Global meta-analysis reveals low consistency of biodiversity congruence relationships

Combining environmental DNA and remote sensing for efficient, fine-scale mapping of arthropod biodiversity

Arthropods contribute importantly to ecosystem functioning but remain understudied. This undermines the validity of conservation decisions. Modern methods are now making arthropods easier to study, since arthropods can be mass-trapped, mass-identified, and semi-mass-quantified into 'many-row (observation), many-column (species)' datasets, with homogeneous error, high resolution, and copious environmental-covariate information. These 'novel community datasets' let us efficiently generate information on arthropod species distributions, conservation values, uncertainty, and the magnitude and direction of human impacts. We use a DNA-based method (barcode mapping) to produce an arthropod-community dataset from 121 Malaise-trap samples, and combine it with 29 remote-imagery layers using a deep neural net in a joint species distribution model. With this approach, we generate distribution maps for 76 arthropod species across a 225 km2 temperate-zone forested landscape. We combine the maps to visualize the fine-scale spatial distributions of species richness, community composition, and site irreplaceability. Old-growth forests show distinct community composition and higher species richness, and stream courses have the highest site-irreplaceability values. With this 'sideways biodiversity modelling' method, we demonstrate the feasibility of biodiversity mapping at sufficient spatial resolution to inform local management choices, while also being efficient enough to scale up to thousands of square kilometres. This article is part of the theme issue 'Towards a toolkit for global insect biodiversity monitoring'.

Concordance among lacustrine communities are low and inconsistent in the conterminous United States

Concordance occurs when two or more biological groups are correlated to each other. Examining the degree of concordance between communities has been a central goal in ecology. However, few studies have assessed the levels of community concordance at large spatial scales. We used a dataset obtained by the National Lakes Assessment (United States Environmental Protection Agency) to evaluate whether (i) the levels of concordance between aquatic communities were higher at the continental scale than within individual ecoregions of the United States and (ii) whether the levels of concordance between phytoplankton and zooplankton were higher than those between the plankton and macroinvertebrates communities. At the continental scale, the levels of concordance between different pairs of aquatic communities were low and did not exceed those within the ecoregions. Furthermore, levels of concordance varied considerably among ecoregions. Our results suggest that interactions between aquatic communities likely determined concordance patterns; however, the expectation of higher levels of concordance between the phytoplankton and zooplankton communities than between them and the macroinvertebrates community was not supported. The consistently low and variable levels of concordance suggest that using surrogate groups is not recommendable for monitoring lakes in the United States, both at the continental and regional scales. According to our results, the prospect of using the surrogacy approach was low even for aquatic communities that are highly interactive or driven by similar environmental factors.

The ecological and biodiversity conservation values of farm dams: A systematic review

Biodiversity is in rapid decline globally with agriculture being one of the leading causes. Within agricultural landscapes, some features provide a benefit to biodiversity that is disproportionate to their spatial area. An interesting example is artificial ponds-or farm dams-which can support a large variety of taxa. Here, we present a global review of farm dam research related to biodiversity conservation objectives to provide an overview of the topics, key research insights, and the characteristics of current research. We used a three-stage process to screen literature and identified 104 relevant papers across 27 countries encompassing studies of 13 different taxa. Most of the studies were short-term (less than 5 years) with small sample sizes (less than 20 sites). Of the 104 papers, 88 were focussed primarily on ecological outcomes, such as species richness or abundance, and 15 on primary production outcomes, such as crop and livestock yield, despite addressing or measuring ecological metrics. Only one study measured both ecological and primary production outcomes. Studies frequently examined how the features of dams (79 studies) and attributes of the surrounding landscape (47 studies) impact particular species and communities. Terrestrial mammals (1 study) were under-represented in the literature with macrophytes (28 studies), macroinvertebrates (26 studies), and amphibians (19 studies) receiving the most attention. Our results reveal a growing trend towards recognizing farm dams as habitats for various taxa, including amphibians, beetles, dragonflies, and other macroinvertebrates within agricultural environments. Significant knowledge gaps exist in understanding how dam age, invasive species, and effective management practices impact the biodiversity conservation values of farm dams. Future research should emphasize enhancing biodiversity by collaborating with landholders to increase habitat through strategic vegetation planning, minimizing runoff and nutrient inflow, and restricting stock access.

Adaptive monitoring in action-what drives arthropod diversity and composition in central European beech forests?

Recent studies suggest that arthropod diversity in German forests is declining. Currently, different national programs are being developed to monitor arthropod trends and to unravel the effects of forest management on biodiversity in forests. To establish effective long-term monitoring programs, a set of drivers of arthropod diversity and composition as well as suitable species groups have to be identified. To aid in answering these questions, we investigated arthropod data collected in four Hessian forest reserves (FR) in the 1990s. To fully utilize this data set, we combined it with results from a retrospective structural sampling design applied at the original trap locations in central European beech (Fagus sylvatica) forests. As expected, the importance of the different forest structural, vegetation, and site attributes differed largely between the investigated arthropod groups: beetles, spiders, Aculeata, and true bugs. Measures related to light availability and temperature such as canopy cover or potential radiation were important to all groups affecting either richness, composition, or both. Spiders and true bugs were affected by the broadest range of explanatory variables, which makes them a good choice for monitoring general trends. For targeted monitoring focused on forestry-related effects on biodiversity, rove and ground beetles seem more suitable. Both groups were driven by a narrower, more management-related set of variables. Most importantly, our study approach shows that it is possible to utilize older biodiversity survey data. Although, in our case, there are strong restrictions due to the long time between species and structural attribute sampling.

