Showing papers in "Diversity and Distributions in 2015"

How global biodiversity hotspots may go unrecognized: Lessons from the North American Coastal Plain

Abstract: Biodiversity hotspots are conservation priorities. We identify the North American Coastal Plain (NACP) as a global hotspot based on the classic definition, a region with > 1500 endemic plant species and > 70% habitat loss. This region has been bypassed in prior designations due to misconceptions and myths about its ecology and history. These fallacies include: (1) young age of the NACP, climatic instability over time and submergence during high sea-level stands; (2) climatic and environmental homogeneity; (3) closed forest as the climax vegetation; and (4) fire regimes that are mostly anthropogenic. We show that the NACP is older and more climatically stable than usually assumed, spatially heterogeneous and extremely rich in species and endemics for its range of latitude, especially within pine savannas and other mostly herbaceous and fire-dependent communities. We suspect systematic biases and misconceptions, in addition to missing information, obscure the existence of similarly biologically significant regions world-wide. Potential solutions to this problem include (1) increased field biological surveys and taxonomic determinations, especially within grassy biomes and regions with low soil fertility, which tend to have much overlooked biodiversity; (2) more research on the climatic refugium role of hotspots, given that regions of high endemism often coincide with regions with low velocity of climate change; (3) in low-lying coastal regions, consideration of the heterogeneity in land area generated by historically fluctuating sea levels, which likely enhanced opportunities for evolution of endemic species; and (4) immediate actions to establish new protected areas and implement science-based management to restore evolutionary environmental conditions in newly recognized hotspots.

Conservation in Brazil needs to include non‐forest ecosystems

Abstract: In the past decades, Brazil made important progress in the conservation of forest ecosystems. Non-forest ecosystems (NFE), in contrast, have been neglected, even though they cover large parts of the country and have biodiversity levels comparable to forests. To avoid losing much of its biodiversity and ecosystem services, conservation and sustainable land use policies in Brazil need to be extended to NFE. A strategy for conservation of Brazil's NFE should encompass the following elements: (1) creation of new large protected areas in NFE; (2) enforcement of legal restrictions of land use; (3) extension of subsidy programs and governance commitments to NFE; (4) improvement of ecosystem management and sustainable use in NFE; and (5) improvement of monitoring of land use change in NFE. If Brazil managed to extend its conservation successes to NFE, it not only would contribute significantly to conservation of its biodiversity, but also could take the lead in conservation of NFE world-wide.

Corridors for aliens but not for natives: effects of marine urban sprawl at a regional scale

Abstract: Aim The global sprawl of marine hard infrastructure (eg breakwaters, sea walls and jetties) can extensively modify coastal seascapes, but the knowledge of such impacts remains limited to local scales We examined the regional-scale effects of marine artificial habitats on the distribution and abundance of assemblages of ascidians, a key group of ecosystem engineer species in benthic fouling systems Location Five hundred kilometers of coastline in the North Adriatic Sea Methods We sampled a variety of natural reefs, marine infrastructures and marinas, and tested hypotheses about the role of habitat type and location in influencing the relative distribution and abundance of both native and nonindigenous species Results Assemblages differed significantly between natural and artificial habitats and among different types of artificial habitats Non-indigenous species were 2–3 times more abundant on infrastructures built along sedimentary coastlines than on natural rocky reefs or infrastructures built close to rocky coastlines Conversely, native species were twice as abundant on natural reefs than on nearby infrastructures and were scarce to virtually absent on infrastructures built along sedimentary coasts The species composition of assemblages in artificial habitats was more similar to that of marinas than of natural reefs, independently of their location Main conclusions Our results show that marine infrastructures along sandy shores disproportionally favour non-indigenous over native hard bottom species, affecting their spread at regional scales This is particularly concerning for coastal areas that have low natural densities of rocky reef habitats We discuss design and management options to improve the quality as habitat of marine infrastructures and to favour their preferential use by native species over nonindigenous ones

Framework and guidelines for implementing the proposed IUCN Environmental Impact Classification for Alien Taxa (EICAT)

Abstract: Recently, Blackburn et al. (2014) developed a simple, objective and transparent method for classifying alien taxa in terms of the magnitude of their detrimental environmental impacts in recipient areas. Here, we present a comprehensive framework and guidelines for implementing this method, which we term the Environmental Impact Classification for Alien Taxa, or EICAT. We detail criteria for applying the EICAT scheme in a consistent and comparable fashion, prescribe the supporting information that should be supplied along with classifications, and describe the process for implementing the method. This comment aims to draw the attention of interested parties to the framework and guidelines, and to present them in their entirety in a location where they are freely accessible to any potential users.

Harnessing the biodiversity value of Central and Eastern European farmland

Abstract: A large proportion of European biodiversity today depends on habitat provided by low-intensity farming practices, yet this resource is declining as European agriculture intensifies. Within the European Union, particularly the central and eastern new member states have retained relatively large areas of species-rich farmland, but despite increased investment in nature conservation here in recent years, farmland biodiversity trends appear to be worsening. Although the high biodiversity value of Central and Eastern European farmland has long been reported, the amount of research in the international literature focused on farmland biodiversity in this region remains comparatively tiny, and measures within the EU Common Agricultural Policy are relatively poorly adapted to support it. In this opinion study, we argue that, 10 years after the accession of the first eastern EU new member states, the continued under-representation of the low-intensity farmland in Central and Eastern Europe in the international literature and EU policy is impeding the development of sound, evidence-based conservation interventions. The biodiversity benefits for Europe of existing low-intensity farmland, particularly in the central and eastern states, should be harnessed before they are lost. Instead of waiting for species-rich farmland to further decline, targeted research and monitoring to create locally appropriate conservation strategies for these habitats is needed now.

