Current Biodiversity Patterns Research Articles

Uncovering glacial footprints and identifying phylogeographic units in the freshwater crab Potamon elbursi Pretzmann, 1962 (Decapoda: Potamidae) based on mitochondrial data

The current patterns of biodiversity have significantly been affected by glacial-interglacial cycles during the Pleistocene period. True freshwater crabs are considered as poor dispersers and terrestrial barriers restrict gene flow between their local populations. Recent studies, however, suggest that certain environmental conditions, such as periods of heavy rainfall and humidity, can facilitate their between-drainage dispersal and will result in the evolution of homogenous genetic patterns among different drainage systems. Here we tested this hypothesis by comparing populations of the endemic freshwater crab Potamon elbursi Pretzmann, 1962 distributed in two drainage systems, the Caspian Sea and Namak Lake, in northern Iran. Our results based on the genetic analysis of 70 new and 61 previously published sequences of the mitochondrial cytochrome oxidase subunit I gene revealed a substantial haplotype diversity in some populations and high levels of local population structuring in others. Initially, we found mixed evidence of genetic differentiation and connectivity among drainages and populations. Genetic differentiation between the two drainages only became apparent after the Sepirdood population (which belongs to the Caspian Sea drainage) was excluded. Subsequently, the two drainages showed significant genetic distinctions, with a limited gene flow between them. Our demographic analyses supported recent population bottlenecks, followed by a rapid demographic and/or spatial expansion dating back to the Pleistocene climatic fluctuations. Species distribution modelling suggests that precipitation during warm weather conditions profoundly affects the distribution of P. elbursi. This study indicates that freshwater crabs can override short land barriers under favorable weather conditions and will have conservation implications in the face of contemporary climatic fluctuations.

An ecological perspective for analysing rural depopulation and abandonment

Abstract Population loss in rural areas is rapidly increasing in high‐income countries, raising concerns and debate, given its socio‐economic consequences. Despite the evident environmental dimension of the phenomenon, ecological knowledge has been neglected in the analysis of actions aiming to reverse rural depopulation. Particularly, cultural landscapes reflect memories of ecological processes that have configured current patterns of biodiversity and ecosystem services. Based on ecological principles, we present a conceptual procedure to assess the behaviour of social–ecological systems subjected to depopulation, projecting their expected trajectories through time within a framework defined jointly by demographic and environmental–ecological dimensions (in our case, biodiversity, carbon storage, pollution control, water resources and soil conservation). We applied this procedure to various alternative interventions designed to confront depopulation in Spain: (1) non‐intervention, (2) maintenance of the historical landscape configuration, (3) active conservation, (4) extensive, sustainable land use and (5) intensified land use. We conclude that extensive, sustainable land use better optimizes criteria of demographic consolidation, environmental impact, resilience and implementation of actions confronting depopulation. We highlight the need to incorporate ecological knowledge into the assessment and application of actions confronting rural depopulation. Read the free Plain Language Summary for this article on the Journal blog.

Evolutionary and ecological trends in the Neotropical cycad genus Dioon (Zamiaceae): An example of success of evolutionary stasis

AbstractCycads represent an example of the success of evolutionary stasis. Despite their early origin, they survived multiple events of mass extinction and diversified in modern tropical ecosystems during the Cenozoic without major changes in their morphology. What factors have allowed their persistence and diversification despite their conservative nature? We reviewed documentation on the micro‐ and macro‐evolutionary processes involved in the diversification of the Neotropical genus Dioon. Dioon comprises 18 species from varied habitats in Mexico and Honduras, and serves as a model to understand the patterns of cycad diversification. Here, we synthesize evidence reached from different fields, especially biogeography, phylogenetics, population ecology, and speciation, to propose a mechanism that can explain the current patterns of biodiversity in Dioon. At the macroevolutionary scale, a Paleogene origin for Dioon is more likely than an alternative hypothesis of a Neogene origin. Dioon lineages have dispersed along with the expansion of tropical forests throughout main mountain chains. Subsequently, climate change, and particularly aridification, promoted the fragmentation of the tropical forests, allowing the main Dioon clades to evolve in isolation at distinct biogeographic regimes. At the microevolutionary scale, low seed dispersal capability, stochastic demographic processes, and niche conservatism restrict the lineages to isolate themselves at narrow habitats, promoting local adaptation in populations. Local adaptation seems to be a process achieved through many generations under stabilizing selection. Altogether, these processes shaped the diversification in Dioon. This review attempts to stimulate further research on cycads and other biological groups that have diversified despite their apparent evolutionary stasis.