Correlated biodiversity change between plant and insect assemblages resurveyed after 80 years across a dynamic habitat mosaic

Historical data on co-occurring taxa are extremely rare. As such, the extent to which distinct co-occurring taxa experience similar long-term patterns in species richness and compositional change (e.g., when exposed to a changing environment) is not clear. Using data from a diverse ecological community surveyed in the 1930s and resurveyed in the 2010s, we investigated whether local plant and insect assemblages displayed cross-taxon congruence-that is, spatiotemporal correlation in species richness and compositional change-across six co-occurring taxa: vascular plants, non-vascular plants, grasshoppers and crickets (Orthoptera), ants (Hymenoptera: Formicinae), hoverflies (Diptera: Syrphidae), and dragonflies and damselflies (Odonata). All taxa exhibited high levels of turnover across the ca. 80-year time period. Despite minimal observed changes at the level of the whole study system, species richness displayed widespread cross-taxon congruence (i.e., correlated temporal change) across local assemblages within the study system. Hierarchical logistic regression models suggest a role for shared responses to environmental change underlying cross-taxon correlations and highlight stronger correlations between vascular plants and their direct consumers, suggesting a possible role for biotic interactions between these groups. These results provide an illustration of cross-taxon congruence in biodiversity change using data unique in its combination of temporal and taxonomic scope, and highlight the potential for cascading and comparable effects of environmental change (abiotic and biotic) on co-occurring plant and insect communities. However, analyses of historical resurveys based on currently available data come with inherent uncertainties. As such, this study highlights a need for well-designed experiments, and monitoring programs incorporating co-occurring taxa, to determine the underlying mechanisms and prevalence of congruent biodiversity change as anthropogenic environmental change accelerates apace.

Modeling climate change impacts on potential global distribution of Tamarixia radiata Waterston (Hymenoptera: Eulophidae)

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), is an efficient vector of "Candidatus Liberibacter" species, the causative agents implicated in citrus greening or huanglongbing (HLB). HLB is the most devastating citrus disease and has killed millions of citrus trees worldwide. Classical biological control using Tamarixia radiata Waterston (Hymenoptera: Eulophidae) against ACP has been successful in some regions. Climatic conditions are critical in determining suitable areas for the geographical distribution of T. radiata. However, paucity of information on climate change impacts on the global spread of T. radiata restricts international efforts to manage ACP with T. radiata. We investigated the potential global distribution of T. radiata using 317 native and non-native occurrence records and 20 environmental data sets (with correlation coefficients (|r| > 0.7)). Using the Maximum Entropy model, these data were analyzed for two shared socioeconomic pathways (SSPs) and two time periods (2030s and 2050s). We showed that habitat suitability for T. radiata occurred in all continents except Antarctica. However, the highly suitable areas for T. radiata were found in parts of the Americas, Asia, Africa and Oceania. The climate suitable areas would increase until the 2050s. The predictions showed that mean temperature of coldest quarter and precipitation of warmest quarter were the most important environmental variables that influenced the distribution of T. radiata. The model reliably predicted habitat suitability for T. radiata, which can be adapted in classical biological control programs to effectively manage ACP in an environmentally friendly manner.

Progress in 'taxonomic sufficiency' in aquatic biological investigations

The 'taxonomic sufficiency' (TS) approach has been applied to algae, protists, invertebrates, and vertebrates, generally by aggregating species-level abundance data to a higher taxonomic level, where genus-level data are often highly correlated with species-level data and are a valid proxy level. The TS approach offers the possibility of a comparison of data from different geographical areas and highlights the effects of contaminants. The TS approach is stable in the face of different researchers and in the comparison of long-term biological survey data. The effectiveness of the TS approach may increase with increasing environmental gradients or spatial area. The TS approach should be avoided when the spatial area is small and small differences in species-level data are considered important, so as not to cancel out the distribution patterns specific to the local environment of the biological taxa.

Spatial relationships between fishes and amphibians: implications for conservation planning in a Neotropical Hotspot

Species distribution patterns are widely used to guide conservation planning and are a central issue in ecology. The usefulness of spatial correlation analysis has been highlighted in several ecological applications so far. However, spatial assumptions in ecology are highly scale-dependent, in which geographical relationships between species diversity and distributions can have different conservation concerns. Here, an integrative landscape planning was designed to show the spatial distribution patterns of taxonomic and functional diversity of amphibians and fishes, from multiple species traits regarding morphology, life history, and behavior. We used spatial, morphological, and ecological data of amphibians and fishes to calculate the functional diversity and the spatial correlation of species. Mapping results show that the higher taxonomic and functional diversity of fishes is concentrated in the West Atlantic Forest. Considering amphibians, are located in the East portion of the biome. The spatial correlation of species indicates the regions of the Serra do Mar and the extreme southern part of the Central Corridor as the main overlapped species distribution areas between both groups. New key conservation sites were reported within the Brazilian Atlantic Forest hotspot, revealing cross-taxon mismatches between terrestrial and freshwater ecosystems. This study offers useful spatial information integrating suitable habitats of fishes and amphibians to complement existing and future research based on terrestrial and freshwater conservation. New priorities for biodiversity conservation in rich-species regions highlight the importance of spatial pattern analysis to support land-use planning in a macroecological context.

Determining Effective Environmental Factors in the Distribution of Endangered Endemic Medicinal Plant Species Using the BMLR Model: The Example of Wild Celery (Kelussia odoratissima Mozaff., Apiaceae) in Zagros (Iran)

Kelussia odoratissima Mozaff. is a medicinal species native to Iran. The goal of this research was to determine the environmental factors important for the distribution of K. doratissima in Iran using BMLR modeling. Six random transects were established throughout the species’ habitat, and 220 quadrats with an area of 4 m2 were plotted. The canopy cover percentages of K. doratissima were estimated in each quadrat. Topographic factors, including elevation, slope, and aspect maps, were generated by creating DEM images. Land use, land evaluation, evaporation, temperature, and precipitation maps of the area were created accordingly. The data collected from the experiments were analyzed using the Minitab and R statistical packages. To determine the effect of the studied factors in the distribution of K. doratissima, we ran a set of backward multiple linear regressions. The results showed that the effects of evaporation, elevation, and slope were significant in the species’ distribution, with elevation having a positive effect and evaporation and slope showing negative effects. Further, elevation had the highest effect on distribution (greatest absolute value of beta at 9.660). The next most significant factors in the plant’s distribution were evaporation (beta = 8.282) and slope (beta = 0.807), respectively.

