Shifts of community composition and population density substantially affect ecosystem function despite invariant richness.

There has been considerable focus on the impacts of environmental change on ecosystem function arising from changes in species richness. However, environmental change may affect ecosystem function without affecting richness, most notably by affecting population densities and community composition. Using a theoretical model, we find that, despite invariant richness, (1) small environmental effects may already lead to a collapse of function; (2) competitive strength may be a less important determinant of ecosystem function change than the selectivity of the environmental change driver and (3) effects on ecosystem function increase when effects on composition are larger. We also present a complementary statistical analysis of 13 data sets of phytoplankton and periphyton communities exposed to chemical stressors and show that effects on primary production under invariant richness ranged from -75% to +10%. We conclude that environmental protection goals relying on measures of richness could underestimate ecological impacts of environmental change.

[1]  G. Likens,et al.  Technical Report: Human Alteration of the Global Nitrogen Cycle: Sources and Consequences , 1997 .

[2]  J. Cornelissen,et al.  Scaling environmental change through the community‐level: a trait‐based response‐and‐effect framework for plants , 2008 .

[3]  M. J. Hensel,et al.  Biodiversity enhances ecosystem multifunctionality across trophic levels and habitats , 2015, Nature Communications.

[4]  Rachael Winfree,et al.  Abundance of common species, not species richness, drives delivery of a real-world ecosystem service. , 2015, Ecology letters.

[5]  F. Bongers,et al.  Biomass is the main driver of changes in ecosystem process rates during tropical forest succession. , 2015, Ecology.

[6]  R Core Team,et al.  R: A language and environment for statistical computing. , 2014 .

[7]  Hideyasu Shimadzu,et al.  Estimates of local biodiversity change over time stand up to scrutiny , 2016, bioRxiv.

[8]  O. Schmitz,et al.  Physiological Stress as a Fundamental Mechanism Linking Predation to Ecosystem Functioning , 2010, The American Naturalist.

[9]  K. Gaston,et al.  Commonness, population depletion and conservation biology. , 2008, Trends in ecology & evolution.

[10]  D. Baird,et al.  Determining genetic variability in the distribution of sensitivities to toxic stress among and within field populations of Daphnia magna. , 2002, Environmental science & technology.

[11]  F. De Laender,et al.  The combined effects of biotic and abiotic stress on species richness and connectance , 2017, PloS one.

[12]  S. Gaines,et al.  Species diversity: from global decreases to local increases , 2003 .

[13]  Christian Ritz,et al.  Toward a unified approach to dose–response modeling in ecotoxicology , 2010, Environmental toxicology and chemistry.

[14]  M. C. Urban.  Accelerating extinction risk from climate change , 2015, Science.

[15]  F. Pomati,et al.  Assessing triclosan-induced ecological and trans-generational effects in natural phytoplankton communities: a trait-based field method , 2013, Ecotoxicology.

[16]  A. Ives,et al.  Species interactions and a chain of indirect effects driven by reduced precipitation. , 2014, Ecology.

[17]  Tadashi Fukami,et al.  Community assembly: alternative stable states or alternative transient states? , 2011, Ecology letters.

[18]  Bastian Steudel,et al.  Biodiversity effects on ecosystem functioning change along environmental stress gradients. , 2012, Ecology letters.

[19]  P. Legendre,et al.  vegan : Community Ecology Package. R package version 1.8-5 , 2007 .

[20]  S. Collins,et al.  A framework for assessing ecosystem dynamics in response to chronic resource alterations induced by global change. , 2009, Ecology.

[21]  M. Bertness,et al.  Positive interactions in communities. , 1994, Trends in ecology & evolution.

[22]  Emily S. Bernhardt,et al.  Synthetic chemicals as agents of global change , 2017 .

[23]  N. Williams,et al.  Extinction order and altered community structure rapidly disrupt ecosystem functioning. , 2005, Ecology letters.

[24]  B. Cardinale.  Biodiversity improves water quality through niche partitioning , 2011, Nature.

[25]  T. Fukami.  Historical Contingency in Community Assembly: Integrating Niches, Species Pools, and Priority Effects , 2015 .

[26]  Amaury Lambert,et al.  Mass extinction in poorly known taxa , 2015, Proceedings of the National Academy of Sciences.

[27]  Florian D. Schneider,et al.  Climate change in size-structured ecosystems , 2012, Philosophical Transactions of the Royal Society B: Biological Sciences.

[28]  A. Magurran,et al.  Fifteen forms of biodiversity trend in the Anthropocene. , 2015, Trends in ecology & evolution.

[29]  Sinéad Collins,et al.  Integrating physiological, ecological and evolutionary change: a Price equation approach. , 2009, Ecology letters.

[30]  Andrew Gonzalez,et al.  The functional role of producer diversity in ecosystems. , 2011, American journal of botany.

[31]  D. Tilman,et al.  Biodiversity and Ecosystem Functioning , 2014 .

[32]  M. J. Hensel,et al.  Recent Trends in Local-Scale Marine Biodiversity Reflect Community Structure and Human Impacts , 2015, Current Biology.

[33]  S. Wood.  Generalized Additive Models: An Introduction with R , 2006 .

[34]  H. D. Cooper,et al.  Scenarios for Global Biodiversity in the 21st Century , 2010, Science.

[35]  Hideyuki Doi,et al.  Genetic diversity increases regional variation in phenological dates in response to climate change , 2010 .

[36]  B. Kerr,et al.  Analyzing the effects of species gain and loss on ecosystem function using the extended Price equation partition , 2012 .

[37]  A. A. Koelmans,et al.  Impact of triphenyltin acetate in microcosms simulating floodplain lakes. I. Influence of sediment quality , 2006, Ecotoxicology.

