Showing papers on "Biodiversity published in 2019"
TL;DR: In this paper, a comprehensive review of 73 historical reports of insect declines from across the globe, and systematically assess the underlying drivers of insect extinction, reveals dramatic rates of decline that may lead to the extinction of 40% of the world's insect species over the next few decades.
1,754 citations
Carleton University1, Michigan State University2, University of Saskatchewan3, University of California, Santa Barbara4, Federation University Australia5, University of Colorado Boulder6, McMaster University7, Mount Allison University8, University of Washington9, Cardiff University10, Queen's University11, Leibniz Association12, University of Hong Kong13
TL;DR: Efforts to reverse global trends in freshwater degradation now depend on bridging an immense gap between the aspirations of conservation biologists and the accelerating rate of species endangerment.
Abstract: In the 12 years since Dudgeon et al. (2006) reviewed major pressures on freshwater ecosystems, the biodiversity crisis in
the world’s lakes, reservoirs, rivers, streams and wetlands has deepened. While lakes, reservoirs and rivers cover only
2.3% of the Earth’s surface, these ecosystems host at least 9.5% of the Earth’s described animal species. Furthermore,
using the World Wide Fund for Nature’s Living Planet Index, freshwater population declines (83% between 1970 and
2014) continue to outpace contemporaneous declines in marine or terrestrial systems. The Anthropocene has brought
multiple new and varied threats that disproportionately impact freshwater systems. We document 12 emerging threats
to freshwater biodiversity that are either entirely new since 2006 or have since intensified: (i) changing climates; (ii)
e-commerce and invasions; (iii) infectious diseases; (iv) harmful algal blooms; (v) expanding hydropower; (vi) emerging
contaminants; (vii) engineered nanomaterials; (viii) microplastic pollution; (ix) light and noise; (x) freshwater salinisation;
(xi) declining calcium; and (xii) cumulative stressors. Effects are evidenced for amphibians, fishes, invertebrates, microbes,
plants, turtles and waterbirds, with potential for ecosystem-level changes through bottom-up and top-down processes.
In our highly uncertain future, the net effects of these threats raise serious concerns for freshwater ecosystems. However,
we also highlight opportunities for conservation gains as a result of novel management tools (e.g. environmental flows,
environmental DNA) and specific conservation-oriented actions (e.g. dam removal, habitat protection policies,managed
relocation of species) that have been met with varying levels of success.Moving forward, we advocate hybrid approaches
that manage fresh waters as crucial ecosystems for human life support as well as essential hotspots of biodiversity and
ecological function. Efforts to reverse global trends in freshwater degradation now depend on bridging an immense gap
between the aspirations of conservation biologists and the accelerating rate of species endangerment.
1,230 citations
Marine Biological Association of the United Kingdom1, University of Western Australia2, Australian Research Council3, Dalhousie University4, University of Tasmania5, University of Canterbury6, University of Tsukuba7, Aberystwyth University8, Scottish Association for Marine Science9, University of New South Wales10, Australian Institute of Marine Science11, Barcelona Supercomputing Center12, Commonwealth Scientific and Industrial Research Organisation13, Hobart Corporation14, University of Washington15, Edith Cowan University16
TL;DR: In this article, the authors quantify trends and attributes of extreme regional ocean warming (marine heatwaves, MHWs) across all ocean basins and examine their biological impacts from species to ecosystems.
Abstract: The global ocean has warmed substantially over the past century, with far-reaching implications for marine ecosystems. Concurrent with long-term persistent warming, discrete periods of extreme regional ocean warming (marine heatwaves, MHWs) have increased in frequency. Here we quantify trends and attributes of MHWs across all ocean basins and examine their biological impacts from species to ecosystems. Multiple regions in the Pacific, Atlantic and Indian Oceans are particularly vulnerable to MHW intensification, due to the co-existence of high levels of biodiversity, a prevalence of species found at their warm range edges or concurrent non-climatic human impacts. The physical attributes of prominent MHWs varied considerably, but all had deleterious impacts across a range of biological processes and taxa, including critical foundation species (corals, seagrasses and kelps). MHWs, which will probably intensify with anthropogenic climate change, are rapidly emerging as forceful agents of disturbance with the capacity to restructure entire ecosystems and disrupt the provision of ecological goods and services in coming decades.
731 citations
TL;DR: The results suggest that major drivers of arthropod decline act at larger spatial scales, and are associated with agriculture at the landscape level, which implies that policies need to address the landscape scale to mitigate the negative effects of land-use practices.
Abstract: Recent reports of local extinctions of arthropod species1, and of massive declines in arthropod biomass2, point to land-use intensification as a major driver of decreasing biodiversity. However, to our knowledge, there are no multisite time series of arthropod occurrences across gradients of land-use intensity with which to confirm causal relationships. Moreover, it remains unclear which land-use types and arthropod groups are affected, and whether the observed declines in biomass and diversity are linked to one another. Here we analyse data from more than 1 million individual arthropods (about 2,700 species), from standardized inventories taken between 2008 and 2017 at 150 grassland and 140 forest sites in 3 regions of Germany. Overall gamma diversity in grasslands and forests decreased over time, indicating loss of species across sites and regions. In annually sampled grasslands, biomass, abundance and number of species declined by 67%, 78% and 34%, respectively. The decline was consistent across trophic levels and mainly affected rare species; its magnitude was independent of local land-use intensity. However, sites embedded in landscapes with a higher cover of agricultural land showed a stronger temporal decline. In 30 forest sites with annual inventories, biomass and species number—but not abundance—decreased by 41% and 36%, respectively. This was supported by analyses of all forest sites sampled in three-year intervals. The decline affected rare and abundant species, and trends differed across trophic levels. Our results show that there are widespread declines in arthropod biomass, abundance and the number of species across trophic levels. Arthropod declines in forests demonstrate that loss is not restricted to open habitats. Our results suggest that major drivers of arthropod decline act at larger spatial scales, and are (at least for grasslands) associated with agriculture at the landscape level. This implies that policies need to address the landscape scale to mitigate the negative effects of land-use practices. Analyses of a dataset of arthropod biomass, abundance and diversity in grassland and forest habitats in Germany for the period 2008–2017 reveal that drivers of arthropod declines act at the landscape level.
