UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

A spatial simulation model for evaluating the response of rare and endangered species to conservation strategies and forest practices: a case study on the northern spotted owl Demarchi, Donald Andrew


A spatially explicit forest harvesting and individual-based population simulation model has been developed. This model was used to assess the response of rare or endangered forest wildlife to forest harvesting policies and conservation options. A specific focus was on the examining the efficacy of proposed management options for the northern spotted owl population in British Columbia. The forest harvest simulation component was used to construct spatial and temporal patterns of logging activities in the Fraser and Soo timber supply areas. Forest simulations were based on a forest inventory database of 25-ha resolution, and simulated harvests were subject to constraints imposed by the Forest Practices Code and wildlife conservation options. The delineation of breeding territories over this database was done using a submodel that maps likely territory areas following geographic constraints of the landscape, resulting in a "mosaic" of variously shaped territories. This allowed for aggregation of the finer scale forest-state data into simple indices of habitat quality for owls. These indices were updated on a yearly basis as the forest either aged or was harvested. The individual-based population simulator used "coarser" territory/habitat maps to simulate dispersal, location and fates of individual female owls (i.e., breeding pairs). Simulations suggest that a major limiting factor is the low survival rate of dispersing juvenile owls. The proposed management plans do not adequately address this problem and may, in fact, be detrimental to the owl population. These small conservation areas increase logging pressure on the surrounding areas. As a result, juveniles are forced to disperse from their natal habitats into marginal habitats where the risk of mortality is increased. Reduction in the annual allowable cut is more important than any proposed configuration of Spotted Owl Conservation Areas.

Item Media

Item Citations and Data


For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.