Population Ecology and Conservation Translocation of the Narrow-Headed Gartersnake in Central Arizona

Abstract

The narrow-headed gartersnake (Thamnophis rufipunctatus) is a federally threatened species endemic to the Mogollon Rim in central Arizona and western New Mexico. This species has declined its range primarily due to habitat loss, degradation and invasive species. Additional information on this species’ ecology, particularly empirical estimates of movement and demographic parameters, are particularly important for the management and conservation of this species. We conducted a three-year mark-recapture study of narrow-headed gartersnakes in Canyon Creek in central Arizona. In chapter 1, we compared capture rates, individual growth rates, movement, and apparent survival between narrow-headed gartersnakes and a syntopic, non-imperiled species of gartersnake, the western terrestrial gartersnake (Thamnophis elegans). While we captured more western terrestrial gartersnakes during our study, we did not find marked differences between these two species in the metrics we examined. We also documented the successful application of passive PIT tag arrays for monitoring PIT-tagged gartersnakes. In chapter 2, we evaluated the post-release growth, movement, and apparent survival zoo-born narrow-headed gartersnakes from the Arizona Center for Nature Conservation/Phoenix Zoo’s breeding program and compared these metrics to those of wild narrow-headed gartersnakes. We released four different groups of zoo-born individuals representing two cohorts (young-of-year and holdover). We documented multiple instances of survival across one and two winters post-release by zoo-born individuals from The Arizona Center for Nature Conservation/Phoenix Zoo. We did not find marked differences between zoo-born and wild individuals although holdover individuals tended to have the greatest movement distances and lowest apparent survival. Our results can provide guidelines for the future use of conservation translocations for narrow-headed gartersnake recovery.