625 citations
539 citations
University of Würzburg1, National University of Comahue2, Spanish National Research Council3, Swedish University of Agricultural Sciences4, University of Lisbon5, Universidade Federal de Goiás6, Stanford University7, Commonwealth Scientific and Industrial Research Organisation8, National University of Río Negro9, ETH Zurich10, Cornell University11, University of California, Davis12, The Nature Conservancy13, Wageningen University and Research Centre14, University of British Columbia15, Great Lakes Bioenergy Research Center16, University of California, Santa Cruz17, University of Padua18, University of New England (Australia)19, Lund University20, University of Göttingen21, University of La Rochelle22, Institut national de la recherche agronomique23, Federal University of Ceará24, University of Freiburg25, Concordia University Wisconsin26, University of Belgrade27, National University of Tucumán28, Michigan State University29, University of Brasília30, University of Greenwich31, University of Reading32, University of Wisconsin-Madison33, National Institute of Amazonian Research34, Boise State University35, University of Texas at Austin36, University of Haifa37, Kansas State University38, University of Hamburg39, Bioversity International40, University of California, Santa Barbara41, Seattle University42, University of Vienna43, University of Florida44, Centro Agronómico Tropical de Investigación y Enseñanza45, National Audubon Society46, University of Buenos Aires47, Virginia Tech48, University of Bordeaux49, University of Auckland50, University of California, Berkeley51, University College Dublin52, Trinity College, Dublin53, University of Tokyo54, Federal University of Bahia55, Lincoln University (New Zealand)56, National Institute for Environmental Studies57, International Food Policy Research Institute58, Xi'an Jiaotong-Liverpool University59
TL;DR: Using a global database from 89 studies (with 1475 locations), the relative importance of species richness, abundance, and dominance for pollination; biological pest control; and final yields in the context of ongoing land-use change is partitioned.
Abstract: Human land use threatens global biodiversity and compromises multiple ecosystem functions critical to food production. Whether crop yield-related ecosystem services can be maintained by a few dominant species or rely on high richness remains unclear. Using a global database from 89 studies (with 1475 locations), we partition the relative importance of species richness, abundance, and dominance for pollination; biological pest control; and final yields in the context of ongoing land-use change. Pollinator and enemy richness directly supported ecosystem services in addition to and independent of abundance and dominance. Up to 50% of the negative effects of landscape simplification on ecosystem services was due to richness losses of service-providing organisms, with negative consequences for crop yields. Maintaining the biodiversity of ecosystem service providers is therefore vital to sustain the flow of key agroecosystem benefits to society.
434 citations
TL;DR: The role of mountains as refugia for biodiversity may well come under threat, with ongoing global changes in climate and land use, likely playing a key role in generating and maintaining diversity.
Abstract: Mountains contribute disproportionately to the terrestrial biodiversity of Earth, especially in the tropics, where they host hotspots of extraordinary and puzzling richness. With about 25% of all land area, mountain regions are home to more than 85% of the world’s species of amphibians, birds, and mammals, many entirely restricted to mountains. Biodiversity varies markedly among these regions. Together with the extreme species richness of some tropical mountains, this variation has proven challenging to explain under traditional climatic hypotheses. However, the complex climatic characteristics of rugged mountain regions differ fundamentally from those of lowland regions, likely playing a key role in generating and maintaining diversity. With ongoing global changes in climate and land use, the role of mountains as refugia for biodiversity may well come under threat.
394 citations
TL;DR: Powney et al. as discussed by the authors used occupancy models to estimate the degree of loss in wild bee and hoverfly species across Great Britain, and report a 55% decline in upland species and a 12% increase in dominant crop pollinators.
Abstract: Pollination is a critical ecosystem service underpinning the productivity of agricultural systems across the world. Wild insect populations provide a substantial contribution to the productivity of many crops and seed set of wild flowers. However, large-scale evidence on species-specific trends among wild pollinators are lacking. Here we show substantial inter-specific variation in pollinator trends, based on occupancy models for 353 wild bee and hoverfly species in Great Britain between 1980 and 2013. Furthermore, we estimate a net loss of over 2.7 million occupied 1 km2 grid cells across all species. Declines in pollinator evenness suggest that losses were concentrated in rare species. In addition, losses linked to specific habitats were identified, with a 55% decline among species associated with uplands. This contrasts with dominant crop pollinators, which increased by 12%, potentially in response agri-environment measures. The general declines highlight a fundamental deterioration in both wider biodiversity and non-crop pollination services. Pollinator loss is a concern but data on their status is lacking. Here Powney et al. use occupancy modelling to estimate the degree of loss in wild bee and hoverfly species across Great Britain, and report a 55% decline in upland species and a 12% increase in dominant crop pollinators.
