Population and community resilience in multitrophic communities.

Diversity-stability relationships have long been a topic of controversy in ecology, but one whose importance has been re-highlighted by increasing large-scale threats to global biodiversity. The ability of a community to recover from a perturbation (or resilience) is a common measure of stability that has received a large amount of theoretical attention. Yet, general expectations regarding diversity-resilience relations remain elusive. Moreover, the effects of productivity and its interaction with diversity on resilience are equally unclear. We examined the effects of species diversity, species composition, and productivity on population-and community-level resilience in experimental aquatic food webs composed of bacteria, algae, heterotrophic protozoa, and rotifers. Productivity manipulations were crossed with manipulations of the number of species and species compositions within trophic groups. Resilience was measured by perturbing communities with a nonselective, density-independent, mortality event and comparing responses over time between perturbed communities and controls. We found evidence that species diversity can enhance resilience at the community level (i.e., total community biomass), though this effect was more strongly expressed in low-productivity treatments. Diversity effects on resilience were driven by a sampling/selection effect, with resilient communities showing rapid response and dominance by a minority of species (primarily unicellular algae). In contrast, diversity had no effect on mean population-level resilience. Instead, the ability of a community's populations to recover from perturbations was dependent on species composition. We found no evidence of an effect of productivity, either positive or negative, on community- or population-level resilience. Our results indicate that the role of diversity as an insurer of stability may depend on the level of biological organization at which stability is measured, with effects emerging only when focusing on aggregate community properties.

[1]  Lewi Stone,et al.  Ecosystem Resilience, Stability, and Productivity: Seeking a Relationship , 1996, The American Naturalist.

[2]  D. L. DeAngelis,et al.  Dynamics of Nutrient Cycling and Food Webs , 1992, Population and Community Biology Series.

[3]  Benjamin Smith,et al.  A consumer's guide to evenness indices , 1996 .

[4]  D. Doak,et al.  Physical stress and diversity-productivity relationships: The role of positive interactions , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[5]  D. L. Angelis,et al.  STABILITY AND CONNECTANCE IN FOOD WEB MODELS , 1975 .

[6]  Daniel Goodman,et al.  The Theory of Diversity-Stability Relationships in Ecology , 1975, The Quarterly Review of Biology.

[7]  Owen L. Petchey,et al.  Species loss and the structure and functioning of multitrophic aquatic systems , 2004 .

[8]  H. Berger,et al.  A user‐friendly guide to the ciliates (Protozoa, Ciliophora) commonly used by hydrobiologists as bioindicators in rivers, lakes, and waste waters, with notes on their ecology , 1996 .

[9]  Christopher F. Steiner,et al.  Temporal stability of aquatic food webs: partitioning the effects of species diversity, species composition and enrichment , 2005 .

[10]  David Tilman,et al.  Biodiversity, Stability, and Productivity in Competitive Communities , 2000, The American Naturalist.

[11]  K. McCann.  The diversity–stability debate , 2000, Nature.

[12]  J. Fox,et al.  Stability and complexity in microcosm communities , 2002 .

[13]  Michael A. Huston,et al.  Hidden treatments in ecological experiments: re-evaluating the ecosystem function of biodiversity , 1997, Oecologia.

[14]  M. Loreau,et al.  Biodiversity and ecosystem functioning : synthesis and perspectives , 2002 .

[15]  D. Tilman.  THE ECOLOGICAL CONSEQUENCES OF CHANGES IN BIODIVERSITY: A SEARCH FOR GENERAL PRINCIPLES101 , 1999 .

[16]  S. McNaughton.  Diversity and Stability of Ecological Communities: A Comment on the Role of Empiricism in Ecology , 1977, The American Naturalist.

[17]  H. William Hunt,et al.  Influence of Productivity on the Stability of Real and Model Ecosystems , 1993, Science.

[18]  M. Rosenzweig.  Paradox of Enrichment: Destabilization of Exploitation Ecosystems in Ecological Time , 1971, Science.

[19]  A. Ives,et al.  Effects of species diversity on the primary productivity of ecosystems: extending our spatial and temporal scales of inference , 2004 .

[20]  Tom Fenchel,et al.  Intrinsic rate of natural increase: The relationship with body size , 1974, Oecologia.

[21]  R. May,et al.  Stability and Complexity in Model Ecosystems , 1976, IEEE Transactions on Systems, Man, and Cybernetics.

[22]  R. Wetzel.  Limnology: Lake and River Ecosystems , 1975 .

[23]  K. L. Cottingham,et al.  ZOOPLANKTON COMMUNITY STRUCTURE AFFECTS HOW PHYTOPLANKTON RESPOND TO NUTRIENT PULSES , 2004 .

[24]  M E Gilpin,et al.  Enriched predator-prey systems: theoretical stability. , 1972, Science.

[25]  G. Allison,et al.  THE INFLUENCE OF SPECIES DIVERSITY AND STRESS INTENSITY ON COMMUNITY RESISTANCE AND RESILIENCE , 2004 .

[26]  D. Tilman,et al.  Plant diversity and ecosystem productivity: theoretical considerations. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[27]  Anthony R. Ives,et al.  Food-web interactions govern the resistance of communities after non-random extinctions , 2004, Nature.

[28]  R. Westbrooks,et al.  Extinction and Ecosystem Function in the Marine Benthos , 2004 .

[29]  M. Loreau,et al.  Phenotypic diversity and stability of ecosystem processes. , 1999, Theoretical population biology.

[30]  Stuart L. Pimm,et al.  On the Risk of Extinction , 1988, The American Naturalist.

[31]  S. Pimm.  The complexity and stability of ecosystems , 1984, Nature.

[32]  B. Schmid,et al.  Diversity-dependent production can decrease the stability of ecosystem functioning , 2002, Nature.

[33]  Zi-zhen Li,et al.  Stochastic ecosystem resilience and productivity: seeking a relationship , 2002 .

[34]  D. Haydon.  Pivotal Assumptions Determining the Relationship between Stability and Complexity: An Analytical Synthesis of the Stability-Complexity Debate , 1994, The American Naturalist.

[35]  M. Loreau,et al.  Biodiversity as spatial insurance in heterogeneous landscapes , 2003, Proceedings of the National Academy of Sciences of the United States of America.

[36]  Michel Loreau,et al.  Spatial Flows and the Regulation of Ecosystems , 2004, The American Naturalist.

[37]  P. Lundberg,et al.  Ecosystem resilience and productivity : are predictions possible ? , 1998 .

[38]  Michel Loreau,et al.  Partitioning selection and complementarity in biodiversity experiments , 2001, Nature.

[39]  L. Milne,et al.  The Balance of Nature , 1953, Oryx.