An overview of reviews of conservation flagships: evaluating fundraising ability and surrogate power

The main role of flagship species in biodiversity conservation is to raise awareness and funds for conservation. Because of their marketing role, flagship species are often selected based on other than biodiversity related criteria, such as species charisma or aesthetic appeal. Nonetheless, funds raised through flagship species are often used to protect the species itself, making it important to evaluate the effectiveness of flagship species as conservation tools: For example, could superior fundraising ability outweigh the low biodiversity surrogate power of a flagship, justifying this ambivalent role in conservation? To assess flagship effectiveness from this dual perspective, we must synthesize evidence on a) the fundraising potential of flagship species vs. other conservation targets, such as ecosystems or biodiversity, and b) the biodiversity surrogate power of potential flagship taxa. We approached this broad topic through an overview of reviews on both subtopics. We found no evidence that charismatic flagship species were superior fundraisers over other conservation targets. In addition, studies evaluating the biodiversity surrogacy power of different taxa had mainly resulted in mixed findings, contesting the overall usefulness of the concept in conservation. The variability of study setups and methods made comparisons between studies difficult, highlighting the need to standardize future research (e.g., standardizing explanatory variables). Further possible reasons for lack of conclusive evidence on fundraising potential are the dominance of factors other than flagship identity (e.g., scope and conservation status) and differences in donor preferences. We recommend Environmental NGOs to develop and diversify their fundraising strategies based on best available knowledge, and rely less on mere species charisma.

Taxonomic and functional diversity of birds in a rural landscape of high Andean forest, Colombia

We evaluated the taxonomic and functional diversity of birds in a rural landscape in the north-eastern Andes of Colombia. We carried out seven field trips and used transects of 300 m, separated from each other by 500 m in the dominant plant cover of the rural landscape. We measured alpha (α) and beta (β) diversity at both the taxonomic and functional levels. We registered 10 orders, 21 families, 56 genera and 63 species of birds. In wooded pasture, we recorded 55 species and a relative abundance of 66% and 44 and 34% for an Andean forest fragment. The species that contributed the most to the dissimilarity between the covers were Zonotrichia capensis, Turdus fuscater, Mecocerculus leucophrys, Atlapetes latinuchus and Crotophaga ani. We identified nine functional types, where G1 was made up of small species with anissodactyl and pamprodactyl legs that were insectivorous, frugivorous and nectarivorous as the best represented. The FEve and FDiv were 0.51 and 0.74, respectively in the Andean forest fragment plant cover and, for the wooded pasture, the FEve was 0.45 and the FDiv was 0.81. Both cover types contributed to the diversity of the rural landscape and the dynamics that existed between them formed a complementary factor that favoured the taxonomic and functional richness of the characterised rural landscape.

Global determinants and conservation of evolutionary and geographic rarity in land vertebrates

Deciphering global trends in phylogenetic endemism is crucial for understanding broad-scale evolutionary patterns and the conservation of key elements of biodiversity. However, knowledge to date on global phylogenetic endemism and its determinants has been lacking. Here, we conduct the first global analysis of phylogenetic endemism patterns of land vertebrates (>30,000 species), their environmental correlates, and threats. We found that low temperature seasonality and high topographic heterogeneity were the main global determinants of phylogenetic endemism. While phylogenetic endemism hotspots cover 22% of Earth, these regions currently have a high human footprint, low natural land cover, minimal protection, and will be greatly affected by climate change. Evolutionarily unique, narrow-range species are crucial for sustaining biodiversity in the face of environmental change. Our global study advances the current understanding of this imperilled yet previously overlooked facet of biodiversity.

Cross-taxon congruence of aquatic microbial communities across geological ages in Iceland: Stochastic and deterministic processes

Biotic groups usually have nonrandom cross-taxon relationships in their biodiversity or compositions across sites, but it is poorly known how such congruence varies across long-term ecosystem development, and what are the ecological processes underlying biodiversity patterns. Here, we examined the cross-taxon congruence in diversity and compositions of bacteria, fungi and diatoms in streams from four regions with different geological ages in Iceland, and further studied their community assembly processes. Bacteria and fungi showed contrasting trends in alpha and gamma diversities across geological ages, while their beta diversity patterns were consistent, being the lowest in the oldest region. The three taxonomic groups had the strongest cross-taxon congruence of beta diversity in the oldest region, while the weakest for intermediate-aged regions. Although environmental variables played important roles in shaping their congruence, biotic interaction had nonnegligible influences. Deterministic processes, being dominant for bacteria and fungi, had the highest relative influence in intermediate-aged regions, whereas diatoms showed higher stochasticity. We proposed a four-phase conceptual model to show how the balance of deterministic and stochastic processes changes across geological ages. Taken together, our results provide an advanced understanding of cross-taxon congruence and community assembly processes for aquatic communities over long-term periods of geological age.