388 citations
University of Würzburg1, Lund University2, Swedish University of Agricultural Sciences3, Commonwealth Scientific and Industrial Research Organisation4, University of Reading5, Wageningen University and Research Centre6, University of Padua7, University of Rennes8, University of Salamanca9, Agrocampus Ouest10, Sant'Anna School of Advanced Studies11, Spanish National Research Council12, Aix-Marseille University13, University of Kiel14, University of Freiburg15, University of Jyväskylä16, University of Koblenz and Landau17, University of Marburg18, Technische Universität München19, University of Natural Resources and Life Sciences, Vienna20, National University of Río Negro21, Instituto Nacional de Biodiversidad22, University of Giessen23, University of Belgrade24, Institut national de la recherche agronomique25, University of Extremadura26, University of Bordeaux27, University of Bern28, CABI29, University of Göttingen30, Pir Mehr Ali Shah Arid Agriculture University31
TL;DR: In landscapes with high edge density, 70% of pollinator and 44% of natural enemy species reached highest abundances and pollination and pest control improved 1.7- and 1.4-fold respectively, suggesting that enhancing edge density in European agroecosystems can promote functional biodiversity and yield-enhancing ecosystem services.
Abstract: Managing agricultural landscapes to support biodiversity and ecosystem services is a key aim of a sustainable agriculture. However, how the spatial arrangement of crop fields and other habitats in landscapes impacts arthropods and their functions is poorly known. Synthesising data from 49 studies (1515 landscapes) across Europe, we examined effects of landscape composition (% habitats) and configuration (edge density) on arthropods in fields and their margins, pest control, pollination and yields. Configuration effects interacted with the proportions of crop and non-crop habitats, and species’ dietary, dispersal and overwintering traits led to contrasting responses to landscape variables. Overall, however, in landscapes with high edge density, 70% of pollinator and 44% of natural enemy species reached highest abundances and pollination and pest control improved 1.7- and 1.4-fold respectively. Arable-dominated landscapes with high edge densities achieved high yields. This suggests that enhancing edge density in European agroecosystems can promote functional biodiversity and yield-enhancing ecosystem services.
321 citations
Martin Luther University of Halle-Wittenberg1, Denison University2, University of Helsinki3, University of Aveiro4, University of St Andrews5, Memorial University of Newfoundland6, University of Maine7, University of Edinburgh8, University of Massachusetts Boston9, McGill University10, Leipzig University11, University of Minnesota12, Northern Illinois University13, University of British Columbia14, Université de Sherbrooke15, National Oceanography Centre16
TL;DR: Examining spatial variation in species richness and composition change using more than 50,000 biodiversity time series from 239 studies found clear geographic variation in biodiversity change, suggesting that biodiversity change may be spatially structured.
Abstract: Human activities are fundamentally altering biodiversity. Projections of declines at the global scale are contrasted by highly variable trends at local scales, suggesting that biodiversity change may be spatially structured. Here, we examined spatial variation in species richness and composition change using more than 50,000 biodiversity time series from 239 studies and found clear geographic variation in biodiversity change. Rapid compositional change is prevalent, with marine biomes exceeding and terrestrial biomes trailing the overall trend. Assemblage richness is not changing on average, although locations exhibiting increasing and decreasing trends of up to about 20% per year were found in some marine studies. At local scales, widespread compositional reorganization is most often decoupled from richness change, and biodiversity change is strongest and most variable in the oceans.
TL;DR: The high biodiversity of certain mountains reflects the interplay of multiple evolutionary mechanisms: enhanced speciation rates with distinct opportunities for coexistence and persistence of lineages, shaped by long-term climatic changes interacting with topographically dynamic landscapes.
Abstract: Mountain regions are unusually biodiverse, with rich aggregations of small-ranged species that form centers of endemism. Mountains play an array of roles for Earth’s biodiversity and affect neighboring lowlands through biotic interchange, changes in regional climate, and nutrient runoff. The high biodiversity of certain mountains reflects the interplay of multiple evolutionary mechanisms: enhanced speciation rates with distinct opportunities for coexistence and persistence of lineages, shaped by long-term climatic changes interacting with topographically dynamic landscapes. High diversity in most tropical mountains is tightly linked to bedrock geology—notably, areas comprising mafic and ultramafic lithologies, rock types rich in magnesium and poor in phosphate that present special requirements for plant physiology. Mountain biodiversity bears the signature of deep-time evolutionary and ecological processes, a history well worth preserving.
TL;DR: In this article, the authors used global decadal land-use projections to year 2070 for a range of shared socioeconomic pathways, which are linked to particular representative concentration pathways, to evaluate potential losses in range-wide suitable habitat and extinction risks for approximately 19,400 species of amphibians, birds and mammals.
Abstract: Habitat transformations caused by human land-use change are considered major drivers of ongoing biodiversity loss1–3, and their impact on biodiversity is expected to increase further this century4–6. Here, we used global decadal land-use projections to year 2070 for a range of shared socioeconomic pathways, which are linked to particular representative concentration pathways, to evaluate potential losses in range-wide suitable habitat and extinction risks for approximately 19,400 species of amphibians, birds and mammals. Substantial declines in suitable habitat are identified for species worldwide, with approximately 1,700 species expected to become imperilled due to land-use change alone. National stewardship for species highlights certain South American, Southeast Asian and African countries that are in particular need of proactive conservation planning. These geographically explicit projections and model workflows embedded in the Map of Life infrastructure are provided to facilitate the scrutiny, improvements and future updates needed for an ongoing and readily updated assessment of changing biodiversity. These forward-looking assessments and informatics tools are intended to support national conservation action and policies for addressing climate change and land-use change impacts on biodiversity. This paper uses a range of shared socioeconomic pathways scenarios to estimate the future terrestrial vertebrate habitat loss and extinction risk that could result from projected global land-use change.
