Researchers from York University have collaborated on a study investigating how climate change can impact the blunt-nosed leopard lizard (Gambelia sila), a federally endangered species that is at risk of extirpation.
Faculty of Science Professor Christopher Lortie and York University graduate students Nargol Ghazian, Malory Owen and Mario Zuliani worked with colleagues from California Polytechnic State University and the U.S. Bureau of Land Management to study how projected increases in ambient temperatures could put the animal at risk for localized extinction within the study site – the Elkhorn Plain in the Carrizo Plain National Monument, California. This area is characterized by extremely harsh, arid summers and cool winters.
Published in the journal Conservation Physiology, the study “Thermal ecology of the federally endangered blunt-nosed leopard lizard” shows that with projected 1 and 2 degrees Celsius increases to 2018 ambient temperatures, G. sila will lose additional hours of activity time that will compound stressors faced by this population potentially leading to extirpation.
“For animals (and plants) living at the edge of extreme conditions, even subtle nudges in climate can push species toward local extirpation from sites if not extinction,” said Lortie. “Large protected areas in Canada and in the U.S.A. are sanctuaries not just for biodiversity and natural beauty, but often refuges from competing anthropogenic pressures. If these climatic nudges continue, even with protected spaces, it will likely be challenging for many species to adapt or to move to other sites (that are likely not protected).”
Recognizing how climate change will impact populations can aid in making decisions about approaches for conservation of endangered species.
Researchers collected data on the field-active body temperatures, preferred body temperatures and upper thermal tolerance of G. sila. The investigation included: studying patterns in lizard body temperatures; quantifying the lizards’ thermoregulatory accuracy; determining the number of hours the lizards are currently thermally restricted in microhabitat use; projecting how the number of restricted hours will change as ambient temperatures rise; and assessing the importance of burrows and shade-providing shrubs in both current and future thermal ecology of the lizard.
Lizards maintained fairly consistent daytime body temperatures during the active season, and the use of burrows and shrubs increased as the season progressed and ambient temperatures rose. Researchers observed that the lizards are forced to seek refuge under shrubs and burrows for 75 per cent of daylight hours to avoid surpassing their upper thermal threshold.
This trend indicates that with an increase in ambient temperature and without adequate thermal buffers, the lizards will experience an increase in energy expenditure during the day resulting in loss of foraging opportunities, as well as decreased energy for reproduction and growth.
If nothing is done to mitigate the effects of climate change and make important decisions about the management of this habitat, the extirpation of this population and potentially extinction of the entire species is a distinct possibility.