Coupled beta diversity patterns among coral reef benthic taxa

Unraveling the processes that drive diversity patterns remains a central challenge for ecology, and an increased understanding is especially urgent to address and mitigate escalating diversity loss. Studies have primarily focused on singular taxonomic groups, but recent research has begun evaluating spatial diversity patterns across multiple taxonomic groups and suggests taxa may have congruence in their diversity patterns. Here, we use surveys of the coral reef benthic groups: scleractinian corals, macroalgae, sponges and gorgonians conducted in the Bahamian Archipelago across 27 sites to determine if there is congruence between taxonomic groups in their site-level diversity patterns (i.e. alpha diversity: number of species, and beta diversity: differences in species composition) while accounting for environmental predictors (i.e. depth, wave exposure, market gravity (i.e. human population size and distance to market), primary productivity, and grazing). Overall, we found that the beta diversities of these benthic groups were significant predictors of each other. The most consistent relationships existed with algae and coral, as their beta diversity was a significant predictor of every other taxa's beta diversity, potentially due to their strong biotic interactions and dominance on the reef. Conversely, we found no congruence patterns in the alpha diversity of the taxa. Market gravity and exposure showed the most prevalent correlation with both alpha and beta diversity for the taxa. Overall, our results suggest that coral reef benthic taxa can have spatial congruence in species composition, but not number of species, and that future research on biodiversity trends should consider that taxa may have non-independent patterns.

Multiple forms of hotspots of tetrapod biodiversity and the challenges of open-access data scarcity

The uneven spatial distribution of biodiversity is a defining feature of nature. In fact, the implementation of conservation actions both locally and globally has progressively been guided by the identification of biodiversity 'hotspots' (areas with exceptional biodiversity). However, different regions of the world differ drastically in the availability of fine-scale data on the diversity and distribution of species, thus limiting the potential to assess their local environmental priorities. Within South America-a megadiverse continent-Uruguay represents a peculiar area where multiple tropical and non-tropical eco-regions converge, creating highly heterogeneous ecosystems, but where the systematic quantification of biodiversity remains largely anecdotal. To investigate the constraints posed by the limited access to biodiversity data, we employ the most comprehensive database for tetrapod vertebrates in Uruguay (spanning 664 species) assembled to date, to identify hotspots of species-richness, endemism and threatened species for the first time. Our results reveal negligible spatial congruence among biodiversity hotspots, and that tetrapod sampling has historically concentrated in only a few areas. Collectively, our study provides a detailed account of the areas where urgent biodiversity monitoring efforts are needed to develop more accurate knowledge on biodiversity patterns, offering government and environmental bodies a critical scientific resource for future planning.

Environmental factors influencing fine-scale distribution of Antarctica's only endemic insect

Species distributions are dependent on interactions with abiotic and biotic factors in the environment. Abiotic factors like temperature, moisture, and soil nutrients, along with biotic interactions within and between species, can all have strong influences on spatial distributions of plants and animals. Terrestrial Antarctic habitats are relatively simple and thus good systems to study ecological factors that drive species distributions and abundance. However, these environments are also sensitive to perturbation, and thus understanding the ecological drivers of species distribution is critical for predicting responses to environmental change. The Antarctic midge, Belgica antarctica, is the only endemic insect on the continent and has a patchy distribution along the Antarctic Peninsula. While its life history and physiology are well studied, factors that underlie variation in population density within its range are unknown. Previous work on Antarctic microfauna indicates that distribution over broad scales is primarily regulated by soil moisture, nitrogen content, and the presence of suitable plant life, but whether these patterns are true over smaller spatial scales has not been investigated. Here we sampled midges across five islands on the Antarctic Peninsula and tested a series of hypotheses to determine the relative influences of abiotic and biotic factors on midge abundance. While historical literature suggests that Antarctic organisms are limited by the abiotic environment, our best-supported hypothesis indicated that abundance is predicted by a combination of abiotic and biotic conditions. Our results are consistent with a growing body of literature that biotic interactions are more important in Antarctic ecosystems than historically appreciated.

Characterizing Land Use Impacts on Functional Plant Diversity for Life Cycle Assessments

Decision support tools such as life cycle assessment (LCA) increasingly aim to account for impacts on biodiversity. While taxonomic measures like species richness have been implemented, they do not fully grasp the impacts on ecosystem functioning. Functional diversity, derived from the species' traits, is more representative of ecosystem processes. This study provides a framework for developing characterization factors for functional diversity as affected by land use. It exploits the large databases on plant traits and species composition that have recently become available and allow bringing biodiversity impact assessment to the next level. Three functional diversity indices therein describe different aspects of functional diversity, namely richness, evenness, and divergence. Applying our framework to Germany as a proof of concept, we show significant losses in functional plant diversity when converting natural forests to agricultural land use. Consistently across different forests and agricultural systems, functional richness decreases steeply and functional divergence moderately upon occupation. In contrast, functional evenness exhibits opposite trends. The resulting characterization factors are likely to be representative of temperate regions. The framework is flexible and applicable to larger scales and other impact categories. As such, it facilitates harmonizing biodiversity impact assessments and better represents ecosystem functioning by incorporating functional diversity.

Salix transect of Europe: patterns in the distribution of willow-feeding psyllids (Hemiptera: Psylloidea) from Greece to arctic Norway

Background Psyllids are oligophagous phytophagous insects with many specialist willow (Salix spp.) feeding species in two genera (Cacopsylla and Bactericera). We examine the patterns of distribution and co-occurrence of willow-feeding species at 42 willow sites across Europe forming a transect from Greece (lat. 38.8 °N) to arctic Norway (lat. 70.6 °N). The transect and sites have been described in previous papers. New information A total of 1245 individual psyllids were examined from 23 species of willow over the transect, representing 17 willow-feeding species (11 Cacopsylla and 6 Bactericera). Numerous species were very widely distributed, with two species, Bactericera albiventris (Foerster, 1848) and Cacopsylla pulchra (Zetterstedt, 1840), occurring from Greece to Finland. Other widespread species (Romania to Finland) were Cacopsylla ambigua (Foerster, 1848) and Bactericera curvatinervis (Foerster, 1848). The mean number of psyllid species per site was 2.4 (1.3 Cacopsylla, 1.1 Bactericera).

