Genetic diversity within species

Abstract

Based on our review of literature and survey of geneticists workingon California taxa, we find genetic information lacking for most speciesin the Sierra Nevada. This situation is likely to remain infuture, with specific groups of taxa or occasional rare or high-interestspecies receiving specific study. Where we do have empirical information,we find few generalities emerging, except occasionally withinclosely related or ecologically similar taxa. Despite these difficultiesin assessing genetic diversity, we direct attention to situations estimatedto be most deserving of attention from a genetic standpoint.Severe wildfire: With the significantly increased risk of severefires currently facing the Sierra Nevada, large, stand-replacingfires present significant risks to gene pools of most middle- andlow-elevation Sierran forests, with direct and indirect consequencesto the genetic diversity of plants and animals that livein them.Habitat alteration: For most taxonomic groups evaluated in theSierra Nevada, the major threat to genetic diversity is habitatdestruction, degradation, or fragmentation. Estimated effectsinvolve not only direct losses of population-level genetic structuraldiversity but also changes in genetic processes (gene flow,selection), effective population sizes, and genetically based fitnesstraits...

Citation

Rogers, D. L., Millar, C. I., and Westfall, R. D. 1996. Genetic diversity within species. Sierra Nevada Ecosystem Project, Final report to Congress, Volume II, Assessments and Scientific Basis for Management Options, Centers for water and Wildland Resources, Report No. 37, University of California, Davis, California