[38]  S. Polasky,et al.  Nutrient enrichment, biodiversity loss, and consequent declines in ecosystem productivity , 2013, Proceedings of the National Academy of Sciences.

[39]  J. Fox,et al.  Using the Price Equation to partition the effects of biodiversity loss on ecosystem function. , 2006, Ecology.

[40]  T. Brock,et al.  Sensitivity of macrophyte-dominated freshwater microcosms to chronic levels of the herbicide linuron. II. Community metabolism and invertebrates. , 1997, Ecotoxicology and environmental safety.

[41]  M. Cadotte,et al.  Consequences of dominance: a review of evenness effects on local and regional ecosystem processes. , 2008, Ecology.

[42]  T. Balser,et al.  Microbial stress-response physiology and its implications for ecosystem function. , 2007, Ecology.

[43]  Dolors Vaqué,et al.  Warming effects on marine microbial food web processes: how far can we go when it comes to predictions? , 2010, Philosophical Transactions of the Royal Society B: Biological Sciences.

[44]  Sandra Díaz,et al.  Scaling environmental change through the community‐level: a trait‐based response‐and‐effect framework for plants , 2008 .

[45]  A. Fargašová.  Comparative study of ecotoxicological effect of triorganotin compounds on various biological subjects. , 1997, Ecotoxicology and environmental safety.

[46]  S. Sultan,et al.  Ecological consequences of phenotypic plasticity. , 2005, Trends in ecology & evolution.

[47]  E. Carmack,et al.  Smallest Algae Thrive As the Arctic Ocean Freshens , 2009, Science.

[48]  D. Marshall,et al.  Environmental stress, facilitation, competition, and coexistence. , 2013, Ecology.

[49]  Lander Baeten,et al.  Global meta-analysis reveals no net change in local-scale plant biodiversity over time , 2013, Proceedings of the National Academy of Sciences.

[50]  M. Grote,et al.  Organic chemicals jeopardize the health of freshwater ecosystems on the continental scale , 2014, Proceedings of the National Academy of Sciences.

[51]  D. Baird,et al.  Contaminant driven genetic erosion: A case study with Daphnia longispina , 2012, Environmental toxicology and chemistry.

[52]  D. Wardle,et al.  Terrestrial Ecosystem Responses to Species Gains and Losses , 2011, Science.

[53]  Johan Ehrlén,et al.  Predicting changes in the distribution and abundance of species under environmental change , 2015, Ecology letters.

[54]  C. Mora,et al.  Alternative hypotheses to explain why biodiversity-ecosystem functioning relationships are concave-up in some natural ecosystems but concave-down in manipulative experiments , 2014, Scientific Reports.

[55]  Anna Eklöf,et al.  Species loss and secondary extinctions in simple and complex model communities. , 2006, The Journal of animal ecology.

[56]  Mark A. Burgman,et al.  The IUCN Red List of Ecosystems: Motivations, Challenges, and Applications , 2015 .

[57]  Ross A. Thompson,et al.  Anthropogenic environmental changes affect ecosystem stability via biodiversity , 2015 .

[58]  K. Sabbe,et al.  Different response–effect trait relationships underlie contrasting responses to two chemical stressors , 2017 .

[59]  Mark Vellend,et al.  Ecological consequences of genetic diversity. , 2008, Ecology letters.

[60]  Michel Loreau,et al.  Estimating local biodiversity change: a critique of papers claiming no net loss of local diversity. , 2016, Ecology.

[61]  Ben Collen,et al.  Global effects of land use on local terrestrial biodiversity , 2015, Nature.

[62]  P. Chesson.  Mechanisms of Maintenance of Species Diversity , 2000 .

[63]  D. Erwin,et al.  Rarity in mass extinctions and the future of ecosystems , 2015, Nature.

[64]  V. Grimm,et al.  Biodiversity and ecosystem functioning decoupled: invariant ecosystem functioning despite non‐random reductions in consumer diversity , 2016 .

[65]  P. Marquet,et al.  A Significant Upward Shift in Plant Species Optimum Elevation During the 20th Century , 2008, Science.

[66]  Colin R. Janssen,et al.  Per capita interactions and stress tolerance drive stress-induced changes in biodiversity effects on ecosystem functions , 2016, Nature Communications.

[67]  Carlos J. Melián,et al.  Reintroducing Environmental Change Drivers in Biodiversity-Ecosystem Functioning Research. , 2016, Trends in ecology & evolution.

[68]  Jonathan D. G. Jones,et al.  Assemblage Time Series Reveal Biodiversity Change but Not Systematic Loss , 2018 .

[69]  R. Pardini,et al.  Ecological filtering or random extinction? Beta‐diversity patterns and the importance of niche‐based and neutral processes following habitat loss , 2015 .

[70]  Heather McGraw,et al.  Human Alteration of the Global Nitrogen Cycle , 2004 .

[71]  M. Loreau,et al.  Biodiversity and ecosystem functioning: a mechanistic model. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[72]  Michael D. Collins,et al.  Supporting Online Material Materials and Methods Figs. S1 to S3 Tables S1 and S2 References Plant Genotypic Diversity Predicts Community Structure and Governs an Ecosystem Process , 2022 .

[73]  J. Fox,et al.  Revealing how species loss affects ecosystem function: the trait-based Price Equation partition. , 2008, Ecology.

[74]  S. Hubbell,et al.  The unified neutral theory of biodiversity and biogeography at age ten. , 2011, Trends in ecology & evolution.

[75]  P. Ehrlich,et al.  Accelerated modern human–induced species losses: Entering the sixth mass extinction , 2015, Science Advances.

[76]  S. Ernest,et al.  Species-level and community-level responses to disturbance: a cross-community analysis. , 2014, Ecology.