Individual-based spatially-explicit model of an herbivore and its resource: the effect of habitat reduction and fragmentation

Authored by T Kostova, T Carlsen, J Kercher

Date Published: 2004

DOI: 10.1016/j.crvi.2003.11.010

Sponsors: United States Department of Energy (DOE)

Platforms: C++

Model Documentation: Other Narrative Mathematical description

Model Code URLs: Model code not found

Abstract

We present an individual-based, spatially-explicit model of the dynamics of a small mammal and its resource. The life histories of each individual animal are modeled separately. The individuals can have the status of residents or wanderers and belong to behaviorally differing groups of juveniles or adults and males or females. Their territory defending and monogamous behavior is taken into consideration. The resource, green vegetation, grows depending on seasonal climatic characteristics and is diminished due to the herbivore's grazing. Other specifics such as a varying personal energetic level due to feeding and starvation of the individuals, mating preferences, avoidance of competitors, dispersal of juveniles, as a result of site overgrazing, etc., are included in the model. We determined model parameters from real data for the species Microtus ochrogaster (prairie vole). The simulations are done for a case of an enclosed habitat without predators or other species competitors. The goal of the study is to find the relation between size of habitat and population persistence. The experiments with the model show the populations go extinct due to severe overgrazing, but that the length of population persistence depends on the area of the habitat as well as on the presence of fragmentation. Additionally, the total population size of the vole population obtained during the simulations exhibits yearly fluctuations as well as multi-yearly peaks of fluctuations. This dynamics is similar to the one observed in prairie vole field studies. (C) 2004 Academie des sciences. Published by Elsevier SAS. All rights reserved.

Tags

Diversity patterns Simulation-model Population-dynamics Microtus-ochrogaster Central illinois Home range size Prairie vole Eastern kansas Pennsylvanicus