Description and application of program search: A newly developed spatially explicit population model
Abstract
Spatially explicit population models (SEPMs) are important tools for conservation, but have been criticized as being behaviorally minimalistic. SEPMs with simple behavior fail to exploit fully the potential benefits of including the complexity of animals' responses to space. To investigate questions related to behavioral mechanisms that occur at fine scales, I present Program SEARCH (Spatially Explicit Animal Response to Composition of Habitat), an individual based, behaviorally complex SEPM that allows researchers to simulate animal dispersal across complex, realistic landscapes while modeling a range of search processes and habitat selection rules. SEARCH can be used to simulate a wide variety of animals over multiple successive dispersal seasons. Temporally dynamic landscapes can be simulated in SEARCH to reflect changes in habitat quality and/or spatial arrangement. Animals in SEARCH are parameterized to reflect movement behavior, energetics, and home-range requirements. Baseline landscape and animal parameter values can be modified to reflect variability caused by gender, activity mode, behavioral mode, time of day, and date. As SEARCH can be run for multiple years, stochastic reproduction is modeled and resident females reproduce annually. To illustrate SEARCH's capabilities I first present case studies using 3 mammalian systems: eastern chipmunks ( Tamias striatus), raccoons (Procyon lotor), and American martens (Martes americana). In these systems I illustrate some of the novel capabilities of SEARCH and their effect on simulation results. I further apply program SEARCH to a raccoon population in north-central Indiana where virtual raccoons were parameterized using field and literature values. These values were calibrated using a pattern-oriented approach and the best-fit parameters were applied to validation runs simulating raccoon population reduction. The time to simulated recolonization of vacant forest patches was compared to observed times. In all cases, SEARCH underestimated reinvasion times for removal areas. Despite this, SEARCH has the potential to be applied to a number of study systems and can serve as an important tool for conservation research.
Degree
M.S.
Advisors
Zollner, Purdue University.
Subject Area
Wildlife Conservation|Ecology
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