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Mitigation ponds offer drought resiliency for western spadefoot (Spea hammondii) populations

May 25, 2020

Synergistic effects of habitat loss, drought, and climate change exacerbate amphibian declines. In southern California urbanization continues to convert natural habitat, while prolonged drought reduces surface water availability. Protection of biodiversity may be provided through mitigation; however, the long-term effectiveness of different strategies is often unreported. As a mitigation measure for building a new development within occupied Spea hammondii (western spadefoot) habitat in Orange County, California, artificial breeding pools were constructed at two off-site locations. Spea hammondii tadpoles were translocated from the pools at the development site to two off-site locations in 2005–2006. We conducted surveys a decade later (2016) to determine if S. hammondii were persisting and breeding successfully at either the original development site or the human-made pools at the two mitigation sites. We also verified hydroperiods of any existing pools at all three locations to see if any held water long enough for successful S. hammondii recruitment through metamorphosis.

During our study, no pooling water was detected at two of three main sites surveyed, and no S. hammondii were observed at these locations. Twelve of the 14 pools created at only one of the two mitigation sites held water for over 30 d, and we detected successful breeding at seven of these pools. Recruitment in some mitigation ponds indicated that S. hammondii habitat can be created and maintained over 10+ yr, even during the fifth year of a catastrophic drought. Therefore, this may also serve as a conservation strategy to mitigate climate change and habitat loss.

Citation Information

Publication Year 2020
Title Mitigation ponds offer drought resiliency for western spadefoot (Spea hammondii) populations
DOI 10.3160/0038-3872-119.1.6
Authors Katherine L. Baumberger, Adam R. Backlin, Elizabeth Gallegos, Cynthia Joan Hitchcock, Robert N. Fisher
Publication Type Article
Publication Subtype Journal Article
Series Title Bulletin, Southern California Academy of Sciences
Index ID 70210617
Record Source USGS Publications Warehouse
USGS Organization Western Ecological Research Center

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