RELEASE OR TRANSLOCATION HABITAT FOR THE ENDANGERED BLUNT-NOSED LEOPARD LIZARD (GAMBELIA SILA) | |||
Emily E Bergman; Fresno Chaffee Zoo; ebergman@fresnochaffeezoo.org; Steve Hromada, Steven Sharp, Mark Halvorsen, Lynn Myers, Michael Westphal, Rory Telemeco | |||
Blunt-nosed Leopard Lizards (Gambelia sila) are a federal- and endangered species and have fully-protected status in California. Until recently, this prevented issuance of incidental take permits (ITPs) for G. sila and thus translocation from project sites to protected areas. This restriction was recently loosened, and translocation may soon be permitted under some scenarios, In 2020, Fresno Chaffee Zoo received emergency permission to collect 7 lizards from Panoche Plateau to form a captive breeding colony and repatriate offspring back to Panoche Plateau, providing an opportunity to understand the conditions necessary for colonization or translocation. Over 2023 and 2024 we released 137 yearling (~10-month old) lizards back to Panoche Plateau outfitted with radio-transmitters for post-release monitoring. High precipitation in 2022-2023 resulted in high cover of invasive annual grasses, drastically reducing habitat quality. We manually mowed 50m2 plots around our 2023 release locations. Released lizards used less area than three remnant wild lizards at the plateau or lizards in a neighboring wild population despite mowing, likely because thatch still hindered movement. Instead of mowing in 2024, we selected release locations that had features heavily utilized by wild G. sila such as access to open ground , burrows, and shrubs for thermoregulation and predator protection. Although lizards released in 2024 had higher rates of predation, they used more area and behaved more naturally than lizards released in 2023. Our observations suggest that successful translocation of G. sila will require release sites to include the key features that we selected in 2024, and if thatch is present releases are unlikely to be successful. | |||
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