DATE: 2005-10-14 06:59:55 +0900
論文セミナー 2005-10-14
Clark, JS, Mohan J, Dietze M and Ibanez I. 2003.
Coexistence: How to identify trophic trade-offs. Ecology 84:17-31.
Abstract:
Analyses of growth response to resource availability are the basis for
interpreting whether trophic trade-offs contribute to diversity. If
different species respond most to resources that are limiting at different
times, then those differences may trade off with other trophic or
life-history traits that, together, help to maintain diversity. The
statistical models used to infer trophic differences do not accommodate
uncertainty in resources and variability in how individuals use resources.
We provide hierarchical models for resource-growth responses that
accommodate stochasticity in parameters and in data, despite the fact that
causes are typically unknown. A complex joint posterior distribution taken
over > 102 parameters is readily integrated to provide a
comprehensive accounting of uncertainty in the growth response, together
with a small number of hyperparameters that summarize the population
response. An application involving seedling growth response to light
availability shows that large trophic differences among species suggested by
traditional models can be an artifact of the assumption that all individuals
respond identically. The hierarchical analysis indicates broad trophic
overlap, with the implication that slow dynamics play a more important role
in preserving diversity than is widely believed.