University of Toulouse1, Paul Valéry University, Montpellier III2, King Juan Carlos University3, Research Institute of Organic Agriculture4, University of Göttingen5, Centre national de la recherche scientifique6, Agrocampus Ouest7, Université Paris-Saclay8, Lund University9, Institut national de la recherche agronomique10, University of La Rochelle11, University of Paris12, Carleton University13, University of Montpellier14, University of Rennes15, University of Lleida16, University of Alicante17, University of Murcia18, British Trust for Ornithology19, Spanish National Research Council20
TL;DR: This study provides large-scale, multitrophic, cross-regional evidence that increasing crop heterogeneity can be an effective way to increase biodiversity in agricultural landscapes without taking land out of agricultural production.
Abstract: Agricultural landscape homogenization has detrimental effects on biodiversity and key ecosystem services. Increasing agricultural landscape heterogeneity by increasing seminatural cover can help to mitigate biodiversity loss. However, the amount of seminatural cover is generally low and difficult to increase in many intensively managed agricultural landscapes. We hypothesized that increasing the heterogeneity of the crop mosaic itself (hereafter “crop heterogeneity”) can also have positive effects on biodiversity. In 8 contrasting regions of Europe and North America, we selected 435 landscapes along independent gradients of crop diversity and mean field size. Within each landscape, we selected 3 sampling sites in 1, 2, or 3 crop types. We sampled 7 taxa (plants, bees, butterflies, hoverflies, carabids, spiders, and birds) and calculated a synthetic index of multitrophic diversity at the landscape level. Increasing crop heterogeneity was more beneficial for multitrophic diversity than increasing seminatural cover. For instance, the effect of decreasing mean field size from 5 to 2.8 ha was as strong as the effect of increasing seminatural cover from 0.5 to 11%. Decreasing mean field size benefited multitrophic diversity even in the absence of seminatural vegetation between fields. Increasing the number of crop types sampled had a positive effect on landscape-level multitrophic diversity. However, the effect of increasing crop diversity in the landscape surrounding fields sampled depended on the amount of seminatural cover. Our study provides large-scale, multitrophic, cross-regional evidence that increasing crop heterogeneity can be an effective way to increase biodiversity in agricultural landscapes without taking land out of agricultural production.
University of Würzburg1, University of Bayreuth2, University of Marburg3, University of Göttingen4, University of Ulm5, University of Bern6, University of Copenhagen7, Karlsruhe Institute of Technology8, Tanzania Commission for Science and Technology9, Technische Universität München10, College of African Wildlife Management11, University of Jena12, University of Oldenburg13, University of KwaZulu-Natal14, University of Dar es Salaam15, Tanzania Wildlife Research Institute16, Goethe University Frankfurt17, Kazan Federal University18, Smithsonian Tropical Research Institute19
TL;DR: The study reveals that climate can modulate the effects of land use on biodiversity and ecosystem functioning, and points to a lowered resistance of ecosystems in climatically challenging environments to ongoing land-use changes in tropical mountainous regions.
Abstract: Agriculture and the exploitation of natural resources have transformed tropical mountain ecosystems across the world, and the consequences of these transformations for biodiversity and ecosystem functioning are largely unknown1-3. Conclusions that are derived from studies in non-mountainous areas are not suitable for predicting the effects of land-use changes on tropical mountains because the climatic environment rapidly changes with elevation, which may mitigate or amplify the effects of land use4,5. It is of key importance to understand how the interplay of climate and land use constrains biodiversity and ecosystem functions to determine the consequences of global change for mountain ecosystems. Here we show that the interacting effects of climate and land use reshape elevational trends in biodiversity and ecosystem functions on Africa's largest mountain, Mount Kilimanjaro (Tanzania). We find that increasing land-use intensity causes larger losses of plant and animal species richness in the arid lowlands than in humid submontane and montane zones. Increases in land-use intensity are associated with significant changes in the composition of plant, animal and microorganism communities; stronger modifications of plant and animal communities occur in arid and humid ecosystems, respectively. Temperature, precipitation and land use jointly modulate soil properties, nutrient turnover, greenhouse gas emissions, plant biomass and productivity, as well as animal interactions. Our data suggest that the response of ecosystem functions to land-use intensity depends strongly on climate; more-severe changes in ecosystem functioning occur in the arid lowlands and the cold montane zone. Interactions between climate and land use explained-on average-54% of the variation in species richness, species composition and ecosystem functions, whereas only 30% of variation was related to single drivers. Our study reveals that climate can modulate the effects of land use on biodiversity and ecosystem functioning, and points to a lowered resistance of ecosystems in climatically challenging environments to ongoing land-use changes in tropical mountainous regions.
TL;DR: It is found that greater effective diversity of crops at the national level is associated with increased temporal stability of total national harvest, and increasing national effective crop diversity may be an additional way to address this challenge.
Abstract: Increasing global food demand, low grain reserves and climate change threaten the stability of food systems on national to global scales1–5. Policies to increase yields, irrigation and tolerance of crops to drought have been proposed as stability-enhancing solutions1,6,7. Here we evaluate a complementary possibility—that greater diversity of crops at the national level may increase the year-to-year stability of the total national harvest of all crops combined. We test this crop diversity–stability hypothesis using 5 decades of data on annual yields of 176 crop species in 91 nations. We find that greater effective diversity of crops at the national level is associated with increased temporal stability of total national harvest. Crop diversity has stabilizing effects that are similar in magnitude to the observed destabilizing effects of variability in precipitation. This greater stability reflects markedly lower frequencies of years with sharp harvest losses. Diversity effects remained robust after statistically controlling for irrigation, fertilization, precipitation, temperature and other variables, and are consistent with the variance-scaling characteristics of individual crops required by theory8,9 for diversity to lead to stability. Ensuring stable food supplies is a challenge that will probably require multiple solutions. Our results suggest that increasing national effective crop diversity may be an additional way to address this challenge. A greater diversity of crops at the national level increases the temporal stability of total national harvest, reflecting markedly lower frequencies of years with sharp harvest losses.
