Species richness

About: Species richness is a research topic. Over the lifetime, 61672 publications have been published within this topic receiving 2183796 citations.

The relationship in lake communities between primary productivity and species richness

Abstract: An understanding of the relationship between species richness and productivity is crucial to understanding biodiversity in lakes. We investigated the relationship between the primary productivity of lake ecosystems and the number of species for lacustrine phytoplankton, rotifers, cladocerans, copepods, macrophytes, and fish. Our study includes two parts: (1) a survey of 33 well-studied lakes for which data on six major taxonomic groups were available; and (2) a comparison of the effects of short- and long-term whole-lake nutrient addition on primary productivity and planktonic species richness. In the survey, species richness of all six taxa showed a significant quadratic response to increased annual primary productivity ( 14 C estimate, g C-m -2 -yr -1 ) when lake area is taken into account. However, the richness-productivity relationship for phytoplankton and fish was strongly dependent on lake area. The relationship for phytoplankton, rotifers, cladocerans, copepods, and macrophytes was significantly unimodal. Species richness generally peaked at levels of primary productivity in the range of 30-300 g C-m -2 -yr -1 . For the average lake size, the highest biodiversity tended to occur in lakes with relatively low primary productivity, such as those found in the Northern Temperate Lakes Long-Term Ecological Research (LTER) site in the upper Midwest (United States) and in the Experimental Lakes Area of Ontario (Canada). Based on short-term (3 yr) and long-term (21-24 yr) experiments, we tested whether individual lakes respond to whole-lake enrichment experiments in the manner suggested by analyses of survey data. Experimental addition of nutrients produced varied and unpredictable responses in species richness, probably due to transient dynamics and time lags. Responses to nutrient addition were taxon and lake specific. Phytoplankton showed a variety of relationships between species richness and pelagic primary productivity (PPR), depending on the history of enrichment and recovery. No significant effect of primary productivity on rotifer richness occurred in any of the experimental lakes, whereas richness of crustacean zooplankton was negatively correlated with primary productivity in both the short- and long-term experiments.

Niche properties and geographical extent as predictors of species sensitivity to climate change

Abstract: Aim Bioclimatic envelope models are often used to make projections of species' potential responses to climate change. It can be hypothesized that species with different kinds of distributions in environmental niche and geographical space may respond differently to changes in climate. Here, we compare projections of shifts in species ranges with simple descriptors of species niche (position and breadth) and geographical (range size) distributions. Location Europe. Methods The future distribution for 1200 European plant species were predicted by niche-based models using seven climate variables known to have an important role in limiting plant species distributions. Ecological niche properties were estimated using a multivariate analysis. Species range changes were then related to species niche properties using generalized linear models. Results Generally, percentage of remaining suitable habitat in the future increased linearly with niche position and breadth. Increases in potential suitable habitat were associated with greater range size, and had a hump-shaped relationship with niche position on temperature gradient. By relating species chorotypes to percentage of remaining or gained habitat, we highlighted biogeographical patterns of species sensitivity to climate change. These were clearly related to the degree of exposure according to regional patterns of projected climate change. Main conclusion This study highlights general patterns about the relationships between sensitivity of species to climate change and their ecological properties. There is a strong convergence between simple inferences based on ecological characteristics of species and projections by bioclimatic 'envelope' models, confirming macroecological assumptions about species sensitivity based on niche properties. These patterns appear to be most strongly driven by the exposure of species to climate change, with additional effects of species niche characteristics. We conclude that simple species niche properties are powerful indicators of species' sensitivity to climate change.