Historic and prehistoric human-driven extinctions have reshaped global mammal diversity patterns

Abstract: Aim To assess the extent to which humans have reshaped Earth's biodiversity, by estimating natural ranges of all late Quaternary mammalian species, and to compare diversity patterns based on these with diversity patterns based on current distributions. Location Globally. Methods We estimated species, functional and phylogenetic diversity patterns based on natural ranges of all mammalian species (n = 5747 species) as they could have been today in the complete absence of human influence through time. Following this, we compared macroecological analyses of current and natural diversity patterns to assess whether human-induced range changes bias evolutionary and ecological analyses based on current diversity patterns. Results We find that current diversity patterns have been drastically modified by humans, mostly due to global extinctions and regional to local extirpations. Current and natural diversities exhibit marked deviations virtually everywhere outside sub-Saharan Africa. These differences are strongest for terrestrial megafauna, but also important for all mammals combined. The human-induced changes led to biases in estimates of environmental diversity drivers, especially for terrestrial megafauna, but also for all mammals combined. Main conclusions Our results show that fundamental diversity patterns have been reshaped by human-driven extinctions and extirpations, highlighting humans as a major force in the Earth system. We thereby emphasize that estimating natural distributions and diversities is important to improve our understanding of the evolutionary and ecological drivers of diversity as well as for providing a benchmark for conservation.

Accounting for spatially biased sampling effort in presence‐only species distribution modelling

Abstract: Aim Presence-only datasets represent an important source of information on species' distributions. Collections of presence-only data, however, are often spatially biased, particularly along roads and near urban populations. These biases can lead to inaccurate inferences and predicted distributions. We demonstrate a new approach of accounting for effort bias in presence-only data by explicitly incorporating sample biases in species distribution modelling. Location Alberta, Canada. Methods First, we used logistic regression to model sampling effort of recorded rare vascular plants, bryophytes and butterflies in Alberta. Second, we simulated presence/absence data for nine ‘virtual’ species based on three relative occurrence thresholds – common, rare and very rare – for each taxonomic group. We sampled these virtual species using our bias model to represent typical sampling effort characteristic of presence-only datasets. We then modelled the distributions of these virtual species using logistic regression and attempted to recover their original simulated distributions using a sample weighting term (prior weight) estimated as the inverse of probability of sampling. Bias-adjusted model estimates were compared to those obtained from random samples and biased samples without adjustment. We also compared prior-weight adjustment to bias-file and target-group background approaches in Maxent. Results Sample weighting recovered regression coefficients and mapped predictions estimated from unbiased presence-only data and improved model predictive accuracy as evaluated by regression and correlation coefficients, sensitivity and specificity. Similar model improvements were achieved using the Maxent bias-file method, but results were inconsistent for the target-group background approach. Main conclusions These results suggest that sample weighting can be used to account for spatially biased presence-only datasets in species distribution modelling. The framework presented is potentially widely applicable due to availability of online biodiversity databases and the flexibility of the approach.

Comparing species distribution models constructed with different subsets of environmental predictors

Abstract: Aim To assess the usefulness of combining climate predictors with additional types of environmental predictors in species distribution models for rangerestricted species, using common correlative species distribution modelling approaches. Location Florida, USA Methods We used five different algorithms to create distribution models for 14 vertebrate species, using seven different predictor sets: two with bioclimate predictors only, and five ‘combination’ models using bioclimate predictors plus ‘additional’ predictors from groups representing: human influence, land cover, extreme weather or noise (spatially random data).We use a linear mixed-model approach to analyse the effects of predictor set and algorithm on model accuracy, variable importance scores and spatial predictions. Results Regardless of modelling algorithm, no one predictor set produced significantly more accurate models than all others, though models including human influence predictors were the only ones with significantly higher accuracy than climate-only models. Climate predictors had consistently higher variable importance scores than additional predictors in combination models, though there was variation related to predictor type and algorithm. While spatial predictions varied moderately between predictor sets, discrepancies were significantly greater between modelling algorithms than between predictor sets. Furthermore, there were no differences in the level of agreement between binary ‘presence–absence’ maps and independent species range maps related to the predictor set used. Main conclusions Our results indicate that additional predictors have relatively minor effects on the accuracy of climate-based species distribution models and minor to moderate effects on spatial predictions. We suggest that implementing species distribution models with only climate predictors may provide an effective and efficient approach for initial assessments of environmental suitability.