Slowing taxon cycle can explain biodiversity patterns on islands: Insights into the biogeography of the tropical South Pacific from molecular data

AbstractIslands in the tropical Pacific Ocean are renowned for high biodiversity and endemism despite having relatively small landmasses. However, our knowledge of how this biodiversity is formed remains limited. The taxon cycle, where well‐dispersed, earlier colonizers become displaced from coastal to inland habitats by new waves of colonizers, producing isolated, range‐restricted species, has been proposed to explain current biodiversity patterns. Here, we integrate the outcomes of phylogenetic studies in the region to investigate the sources, age, number of colonizations, and diversification of 16 archipelagos in the tropical and subtropical South Pacific. We then evaluate whether the results support the taxon cycle as a plausible mechanism for these observations. We find that most species in the Pacific arrived less than 5 Mya from geographically close sources, suggesting that colonization by new taxa is a frequent and ongoing process. Therefore, our findings are broadly consistent with the theory of the Taxon Cycle, which posits that ongoing colonization results in the gradual displacement of established lineages. Only the oldest archipelagos, New Caledonia and Fiji, do not conform to this trend, having proportionally less recent colonization events, suggesting that the taxon cycle may slow on older islands. This conclusion is further validated by New Caledonia having lower diversification rate estimates than younger islands. We found that diversification rates across archipelagos are negatively correlated with area and age. Therefore, a taxon cycle that slows with island age appears to be a suitable concept for understanding the dynamic nature and biodiversity patterns of the Pacific Islands.

Sedimentary DNA reveals the link between microbial community dynamics and climate during the late last glaciation in the offshore region of the Zambezi River, Southwest Indian Ocean

Reconstructing the relationship between microbial communities and past abrupt climate change is of great importance for understanding current biodiversity patterns and predicting changes under future climate scenarios. However, little is currently known about how microbial communities respond to changes in key environmental stages due to a lack of research in this area. Here, we examine the variability in the communities of bacteria, archaea, and fungi from sediments deposited offshore region of the Zambezi River between 21.7 and 9.6 thousand years ago (ka) (covering the last glacial maximum, or LGM, and the early Holocene) using DNA metabarcoding approach via high-throughput sequencing. The results showed that (1) microbial assemblages differed across three key time intervals, with the last deglaciation having the most homogeneous prokaryotic assemblages, while for fungal communities in the LGM, and the early Holocene and LGM differing the most; (2) the warm early Holocene showed the highest diversity, whereas the lowest diversity was found in the LGM; and (3) the selected indicator species better reflected the climatic characteristics of different environmental stages. These results highlight the power of ancient sedimentary DNA to refine our understanding of microbial dynamics in marine sedimentary systems near large rivers, thus providing a basis for better modeling ecological processes in further research.

Human impact on vegetation at Lago di Vedana (Dolomites, Northern Italy) during the last seven centuries

Studying the legacies of past human-environment interactions is essential for understanding current landscape and biodiversity patterns. Human influences on past terrestrial and aquatic vegetation are reconstructed based on palynological analysis conducted on a sediment core from Lago di Vedana (Province of Belluno, Northern Italy). This study represents the first pollen record from the Dolomitic lowlands with varying anthropogenic influences throughout the last 700 years. The radiocarbon-dated pollen record begins ca. A.D. 1300 with semi-open forest and moderate human impact, possibly due to activities of the nearby hospice of San Gottardo. Human impact increased with the foundation of the Vedana Charterhouse in the immediate catchment of the lake in A.D. 1457. Activities of the monks involved extensive forest clearing, cultivation of Cannabis/Humulus and possibly hemp retting. In the 19th century the composition of cultivated species changed following the transformation of the Charterhouse into a farm. The 20th century is characterized by expansion of forest taxa and a distinct decline of human influences, probably due to a rural exodus and abandonment of agricultural activities. Vegetation development at Lago di Vedana is consistent with general trends in the Italian Alps and reveals local cultivation practices. The results illustrate the close intertwinement of climatic trends and local human influences, modulated by regional socio-cultural developments during the last millennium.