Species Invasions: Insights into Ecology, Evolution, and Biogeography

Abstract: Preface Introduction: Species Invasions as the "Rosetta Stone" of Ecology - D.Sax, John J.Stachowicz & S.D.Gaines PART I: INSIGHTS INTO ECOLOGY Introduction - P.Cassey Insights into Biotic Interactions from Studies of Species Invasions - J.F.Bruno, J.D. Fridley, K.D.Bromberg & M.D.Bertness Species Invasions and the Relationship between Community Saturation, Diversity, and Ecosystem Functioning - J.J.Stachowicz & D.Tilman Invasive Species as a Tool for Studying Species Effects on Ecosystem Processes - C.M.D'Antonio & S.E.Hobbie Biological Invasions and the Loss of Birds on Islands: Insights into the Idiosyncrasies of Extinction - T.M.Blackburn & K.J.Gaston What Introduced Species Tell Us about the Role of Infectious Diseases in Natural Communities - K.D.Lafferty, K.F.Smith, M.E.Torchin, A.P.Dobson & A.M.Kuris PART II: INSIGHTS INTO EVOLUTION Introduction - M.Vellend, A.R.Hughes & R.K.Grosberg Using Invasive Species to Study Evolution - R.B.Huey, G.W.Gilchrist & A.P.Hendry Taxon Cycles: Insights from Invasive Species - R.E.Ricklefs Genetic Bottlenecks in Alien Plant Species: Influence of Mating Systems and Introduction Dynamics - S.J.Novak & R.N.Mack Species Introductions and Invasions: Insights into the Mechanisms that Drive Evolutionary Change - J.P.Wares, A.R.Hughes & R.K.Grosberg Exotic Species: Potential Tests of Theories of Niche Conservatism and Evolution? R.D.Holt, M.Barfield & R.Gomulkiewicz Species Invasions: Underappreciated Tools to Test Fundamental Evolutionary Questions at Large Spatial and Demographic Scales - W.R.Rice & D.F. Sax PART III: INSIGHTS INTO BIOGEOGRAPHY Introduction - J.L.Lockwood Invasion as Expectation: A Historical Fact of Life - G.Vermeij Evolutionary Trajectories in Plant and Soil Microbial Communities: Centaurea Invasions and the Geographic Mosaic of Coevolution - R.M.Callaway, J.L.Hierro & A.S.Thorpe Exotic and Native Species Have Similar Spatial Patterns of Community Composition, Evenness, and Abundance - M.L.McKinney & J.L.Lockwood What Exotic Species Tell Us about Rates of Population Spread and Geographic Range Expansion - B.P.Kinlan & A.Hastings Scaling Patterns in Exotic Species Distribution and Abundance - F.A.Labra, S.R.Abades & P.M.Marquet Species Invasions and Changes in Diversity at Subglobal Scales - J.H.Brown, E.P. White, D.F.Sax & S.D.Gaines Capstone: Studying Species Invasions: Where Do We Go from Here? - D.F.Sax

Fish invasions in the world's river systems: when natural processes are blurred by human activities.

Abstract: Because species invasions are a principal driver of the human-induced biodiversity crisis, the identification of the major determinants of global invasions is a prerequisite for adopting sound conservation policies. Three major hypotheses, which are not necessarily mutually exclusive, have been proposed to explain the establishment of non-native species: the “human activity” hypothesis, which argues that human activities facilitate the establishment of non-native species by disturbing natural landscapes and by increasing propagule pressure; the “biotic resistance” hypothesis, predicting that species-rich communities will readily impede the establishment of non-native species; and the “biotic acceptance” hypothesis, predicting that environmentally suitable habitats for native species are also suitable for non-native species. We tested these hypotheses and report here a global map of fish invasions (i.e., the number of non-native fish species established per river basin) using an original worldwide dataset of freshwater fish occurrences, environmental variables, and human activity indicators for 1,055 river basins covering more than 80% of Earth's surface. First, we identified six major invasion hotspots where non-native species represent more than a quarter of the total number of species. According to the World Conservation Union, these areas are also characterised by the highest proportion of threatened fish species. Second, we show that the human activity indicators account for most of the global variation in non-native species richness, which is highly consistent with the “human activity” hypothesis. In contrast, our results do not provide support for either the “biotic acceptance” or the “biotic resistance” hypothesis. We show that the biogeography of fish invasions matches the geography of human impact at the global scale, which means that natural processes are blurred by human activities in driving fish invasions in the world's river systems. In view of our findings, we fear massive invasions in developing countries with a growing economy as already experienced in developed countries. Anticipating such potential biodiversity threats should therefore be a priority.