Small reserves around hibernation sites may not adequately protect mobile snakes: the example of Great Basin Gophersnakes (Pituophis catenifer deserticola) in British Columbia

Abstract

A common strategy for reptile conservation is to establish reserves around nesting or hibernation sites. The government of British Columbia, Canada, mandates protection of 200–300 ha wildlife habitat areas (WHAs) around hibernation sites of the federally threatened Great Basin Gophersnakes ( Pituophis catenifer deserticola Stejneger, 1893), but practical constraints result in a mean size of 193 ha. To evaluate the efficacy of this reserve size, we radio-tracked 39 adult Gophersnakes at four study sites in the Okanagan Valley in 2006 and 2007. Home ranges averaged 10.5 ± 1.7 ha. The maximum distance traveled from a hibernation site was 2400 m, whereas the maximum distance dispersed averaged 520 ± 65 m. An idealized circular WHA of 193 ha with the hibernation site at the centre would be large enough to contain Gophersnake home ranges, but the dispersal data show that only 85% of snakes would stay within that area. Small or asymmetrical WHAs likely protect even fewer Gophersnake locations. We recommend that WHAs be expanded if possible because the high mobility of Gophersnakes suggests that current reserves may not offer adequate protection.