48 (SD), showing that this species richness was highly variable among cities. The main factor positively influencing wild bee species richness in cities was the area of the city. Conversely, species richness was not significantly related to the total area of urban green spaces in a given city, measured as the spatial extent of urban parks, wastelands and other semi-natural habitats, excluding urban private gardens. Species with conservation status were quite scarce in urban environments, especially when compared to the European Red List of Bees, and we could not link their presence to either city or urban green space area. Dissimilarities in wild bee species community compositions were not associated with any of the studied characteristics of cities. We found that the dissimilarity of wild bee community composition among cities was mainly driven by the rarest species, as the most common ones were found in a majority of the cities sampled. Overall, these results emphasize that larger cities host more wild bee species, but are no refuge for the ones with concerning conservation status. Thus, stakeholders are encouraged to design their cities in favor of biodiversity to better support wild bee communities, and perhaps mitigate the established effect of the urban ecological filter.

Habitat alteration is recognized as one of the most important drivers of biodiversity decline. Urbanization implies a major habitat alteration and its impact on biodiversity depends on type and degrees of habitat modifications. Growing cities generate great heterogeneity with respect to the uses of space that enable the preservation of a certain diversity of amphibians within the urban frame. Our objective is to understand how environments with different levels of urbanization influence local amphibian diversity. We grouped various urban green spaces of a medium-sized and growing city of Argentina in relation to natural and anthropic environmental variables which allows us to describe an urban environmental gradient and we calculate beta diversity among these groups of urban environments considering the richness, composition and abundance of amphibian at each sites' group. From this, we analyze and tested the differences in the functional diversity of amphibians in the defined urban environmental gradient. We hypothesize that: (i) the described spatial heterogeneity would be related to an elevated beta diversity of amphibians within the urban frame; and (ii) the analysis of functional diversity would reveal a stronger biotic or abiotic filtering of the focal community. We found that groups of urban environments with an intermediate degree of urbanization can present a greater functional diversity and species richness than those that are less urbanized. We identified urban avoiders (T. typhonius, P. santafecinus and P. biligonigerus) and urban tolerant species (E. bicolor, R. arenarum, R. dorbignyi, L. macrosternum, L. latinasus, P. albonotatus, D. nanus and S. nasicus). The replacement beta diversity recorded indicated that the species assemblage changes throughout urban environmental gradient, but functionally similar species thrive in the less to the most urbanized sites, allowing them to occupy the entire functional space of the groups of urban environments with different types and degrees of urbanization. [ABSTRACT FROM AUTHOR]

1.  The replacement of native habitats by monocultures has led to the loss of insect biodiversity, including beetles.2.  In an attempt to minimize this loss, Brazilian legislation requires farmers to conserve a proportion of farmland as a Legal Reserve.3.  In this study, we investigated the decay of similarity in beetle communities of soybean monocultures compared to Legal Reserves.4.  To do this, we studied 77 sample points distributed across the transition zone between the Amazon and Cerrado biomes, with a maximum distance of 625 km between the farthest points.5.  Our results show that the transformation of forest areas into monocultures causes a drastic decrease in beta diversity for both herbivores and predators.6.  This pattern is not observed in Legal Reserves, where the communities are, for the most part, different in a short geographic space.7.  We noted an increase in beta diversity between sites at a shorter distance (200 km) compared with soybean monoculture areas (350 km).8.  In these environments, many species are generalist pests that benefit from the simplified landscape.9.  To verify the relationship between species dissimilarity and geographic distances, we used the Chord‐Normalized Expected Species Shared dissimilarity index, replacing Bray–Curtis due to its robustness in dealing with small samples or subsampling.10. We reinforce the importance of Legal Reserves in conserving beetle biodiversity, emphasizing the need for preserved areas distributed throughout the landscape as they play a crucial role in maintaining beta diversity and preserving ecosystem services in anthropized landscapes. [ABSTRACT FROM AUTHOR]

