Long-term monitoring of Dunes Sagebrush Lizards in New Mexico: understanding population trends for conservation insight
Iacchetta, Michael
Acre, Matthew R.
U.S. Geological Survey
Columbia Environmental Research Center
Columbia, Missouri, USA
Hill, Michael T.
Albuquerque, New Mexico, USA
Leavitt, Daniel J.
U.S. Fish and Wildlife Service
Arizona Ecological Services Office
Phoenix, Arizona, USA
Long-term population monitoring projects produce critical information to elucidate the changing demographics of community assemblages and/or target species, including at-risk species. The Dunes Sagebrush Lizard is state listed as endangered in New Mexico, and the species is (once again) proposed to be listed as endangered by the U.S. Fish and Wildlife Service. The Dunes Sagebrush Lizard occupies shinnery oak dunelands, a rare and fragmented habitat type in southeastern New Mexico and adjacent west Texas. To determine the population trends of the Dunes Sagebrush Lizard, we conducted long-term mark-capture-recapture at eight sites across the Dunes Sagebrush Lizard range within New Mexico under standardized monitoring methodology. We also used historical pitfall trapping and publicly available abiotic data to produce abundance models across the species distribution in New Mexico. This starting abundance estimate and life-history information were combined to project the species probability of persistence through population viability analysis (PVA). This PVA was conducted to identify critical parameters that may drive demographics of Dunes Sagebrush Lizard and could be used to better manage the species. Population models from contemporary sampling revealed population vital rates, such as survival and immigration, were greater in 2023 compared to previous years. Overall, population estimates trended positive, except for one site where lizards may have been extirpated. Estimated immigration rates were relatively high (0.92), emigration was moderately high (0.64), and survival was high in 2023 (0.77- 0.78), nearly double the previous year, a trend which has been consistent over the last three years of monitoring. We will continue monitoring efforts with the New Mexico populations of this lizard and conduct additional studies to quantify the lizard’s response to habitat restoration efforts.