Wageningen University and Research Centre1, University of Puerto Rico2, National Autonomous University of Mexico3, Colby College4, National Institute of Amazonian Research5, University of São Paulo6, Federal University of Pernambuco7, University of Alberta8, Paul Sabatier University9, University of Connecticut10, University of Colorado Boulder11, International Institute of Minnesota12, Smithsonian Tropical Research Institute13, Tulane University14, University of Stirling15, Clemson University16, Comisión Nacional para el Conocimiento y Uso de la Biodiversidad17, Universidade Federal de Minas Gerais18, Centro Agronómico Tropical de Investigación y Enseñanza19, Alexander von Humboldt Biological Resources Research Institute20, The Catholic University of America21, Colorado Mesa University22, State University of New York at Purchase23, University of Haifa24, University of Wisconsin-Madison25, Universidade Federal do Rio Grande do Sul26, Universidade Federal de Viçosa27, Costa Rica Institute of Technology28, University of Minnesota29, Pedagogical and Technological University of Colombia30, University of California, Santa Barbara31, Museu Paraense Emílio Goeldi32, University of California, Berkeley33, Columbia University34, New York Botanical Garden35, National University of Singapore36, Yale-NUS College37, Puerto Rico Department of Agriculture38, University of Amsterdam39, Louisiana State University40, University of Puerto Rico, Río Piedras41
TL;DR: This work assesses how tree species richness and composition recover during secondary succession across gradients in environmental conditions and anthropogenic disturbance in an unprecedented multisite analysis for the Neotropics.
Abstract: Old-growth tropical forests harbor an immense diversity of tree species but are rapidly being cleared, while secondary forests that regrow on abandoned agricultural lands increase in extent. We assess how tree species richness and composition recover during secondary succession across gradients in environmental conditions and anthropogenic disturbance in an unprecedented multisite analysis for the Neotropics. Secondary forests recover remarkably fast in species richness but slowly in species composition. Secondary forests take a median time of five decades to recover the species richness of old-growth forest (80% recovery after 20 years) based on rarefaction analysis. Full recovery of species composition takes centuries (only 34% recovery after 20 years). A dual strategy that maintains both old-growth forests and species-rich secondary forests is therefore crucial for biodiversity conservation in human-modified tropical landscapes.
TL;DR: The results suggest that production gains will occur at the costs of biodiversity predominantly in developing tropical regions, while Europe and North America benefit from lower world market prices without putting their own biodiversity at risk.
Abstract: With rising demand for biomass, cropland expansion and intensification represent the main strategies to boost agricultural production, but are also major drivers of biodiversity decline. We investigate the consequences of attaining equal global production gains by 2030, either by cropland expansion or intensification, and analyse their impacts on agricultural markets and biodiversity. We find that both scenarios lead to lower crop prices across the world, even in regions where production decreases. Cropland expansion mostly affects biodiversity hotspots in Central and South America, while cropland intensification threatens biodiversity especially in Sub-Saharan Africa, India and China. Our results suggest that production gains will occur at the costs of biodiversity predominantly in developing tropical regions, while Europe and North America benefit from lower world market prices without putting their own biodiversity at risk. By identifying hotspots of potential future conflicts, we demonstrate where conservation prioritization is needed to balance agricultural production with conservation goals.
University of Leeds1, University of Edinburgh2, University College London3, University of Exeter4, Imperial College London5, National University of Saint Anthony the Abbot in Cuzco6, Universidad Autónoma Gabriel René Moreno7, National Institute of Amazonian Research8, Universidade do Estado de Mato Grosso9, Universidade Federal do Acre10, University of Washington11, University of Los Andes12, Environmental Change Institute13, Centre national de la recherche scientifique14, Lancaster University15, Museu Paraense Emílio Goeldi16, University of Lorraine17, Universidad Nacional de la Amazonía Peruana18, Smithsonian Institution19, University of Montpellier20, James Cook University21, Wageningen University and Research Centre22, Agro ParisTech23, University of Amsterdam24, Naturalis25, Federal University of Western Pará26, State University of Campinas27, National Institute for Space Research28, Florida International University29, University of São Paulo30, Tropenbos International31, Amazon.com32, Federal University of Pará33, Michigan Technological University34, University of Texas at Austin35, Polytechnic University of Valencia36, Venezuelan Institute for Scientific Research37, Royal Museum for Central Africa38, Tecnológico de Antioquia39, George Mason University40, Universidad del Tolima41, National University of Colombia42, Paul Sabatier University43, Georgetown University44, University of La Serena45, Forestry Commission46, Federal University of Alagoas47, Duke University48, Van Hall Larenstein University of Applied Sciences49, University of Nottingham50
TL;DR: A slow shift to a more dry‐affiliated Amazonia is underway, with changes in compositional dynamics consistent with climate‐change drivers, but yet to significantly impact whole‐community composition.