A global assessment of the drivers of threatened terrestrial species richness

High numbers of threatened species might be expected to occur where overall species richness is also high; however, this explains only a proportion of the global variation in threatened species richness. Understanding why many areas have more or fewer threatened species than would be expected given their species richness, and whether that is consistent across taxa, is essential for identifying global conservation priorities. Here, we show that, after controlling for species richness, environmental factors, such as temperature and insularity, are typically more important than human impacts for explaining spatial variation in global threatened species richness. Human impacts, nevertheless, have an important role, with relationships varying between vertebrate groups and zoogeographic regions. Understanding this variation provides a framework for establishing global conservation priorities, identifying those regions where species are inherently more vulnerable to the effects of threatening human processes, and forecasting how threatened species might be distributed in a changing world.

Complex long-term biodiversity change among invertebrates, bryophytes and lichens

Large-scale biodiversity changes are measured mainly through the responses of a few taxonomic groups. Much less is known about the trends affecting most invertebrates and other neglected taxa, and it is unclear whether well-studied taxa, such as vertebrates, reflect changes in wider biodiversity. Here, we present and analyse trends in the UK distributions of over 5,000 species of invertebrates, bryophytes and lichens, measured as changes in occupancy. Our results reveal substantial variation in the magnitude, direction and timing of changes over the last 45 years. Just one of the four major groups analysed, terrestrial non-insect invertebrates, exhibits the declining trend reported among vertebrates and butterflies. Both terrestrial insects and the bryophytes and lichens group increased in average occupancy. A striking pattern is found among freshwater species, which have undergone a strong recovery since the mid-1990s after two decades of decline. We show that, while average occupancy among most groups appears to have been stable or increasing, there has been substantial change in the relative commonness and rarity of individual species, indicating considerable turnover in community composition. Additionally, large numbers of species have experienced substantial declines. Our results suggest a more complex pattern of biodiversity change in the United Kingdom than previously reported.

Investigating microbial associations from sequencing survey data with co-correspondence analysis

Microbial communities, which drive major ecosystem functions, consist of a wide range of interacting species. Understanding how microbial communities are structured and the processes underlying this is crucial to interpreting ecosystem responses to global change but is challenging as microbial interactions cannot usually be directly observed. Multiple efforts are currently focused to combine next-generation sequencing (NGS) techniques with refined statistical analysis (e.g., network analysis, multivariate analysis) to characterize the structures of microbial communities. However, most of these approaches consider a single table of sequencing data measured for several samples. Technological advances now make it possible to collect NGS data on different taxonomic groups simultaneously for the same samples, allowing us to analyse a pair of tables. Here, an analytical framework based on co-correspondence analysis (CoCA) is proposed to study the distributions, assemblages and interactions between two microbial communities. We show the ability of this approach to highlight the relationships between two microbial communities, using two data sets exhibiting various types of interactions. CoCA identified strong association patterns between autotrophic and heterotrophic microbial eukaryote assemblages, on the one hand, and between microalgae and viruses, on the other. We demonstrate also how CoCA can be used, complementary to network analysis, to reorder co-occurrence networks and thus investigate the presence of patterns in ecological networks.

Cross Taxon Congruence Between Lichens and Vascular Plants in a Riparian Ecosystem

Despite that congruence across taxa has been proved as an effective tool to provide insights into the processes structuring the spatial distribution of taxonomic groups and is useful for conservation purposes, only a few studies on cross-taxon congruence focused on freshwater ecosystems and on the relations among vascular plants and lichens. We hypothesized here that, since vascular plants could be good surrogates of lichens in these ecosystems, it would be possible to assess the overall biodiversity of riparian habitats using plant data only. In this frame, we explored the relationship between (a) species richness and (b) community composition of plants and lichens in a wetland area located in central Italy to (i) assess whether vascular plants are good surrogates of lichens and (ii) to test the congruence of patterns of species richness and composition among plants and lichens along an ecological gradient. The general performance of plant species richness per se, as a biodiversity surrogate of lichens, had poor results. Nonetheless, the congruence in compositional patterns between lichens and vascular plants varied across habitats and was influenced by the characteristics of the vegetation. In general, we discussed how the strength of the studied relationships could be influenced by characteristics of the data (presence/absence vs. abundance), by the spatial scale, and by the features of the habitats. Overall, our data confirm that the more diverse and structurally complex the vegetation is, the more diverse are the lichen communities it hosts.

Teamwork makes the dream work: Disentangling cross-taxon congruence across soil biota in black pine plantations

Soil plays a fundamental role in many ecological processes, throughout a complex network of above- and below-ground interactions. This has aroused increasing interest in the use of correlates for biodiversity assessment and has demonstrated their reliability with respect to proxies based on environmental data alone. Although co-variation of species richness and composition in forests has been discussed in the literature, only a few studies have explored these elements in forest plantations, which are generally thought to be poor in biodiversity, being aimed at timber production. Based on this premise our aims were 1) to test if cross-taxon congruence across different groups of organisms (bacteria, vascular plants, mushrooms, ectomycorrhizae, mycelium, carabids, microarthropods, nematodes) is consistent in artificial stands; 2) to evaluate the strength of relationships due to the existing environmental gradients as expressed by abiotic and biotic factors (soil, spatial-topographic, dendrometric variables). Correlations between groups were studied with Mantel and partial Mantel tests, while variance partition analysis was applied to assess the relative effect of environmental variables on the robustness of observed relationships. Significant cross-taxon congruence was observed across almost all taxonomic groups pairs. However, only bacteria/mycelium and mushrooms/mycelium correlations remained significant after removing the environmental effect, suggesting that a strong abiotic influence drives species composition. Considering variation partitioning, the results highlighted the importance of bacteria as a potential indicator: bacteria were the taxonomic group with the highest compositional variance explained by the predictors used; furthermore, they proved to be involved in the only cases where the variance attributed solely to the pure effect of biotic or abiotic predictors was significant. Remarkably, the co-dependent effect of all predictors always explained the highest portion of total variation in all dependent taxa, testifying the intricate and dynamic interplay of environmental factors and biotic interactions in explaining cross-taxon congruence in forest plantations.