Effects of human‐modified landscapes on taxonomic, functional and phylogenetic dimensions of bat biodiversity

Abstract: Aim To identify characteristics of a human-modified landscape that promote taxonomic (TD), functional (FD) and phylogenetic (PD) dimensions of bat biodiversity. Location Caribbean lowlands of northeastern Costa Rica. Methods During the dry and wet seasons, we quantified TD (Simpson's diversity), as well as FD and PD (Rao's quadratic entropy) of phyllostomid bat assemblages at 15 sites that represented a forest loss and fragmentation gradient. FD was estimated separately for each of seven functional components that reflect particular niche axes (e.g. diet, foraging strategy) and for all functional components combined (FDall). PD was based on relatedness of species derived from a supertree. We identified the best explanatory landscape characteristics of each dimension using hierarchical partitioning. Results Landscape effects were dimension and season specific. During the dry season, TD and PD increased with increasing proportions of pasture or size of forest patches, whereas FDall decreased with increasing size of forest patches. During the wet season, TD increased with increasing forest patch size, whereas FDall and PD increased with increasing compactness of forest patches and decreasing proximity. Decomposition of FD into separate functional components revealed different landscape effects on ecological aspects of assemblages. Main conclusions One dimension of biodiversity was not a good surrogate for another. Rather, decomposition of biodiversity into different dimensions and functional components facilitated identification of the aspects of assemblages that are most affected by forest conversion and fragmentation. Areas with intermediate amounts of forest and pasture during the dry season harboured highest diversity from taxonomic, functional and phylogenetic perspectives. During the wet season, areas with large, compact forest patches promoted the dimensions of biodiversity. Placement of areas with even amounts of forest and pasture adjacent to large, compact forest patches (e.g. reserves) may maintain high biodiversity of bats and the ecosystem functions that they provide throughout the year.

From regional to global patterns in vertebrate scavenger communities subsidized by big game hunting

Abstract: Aim Anthropogenic food subsidies are increasingly present in ecosystems, but their impacts remain poorly understood. Big game hunting is a growing activity that annually subsidizes ecosystems with tonnes of carrion world-wide. By feeding on carrion, scavengers support key ecosystem functions and services, becoming key vectors to transfer the impacts of human-mediated food subsidies across ecosystems. We characterize and compare the structure of vertebrate communities feeding on these subsidies, namely big game hunting remains, at a global scale. Location Global. Methods We collected data from a countrywide field study in Spain and broadened it up to nine regions in four continents by reviewing scientific literature. We analysed the structure of the scavenger communities considering species composition, richness and scavenging frequency. Results Seventy-nine vertebrate species, 19% globally threatened, scavenged food subsidies from big game hunting world-wide. Scavenger richness (2.0– 11.0% of vertebrates/region) positively correlated with total vertebrate richness. Although scavenger communities at hunting remains varied among regions, we describe a general structural pattern. Birds and mammals dominate consumption, with birds scavenging twice more frequently than mammals – but more mammal species scavenge compared to birds. Generalists dominate scavenging globally, especially where the presence of obligate scavengers (vultures) and apex predators (e.g. wolves, hyenas, eagles) is low. Main conclusions Anthropogenic food from hunting subsidizes many vertebrate species from different trophic levels and conservation status and thus is expected to affect from populations to ecosystems. Obligate scavengers and apex predators seem to play a key role structuring the scavenger community through top-down mechanisms. The general structure of scavenger communities we describe here provides a benchmark for comparisons of subsidized and non-subsidized communities. More data on the spatio-temporal availability of anthropogenic food subsidies and their consumption by scavengers world-wide are needed to efficiently preserve biodiversity, and the associated ecological functions and services, in increasingly subsidized ecosystems.

Habitat availability for amphibians and extinction threat: a global analysis

Abstract: Aim Habitat loss and degradation are the factors threatening the largest number of amphibian species. However, quantitative measures of habitat availability only exist for a small subset of them. We evaluated the relationships between habitat availability, extinction risk and drivers of threat for the world's amphibians. We developed deductive habitat suitability models to estimate the extent of suitable habitat and the proportion of suitable habitat (PSH) inside the geographic range of each species, covering species and areas for which little or no high-resolution distribution data are available. Location Global. Methods We used information on habitat preferences to develop habitat suitability models at 300-m resolution, by integrating range maps with land cover and elevation. Model performance was assessed by comparing model output with point localities where species were recorded. We then used habitat availability as a surrogate of area of occupancy. Using the IUCN criteria, we identified species having narrow area of occupancy, for which extinction risk is likely underestimated. Results We developed models for 5363 amphibians. Validation success of models was high (94%), being better for forest specialists and generalists than for open habitat specialists. Generalists had proportionally more habitat than forest or open habitat specialists. The PSH was lower for species having small geographical ranges, currently listed as threatened, and for which habitat loss is recognized as a threat. Differences in habitat availability among biogeographical realms were strong. We identified 61 forest species for which the extinction risk may be higher that currently assessed in the Red List, due to limited extent of suitable habitat. Main conclusions Habitat models can accurately predict amphibian distribution at fine scale and allow describing biogeographical patterns of habitat availability. The strong relationship between amount of suitable habitat and extinction threat may help the conservation assessment in species for which limited information is currently available.