Abstract: Most of the planet's diversity is concentrated in the tropics, which includes many regions undergoing rapid climate change. Yet, while climate‐induced biodiversity changes are widely documented elsewhere, few studies have addressed this issue for lowland tropical ecosystems. Here we investigate whether the floristic and functional composition of intact lowland Amazonian forests have been changing by evaluating records from 106 long‐term inventory plots spanning 30 years. We analyse three traits that have been hypothesized to respond to different environmental drivers (increase in moisture stress and atmospheric CO2 concentrations): maximum tree size, biogeographic water‐deficit affiliation and wood density. Tree communities have become increasingly dominated by large‐statured taxa, but to date there has been no detectable change in mean wood density or water deficit affiliation at the community level, despite most forest plots having experienced an intensification of the dry season. However, among newly recruited trees, dry‐affiliated genera have become more abundant, while the mortality of wet‐affiliated genera has increased in those plots where the dry season has intensified most. Thus, a slow shift to a more dry‐affiliated Amazonia is underway, with changes in compositional dynamics (recruits and mortality) consistent with climate‐change drivers, but yet to significantly impact whole‐community composition. The Amazon observational record suggests that the increase in atmospheric CO2 is driving a shift within tree communities to large‐statured species and that climate changes to date will impact forest composition, but long generation times of tropical trees mean that biodiversity change is lagging behind climate change.
TL;DR: This essay explains why freshwater ecosystems are global hotspots of biological richness, despite a panoply of interacting threats that jeopardize biodiversity.
University of Würzburg1, National University of Comahue2, Spanish National Research Council3, Swedish University of Agricultural Sciences4, Universidade Federal de Goiás5, University of Lisbon6, Stanford University7, Commonwealth Scientific and Industrial Research Organisation8, National University of Río Negro9, ETH Zurich10, Cornell University11, University of California, Davis12, The Nature Conservancy13, Wageningen University and Research Centre14, University of British Columbia15, Great Lakes Bioenergy Research Center16, University of California, Berkeley17, University of Padua18, University of New England (United States)19, Lund University20, University of Göttingen21, University of La Rochelle22, Institut national de la recherche agronomique23, Federal University of Ceará24, Concordia University Wisconsin25, University of Belgrade26, National University of Tucumán27, Michigan State University28, University of Brasília29, University of Greenwich30, University of Reading31, University of Wisconsin-Madison32, Boise State University33, University of Texas at Austin34, University of Haifa35, Kansas State University36, University of Freiburg37, University of Hamburg38, University of California, Santa Barbara39, Seattle University40, University of Vienna41, University of Florida42, Centro Agronómico Tropical de Investigación y Enseñanza43, National Audubon Society44, University of Buenos Aires45, Virginia Tech46, University of Bordeaux47, University of Auckland48, University College Dublin49, Trinity College, Dublin50, University of Tokyo51, Federal University of Bahia52, Lincoln University (Pennsylvania)53, National Institute for Environmental Studies54, International Food Policy Research Institute55, Xi'an Jiaotong-Liverpool University56
TL;DR: Using a global database from 89 crop systems, the relative importance of abundance and species richness for pollination, biological pest control and final yields in the context of on-going land-use change is partitioned.
Abstract: Human land use threatens global biodiversity and compromises multiple ecosystem functions critical to food production. Whether crop yield-related ecosystem services can be maintained by few abundant species or rely on high richness remains unclear. Using a global database from 89 crop systems, we partition the relative importance of abundance and species richness for pollination, biological pest control and final yields in the context of on-going land-use change. Pollinator and enemy richness directly supported ecosystem services independent of abundance. Up to 50% of the negative effects of landscape simplification on ecosystem services was due to richness losses of service-providing organisms, with negative consequences for crop yields. Maintaining the biodiversity of ecosystem service providers is therefore vital to sustain the flow of key agroecosystem benefits to society.
Martin Luther University of Halle-Wittenberg1, Leiden University2, University of Natural Resources and Life Sciences, Vienna3, University of Vienna4, Radboud University Nijmegen5, Norwegian University of Science and Technology6, University of Kent7, Netherlands Organisation for Applied Scientific Research8, University of Porto9
TL;DR: The results suggest that to address the biodiversity crisis, governments should take an equitable approach recognizing remote responsibility, and promote a shift of economic development towards activities with low biodiversity impacts.
Abstract: Biodiversity and ecosystem service losses driven by land-use change are expected to intensify as a growing and more affluent global population requires more agricultural and forestry products, and teleconnections in the global economy lead to increasing remote environmental responsibility. By combining global biophysical and economic models, we show that, between the years 2000 and 2011, overall population and economic growth resulted in increasing total impacts on bird diversity and carbon sequestration globally, despite a reduction of land-use impacts per unit of gross domestic product (GDP). The exceptions were North America and Western Europe, where there was a reduction of forestry and agriculture impacts on nature accentuated by the 2007-2008 financial crisis. Biodiversity losses occurred predominantly in Central and Southern America, Africa and Asia with international trade an important and growing driver. In 2011, 33% of Central and Southern America and 26% of Africa's biodiversity impacts were driven by consumption in other world regions. Overall, cattle farming is the major driver of biodiversity loss, but oil seed production showed the largest increases in biodiversity impacts. Forestry activities exerted the highest impact on carbon sequestration, and also showed the largest increase in the 2000-2011 period. Our results suggest that to address the biodiversity crisis, governments should take an equitable approach recognizing remote responsibility, and promote a shift of economic development towards activities with low biodiversity impacts.