Evaluating giant panda as a surrogate species for conservation co-occurring species in the Baishuijiang National Nature Reserve

The establishment of nature reserves is a key approach for biodiversity conservation worldwide. However, the effectiveness of nature reserves established by protecting the habitat needs of surrogate species is questioned. In this study, the Baishuijiang National Nature Reserve (Baishuijiang NNR), located in the Minshan Mountains, China, which is established mainly for the conservation of giant panda (a surrogate for the conservation of other endangered species) was selected. We quantitatively evaluated the conservation effectiveness of the reserve for giant panda and co-occurring species (here, seven protected species) using a maximum entropy model (Maxent), and analyzed spatial congruence between giant panda and other seven species. Results shown that the habitat of giant panda generally included the habitat of other seven protected species, suggesting that conservation of giant panda habitat also allows the conservation for the habitat of almost co-occurring species. Hence, the natural reserve established for giant panda as a surrogate species has a relatively high effectiveness. A high proportion of the suitable habitat for six species is inside the core zone, but a high proportion of the suitable habitat for two species is located in the experimental and buffer zones. Thus, the two species are affected by human activities. To improve the conservation effectiveness of the nature reserve, the management zones need to be amended. The result of the study will be beneficial for future conservation and management of the reserve. This study provides an effective method for evaluating the conservation effectiveness of nature reserves in other area of the worldwide.

Taxon-specific responses to different forestry treatments in a temperate forest

There are only few studies that explore the ecological consequences of forest management on several organism groups. We studied the short-term effects of four forestry treatments including preparation cutting, clear-cutting, retention tree group and gap-cutting in a temperate managed forest on the assemblage structure of understory plants, enchytraeid worms, spiders and ground beetles. Here we show, that the effect of treatments on the different facets of assemblage structure was taxon-specific. Clear-cutting and retention tree group strongly impoverished enchytraeids assemblages. Even if the species richness and cover of plants increased in clear-cutting and gap-cutting, their species composition moderately changed after treatments. For spiders only their species composition was influenced by the treatments, while the response of ground beetles was slightly affected. Short-term effect of forest management interventions on biodiversity might be compensated by the dispersal (spiders, ground beetles) and resilience (plants) of organism groups, however sedentary soil organism showed high sensitivity.

Consistently inconsistent drivers of microbial diversity and abundance at macroecological scales

Macroecology seeks to understand broad-scale patterns in the diversity and abundance of organisms, but macroecologists typically study aboveground macroorganisms. Belowground organisms regulate numerous ecosystem functions, yet we lack understanding of what drives their diversity. Here, we examine the controls on belowground diversity along latitudinal and elevational gradients. We performed a global meta-analysis of 325 soil communities across 20 studies conducted along temperature and soil pH gradients. Belowground taxa, whether bacterial or fungal, observed along a given gradient of temperature or soil pH were equally likely to show a linear increase, linear decrease, humped pattern, trough-shaped pattern, or no pattern in diversity along the gradient. Land-use intensity weakly affected the diversity-temperature relationship, but no other factor did so. Our study highlights disparities among diversity patterns of soil microbial communities. Belowground diversity may be controlled by the associated climatic and historical contexts of particular gradients, by factors not typically measured in community-level studies, or by processes operating at scales that do not match the temporal and spatial scales under study. Because these organisms are responsible for a suite of key processes, understanding the drivers of their distribution and diversity is fundamental to understanding the functioning of ecosystems.

Trophic interactions among vertebrate guilds and plants shape global patterns in species diversity

Trophic interactions play critical roles in structuring biotic communities. Understanding variation in trophic interactions among systems provides important insights into biodiversity maintenance and conservation. However, the relative importance of bottom-up versus top-down trophic processes for broad-scale patterns in biodiversity is poorly understood. Here, we used global datasets on species richness of vascular plants, mammals and breeding birds to evaluate the role of trophic interactions in shaping large-scale diversity patterns. Specifically, we used non-recursive structural equation models to test for top-down and bottom-up forcing of global species diversity patterns among plants and trophic guilds of mammals and birds (carnivores, invertivores and herbivores), while accounting for extrinsic environmental drivers. The results show that trophic linkages emerged as being more important to explaining species richness than extrinsic environmental drivers. In particular, there were strong, positive top-down interactions between mammal herbivores and plants, and moderate to strong bottom-up and/or top-down interactions between herbivores/invertivores and carnivores. Estimated trophic interactions for separate biogeographical regions were consistent with global patterns. Our findings demonstrate that, after accounting for environmental drivers, large-scale species richness patterns in plant and vertebrate taxa consistently support trophic interactions playing a major role in shaping global patterns in biodiversity. Furthermore, these results suggest that top-down forces often play strong complementary roles relative to bottom-up drivers in structuring biodiversity patterns across trophic levels. These findings underscore the importance of integrating trophic forcing mechanisms into studies of biodiversity patterns.