Small but irreplaceable: The conservation value of landscape remnants for urban plant diversity

The widespread decline of biodiversity due to increasing urban development raises the need to timely identify areas most relevant to the conservation of native species, particularly within cities where natural areas are extremely limited. Here, we assess the multiple role of local geomorphological features in shaping patterns and dynamics of plant diversity, with the aim of identifying conservation values and priorities in an urbanised area of Southern Italy. Based on recent and historical lists of vascular plants, we compared the floristic composition of different portions of the area by considering species’ conservation value, ecological and biogeographical traits. We found that landscape remnants, accounting for 5% of the study area, harbour over 85% of the whole plant diversity and a considerable set of exclusive species. Results of Generalised Linear Mixed Models show an outstanding role of landscape remnants for the conservation of native, rare and specialised species. Based on the compositional similarities among sampled sites resulting from hierarchical clustering, these linear landscape elements also play a key role in maintaining the floristic continuity and potential connectivity throughout the urban landscape. By comparing current biodiversity patterns with data from the early XX century, we also show that the considered landscape elements are significantly more likely to host populations of declining native species, underlining their role as refugia against past and future extinctions. Taken together, our findings represent an effective framework to tackle the challenging conservation of nature in cities, namely providing a valuable approach for the identification of priority areas for the conservation of diversity within anthropogenic landscapes.

Sedimentary DNA for tracking the long-term changes in biodiversity

Understanding long-term dynamics is vitally important for explaining current biodiversity patterns and setting conservation goals in a changing world. However, the changes in biodiversity in time and space, particularly the dynamics at the centuries or even longer time scales, are poorly documented because of a lack of continuous monitoring data. The sedimentary DNA (sedDNA) has a great potential for paleo-community reconstruction, and it has recently been used as a powerful tool to characterize past dynamics in terms of biodiversity over geological timescales. In particular, it is useful for prokaryotes and eukaryotes that do not fossilize; hence, it is revolutionizing the scope of paleoecological research. Here, a "Research Weaving" method was performed with systematic maps and bibliometric webs based on the Web of Science for Science Citation Index Expanded, presenting a comprehensive landscape of the sedDNA that traces biological dynamics. We identified that most sedDNA-based studies have focused on microbial dynamics and on using samples from multitypes of sediments. This review summarized the advantages and common applications of sedDNA, focused on the biodiversity in microbial communities, and provided an outlook for the future of sedDNA research.

Influence of Last Glacial Maximum legacies on functional diversity and community assembly of extant Chinese terrestrial vertebrates

Contemporary biodiversity patterns are shaped by not only modern climate but also factors such as past climate fluctuations. Investigating the relative degree of paleoclimate legacy could help us understand the formation of current biodiversity patterns. However, an assessment of this issue in China is lacking. Here, we investigated the phylogenetic structure and functional diversity patterns of Chinese terrestrial vertebrates. We found that Southern China harbored higher functional richness, while Northern and Western China were more phylogenetically clustered with higher functional divergence and evenness, indicating environmental filtering effects. Moreover, we found that drastic Last Glacial Maximum climate changes were positively related to phylogenetic clustering, lower functional richness, and higher functional divergence and evenness, although this effect varied among different taxonomic groups. We further found that mammal communities experiencing more drastic Last Glacial Maximum temperature changes were characterized by "faster" life-history trait values. Our findings provide new evidence of the paleoclimate change legacies influencing contemporary biodiversity patterns that will help guide national-level conservation plans.

Understanding the relative roles of local environmental, geo-climatic and spatial factors for taxonomic, functional and phylogenetic β-diversity of stream fishes in a large basin, Northeast China.