Historical legacies accumulate to shape future biodiversity in an era of rapid global change

Abstract: Aim Biodiversity responses to changing environmental forcing on species are often characterized by considerable time-lags (= relaxation times). Although changes to the occurrence and abundance of species likely have cascading effects (e.g. on species of other trophic levels, genes, community structure and ecosystem processes), current concepts addressing lagged biodiversity responses are limited to single drivers affecting a few biodiversity components (e.g. extinction debt in terms of species numbers or population size). Little attention has been paid to the interacting and cumulative nature of time-lag phenomena. Here, we synthesize current knowledge, mechanisms and implications of delayed biodiversity responses and propose a ‘cumulative biodiversity lags-framework’ which aims to integrate lagged responses of various components of biological organization. Location Global. Results Effects of change in environmental forcing are transmitted along a series of linked cause–effect relationships which act on different biodiversity components (e.g. individuals, populations, species, communities). We show that lagged responses to environmental forcing are caused by different mechanisms (e.g. metapopulation dynamics, dispersal limitation, successional dynamics), which operate sequentially on these intermediary links. Lags manifest themselves on the respective biodiversity component which changes over time; the full relaxation time of a focal system will therefore depend on the aggregate length of different lags. We elucidate key mechanisms and circumstances which are likely to cause cumulative lagged responses, and propose research avenues to improve understanding of cumulative biodiversity lags. Main conclusions The failure to give adequate consideration to widespread cumulative time-lags often masks the full extent of biodiversity changes that have already been triggered. Effects that are particularly relevant for human livelihoods (e.g. changes in the provision of ecosystem services) may emerge with the most pronounced delay. Accordingly, the consideration of appropriate temporal scales should become a key topic in future work at the science–policy interface.

Ecological specialization matters: long‐term trends in butterfly species richness and assemblage composition depend on multiple functional traits

Abstract: Aim To quantify spatio-temporal changes in species richness and assemblage composition of Danish butterflies over more than 100 years and to assess whether different functional groups of butterflies show different temporal trajectories. Location Denmark, Europe. Methods We applied species accumulation curves to estimate relative species richness changes from unequally sampled occurrence records, collected over more than a century (1900-2012), at local (i.e. 10 km× 10 km) and regional (country-wide) spatial scales. Furthermore, we calculated similarity in species composition between 10 km× 10 km grid cells to evaluate changes in assemblage composition (i.e. biotic homogenization) of butterflies through space and time. Trends were evaluated for all butterflies as well as for three functional groups, using hierarchical clustering and species-specific values of eight ecological traits. Results We document severe declines in butterfly diversity over the last century, with substantial regional-scale extinctions leading to a net loss of 10% of all Danish butterfly species. Segregating species into functional groups showed that the highest rate of regional extinction occurred among sedentary habitat specialists overwintering in the egg stage, while the most severe local-scale declines occurred among sedentary host plant specialists overwintering in the larval stage. In contrast, mobile generalist species with mature overwintering stages showed stable richness trends throughout the century. However, a pervasive spatio-temporal biotic homogenization of butterfly assemblages was revealed for all functional groups. Main conclusions Our results suggest that observed changes in species richness were driven by a gradual replacement of ecological specialists by broadly adapted ecological generalists. In addition to drawing attention to a severe long-term impoverishment of the Danish butterfly fauna, our results suggest that trajectories of butterfly species richness and assemblage composition over the last century are related to multiple functional traits, highlighting the need to consider different aspects of ecological specialization when assessing extinction risk.

Similar but not equivalent: ecological niche comparison across closely–related Mexican white pines

Abstract: Aim In the face of global environmental change, identifying the factors that shape the ecological niches of species and understanding the mechanisms behind them can help to draft effective conservation plans. The differences in the ecological factors that shape species distributions may then help to highlight differences between closely related taxa. We investigate the applicability of ecological niche modelling and the comparison of species distributions in ecological niche space to detect areas with priority for biodiversity conservation and to analyse differences in the ecological niche spaces used by closely related taxa. Location United States of America, Mexico and Central America. Methods We apply ordination and ecological niche modelling techniques to assess the main environmental drivers of the distribution of Mexican white pines (Pinus: Pinaceae). Furthermore, we assess the similarities and differences of the ecological niches occupied by closely related taxa. We analyse whether Mexican white pines occupy similar or equivalent ecological niches. Results All the studied taxa presented different responses to the environmental factors, resulting in a unique combination of niche conditions. Our stacked habitat suitability maps highlighted regions in southern Mexico and northern Central America as highly suitable for most species and thus with high conservation value. By quantitatively assessing the niche overlap, similarity and equivalency of Mexican white pines, our results prove that the distribution of one species cannot be implied by the distribution of another, even if these taxa are considered closely related. Main conclusions The fact that each Mexican white pine is constrained by a unique set of environmental conditions, and thus, their non-equivalence of ecological niches has direct implications for conservation as this highlights the inadequacy of one-fits all type of conservation measure.

