AMERICAN BADGER AND BURROWING OWL HABITAT SUITABILITY ASSESSMENT
|Tanya Diamond; Pathways for Wildlife; email@example.com; Ahiga Sandoval, Jessie Quinn, Ken Hickman, Yiwei Wang, Dan Wenny, Karine Tokatlian
American badger (Taxidea taxus) and western burrowing owl (Athene cunicularia hypugaea) occur in the San Francisco peninsula however information about their population status and distribution was limited. The Midpeninsula Regional Open Space District (District) funded a study of both species in order to best manage them and their habitats within District properties, and to contribute to regional species conservation. Study methods included GIS analysis to create habitat suitability models and a badger linkage model, field surveys and camera trapping to ground truth models, and genetic analysis of badger hair. More than half (58%) of all collected badger observations were found within six District properties clustered along Skyline Ridge/Hwy 35. Model results show that badger habitat in the peninsula is heavily fragmented by natural and anthropogenic factors, and their pathways of movement are narrowly restricted which highlights the importance of maintaining landscape permeability for this wide ranging species. Three primary badger movement linkages were identified: 1) a central network of habitat connections between District properties along Skyline Ridge/Hwy 35, 2) a coastal linkage running from north of San Mateo down to Santa Cruz, and 3) an eastern linkage running from Skyline Ridge/Hwy 35 to Coyote Valley. The coastal linkage provides more suitable badger habitat compared to the eastern linkage and may be the only viable pathway for badgers to reach the central District population. Results suggest that moderate grass management is beneficial for both species. Results supported anecdotal knowledge that burrowing owls winter in some District properties but do not breed there. Twenty-five individual badgers were identified using genetic analysis, eleven of which were collected within District properties, however sample amplification rates were not successful enough to calculate a badger population size in the peninsula. Results suggest that badgers on the peninsula appear to be an isolated population with some degree of inbreeding, and as less genetically diverse than populations to the north and south. The District is pursuing opportunities to continue genetic sampling achieve a badger population size metric. Results inform an array of future management opportunities include maintaining grassland connectivity, identifying and enhancing bottlenecks along linkages (wildlife friendly culverts, vegetation management), using artificial burrows to enhance existing wintering owl habitat, acquiring properties to strategically support grassland connectivity, and develop regional support for species conservation and listing consideration.