Impacts Of Roads On The Population Genetic Structure Of The Lizard Uta stansburiana In The Northern Chihuahuan Desert

Urbanization can have significant ecological effects on natural populations, including habitat fragmentation through increased road density. One road effect of concern is their potential to limit wildlife movements. Roads may disrupt gene flow, causing increased inbreeding, decreased genetic diversity, and increased genetic differentiation. In this study we investigate how two roads, interstate highway I-10 and rural country road NM-9, affect population genetic structure of side-blotched lizards (Uta stansburiana) in the northern Chihuahuan Desert of New Mexico. Tissue samples were collected on both sides of each road, plus one control site per road. Nine microsatellite loci were amplified to determine signatures of disrupted gene flow. Genotypes were obtained for 197 individuals from four sites, one from I-10 (n=78) and three from NM-9 (n=54, 52, 13), a total of eight sub-populations. Preliminary results indicate similar levels of genetic diversity within sub-populations. Mean effective allelic richness ranged from 1.9 to 2.4 alleles/locus. Mean heterozygosities over all loci ranged from 0.34 to 0.42. Pairwise F_ST values (0.008 to 0.032) and Nei’s genetic distances (0.008 to 0.036), indicate negligible genetic differentiation between the sub-populations. Results show that sub-populations are genetically indistinguishable from each other, even populations separated by 50 km. Genotypes from individuals from the remaining sites, along with locations outside the study area, will provide further information about levels of population differentiation across the landscape. These results, combined with those from an associated demographic study, will aid our understanding of how roads impact lizard dispersal and the genetic diversity of their populations.