The primary objective of this study was to determine the relative roles of local environmental (Local), geo-climatic (Geo), and spatial (Spatial) factors to taxonomic, functional, and phylogenetic β-diversity of stream fish in a large basin in Northeast China. We quantified the current biodiversity patterns of fish communities in the Hun-Tai River using β-diversity. We assessed (i) corresponding contributions of turnover and nestedness within the taxonomic, functional, and phylogenetic β-diversity of fishes; (ii) correlations among β-diversity facets (i.e., taxonomic, functional, and phylogenetic facets); (iii) relative contributions of Local, Geo, and Spatial factors to β-diversity. We collected fish communities from 171 sampling sites. Mantel tests were used to examine the correlation of three facets of β-diversity and their components (i.e., total, nestedness, and turnover). Distance-based redundancy analysis and variation partitioning assess the relative contributions of Local, Geo, and Spatial factors to β-diversity. We found that turnover is the main driving mechanism for β-diversity in fish. Among the facets of β-diversity, taxonomic and phylogenetic facets have strong ecological information association.Spatial factors have a general contribution to various facets of β-diversity and its components. From aspects of fish β-diversity conservation, connectivity and habitat heterogeneity need to be maintained in the entire aquatic environment. In addition, protecting taxonomic β-diversity is helpful for maintaining phylogenetic β-diversity.

Current and future geographic patterns of bird diversity dimensions of the Yucatan Peninsula and their representativeness in natural protected areas

ABSTRACT The deviation of expected relationships between taxonomic (TD), phylogenetic (PD), and functional (FD) diversity may inform about some processes (speciation, extinction, competition, and migration) responsible for current biodiversity patterns. We studied the relationship between different dimensions of bird diversity (TD, PD, and FD) of the Yucatan Peninsula (YP) in a context of future climate change. We used ecological niche models to predict the current and future potential distribution of 257 bird species of the YP and estimate their TD, PD, and FD. We calculated a standardized effect size of PD (SES.PD) and FD (SES.FD) to provide an estimation of phylogenetic and functional diversity, independent from species richness. Finally, we evaluated the effectiveness of the system of PAs comparing the observed diversity values in each PA versus what is expected for a null model. We found a positive correlation between PD and TD, and a negative correlation between FD and TD in the current and future scenarios. Finally, we found that none of the PAs protect more diversity of birds than expected by a null model. Our results suggest that macroevolutionary processes have played an important role in the composition of the current Yucatan Peninsula avian assemblages. Our assessment of the effectiveness of the PAs suggests the need to adopt an integrative approach to biodiversity conservation in the YP.

Historical biogeographical analysis of the Udoteaceae (Bryopsidales, Chlorophyta) elucidates origins of high species diversity in the Central Indo-Pacific, Western Indian Ocean and Greater Caribbean regions

There is a growing interest in elucidating the biogeographical processes underlying biodiversity patterns of seaweeds, with recent studies largely focusing on red and brown macroalgae. This study focuses on the siphonous green algal family Udoteaceae, which is diverse and globally distributed in tropical to warm-temperate seas, and includes species that form important components of tropical reefs. We explored the historical processes that have shaped current biodiversity patterns in the family by analyzing a comprehensive dataset of 568 specimens sampled across its geographical range, and including 45 species, corresponding to 59% of the known diversity. Historical biogeographical analysis was based on a three-locus time-calibrated phylogeny, and probabilistic modeling of geographical range evolution. Many species were found to have restricted ranges, indicative of low dispersal capacity. Our analysis points toward a Western Tethys origin and early diversification of the Udoteaceae in the Triassic period. Three centers of diversity were identified, which are, in order of highest species richness, the Central Indo-Pacific, the Western Indian Ocean, and the Greater Caribbean. Different drivers have likely played a role in shaping these diversity centres. Species richness in the Central Indo-Pacific likely resulted from speciation within the region, as well as recolonization from neighbouring regions, and overlap of some wider ranged species, corroborating the “biodiversity feedback” model. Species richness in the Western Indian Ocean can be explained by ancient and more recent diversification within the region, and dispersal from the Central Indo-Pacific. The Greater Caribbean region was colonized more recently, followed by diversification within the region.