Divergent biodiversity change within ecosystems

The Earth's ecosystems are under unprecedented pressure, yet the nature of contemporary biodiversity change is not well understood. Growing evidence that community size is regulated highlights the need for improved understanding of community dynamics. As stability in community size could be underpinned by marked temporal turnover, a key question is the extent to which changes in both biodiversity dimensions (temporal α- and temporal β-diversity) covary within and among the assemblages that comprise natural communities. Here, we draw on a multiassemblage dataset (encompassing vertebrates, invertebrates, and unicellular plants) from a tropical freshwater ecosystem and employ a cyclic shift randomization to assess whether any directional change in temporal α-diversity and temporal β-diversity exceeds baseline levels. In the majority of cases, α-diversity remains stable over the 5-y time frame of our analysis, with little evidence for systematic change at the community level. In contrast, temporal β-diversity changes are more prevalent, and the two diversity dimensions are decoupled at both the within- and among-assemblage level. Consequently, a pressing research challenge is to establish how turnover supports regulation and when elevated temporal β-diversity jeopardizes community integrity.

Varying congruence among spatial patterns of vascular plants and vertebrates based on habitat groups

Proxies are adopted to represent biodiversity patterns due to inadequate information for all taxa. Despite the wide use of proxies, their efficacy remains unclear. Previous analyses focused on overall species richness for fewer groups, affecting the generality and depth of inference. Biological taxa often exhibit very different habitat preferences. Habitat groupings may be an appropriate approach to advancing the study of richness patterns. Diverse geographical patterns of species richness and their potential mechanisms were then examined for habitat groups. We used a database of the spatial distribution of 32,824 species of mammals, birds, reptiles, amphibians and plants from 2,376 counties across China, divided the five taxa into 30 habitat groups, calculated Spearman correlations of species richness among taxa and habitat groups, and tested five hypotheses about richness patterns using multivariate models. We identified one major group [i.e., forest- and shrub-dependent (FS) groups], and some minor groups such as grassland-dependent vertebrates and desert-dependent vertebrates. There were mostly high or moderate correlations among FS groups, but mostly low or moderate correlations among other habitat groups. The prominent variables differed among habitat groups of the same taxon, such as birds and reptiles. The sets of predictors were also different within the same habitat, such as forests, grasslands, and deserts. Average correlations among the same habitat groups of vertebrates and among habitat groups of a single taxon were low or moderate, except correlations among FS groups. The sets of prominent variables of species richness differed strongly among habitat groups, although elevation range was the most important variable for most FS groups. The ecological and evolutionary processes that underpin richness patterns might be disparate among different habitat groups. Appropriate groupings based on habitats could reveal important patterns of richness gradients and valuable biodiversity components.

Incorporating threat in hotspots and coldspots of biodiversity and ecosystem services

Spatial prioritization could help target conservation actions directed to maintain both biodiversity and ecosystem services. We delineate hotspots and coldspots of two biodiversity conservation features and five regulating and cultural services by incorporating an indicator of 'threat', i.e. timber harvest profitability for forest areas in Telemark (Norway). We found hotspots, where high values of biodiversity, ecosystem services and threat coincide, ranging from 0.1 to 7.1% of the area, depending on varying threshold levels. Targeting of these areas for conservation follows reactive conservation approaches. In coldspots, high biodiversity and ecosystem service values coincide with low levels of threat, and cover 0.1-3.4% of the forest area. These areas might serve proactive conservation approaches at lower opportunity cost (foregone timber harvest profits). We conclude that a combination of indicators of biodiversity, ecosystem services and potential threat is an appropriate approach for spatial prioritization of proactive and reactive conservation strategies.

Disentangling effects of abiotic factors and biotic interactions on cross-taxon congruence in species turnover patterns of plants, moths and beetles

High cross-taxon congruence in species diversity patterns is essential for the use of surrogate taxa in biodiversity conservation, but presence and strength of congruence in species turnover patterns, and the relative contributions of abiotic environmental factors and biotic interaction towards this congruence, remain poorly understood. In our study, we used variation partitioning in multiple regressions to quantify cross-taxon congruence in community dissimilarities of vascular plants, geometrid and arciinid moths and carabid beetles, subsequently investigating their respective underpinning by abiotic factors and biotic interactions. Significant cross-taxon congruence observed across all taxon pairs was linked to their similar responses towards elevation change. Changes in the vegetation composition were closely linked to carabid turnover, with vegetation structure and associated microclimatic conditions proposed causes of this link. In contrast, moth assemblages appeared to be dominated by generalist species whose turnover was weakly associated with vegetation changes. Overall, abiotic factors exerted a stronger influence on cross-taxon congruence across our study sites than biotic interactions. The weak congruence in turnover observed particularly between plants and moths highlights the importance of multi-taxon approaches based on groupings of taxa with similar turnovers, rather than the use of single surrogate taxa or environmental proxies, in biodiversity assessments.

Drivers of the composition and diversity of carabid functional traits in UK coniferous plantations

Functional diversity (FD) is increasingly used as a metric to evaluate the impact of forest management strategies on ecosystem functioning. Management interventions that aim to maximise FD require knowledge of multiple environmental drivers of FD, which have not been studied to date in temperate coniferous production forests. We quantified the relative importance of abiotic (forest management) and biotic (ground vegetation community) drivers of carabid FD and trait distribution in 44 coniferous plantation forest stands across the UK. Carabid FD declined with canopy cover and carabid body length correlated negatively with the percentage of open semi-natural area surrounding a plot. We conclude that forest management could enhance carabid FD through initiatives that emulate natural disturbance regimes through gap creation. We found that neither functional nor taxonomic metrics of vegetation diversity correlated with carabid FD, suggesting that restoration of plant communities, a major goal of forest restoration efforts, will not necessarily enhance carabid FD in coniferous plantations.

