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Historic Drought Helps Predict How Climate Change Might Affect an Endangered Species

BLM LogoExtreme 2012-2014 drought a "crystal ball" into future climate change

The Bureau of Land Management, the University of California at Santa Cruz, and The Nature Conservancy announce the release of a new study documenting the negative effects of the 2012-2014 drought, the most severe multi-year drought in southwestern North America in the past 1200 years, on an endangered lizard in the San Joaquin Desert of California. The results provide a unique glimpse into the potential effects of future droughts expected in California as a result of climate change, and provide guidance on how to buffer these negative effects to avoid species extinction.

The fieldwork for the study, which appeared in the May 2 online journal PLoS One, was conducted in the fall of 2014. Preliminary surveys of endangered blunt-nosed leopard lizards in the San Joaquin Desert of California revealed that some populations failed to reproduce during the drought, causing concern about potential extinction effects on this critically endangered species. To determine whether this phenomenon was widespread or isolated to particularly vulnerable populations, researchers rapidly deployed personnel to conduct surveys of all known blunt-nosed leopard lizard populations.

"When the drought hit, we were positioned to team up with our partners and take advantage of this unique opportunity to assess the potential effects of climate change on a vulnerable species," said Mike Westphal, BLM ecologist and lead author of the study. "Thanks to the geographic nature of the study, we were also able to identify key climate refugia for the species."

Previous studies had documented links between drought and reproduction in populations of blunt-nosed leopard lizards. Because the drought produced geographic variation in the amount of rainfall across all of the populations of blunt-nosed leopard lizards, the new study was able to demonstrate this relationship range-wide, allowing researchers to exploit the drought to predict how future climate change might affect the extinction potential of the blunt-nosed leopard lizard and other desert-adapted endangered species.

"This study has serious implications not just for animals in California, but potentially for species all over the world affected by climate change. Our work suggests that the drought of 2012-2014 has had serious effects on the long-term survival of the blunt-nosed lizard, and significant intervention may be needed to preserve the future of these animals," said Scott Butterfield, The Nature Conservancy scientist and study coauthor. "As we consider the fallout from rising temperatures in California, it's important to think of what would best help species like the blunt-nosed leopard lizard survive – which includes preserving valuable desert habitat."

The study provides an excellent example of how collaborative research among land management agencies, wildlife agencies, non-governmental organizations, and universities can produce important insights into the potential effects of climate change. The results of the study are anticipated to guide ongoing conservation efforts in the San Joaquin Desert region of California. More importantly, the success of the study should provide encouragement to other researchers to take full advantage of extreme weather events such as historic droughts to learn about the future potential effects of climate change.