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The Montana Cooperative Wildlife Research Unit

The University of Montana

Mitchell, M. S., and R. A. Powell.  2004.  A mechanistic home range model for optimal use of spatially distributed resources.  Ecological Modelling.  177:209-232 [PDF]

The Questing Beast (Q_BEAST.SAS) is a spatially explicit, individual-based model for generating simulated home ranges that are optimal with respect to spatially distributed resources. The model allows 1 of 2 optimization strategies to be explored, resource-maximization and area-minimization. The model also allows the user to evaluate effects of resource depression on home ranges, as well as effects of differing resource thresholds on area-minimizing home  ranges.  As currency for optimization, the model uses georeferenced values ranging from 0 to 1, representing an index of habitat quality (variable NDX). To allow the user to evaluate how optimal home ranges might vary with different spatial distributions of NDX, 5 different simulated landscapes are provided, each differing in the spatial continuity of NDX.  The program is written in SAS v8 language, and makes use of SAS data sets for storing both input and output for the model.

Q_BEAST.SAS: SAS program for simulating optimal home ranges.


The following ZIP file needs to be downloaded and saved to a SAS working directory to run the Questing Beast:

SAS HABITAT.ZIP

HABITAT1.sas7bdat: SAS dataset containing georeferenced NDX values representing a landscape with highly discontinuous, over-dispersed resources (Moran’s I = -0.8). Each NDX value is a different as possible from its neighbors, resulting in a lattice-like landscape.

HABITAT2.sas7bdat: SAS dataset containing georeferenced NDX values representing a landscape with randomly distributed resources (Moran’s I=0). 

HABITAT3.sas7bat: SAS dataset containing georeferenced NDX values representing a landscape with slightly clumped resources 
(Moran’s I=0.35).

HABITAT4.sas7bat: SAS dataset containing georeferenced NDX values representing a landscape with moderately clumped resources (Moran’s I=0.71).

HABITAT5.sas7.bat: SAS dataset containing georeferenced NDX values representing a landscape with highly clumped resources  (Moran’s I=0.89).

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