Identifying key federal, state, and private lands strategies for achieving 30 × 30 in the United States

AbstractAchieving ambitious goals to conserve at least 30% of U.S. lands and waters by 2030 (“30 × 30”) will require a multiscale baseline understanding of current protections, key decisionmakers, and policy tools for moving forward. To help conservationists and decisionmakers support the science‐based call to address the biodiversity and climate crises, we analyze the current spatial patterns of biodiversity and carbon in the United States relative to protected areas and present a typology for classifying land contributions toward the 30 × 30 goals. Analyses demonstrate that 30% is achievable nationally, but spatial heterogeneity highlights the need for tailored approaches from a mix of authorities at federal, regional, and state scales. Current land protections rarely overlap with areas essential for conserving imperiled species biodiversity and mitigating climate change. One‐fifth of unprotected biodiversity hotspots and over 8% carbon‐rich areas face a higher risk of land conversion by 2050. In contrast, 3.6% of key biodiversity areas and 15.6% of carbon‐rich areas may experience higher climate exposure. Policy considerations for making practical, substantive progress toward ecologically meaningful achievement of 30 × 30 goal include the need for significant investments in public and private lands conservation.

Identifying traits that enable lizard adaptation to different habitats

AbstractAimSpecies adapt differently to contrasting environments, such as open habitats with sparse vegetation and forested habitats with dense forest cover. We investigated colonization patterns in the open and forested environments in the diagonal of open formations and surrounding rain forests (i.e. Amazonia and Atlantic Forest) in Brazil, tested whether the diversification rates were affected by the environmental conditions and identified traits that enabled species to persist in those environments.LocationSouth America, Brazil.TaxonSquamata, Lizards.MethodsWe used phylogenetic information and the current distribution of species in open and forested habitats to estimate ancestral ranges and identify range shifts relative to the current habitats. To evaluate whether these environments influenced species diversification, we tested 12 models using a Hidden Geographic State Speciation and Extinction analysis. Finally, we combined phylogenetic relatedness and species traits in a machine learning framework to identify the traits permitting adaptation in those contrasting environments.ResultsWe identified 41 total transitions between open and forested habitats, of which 80% were from the forested habitats to the open habitats. Widely distributed species had higher speciation, turnover, extinction, and extinction fraction rates than species in forested or open habitats, but had also the lower net diversification rate. Mean body temperature, microhabitat, female snout–vent length and diet were identified as putative traits that enabled adaptation to different environments, and phylogenetic relatedness was an important predictor of species occurrence.Main conclusionsTransitions from forested to open habitats are most common, highlighting the importance of habitat shift in current patterns of biodiversity. The combination of phylogenetic reconstruction of ancestral distributions and the machine learning framework enables us to integrate organismal trait data, environmental data and evolutionary history in a manner that could be applied on a global scale.

Environmental Drivers of Diversification and Hybridization in Neotropical Butterflies

Studying how the environment shapes current biodiversity patterns in species rich regions is a fundamental issue in biogeography, ecology, and conservation. However, in the Neotropics, the study of the forces driving species distribution and richness, is mostly based on vertebrates and plants. In this study, we used 54,392 georeferenced records for 46 species and 1,012 georeferenced records for 38 interspecific hybrids of the Neotropical Heliconius butterflies to investigate the role of the environment in shaping their distribution and richness, as well as their geographic patterns of phylogenetic diversity and phylogenetic endemism. We also evaluated whether niche similarity promotes hybridization in Heliconius. We found that these insects display five general distribution patterns mostly explained by precipitation and isothermality, and to a lesser extent, by altitude. Interestingly, altitude plays a major role as a predictor of species richness and phylogenetic diversity, while precipitation explains patterns of phylogenetic endemism. We did not find evidence supporting the role of the environment in facilitating hybridization because hybridizing species do not necessarily share the same climatic niche despite some of them having largely overlapping geographic distributions. Overall, we confirmed that, as in other organisms, high annual temperature, a constant supply of water, and spatio-topographic complexity are the main predictors of diversity in Heliconius. However, future studies at large scale need to investigate the effect of microclimate variables and ecological interactions.