Local and landscape management drive trait-mediated biodiversity of nine taxa on small grassland fragments

Abstract: AimBiodiversity across the globe is heavily eroded by intensified management at local and landscape scales. Species communities of calcareous grasslands, which are among Europe's most diverse habitats, are severely threatened by the cessation of appropriate traditional management, loss of habitat connectivity and simplification of the surrounding landscape. However, our understanding of these often interrelated factors remains limited, in particular for trait-mediated responses across taxa. Here, we test the independent effects of local management (grazing, mowing and abandonment), habitat connectivity (measured by a connectivity index) and landscape complexity (indicated by the percentage of arable land) on nine taxa: plants, butterflies, bees, grasshoppers, hoverflies, spiders, true bugs, rove beetles and leafhoppers on small semi-natural calcareous grassland remnants (<1ha). LocationCentral Germany. MethodsWe use a joint analysis across taxa to identify general and trait-mediated responses (body size and Red List status) in species richness, abundance and community composition. ResultsWe identified three key drivers of local diversity patterns: First, an increasing proportion of arable land from 10% to 80% led to a 29% loss of overall species richness. Second, despite differences between taxa, increasing habitat connectivity generally enhanced species richness. Connectivity effects were more accentuated in the large species per taxon, which can be expected to be good dispersers. Finally, grazing reduced species richness and abundance much more than annual mowing or short-term abandonment (5-15years), in particular for red-listed species. We attribute this to plant resource removal through overgrazing and trampling. Main conclusionsFor the conservation management of small calcareous grasslands, we advocate an alternating strategy of mowing or lenient grazing and short-term abandonment, prioritizing connected fragments surrounded by diverse landscapes. Despite taxon-specific responses, our study across nine taxa demonstrates universal, trait-mediated effects of management, landscape complexity and connectivity on local biodiversity in fragmented communities.

The role of waterbirds in the dispersal of aquatic alien and invasive species

Abstract: Aim: To review existing literature on the ability of waterbirds to spread aquatic alien and invasive species, and to assess the relevance of bird-mediated dispersal for the conservation of freshwater ecosystems. Location: Global. Methods: Literature Review. Results: A systematic review of the literature revealed that quantitative studies investigating dispersal of alien organisms by waterbirds are rare (n = 14). Most studies citing waterbird dispersal rely on anecdotes or inferences from morphological dispersal syndromes. However, evidence from each stage of dispersal (i.e. emigration, transport and immigration) shows that waterbirds can carry alien plants and invertebrates internally and externally; transport them between water bodies at a variety of spatial scales; and deposit viable propagules in sites suited to aquatic invasive species. Main conclusions: Our review suggests that waterbirds can and do act as important dispersal vectors for freshwater invasive species. Further experimental and field based research on the numbers and viability of moved alien propagules, and the roles of different species in the bird community, is needed. Furthermore, consideration of the spatially explicit manner in which birds move is imperative to understanding invasive spread. Populations of alien aquatic species in seemingly isolated wetlands can no longer be considered contained if they are able to be spread through waterbird-mediated dispersal, and containment measures must recognize such opportunities for further spread. Changing waterbird movement patterns, driven by climate and land use change, further add to the challenge of managing invasive species and offers an interesting opportunity for future research. The study of waterbird-mediated dispersal of aquatic alien invasive species provides insights not only into species invasions, but more generally into movement ecology, population ecology and biogeography.

Climate-driven changes in winter abundance of a migratory waterbird in relation to EU protected areas

Abstract: AimSpecies are responding to climate change by changing their distributions, creating debate about the effectiveness of existing networks of protected areas. As a contribution to this debate, we assess whether regional winter abundances and distribution of the Smew Mergellus albellus, a migratory waterbird species listed on Annex I (EU Birds Directive) that overwinters exclusively in European wetlands, changed during 1990-2011, the role of global warming in driving distributional changes and the effectiveness of the network of Special Protection Areas (SPAs, EU Birds Directive) in the context of climate change. LocationEurope. MethodsWe used site-specific counts (6,883 sites) from 16 countries covering the entire flyway to estimate annual abundance indices and trends at country, region (north-eastern, central and south-western) and flyway scales, inside and outside SPAs. We fitted autoregressive models to assess the effect of winter temperature on the annual abundance indices whilst accounting for autocorrelation. ResultsThe Smew wintering distribution shifted north-eastwards in Europe in accordance with the predictions of global warming, with increasing numbers in the north-eastern region and declines in the central region. Trends in wintering numbers were more positive in SPAs on the north-eastern and south-western part of the flyway. However, a large proportion of the wintering population remains unprotected in north-eastern areas outside of the existing SPA network. Main conclusionsSPAs accommodated climate-driven abundance changes in the north-eastern region of the wintering distribution by supporting increasing numbers of Smew in traditional and newly colonized areas. However, we highlight gaps in the current network, suggesting that urgent policy responses are needed. Given rapid changes in species distributions, we urge regular national and international assessments of the adequacy of the EU Natura 2000 network to ensure coherence in site-safeguard networks for this and other species. (Less)

Ecological impacts of invading seaweeds: a meta-analysis of their effects at different trophic levels

Abstract: Aim Biological invasions are among the main threats to biodiversity. To promote a mechanistic understanding of the ecological impacts of non-native seaweeds, we assessed how effects on resident organisms vary according to their trophic level. Location Global. Methods We performed meta-analytical comparisons of the effects of non-native seaweeds on both individual species and communities. We compared the results of analyses performed on the whole dataset with those obtained from experimental data only and, when possible, between rocky and soft bottoms. Results Meta-analyses of data from 100 papers revealed consistent negative effects of non-native seaweeds across variables describing resident primary producer communities. In contrast, negative effects of seaweeds on consumers emerged only on their biomass and, limited to rocky bottoms, diversity. At the species level, negative effects were consistent across primary producers' response variables, while only the survival of consumers other than herbivores or predators (e.g. deposit/suspension feeders or detritivores) decreased due to invasion. Excluding mensurative data, negative effects of seaweeds persisted only on resident macroalgal communities and consumer species survival, while switched to positive on the diversity of rocky-bottom consumers. However, negative effects emerged for biomass and, in rocky habitats, density of consumers other than herbivores or predators. Main conclusions Our results support the hypothesis that seaweeds' effects on resident biodiversity are generally more negative within the same trophic level than on higher trophic guilds. Finer trophic grouping of resident organisms revealed more complex impacts than previously detected. High heterogeneity in the responses of some consumer guilds suggests that impacts of non-native seaweeds at higher trophic levels may be more invader- and species-specific than competitive effects at the same trophic level. Features of invaded habitats may further increase variability in seaweeds' impacts. More experimental data on consumers' response to invasion are needed to disentangle the effects of non-native seaweeds from those of other environmental stressors.

