A guide to central place effects in foraging.
We develop a general patch-use model of central place foraging, which subsumes and extends several previous models. The model produces a catalog of central place effects predicting how distance from a central place influences the costs and benefits of foraging, load-size, quitting harvest rates, and giving-up densities. In the model, we separate between costs that are load-size dependent, i.e. a direct effect of the size of the load, and load-size independent effects, such as correlations between distance and patch qualities. We also distinguish between predictions of between- and within-environment comparisons. Foraging costs, giving-up densities and quitting harvest rates should almost always increase with distance with these effects amplified by increases in metabolic costs, predation risk and load-costs. With respect to load-size: when comparing foraging in patches within an environment, we should often expect smaller loads to be taken from distant patches (negative distance-load correlation). However, when comparing between environments, there should be a positive correlation between average distance and load-size.
Olsson
Ola
O
Department of Animal Ecology, Lund University, Sweden. ola.olsson@zooekol.lu.se
Brown
Joel S
JS
Helf
Kurt L
KL
D000818:Animals; D005106:Exploratory Behavior; D005247:Feeding Behavior; D015233:Models, Statistical; D008962:Models, Theoretical