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Population genetic connectivity patterns in the endangered blunt-nosed leopard lizard Gambelia sila reveal clues about the former landscape of California’s San Joaquin Desert

Released: 2015
Citation:
Richmond, JQ, DA Wood, MF Westphal, RN Fisher. 2015. Population genetic connectivity patterns in the endangered blunt-nosed leopard lizard Gambelia sila reveal clues about the former landscape of California’s San Joaquin Desert. American Society of Ichthyologists and Herpetologist 2015 Annual Meeting, Reno, Nevada. 15-19 July 2015. 

Since the late 1800s, California’s San Joaquin Desert has become an infamous hotspot of threatened and endangered species due to the rapid and near complete transformation of this ecoregion’s natural landscape. Much of the Desert encompasses the San Joaquin Valley, an area historically partitioned by a series of westward draining rivers and creeks that emptied out of the Sierra Nevada and into three large lakes on the Valley floor. These lakes, their surrounding wetlands, and riparian areas along the rivers that fed them, may have presented barriers to gene exchange for a number of xeric-adapted vertebrate species like the endangered blunt-nosed leopard lizard Gambelia sila, a San Joaquin Valley endemic that inhabits sparsely vegetated desert scrub habitat. We used mtDNA sequences, microsatellite allele frequency data, and restriction-associated digest sequences from 18 locations covering the range of G. sila to test the extent to which population structuring and gene exchange were shaped by mesic habitat or other barriers within this otherwise desert ecoregion. Our results suggest that wetland and riparian areas did little to impede historical movement across the Valley floor, and instead point to precipitation patterns owing to topographic effects as a more cogent factor in determining population structuring and directionality of gene flow. This work identifies areas that were important dispersal corridors for G. sila prior to humanity’s major alteration of the landscape, and can be used to guide habitat restoration efforts for this and numerous other xeric-adapted species of conservation concern in the San Joaquin Desert.

 

 

 

 



This product is associated with the following project:
Mapping habitat and genetic diversity in the desert southwest

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