Climate change‐induced decline in bamboo habitats and species diversity: implications for giant panda conservation

Abstract: AimConservation strategies must anticipate how climate change may alter the geographic distributions of limited food resources for highly specialized species. Here, we use bamboo as a case study to investigate climate change-induced changes in species diversity and discuss how to protect the critical food species for giant pandas. LocationGiant panda habitats. MethodsUsing a niche-based model and the most updated climate projections, we projected the current and future distribution of 16 bamboo species under no and universal dispersal assumptions. We then assessed the impact of climate change on bamboo forests and their alpha and beta diversities in the giant panda habitats and reserves. ResultsUnder both dispersal assumptions and three RCPs, six bamboo species are projected to vanish from panda habitats as climate change progresses, resulting in a great loss of the current bamboo forests. Although about half of the bamboo species may potentially colonize new climatically suitable areas under universal dispersal, the other species would experience significant habitat loss. Consequently, climate change would reduce both the alpha and beta diversity of bamboo species in panda habitats. Meanwhile, the proportion of single-species bamboo forests would significantly increase. The decline in bamboo forests and diversity would be most drastic in Qinling, Daxiangling and Qionglaishan Mountains, whereas those in the north-west of Minshan Mountains and Liangshan Mountains may increase. Main conclusionsClimate change-induced decline in bamboo habitats and species diversity would pose a severe challenge to the food availability of giant pandas. We posit that human-assisted adaptation and increasing bamboo species diversity are critical to ensuring food security of the giant panda in a changing climate. Our results indicate that conservation planning should not only incorporate species range shifts but also diversity patterns in communities under climate change.

Additive effects of climate change on connectivity between marine protected areas and larval supply to fished areas

Abstract: Aim To study the combined effects of climate change on connectivity between marine protected areas (MPAs) and larval supply to the continental shelf Location The Mediterranean Sea, where sea surface temperatures are expected to strongly increase by the end of the 21st century, represents an archetypal situation with a dense MPA network but resource overexploitation outside Methods Using an individual-based mechanistic model of larval transport, forced with an emission-driven regional climate change scenario for the Mediterranean Sea, we explored the combined effects of changes in hydrodynamics, adult reproductive timing and larval dispersal on the connectivity among MPAs and their ability to seed fished areas with larvae Results We show that, over the period 1970–2099, larval dispersal distances would decrease by 10%, the continental shelf area seeded with larvae would decrease by 3% and the larval retention fraction would increase by 5%, resulting in higher concentration of larvae in smaller areas of the continental shelf However, connectance within the MPA network would increase by 5% as more northern MPAs would become suitable for reproduction with increasing temperatures We also show that the effects of changes in adult reproductive timing and larval dispersal on connectivity patterns are additive Main conclusions Climate change will influence connectivity and the effectiveness of MPA networks, and should receive more attention in future conservation planning and large-scale population dynamics

The potential of symptomless potted plants for carrying invasive soilborne plant pathogens

Abstract: Aim The most common pathway for the movement of plant pests across borders is the horticultural trade in live plants, especially potted ornamentals. Soilborne pathogens, possibly alien and potentially invasive, have a higher possibility of surviving transportation and becoming established at their destination if they are carried in potted plants. The European Union (EU) has an open-door phytosanitary system, under which any plant that is not specifically regulated can be imported. Inspections are focussed on a small number of economically important plant pests and even then limited to visual examinations of the aerial parts of the plant. Inspections fail to detect regulated pests or others internal to the tissues, or in the soil, if plants appear asymptomatic, or if incipient symptoms are limited to the roots. Phytophthora, a soilborne pathogen universally infamous for its ruinous outbreaks, but poorly regulated in Europe, was chosen to illustrate the risk inherent in the nursery pathway. The aim of this study was to demonstrate the level of infestation by Phytophthora in ornamental plants largely traded to, from and within Europe. Location European Union. Methods As Phytophthora species are not easily isolated, a real-time PCR assay was developed, based on a genus-specific TaqMan MGB probe, to detect the pathogens in plant tissues or soil even when present at low concentrations, and before symptoms occurred. Phytophthora species were identified by isolation and sequencing of the ITS (internal transcribed spacer) region. Results Phytophthora was detected by qPCR in 87% of the tested pots and in 70% of the asymptomatic potted plants. Potted plants in soil carried several Phytophthora species without showing any external symptoms. Main conclusions The results of this study strongly support the case for more rigorous European legislation on the trade of live plants in pots. As eradication of soilborne organisms is difficult, if not impossible, an embargo on plant movements into the EU and between member states is the only advisable measure against the spread of these pathogens.