Automated detection of former field systems from airborne laser scanning data: a new approach for Historical Ecology

Former field systems (FFS) are the most widespread traces of ancient activities in present European landscapes and represent significant perturbations to ecosystems. Through its ability to penetrate forest canopies and detect microlandforms, Airborne Laser Scanning data reveal archaeological relics over large areas, from periods older than the first available Historical Topographic Maps. Mapping these traces from ALS-derived data (e.g. Digital Elevation Model (DEM)) thus allows for a determination of a new temporal baseline in order to evaluate the effects of a longer history on current patterns of biodiversity. Here, we evaluate the ability of traditional machine learning (Random Forest-RF) and deep learning (Fully Connected Networks-FCN) models to detect Medieval Terraced slopes and Ridges and Furrows (RaF) from an ALS-derived DEM in the southern Vosges (1462 km2). We used a combination of Local Binary Patterns and topographical metrics to measure properties of FFS and to train detection models. We then assessed the relative performance of each model semantically and spatially. Our results demonstrated the high suitability of our approach for reproducing major trends in the landscape with a high level of similarity between the predicted and reference spatial patterns (Structural Similarity Index - SSIM > 0.75). RF outperformed FCN for Terraced Slopes, whilst minimizing the false positive rate. FCN slightly outperformed RF for the RaF dataset but showed promising abilities to survey unseen data with a low sensitivity to annotation errors. We suggest that this approach has the potential to offer new spatio-temporal possibilities in Historical Ecology studies as a means of automatically detecting past archaeological ecosystems from a landscape to a regional scale.

How do habitat amount and habitat fragmentation drive time-delayed responses of biodiversity to land-use change?

Land-use change is a root cause of the extinction crisis, but links between habitat change and biodiversity loss are not fully understood. While there is evidence that habitat loss is an important extinction driver, the relevance of habitat fragmentation remains debated. Moreover, while time delays of biodiversity responses to habitat transformation are well-documented, time-delayed effects have been ignored in the habitat loss versus fragmentation debate. Here, using a hierarchical Bayesian multi-species occupancy framework, we systematically tested for time-delayed responses of bird and mammal communities to habitat loss and to habitat fragmentation. We focused on the Argentine Chaco, where deforestation has been widespread recently. We used an extensive field dataset on birds and mammals, along with a time series of annual woodland maps from 1985 to 2016 covering recent and historical habitat transformations. Contemporary habitat amount explained bird and mammal occupancy better than past habitat amount. However, occupancy was affected more by the past rather than recent fragmentation, indicating a time-delayed response to fragmentation. Considering past landscape patterns is therefore crucial for understanding current biodiversity patterns. Not accounting for land-use history ignores the possibility of extinction debt and can thus obscure impacts of fragmentation, potentially explaining contrasting findings of habitat loss versus fragmentation studies.

Isolation by environment and recurrent gene flow shaped the evolutionary history of a continentally distributed Neotropical treefrog

AbstractAimPhylogeographic studies show how historical and current changes in landscapes shape the geographic distribution of genetic diversity in species of animals and plants. In particular, for the species of the Diagonal of Open Formations (DOF), the compartmentalization of the Central Brazilian Plateau (CBP) during the Tertiary and climatic oscillations during the Quaternary have often been invoked to explain the origin and current patterns of biodiversity. We investigated how landscape changes and climatic oscillations shaped the distribution and diversification history of a widespread South American treefrog.LocationSouth American Diagonal of Open Formations (DOF) including Caatinga, Cerrado, and Chaco biomes.TaxonTreefrog Boana raniceps.MethodsWe used a multi‐locus dataset from 288 individual frogs collected at 115 localities throughout most of the species’ distribution. We used population assignment analysis, species distribution models, historical demography models, approximate Bayesian computation and landscape genetic analyses to test alternative hypotheses of diversification.ResultsWe found two genetic lineages that diverged during the mid‐Pleistocene with continued gene flow. Approximate Bayesian computation supported a scenario of isolation with migration until the Last Glacial Maximum, followed by more recent population expansion in north‐eastern Brazil and stability at the southwest in South America. Isolation by environment was the best predictor of genetic distance between populations, which is in accordance with their different environmental niches. As Boana raniceps is a lowland species, steep slopes in the CBP likely restrained gene flow enough to sustain population divergence. We found evidence for major range contraction during the Last Glacial Maximum, raising the possibility of synergic action of climate change and the CBP compartmentalization in regulating migration.Main conclusionsOur findings highlight how landscape and climatic changes can shape the diversification of DOF biota. Past climatic fluctuations and environmental resistance due to topography acted in concert, forming a semipermeable barrier to gene flow, promoting intraspecific differentiation in a continentally distributed species.

