Thesis

Habitat Occupancy of Bobcats (Lynx rufus) in an Urban Fragmented Landscape

Urbanization subdivides natural landscapes creating isolated fragments separated by novel urban habitats. Species vary in their sensitivity to the process of urban fragmentation where some species can tolerate living in urban areas by exploiting resource subsidies. Mammalian carnivores have been shown to vary in their sensitivity to urban fragmentation where more tolerant species can exploit anthropogenic resources. Bobcats (Lynx rufus) represent an intermediate response to urban fragmentation as they are present in fragmented natural areas but do not thrive in urban development. Bobcats are known to enter urban areas and may tolerate urban fragmented landscapes by harvesting prey from urban environments. Using resource selection functions (RSFs), I modeled the habitat occupancy of 7 female bobcats in the urban fragmented landscape of Thousand Oaks, California. Occupancy models were compared to the distribution and abundance of cottontail rabbits (Sylvilagus spp.) to test if bobcats use urban areas due to an inflated urban rabbit population. Bobcats did go into urban areas, primarily at night; however, rabbit densities in urban areas varied more than rabbit densities in natural habitats. Bobcats occurred more frequently in coastal sage scrub habitats and used habitat edges during nocturnal hours. Rabbit densities in natural habitat patches were the most stable with highest densities in natural edge habitats. Bobcats appear to tolerate urban fragmented landscapes by behaviorally adjusting to resource distribution in natural habitat patches, and not by exploiting urban resource subsidizes. As landscapes become more urbanized, the presence of bobcats can be used to evaluate the ecological integrity of natural fragments as bobcat presence in these areas is likely not mitigated by urban resources.

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