Vegetation resurvey is robust to plot location uncertainty

Abstract: Aim Resurveys of historical vegetation plots are increasingly used for the assessment of decadal changes in plant species diversity and composition. However, historical plots are usually relocated only approximately. This potentially inflates temporal changes and undermines results. Location Temperate deciduous forests in Central Europe. Methods To explore if robust conclusions can be drawn from resurvey studies despite location uncertainty, we compared temporal changes in species richness, frequency, composition and compositional heterogeneity between exactly and approximately relocated plots. We hypothesized that compositional changes should be lower and changes in species richness should be less variable on exactly relocated plots, because pseudo-turnover inflates temporal changes on approximately relocated plots. Results Temporal changes in species richness were not more variable and temporal changes in species composition and compositional heterogeneity were not higher on approximately relocated plots. Moreover, the frequency of individual species changed similarly on both plot types. Main conclusions The resurvey of historical vegetation plots is robust to uncertainty in original plot location and, when done properly, provides reliable evidence of decadal changes in plant communities. This provides important background for other resurvey studies and opens up the possibility for large-scale assessments of plant community change.

Phylogenetic diversity of Amazonian tree communities

Abstract: Aim: To examine variation in the phylogenetic diversity (PD) of tree communities across geographical and environmental gradients in Amazonia. Location: Two hundred and eighty-three c. 1 ha forest inventory plots from across Amazonia. Methods: We evaluated PD as the total phylogenetic branch length across species in each plot (PDss), the mean pairwise phylogenetic distance between species (MPD), the mean nearest taxon distance (MNTD) and their equivalents standardized for species richness (ses.PDss, ses.MPD, ses.MNTD). We compared PD of tree communities growing (1) on substrates of varying geological age; and (2) in environments with varying ecophysiological barriers to growth and survival. Results: PDss is strongly positively correlated with species richness (SR), whereas MNTD has a negative correlation. Communities on geologically young- and intermediate-aged substrates (western and central Amazonia respectively) have the highest SR, and therefore the highest PDss and the lowest MNTD. We find that the youngest and oldest substrates (the latter on the Brazilian and Guiana Shields) have the highest ses.PDss and ses.MNTD. MPD and ses.MPD are strongly correlated with how evenly taxa are distributed among the three principal angiosperm clades and are both highest in western Amazonia. Meanwhile, seasonally dry tropical forest (SDTF) and forests on white sands have low PD, as evaluated by any metric. Main conclusions: High ses.PDss and ses.MNTD reflect greater lineage diversity in communities. We suggest that high ses.PDss and ses.MNTD in western Amazonia results from its favourable, easy-to-colonize environment, whereas high values in the Brazilian and Guianan Shields may be due to accumulation of lineages over a longer period of time. White-sand forests and SDTF are dominated by close relatives from fewer lineages, perhaps reflecting ecophysiological barriers that are difficult to surmount evolutionarily. Because MPD and ses.MPD do not reflect lineage diversity per se, we suggest that PDss, ses.PDss and ses.MNTD may be the most useful diversity metrics for setting large-scale conservation priorities.

The emergent geography of biophysical dispersal barriers across the Indo‐West Pacific

Abstract: AimTo discover and evaluate potential dispersal barriers across the Indo-West Pacific Ocean and to develop spatially explicit hypotheses regarding the location of barriers and their capacity to filter taxa. Additionally, to compare model predictions with previously described barriers and build a more thorough understanding of the region's biogeographic patterns.

Migratory corridors and foraging hotspots: critical habitats identified for Mediterranean green turtles

Abstract: Aim Levels of sea turtle bycatch in the Mediterranean are thought to be unsustainable. We provide a comprehensive overview of adult green turtle (Chelonia mydas) distribution during nesting, migration and foraging phases, highlighting transitory as well as residential areas of high use to facilitate adequate protection for this long‐lived, migratory species. Location Mediterranean Sea. Methods Thirty‐four females were satellite tracked from breeding grounds in the four countries with major nesting (Cyprus, Turkey, Israel and Syria) for a total of 8521 (mean: 251) tracking days in a collaborative effort to summarize the most comprehensive set of distribution data thus far assembled for this species in the Mediterranean. Results Ten foraging grounds are identified, with two major hotspots in Libya accounting for >50% of turtles tracked to conclusive endpoints. The coastlines of Egypt and Libya contain high densities of migrating turtles following the nesting season, particularly July–September, and likely also pre‐nesting (April–June). A high‐use seasonal pelagic corridor running south‐west from Turkey and Cyprus to Egypt is also evident, used by >50% of all tracked turtles. Main conclusions Bycatch levels and mortality rates for the key foraging areas and high‐density seasonal pathways identified here are largely unknown and should be investigated as a priority. We recommend that the Gulf of Sirte in Libya be explored as a potential biodiversity hotspot and considered for proposal as a marine protected area (MPA). Green turtle fidelity to nesting beaches, foraging areas and migratory pathways renders them vulnerable to localized threats but enables targeted mitigation measures and protection.