Leipzig University1, Martin Luther University of Halle-Wittenberg2, Universidade Positivo3, University of Vigo4, Empresa Brasileira de Pesquisa Agropecuária5, ETH Zurich6, Moscow State University7, University of Freiburg8, University of Jena9, University of Catania10, Wageningen University and Research Centre11, Free University of Berlin12, Senckenberg Museum13, Colorado State University14, National Agriculture and Food Research Organization15, University of Nairobi16, Commonwealth Scientific and Industrial Research Organisation17, National Scientific and Technical Research Council18, Brandenburg University of Technology19, Cornell University20, University College Dublin21, United States Forest Service22, University of Toronto23, Aberystwyth University24, State University of New York at Cortland25, National University of Luján26, University of Trier27, University of the Philippines Mindanao28, Razi University29, Josip Juraj Strossmayer University of Osijek30, Kyushu University31, Minnesota Pollution Control Agency32, Aarhus University33, Northern Kentucky University34, Lincoln University (Missouri)35, University of Agricultural Sciences, Dharwad36, Fukushima University37, Matej Bel University38, Lancaster University39, Université d'Abobo-Adjamé40, Tarbiat Modares University41, Pachhunga University College42, University of São Paulo43, University of Hawaii at Hilo44, College of Tropical Agriculture and Human Resources45, Oklahoma State University–Stillwater46, Forest Research Institute47, University of Extremadura48, Katholieke Universiteit Leuven49, Research Institute for Nature and Forest50, Natural Resources Institute Finland51, University of Alcalá52, COMSATS Institute of Information Technology53, King Abdulaziz University54, University of Minnesota55, Federal University of Maranhão56, Jagiellonian University57, Technical University of Berlin58, University of Wisconsin-Madison59, Leibniz Association60, Braunschweig University of Technology61, University of Innsbruck62, Keldysh Institute of Applied Mathematics63, Russian Academy of Sciences64, Khalsa College, Amritsar65, University of La Laguna66, Kōchi University67, Universidad Pública de Navarra68, McGill University69, The Nature Conservancy70, University of Giessen71, Henan University72, University of Saint Mary73
TL;DR: It was found that local species richness and abundance typically peaked at higher latitudes, displaying patterns opposite to those observed in aboveground organisms, which suggest that climate change may have serious implications for earthworm communities and for the functions they provide.
Abstract: Soil organisms, including earthworms, are a key component of terrestrial ecosystems. However, little is known about their diversity, their distribution, and the threats affecting them. We compiled a global dataset of sampled earthworm communities from 6928 sites in 57 countries as a basis for predicting patterns in earthworm diversity, abundance, and biomass. We found that local species richness and abundance typically peaked at higher latitudes, displaying patterns opposite to those observed in aboveground organisms. However, high species dissimilarity across tropical locations may cause diversity across the entirety of the tropics to be higher than elsewhere. Climate variables were found to be more important in shaping earthworm communities than soil properties or habitat cover. These findings suggest that climate change may have serious implications for earthworm communities and for the functions they provide.
TL;DR: The assessment underscores the need for a strategic plan to combat trade with policies that are proactive rather than reactive, which is especially important because species can quickly transition from being safe to being endangered as humans continue to harvest and trade across the tree of life.
Abstract: Wildlife trade is a multibillion dollar industry that is driving species toward extinction. Of >31,500 terrestrial bird, mammal, amphibian, and squamate reptile species, ~18% (N = 5579) are traded globally. Trade is strongly phylogenetically conserved, and the hotspots of this trade are concentrated in the biologically diverse tropics. Using different assessment approaches, we predict that, owing to their phylogenetic replacement and trait similarity to currently traded species, future trade will affect up to 3196 additional species—totaling 8775 species at risk of extinction from trade. Our assessment underscores the need for a strategic plan to combat trade with policies that are proactive rather than reactive, which is especially important because species can quickly transition from being safe to being endangered as humans continue to harvest and trade across the tree of life.
TL;DR: This work makes a number of predictions concerning climate change effects on PSFs and consequences for vegetation-soil-climate feedbacks while acknowledging that they may be context-dependent, spatially heterogeneous, and temporally variable.
Abstract: Plant-soil feedbacks (PSFs) are interactions among plants, soil organisms, and abiotic soil conditions that influence plant performance, plant species diversity, and community structure, ultimately driving ecosystem processes. We review how climate change will alter PSFs and their potential consequences for ecosystem functioning. Climate change influences PSFs through the performance of interacting species and altered community composition resulting from changes in species distributions. Climate change thus affects plant inputs into the soil subsystem via litter and rhizodeposits and alters the composition of the living plant roots with which mutualistic symbionts, decomposers, and their natural enemies interact. Many of these plant-soil interactions are species-specific and are greatly affected by temperature, moisture, and other climate-related factors. We make a number of predictions concerning climate change effects on PSFs and consequences for vegetation-soil-climate feedbacks while acknowledging that they may be context-dependent, spatially heterogeneous, and temporally variable.
TL;DR: A systematic review of studies on Biodiversity and Ecosystem Functioning revealed that in many cases, biodiversity promotes average biomass production and its temporal stability, and pollination success, and factors other than biodiversity can be even more important in driving ecosystem functioning.
