Topic
Species richness
About: Species richness is a research topic. Over the lifetime, 61672 publications have been published within this topic receiving 2183796 citations.
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TL;DR: Evidence of declines (pre-versus post-1980) in local bee diversity in Britain and the Netherlands is found and a causal connection between local extinctions of functionally linked plant and pollinator species is strongly suggested.
Abstract: Despite widespread concern about declines in pollination services, little is known about the patterns of change in most pollinator assemblages. By studying bee and hoverfly assemblages in Britain and the Netherlands, we found evidence of declines (pre-versus post-1980) in local bee diversity in both countries; however, divergent trends were observed in hoverflies. Depending on the assemblage and location, pollinator declines were most frequent in habitat and flower specialists, in univoltine species, and/or in nonmigrants. In conjunction with this evidence, outcrossing plant species that are reliant on the declining pollinators have themselves declined relative to other plant species. Taken together, these findings strongly suggest a causal connection between local extinctions of functionally linked plant and pollinator species.
2,616 citations
TL;DR: In this paper, the authors used a well-replicated field experiment, in which species diversity was directly controlled, to show that ecosystem productivity in 147 grassland plots increased significantly with plant biodiversity.
Abstract: THE functioning and sustainability of ecosystems may depend on their biological diversity1–8. Elton's9 hypothesis that more diverse ecosystems are more stable has received much attention1,3,6,7,10–14, but Darwin's proposal6,15 that more diverse plant communities are more productive, and the related conjectures4,5,16,17 that they have lower nutrient losses and more sustainable soils, are less well studied4–6,8,17,18. Here we use a well-replicated field experiment, in which species diversity was directly controlled, to show that ecosystem productivity in 147 grassland plots increased significantly with plant biodiversity. Moreover, the main limiting nutrient, soil mineral nitrogen, was utilized more completely when there was a greater diversity of species, leading to lower leaching loss of nitrogen from these ecosystems. Similarly, in nearby native grassland, plant productivity and soil nitrogen utilization increased with increasing plant species richness. This supports the diversity–productivity and diversity–sustainability hypotheses. Our results demonstrate that the loss of species threatens ecosystem functioning and sustainability.
2,541 citations
United Nations Environment Programme1, American Museum of Natural History2, Imperial College London3, Swansea University4, University College London5, National University of Cordoba6, Tel Aviv University7, Max Planck Society8, University of Oldenburg9, Microsoft10, University of Oxford11, University of Wisconsin–Eau Claire12
TL;DR: A terrestrial assemblage database of unprecedented geographic and taxonomic coverage is analysed to quantify local biodiversity responses to land use and related changes and shows that in the worst-affected habitats, pressures reduce within-sample species richness by an average of 76.5%, total abundance by 39.5% and rarefaction-based richness by 40.3%.
Abstract: Human activities, especially conversion and degradation of habitats, are causing global biodiversity declines. How local ecological assemblages are responding is less clear--a concern given their importance for many ecosystem functions and services. We analysed a terrestrial assemblage database of unprecedented geographic and taxonomic coverage to quantify local biodiversity responses to land use and related changes. Here we show that in the worst-affected habitats, these pressures reduce within-sample species richness by an average of 76.5%, total abundance by 39.5% and rarefaction-based richness by 40.3%. We estimate that, globally, these pressures have already slightly reduced average within-sample richness (by 13.6%), total abundance (10.7%) and rarefaction-based richness (8.1%), with changes showing marked spatial variation. Rapid further losses are predicted under a business-as-usual land-use scenario; within-sample richness is projected to fall by a further 3.4% globally by 2100, with losses concentrated in biodiverse but economically poor countries. Strong mitigation can deliver much more positive biodiversity changes (up to a 1.9% average increase) that are less strongly related to countries' socioeconomic status.
2,532 citations
TL;DR: A general stochastic dynamic model is developed to assess the effects of species richness on the expected temporal mean and variance of ecosystem processes such as productivity, based on individual species' productivity responses to environmental fluctuations, and provides a strong theoretical foundation for the insurance hypothesis.
Abstract: Although the effect of biodiversity on ecosystem functioning has
become a major focus in ecology, its significance in a fluctuating
environment is still poorly understood. According to the insurance
hypothesis, biodiversity insures ecosystems against declines in their
functioning because many species provide greater guarantees that some
will maintain functioning even if others fail. Here we examine this
hypothesis theoretically. We develop a general stochastic dynamic model
to assess the effects of species richness on the expected temporal mean
and variance of ecosystem processes such as productivity, based on
individual species’ productivity responses to environmental
fluctuations. Our model shows two major insurance effects of species
richness on ecosystem productivity: (i) a buffering
effect, i.e., a reduction in the temporal variance of productivity, and
(ii) a performance-enhancing effect, i.e., an increase
in the temporal mean of productivity. The strength of these insurance
effects is determined by three factors: (i) the way
ecosystem productivity is determined by individual species responses to
environmental fluctuations, (ii) the degree of
asynchronicity of these responses, and (iii) the
detailed form of these responses. In particular, the greater the
variance of the species responses, the lower the species richness at
which the temporal mean of the ecosystem process saturates and the
ecosystem becomes redundant. These results provide a strong theoretical
foundation for the insurance hypothesis, which proves to be a
fundamental principle for understanding the long-term effects of
biodiversity on ecosystem processes.
2,496 citations
American Museum of Natural History1, University of Tartu2, University of Colombo3, Royal Netherlands Academy of Arts and Sciences4, University of Florida5, University of Palermo6, Goethe University Frankfurt7, Hobart Corporation8, Nakhon Phanom University9, University of Bamenda10, University of Gothenburg11, Naturalis12, Swedish University of Agricultural Sciences13, Royal Botanic Gardens14, Universiti Malaysia Sabah15, United States Department of Agriculture16, Forest Research Institute Malaysia17, Humboldt State University18, Chinese Academy of Sciences19, Landcare Research20, University of Western Australia21, Estonian University of Life Sciences22, University of Southern Queensland23, Botanic Garden Meise24, Manchester Metropolitan University25, James Cook University26
TL;DR: Diversity of most fungal groups peaked in tropical ecosystems, but ectomycorrhizal fungi and several fungal classes were most diverse in temperate or boreal ecosystems, and manyfungal groups exhibited distinct preferences for specific edaphic conditions (such as pH, calcium, or phosphorus).
Abstract: Fungi play major roles in ecosystem processes, but the determinants of fungal diversity and biogeographic patterns remain poorly understood. Using DNA metabarcoding data from hundreds of globally distributed soil samples, we demonstrate that fungal richness is decoupled from plant diversity. The plant-to-fungus richness ratio declines exponentially toward the poles. Climatic factors, followed by edaphic and spatial variables, constitute the best predictors of fungal richness and community composition at the global scale. Fungi show similar latitudinal diversity gradients to other organisms, with several notable exceptions. These findings advance our understanding of global fungal diversity patterns and permit integration of fungi into a general macroecological framework.
2,346 citations