Global patterns of agricultural land-use intensity and vertebrate diversity

Abstract: Aim Land-use change is the single biggest cause of biodiversity loss. With a rising demand for resources, understanding how and where agriculture threatens biodiversity is of increasing importance. Agricultural expansion has received much attention, but where high agricultural land-use intensity (LUI) threatens biodiversity remains unclear. We address this knowledge gap with two main research questions: (1) Where do global patterns of LUI coincide with the spatial distribution of biodiversity? (2) Where are regions of potential conflict between different aspects of high LUI and high biodiversity? Location Global. Methods We overlaid thirteen LUI metrics with endemism richness, a range size-weighted species richness indicator, for mammals, birds and amphibians. We then used local indicators of spatial association to delineate statistically significant (P < 0.05) areas of high and low LUI associated with biodiversity. Results Patterns of LUI are heterogeneously distributed in areas of high endemism richness, thus discouraging the use of a single metric to represent LUI. Many regions where high LUI and high endemism richness coincide, for example in South America, China and Eastern Africa, are not within currently recognized biodiversity hotspots. Regions of currently low LUI and high endemism richness, found in many parts of Mesoamerica, Eastern Africa and Southeast Asia, may be at risk as intensification accelerates. Main conclusions We provide a global view of the geographic patterns of LUI and its concordance with endemism richness, shedding light on regions where highly intensive agriculture and unique biodiversity coincide. Past assessments of land-use impacts on biodiversity have either disregarded LUI or included a single metric to measure it. This study demonstrates that such omission can substantially underestimate biodiversity threat. A wider spectrum of relevant LUI metrics needs to be considered when balancing agricultural production and biodiversity.

Conservation planning in agricultural landscapes: hotspots of conflict between agriculture and nature

Abstract: Aim Conservation conflict takes place where food production imposes a cost on wildlife conservation and vice versa. Where does conservation impose the maximum cost on production, by opposing the intensification and expansion of farmland? Where does conservation confer the maximum benefit on wildlife, by buffering and connecting protected areas with a habitable and permeable matrix of crop and non-crop habitat? Our aim was to map the costs and benefits of conservation versus production and thus to propose a conceptual framework for systematic conservation planning in agricultural landscapes. Location World-wide. Methods To quantify these costs and benefits, we used a geographic information system to sample the cropland of the world and map the proportion of non-crop habitat surrounding the cropland, the number of threatened vertebrates with potential to live in or move through the matrix and the yield gap of the cropland. We defined the potential for different types of conservation conflict in terms of interactions between habitat and yield (potential for expansion, intensification, both or neither). We used spatial scan statistics to find ‘hotspots’ of conservation conflict. Results All of the ‘hottest’ hotspots of conservation conflict were in sub-Saharan Africa, which could have impacts on sustainable intensification in this region. Main conclusions Systematic conservation planning could and should be used to identify hotspots of conservation conflict in agricultural landscapes, at multiple scales. The debate between ‘land sharing’ (extensive agriculture that is wildlife friendly) and ‘land sparing’ (intensive agriculture that is less wildlife friendly but also less extensive) could be resolved if sharing and sparing were used as different types of tool for resolving different types of conservation conflict (buffering and connecting protected areas by maintaining matrix quality, in different types of matrix). Therefore, both sharing and sparing should be prioritized in hotspots of conflict, in the context of countryside biogeography.

Climate‐induced resource bottlenecks exacerbate species vulnerability: a review

Abstract: Aim Resource bottlenecks - periods of severe restriction in resource availability - triggered by increased climate variability represent important and little-understood mechanisms through which climate change will affect biodiversity. In this review, we aim to synthesize the key global change processes that exacerbate the severity of bottlenecks in resource availability on animal populations, and outline how adaptation responses can help buffer the impacts.

A pan-European, multipopulation assessment of migratory connectivity in a near-threatened migrant bird

Abstract: Aim The extent to which individuals from different breeding populations mix throughout the non-breeding season (i.e. ‘migratory connectivity’) has important consequences for population dynamics and conservation. Given recent declines of long-distance migrant birds, multipopulation tracking studies are crucial in order to assess the strength of migratory connectivity and to identify key sites en route. Here, we present the first large-scale analysis of migration patterns and migratory connectivity in the globally near-threatened European roller Coracias garrulus. Location Breeding area: Europe; passage area: Mediterranean, sub-Saharan Africa, Arabian Peninsula; wintering area: southern Africa. Methods We synthesize new geolocator data with existing geolocator, satellite tag and ring recovery data from eight countries across Europe. We describe routes and stopover sites, analyse the spatial pattern of winter sites with respect to breeding origin and quantify the strength of connectivity between breeding and winter sites. Results We demonstrate the importance of the northern savanna zone as a stopover region and reveal the easterly spring loop (via Arabia) and leapfrog migration of rollers from eastern populations. Whilst there was some overlap between individuals from different populations over winter, their distribution was non-random, with positive correlations between breeding and autumn/winter longitude as well as between pairwise distance matrices of breeding and winter sites. Connectivity was stronger for eastern populations than western ones. Main conclusions The moderate levels of connectivity detected here may increase the resilience of breeding populations to localized habitat loss on the winter quarters. We also highlight the passage regions crucial for the successful conservation of roller populations, including the Sahel/Sudan savanna for all populations, and the Horn of Africa/Arabian Peninsula for north-eastern rollers.