LOSS AND IMPENDING RECOVERY OF PANOCHE PLATEAU BLUNT-NOSED LEOPARD LIZARDS (GAMBELIA SILA)
|Rory S Telemeco; Fresno Chaffee Zoo; RTelemeco@fresnochaffeezoo.org; Mark Halvorsen, Lynn Myers, Steven Sharp, Michael Westphal
Panoche Plateau supported a robust, genetically distinct population of federal- and CA-endangered Blunt-nosed Leopard Lizards (Gambelia sila) prior to 2014. However, following a drought in 2013-2014, the population declined and was extirpated by 2021. In 2020, our collaborative team from Fresno Chaffee Zoo, Fresno State University, and the US Bureau of Land Management began intensive monitoring of G. sila in the Panoche Hills, investigating multiple potential contributors to G. sila decline such as warming temperatures, predation pressure, pathogen pressure, and water availability. The bulk of evidence suggests that extirpation resulted from reproductive failure in 2014 followed by demographic collapse, potentially exacerbated by heavy recreational use of Panoche Plateau during the early part of the spring reproductive season. Delayed collapse following an extreme climate event could be common and suggests G. sila populations should be carefully observed both during and following the current drought. Otherwise, Panoche Plateau appears to still represent high-quality habitat for G. sila, with low predation pressure and parasite load paired with high-quality thermoregulatory habitat. In spring 2023, we will begin repatriating G. sila produced by the captive colony maintained by Fresno Chaffee Zoo to Panoche Plateau. Animals will be radio-monitored for their entire lives to estimate survival and reproductive output, and these data will be used to better understand habitat features that facilitate population persistence in G. sila.