Meeting Abstract

5.3  Jan. 4  Effects of human disturbance and global warming on hybridization and gene flow in two subspecies of White-crowned Sparrows (Zonotrichia leucophrys) HESS, Christopher M*; O’BRIEN, Sara; DAVIS, Jason; ADDIS, Elizabeth; WINGFIELD, John C. ; University of Portland; University of Washington; University of Washington; University of Washington; University of Washington hess@up.edu

Isolation is an important component in species formation and maintenance of biodiversity. This process of adapting to an environment can be inhibited by gene flow from neighboring populations. The earth is not a static place and periodically, environmental conditions change resulting in altered patterns of gene flow and causing certain taxa to expand or modify their range. There is increasing evidence that global changes at least indirectly caused by humans (i.e. global warming) have led to range shifts in groups such as Drospophila. Our field observations indicate that this process may also be occurring in vertebrates such as the White-crowned Sparrow in the state of Washington. The primarily lowland subspecies Z. l. pugetensis has increased its altitudinal range to the point that it now shares habitat with the montane subspecies Z.l.gambelli. We have observed individuals in the area of overlap that appear intermediate in both morphology and behavior, suggesting hybridization between the two groups, a pattern which was previously unknown in nature. To characterize the frequency of hybridization and to accurately document the rate of spread of alleles we are characterizing gene flow using neutral microsatellite markers. Ultimately, our estimates of gene flow will help us to predict the long term integrity of these two subspecies and begin understanding potential effects of global change on biodiversity.