More heterogeneous environments allow for greater availability of ecological niches, thus favoring greater species diversity. However, it is not yet established how heterogeneity influences taxonomic and functional beta diversity. Therefore, we aimed to determine how environmental heterogeneity affects the patterns of taxonomic and functional beta diversity of planktonic microcrustaceans in reservoirs in different regions (semiarid and humid) in Northeast Brazil, in addition to verifying the influence of dry and rainy periods on these measures. Sampling from the semiarid region was carried out between 2013 and 2016, while samples from the humid region were collected between 2019 and 2021. Environmental heterogeneity and taxonomic and functional beta diversity were greater in the semiarid region, regardless of the hydrological period. However, regardless of the region, taxonomic beta diversity was greater during the dry period, while functional beta diversity did not differ between periods. Both types of diversity were driven mainly by local factors in the semiarid region, considered a region of high environmental heterogeneity due to the geomorphological and climatic characteristics that differentiate it from other regions. This type of study reinforces the need to conserve these reservoirs, especially those located in the semiarid region, as they support greater variability in species composition and functional traits. [ABSTRACT FROM AUTHOR]

This study aimed to achieve a better understanding of the features of zooplankton assemblages in small water bodies and their biodiversity and composition in relation to the presence of fish and accompanying environmental characteristics. This study was conducted in 16 mid-field ponds. Compositional and biodiversity indexes and ordination methods were used to analyze the relationship between zooplankton assemblages in unstable fishless and stable fish ponds. A total of 121 zooplankton taxa were identified. Compositional indicators revealed significant differences in zooplankton assemblages between fish ponds (FPs) and fishless ponds (FLPs). Canonical correspondence analysis indicated that variation in zooplankton assemblages depended on the ponds' features. Most of the high trophic state indicator species were present only in FPs or occurred sporadically in FLPs. Rarefaction and extrapolation indicated a higher number of zooplankton taxa in FPs than in FLPs. The stability of the ecosystem was essential for maintaining the high species richness of zooplankton. Diversity indices were not influenced by variations in species composition or environmental differences among ponds. Diversified pond types are necessary to maintain the heterogeneity of mid-field ponds, which support the high regional biodiversity of zooplankton assemblages. [ABSTRACT FROM AUTHOR]

There is evidence to suggest that vascular epiphytes experience low competition for resources (light, water, and nutrients) compared to terrestrial plants. We tested the hypothesis that low resource competition may lead to higher nestedness among vascular epiphyte assemblages compared to trees. We studied the species composition and biomass of epiphytes and trees along an elevation gradient in a tropical dry forest in SW Ecuador. Both life-forms were inventoried on 25 plots of 400 m2 across five elevation levels (550–1250 m). Tree species density and total species richness increased with elevation, whereas basal area and biomass did not show significant trends. Epiphyte species density and richness both increased strongly with elevation, in parallel to biomass. Plot-level compositional changes were similarly strong for both life-forms. We attribute elevational increases in the species richness of trees and epiphytes to increasing humidity, i.e., more mesic growth conditions. We attribute the more pronounced elevational increase in epiphyte biomass, species density, and richness—the latter coupled with a higher degree of nestedness—to the greater moisture dependency of epiphytes and relatively low direct competition for resources. Our study provides a first comparison of elevational trends in epiphyte and tree diversity and biomass for a tropical dry forest. [ABSTRACT FROM AUTHOR]

Species-rich natural and semi-natural ecosystems are under threat owing to land use change. To conserve the biodiversity associated with these ecosystems, we must identify and target conservation efforts towards functionally important species and supporting habitats that create connections between remnant patches in the landscape. Here, we use a multi-layer network approach to identify species that connect a metanetwork of plant–bee interactions in remnant semi-natural grasslands which are biodiversity hotspots in European landscapes. We investigate how these landscape connecting species, and their interactions, persist in their proposed supporting habitat, road verges, across a landscape with high human impact. We identify 11 plant taxa and nine bee species that connect semi-natural grassland patches. We find the beta diversity of these connector species to be low across road verges, indicating a poor contribution of these habitats to the landscape-scale diversity in semi-natural grasslands. We also find a significant influence of the surrounding landscape on the beta diversity of connector species and their interactions with implications for landscape-scale management. Conservation actions targeted toward species with key functional roles as connectors of fragmented ecosystems can provide cost-effective management of the diversity and functioning of threatened ecosystems. This article is part of the theme issue 'Connected interactions: enriching food web research by spatial and social interactions'. [ABSTRACT FROM AUTHOR]