A new framework for selecting environmental surrogates

Surrogate concepts are used in all sub-disciplines of environmental science. However, controversy remains regarding the extent to which surrogates are useful for resolving environmental problems. Here, we argue that conflicts about the utility of surrogates (and the related concepts of indicators and proxies) often reflect context-specific differences in trade-offs between measurement accuracy and practical constraints. By examining different approaches for selecting and applying surrogates, we identify five trade-offs that correspond to key points of contention in the application of surrogates. We then present an 8-step Adaptive Surrogacy Framework that incorporates cross-disciplinary perspectives from a wide spectrum of the environmental sciences, aiming to unify surrogate concepts across disciplines and applications. Our synthesis of the science of surrogates is intended as a first step towards fully leveraging knowledge accumulated across disciplines, thus consolidating lessons learned so that they may be accessible to all those operating in different fields, yet facing similar hurdles.

Multitrophic diversity in a biodiverse forest is highly nonlinear across spatial scales

Subtropical and tropical forests are biodiversity hotspots, and untangling the spatial scaling of their diversity is fundamental for understanding global species richness and conserving biodiversity essential to human well-being. However, scale-dependent diversity distributions among coexisting taxa remain poorly understood for heterogeneous environments in biodiverse regions. We show that diversity relations among 43 taxa-including plants, arthropods and microorganisms-in a mountainous subtropical forest are highly nonlinear across spatial scales. Taxon-specific differences in β-diversity cause under- or overestimation of overall diversity by up to 50% when using surrogate taxa such as plants. Similar relationships may apply to half of all (sub)tropical forests-including major biodiversity hotspots-where high environmental heterogeneity causes high biodiversity and species turnover. Our study highlights that our general understanding of biodiversity patterns has to be improved-and that much larger areas will be required than in better-studied lowland forests-to reliably estimate biodiversity distributions and devise conservation strategies for the world's biodiverse regions.

Text analysis tools for identification of emerging topics and research gaps in conservation science

Keeping track of conceptual and methodological developments is a critical skill for research scientists, but this task is increasingly difficult due to the high rate of academic publication. As a crisis discipline, conservation science is particularly in need of tools that facilitate rapid yet insightful synthesis. We show how a common text-mining method (latent Dirichlet allocation, or topic modeling) and statistical tests familiar to ecologists (cluster analysis, regression, and network analysis) can be used to investigate trends and identify potential research gaps in the scientific literature. We tested these methods on the literature on ecological surrogates and indicators. Analysis of topic popularity within this corpus showed a strong emphasis on monitoring and management of fragmented ecosystems, while analysis of research gaps suggested a greater role for genetic surrogates and indicators. Our results show that automated text analysis methods need to be used with care, but can provide information that is complementary to that given by systematic reviews and meta-analyses, increasing scientists' capacity for research synthesis.

Emerging spatial patterns in Antarctic prokaryotes

Recent advances in knowledge of patterns of biogeography in terrestrial eukaryotic organisms have led to a fundamental paradigm shift in understanding of the controls and history of life on land in Antarctica, and its interactions over the long term with the glaciological and geological processes that have shaped the continent. However, while it has long been recognized that the terrestrial ecosystems of Antarctica are dominated by microbes and their processes, knowledge of microbial diversity and distributions has lagged far behind that of the macroscopic eukaryote organisms. Increasing human contact with and activity in the continent is leading to risks of biological contamination and change in a region whose isolation has protected it for millions of years at least; these risks may be particularly acute for microbial communities which have, as yet, received scant recognition and attention. Even a matter apparently as straightforward as Protected Area designation in Antarctica requires robust biodiversity data which, in most parts of the continent, remain almost completely unavailable. A range of important contributing factors mean that it is now timely to reconsider the state of knowledge of Antarctic terrestrial prokaryotes. Rapid advances in molecular biological approaches are increasingly demonstrating that bacterial diversity in Antarctica may be far greater than previously thought, and that there is overlap in the environmental controls affecting both Antarctic prokaryotic and eukaryotic communities. Bacterial dispersal mechanisms and colonization patterns remain largely unaddressed, although evidence for regional evolutionary differentiation is rapidly accruing and, with this, there is increasing appreciation of patterns in regional bacterial biogeography in this large part of the globe. In this review, we set out to describe the state of knowledge of Antarctic prokaryote diversity patterns, drawing analogy with those of eukaryote groups where appropriate. Based on our synthesis, it is clear that spatial patterns of Antarctic prokaryotes can be unique at local scales, while the limited evidence available to date supports the group exhibiting overall regional biogeographical patterns similar to the eukaryotes. We further consider the applicability of the concept of “functional redundancy” for the Antarctic microbial community and highlight the requirements for proper consideration of their important and distinctive roles in Antarctic terrestrial ecosystems.

Quantifying Land Use Impacts on Biodiversity: Combining Species-Area Models and Vulnerability Indicators

Habitat degradation and subsequent biodiversity damage often take place far from the place of consumption because of globalization and the increasing level of international trade. Informing consumers and policy makers about the biodiversity impacts "hidden" in the life cycle of imported products is an important step toward achieving sustainable consumption patterns. Spatially explicit methods are needed in life cycle assessment to accurately quantify biodiversity impacts of products and processes. We use the Countryside species-area relationship (SAR) to quantify regional species loss due to land occupation and transformation for five taxa and six land use types in 804 terrestrial ecoregions. Further, we calculate vulnerability scores for each ecoregion based on the fraction of each species' geographic range (endemic richness) hosted by the ecoregion and the IUCN assigned threat level of each species. Vulnerability scores are multiplied with SAR-predicted regional species loss to estimate potential global extinctions per unit of land use. As a case study, we assess the land use biodiversity impacts of 1 kg of bioethanol produced using six different feed stocks in different parts of the world. Results show that the regions with highest biodiversity impacts differed markedly when the vulnerability of species was included.