Document: AND-3-51-17
Ontogenetic niche shifts, flexible behavior and size-structured population dynamics.
DE ROOS, A.M.* 1, K.LEONARDSSON 2, L.PERSSON 2 and G.MITTELBACH 3
University of Amsterdam, The Netherlands 1
Umea University, Sweden 2
Michigan State University, Michigan, USA 3
Abstract:
Flexible behavior in animals has been suggested to have substantial effects on population dynamics. Characteristic for theoretical studies on the implications of flexible behavior for population dynamics is that individual level processes such as foraging rate have been linked to population processes using traditional non-structured predator-prey models. This situation contrasts to the fact that a vast number of experimental studies on flexible predator and prey behavior concern organisms of populations which are typically size/stage-structured. To study the consequences of flexible individual behavior for the stability and persistence of size-structured consumer-resource systems, we analyzed a size-structured population model for a single consumer and two resource populations, each of which lives in its own habitat. Shifts by individual consumers between the habitats were based on a decision rule taking both growth and mortality risk into account. We considered two types of habitat shifts: (1) a single, instantaneous ontogenetic niche shift during consumer life history and (2) a continuous shifting back and forth between habitats, representing a flexible response to current growth and mortality conditions. Flexible behavior was shown to increase persistence of the consumer population, but its influence on population dynamics was small, when population persistence did not critically depend on it. In case flexible behavior has a population dynamical effect, its influence was mainly to induce population cycles by intensifying the competition among cohorts of different sizes.
Keywords: Flexible behavior, size-structure, Ontogenetic niche shifts, population dynamics
This abstract is being presented at: 1:30 PM in session:
Oral Session #46: Modeling Populations and Statistical Ecology.