The aim of this experiment was to study the difference of intestinal microflora of Kazakh horses in grass group and hay group after transfer. Twenty Kazakh mares aged five to six years old under uniform feeding and management conditions in the Tacheng area of Xinjiang were selected and divided into two groups: Fresh Grass Group (QC group) and Dry Grass Group (GC group). They were fed 2 kg of concentrate feed per horse per day. QC group consumed fresh grass daily, while the GC group consumed dry grass daily. At 30 days of the experiment, fecal samples of all horses were collected, and the characteristic sequences of microbial species such as 16S amplified by PCR were detected by high-throughput sequencing technology. There were 28 865 OTU in fecal flora of Kazakh horses in the two groups, and the OTU amount in fecal flora of Kazakh horses in QC group was higher than that in GC group. The results showed that Firmicute, Bacteroidota, Proteobacteria, Verrucomicrobiota, and Spirochaetota were the dominant bacteria in the manure of Kazakh horses in the two groups. The dominant bacteria genera were Solibacillus, Acinetobacter, Rikenellaceae_RC9_gut_group, Treponema, and Ruminococcaceae NK4A214_group. Compared with the GC group, the relative abundances of Actinobacteriota and Rummeliibacillus in feces of Kazakh horses in QC group were significantly increased (P<0.05). LEfSe analysis showed that 65 kinds of bacteria were significantly different in fecal flora of Kazakh horses in the two groups, among which 36 kinds of bacteria were significantly up-regulated in QC group and 29 kinds of bacteria were significantly up-regulated in GC group. The study indicates that the composition structure and community of fecal flora of Kazakh horses were affected by different forage, but the diversity and richness of intestinal flora did not change significantly. More important microbial groups played an important role in fecal flora of Kazakh horses in QC group than in GC group. [ABSTRACT FROM AUTHOR]

Plant taxa and traits do not necessarily show synchronous responses to ecological disturbance. Based on the observation that taxonomically over‐diversified communities might be phenotypically redundant, we speculated that taxonomic and phenotypic community reassembly might be decoupled after fire in Mediterranean ecosystems.We applied a multi‐trait approach to describe plant community re‐assembly after fire across three 20‐year chronosequences based on 117 species and 23 traits, including whole‐plant, above‐ground and below‐ground traits. We quantified the post‐fire trajectories of different plant traits by analysing their community‐weighted means individually. We estimated the short‐ and long‐term phenotypic diversity of burned plots based on sets of traits. We also tested if trait and species turnover are decoupled across post‐fire trajectories. Finally, we calculated phenotypic redundancy, and assessed if above‐ and below‐ground traits have contrasted responses during post‐fire community reassembly.Individually, 16 out of 23 traits were affected by fire in the short term. Plant phenotypic diversity (stdMPD) decreased immediately after fire, driven by changes in whole‐ and above‐ground traits. Both whole‐ and above‐ground stdMPD in burned plots described positive trajectories across the chronosequences tending to converge with long‐unburned plots, whereas below‐ground stdMPD remained unaltered through time.Taxonomic and phenotypic beta diversity showed decoupled trajectories due to a larger species than trait replacement across time since fire. Finally, overall phenotypic redundancy of the studied plant communities described a regressive trajectory, similarly to above‐ground traits, whereas root traits kept a steady phenotypic redundancy through time.Synthesis. We provide evidence that above‐ and below‐ground traits describe different recovery trajectories after fire, with significant effects on the phenotypic redundancy of plant communities. Our results encourage the use of multi‐trait approaches to understand how the plant reassembly operates after disturbance, in order to refine ecological theory. This strategy might improve the efficacy of restoration programs through a functional approach to species selection. [ABSTRACT FROM AUTHOR]