Multiscale drivers of carabid beetle (Coleoptera: Carabidae) assemblages in small European woodlands

AbstractAimThe spatio‐temporal connectivity of forest patches in lowland agricultural landscapes and their age matter to explain current biodiversity patterns across regional as well as biogeographical extents, to the point that their effect exceeds the one of macroclimate for plant diversity in the understorey of temperate forests. Whether this remains true for other taxonomic groups is still largely unknown. Yet, this relative influence has important consequences for ecosystem functioning and the delivery of ecosystem services. Focusing on carabid beetle assemblages, we assessed the relative importance of macroclimatic, landscape and patch attributes in driving local species richness (α‐diversity) and species dissimilarity between patches (β‐diversity).LocationDeciduous forest patches in seven regions along a 2,100‐km‐long latitudinal gradient across the European temperate forest biome, from southern France to central Sweden.MethodsWe sampled 221 forest patches in two 5‐km × 5‐km landscape windows with contrasting management intensities. Carabid beetles were classified into four habitat‐preference guilds: forest‐specialist, forest‐generalist, eurytopic and open‐habitat species. We quantified the multi‐level environmental influence using mixed‐effects models and variation partitioning analysis.ResultsWe found that both α‐ and β‐diversity were primarily determined by macroclimate, acting as a large‐scale ecological filter on carabid assemblages among regions. Forest‐patch conditions, including biotic and abiotic heterogeneity as well as patch age (but not patch size), increased α‐diversity of forest species. Landscape management intensity weakly influenced α‐diversity of forest species, but increased the number of non‐forest species in forest patches. Beta diversity of non‐forest species increased with patch heterogeneity and decreased with landscape management intensity.Main conclusionsOur results highlight the leading role of broad macroclimatic gradients over local and landscape factors in determining the composition of local carabid communities, thereby shedding light on macroecological patterns of arthropod assemblages. This study emphasizes the urgent need for preserving ancient forest patches embedded in agricultural landscapes, even the small and weakly connected ones.

Environmental DNA effectively captures functional diversity of coastal fish communities.

Robust assessments of taxonomic and functional diversity are essential components of research programmes aimed at understanding current biodiversity patterns and forecasting trajectories of ecological changes. Yet, evaluating marine biodiversity along its dimensions is challenging and dependent on the power and accuracy of the available data collection methods. Here we combine three traditional survey methodologies (underwater visual census strip transects [UVCt], baited underwater videos [BUV] and small-scale fishery catches [SSFc]), and one novel molecular technique (environmental DNA metabarcoding [eDNA]-12S rRNA and cytochrome oxidase subunit 1 [COI]) to investigate their efficiency and complementarity in assessing fish diversity. We analysed 1,716 multimethod replicates at a basin scale to measure the taxonomic and functional diversity of Mediterranean fish assemblages. Taxonomic identities were investigated at species, genus and family levels. Functional identities were assessed using combinations of morphological, behavioural and trophic traits. We show that: (a) SSFc provided the higher taxonomic diversity estimates followed by eDNA, and then UVCt and BUV; (b) eDNA was the only method able to gather the whole spectrum of considered functional traits, showing the most functionally diversified and least redundant fish assemblages; and (c) the effectiveness of eDNA in describing functional structure reflected its lack of selectivity towards any considered functional trait. Our findings suggest that the reach of eDNA analysis stretches beyond taxon detection efficiency and provides new insights into the potential of metabarcoding in ecological studies.