Present address: Department of Zoology, Ecology and Plant Sciences, University College, Cork, Cork, Eire.
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Sequentially assembled food webs and extremum principles in ecosystem ecology
Article first published online: 31 MAR 2006
DOI: 10.1111/j.1365-2656.2006.01058.x
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How to Cite
VIRGO, N., LAW, R. and EMMERSON, M. (2006), Sequentially assembled food webs and extremum principles in ecosystem ecology. Journal of Animal Ecology, 75: 377–386. doi: 10.1111/j.1365-2656.2006.01058.x
Publication History
- Issue published online: 31 MAR 2006
- Article first published online: 31 MAR 2006
- Received 7 January 2005; accepted 28 October 2005
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Keywords:
- ascendency;
- goal function;
- invasion resistance;
- permanence;
- succession
Summary
- 1Successional changes during sequential assembly of food webs were examined. This was carried out by numerical methods, drawing one species at a time from a species pool and obtaining the permanent (persistent) community emerging at each step. Interactions among species were based on some simple rules about body sizes of consumers and their prey, and community dynamics were described in terms of flows of biomass density.
- 2Sequential assembly acted as a sieve on the communities, assembled communities having many properties different on average from those of feasible, stable communities taken at random from the species pools.
- 3Time-series of community development were consistent with certain functions thought to go to an extremum (maximum or minimum) in ecosystem ecology, including a rapid early increase in net primary productivity and ascendency, although a clear trend in total biomass density was not evident and resilience decreased rather than increased.
- 4In addition, more gradual changes in food web structure took place during succession to which the ecosystem goal functions were relatively insensitive. These changes included gradual increases in the number of species, invasion resistance, number of loops of length > 2 and number of prey species per consumer species.
- 5We therefore argue that ecosystem and community dynamics can offer complementary insights into the process of ecological succession. The extremum principles of ecosystem ecology highlight some of the major properties of succession, whereas the community ecology sheds light on some more subtle changes taking place within the networks.