Abstract: Approximately 25 years ago, ecologists became increasingly interested in the question of whether ongoing biodiversity loss matters for the functioning of ecosystems. As such, a new ecological subfield on Biodiversity and Ecosystem Functioning (BEF) was born. This subfield was initially dominated by theoretical studies and by experiments in which biodiversity was manipulated, and responses of ecosystem functions such as biomass production, decomposition rates, carbon sequestration, trophic interactions and pollination were assessed. More recently, an increasing number of studies have investigated BEF relationships in non-manipulated ecosystems, but reviews synthesizing our knowledge on the importance of real-world biodiversity are still largely missing. I performed a systematic review in order to assess how biodiversity drives ecosystem functioning in both terrestrial and aquatic, naturally assembled communities, and on how important biodiversity is compared to other factors, including other aspects of community composition and abiotic conditions. The outcomes of 258 published studies, which reported 726 BEF relationships, revealed that in many cases, biodiversity promotes average biomass production and its temporal stability, and pollination success. For decomposition rates and ecosystem multifunctionality, positive effects of biodiversity outnumbered negative effects, but neutral relationships were even more common. Similarly, negative effects of prey biodiversity on pathogen and herbivore damage outnumbered positive effects, but were less common than neutral relationships. Finally, there was no evidence that biodiversity is related to soil carbon storage. Most BEF studies focused on the effects of taxonomic diversity, however, metrics of functional diversity were generally stronger predictors of ecosystem functioning. Furthermore, in most studies, abiotic factors and functional composition (e.g. the presence of a certain functional group) were stronger drivers of ecosystem functioning than biodiversity per se. While experiments suggest that positive biodiversity effects become stronger at larger spatial scales, in naturally assembled communities this idea is too poorly studied to draw general conclusions. In summary, a high biodiversity in naturally assembled communities positively drives various ecosystem functions. At the same time, the strength and direction of these effects vary highly among studies, and factors other than biodiversity can be even more important in driving ecosystem functioning. Thus, to promote those ecosystem functions that underpin human well-being, conservation should not only promote biodiversity per se, but also the abiotic conditions favouring species with suitable trait combinations.
TL;DR: It is shown that biodiversity should peak at moderately high levels of pyrodiversity, and theory and data support the ‘intermediate disturbance hypothesis’ when mean patch species diversity is correlated with mean fire intervals.
Abstract: Many terrestrial ecosystems are fire prone, such that their composition and structure are largely due to their fire regime. Regions subject to regular fire have exceptionally high levels of species richness and endemism, and fire has been proposed as a major driver of their diversity, within the context of climate, resource availability and environmental heterogeneity. However, current fire-management practices rarely take into account the ecological and evolutionary roles of fire in maintaining biodiversity. Here, we focus on the mechanisms that enable fire to act as a major ecological and evolutionary force that promotes and maintains biodiversity over numerous spatiotemporal scales. From an ecological perspective, the vegetation, topography and local weather conditions during a fire generate a landscape with spatial and temporal variation in fire-related patches (pyrodiversity), and these produce the biotic and environmental heterogeneity that drives biodiversity across local and regional scales. There have been few empirical tests of the proposition that 'pyrodiversity begets biodiversity' but we show that biodiversity should peak at moderately high levels of pyrodiversity. Overall species richness is greatest immediately after fire and declines monotonically over time, with postfire successional pathways dictated by animal habitat preferences and varying lifespans among resident plants. Theory and data support the 'intermediate disturbance hypothesis' when mean patch species diversity is correlated with mean fire intervals. Postfire persistence, recruitment and immigration allow species with different life histories to coexist. From an evolutionary perspective, fire drives population turnover and diversification by promoting a wide range of adaptive responses to particular fire regimes. Among 39 comparisons, the number of species in 26 fire-prone lineages is much higher than that in their non-fire-prone sister lineages. Fire and its byproducts may have direct mutagenic effects, producing novel genotypes that can lead to trait innovation and even speciation. A paradigm shift aimed at restoring biodiversity-maintaining fire regimes across broad landscapes is required among the fire research and management communities. This will require ecologists and other professionals to spread the burgeoning fire-science knowledge beyond scientific publications to the broader public, politicians and media.
TL;DR: It is found that OTU richness shows a declining west-to-east diversity gradient that is in agreement with the species richness patterns documented here and previously for birds and trees, suggesting that most taxonomic groups respond to the same overall diversity gradients at large spatial scales.
Abstract: Most knowledge on biodiversity derives from the study of charismatic macro-organisms, such as birds and trees. However, the diversity of micro-organisms constitutes the majority of all life forms on Earth. Here, we ask if the patterns of richness inferred for macro-organisms are similar for micro-organisms. For this, we barcoded samples of soil, litter and insects from four localities on a west-to-east transect across Amazonia. We quantified richness as Operational Taxonomic Units (OTUs) in those samples using three molecular markers. We then compared OTU richness with species richness of two relatively well-studied organism groups in Amazonia: trees and birds. We find that OTU richness shows a declining west-to-east diversity gradient that is in agreement with the species richness patterns documented here and previously for birds and trees. These results suggest that most taxonomic groups respond to the same overall diversity gradients at large spatial scales. However, our results show a different pattern of richness in relation to habitat types, suggesting that the idiosyncrasies of each taxonomic group and peculiarities of the local environment frequently override large-scale diversity gradients. Our findings caution against using the diversity distribution of one taxonomic group as an indication of patterns of richness across all groups.
TL;DR: It is found that plant diversity increases microbial biomass and respiration rates, an effect moderated by stand age, which underlines strong relationships between plant diversity and soil microorganisms across global terrestrial ecosystems and suggests the importance of plant diversity in maintaining belowground ecosystem functioning.
Abstract: Soil microorganisms are key to biological diversity and many ecosystem processes in terrestrial ecosystems. Despite the current alarming loss of plant diversity, it is unclear how plant species diversity affects soil microorganisms. By conducting a global meta-analysis with paired observations of plant mixtures and monocultures from 106 studies, we show that microbial biomass, bacterial biomass, fungal biomass, fungi:bacteria ratio, and microbial respiration increase, while Gram-positive to Gram-negative bacteria ratio decrease in response to plant mixtures. The increases in microbial biomass and respiration are more pronounced in older and more diverse mixtures. The effects of plant mixtures on all microbial attributes are consistent across ecosystem types including natural forests, planted forests, planted grasslands, croplands, and planted containers. Our study underlines strong relationships between plant diversity and soil microorganisms across global terrestrial ecosystems and suggests the importance of plant diversity in maintaining belowground ecosystem functioning.