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Potential Genetic Distinctiveness of the Disjunct Western Yellow Rail Population
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Breeding Yellow Rails are widely distributed in marshes across the boreal and plains zones of Canada and the northernmost U.S. states, with the exception of approximately 600 Yellow Rails that breed in Klamath and western Lake counties in south-central Oregon. Half of these use the Klamath Marsh National Wildlife Refuge, the rest occur in marshes on private and Federal lands within a 45 mile radius of Klamath Marsh NWR. Field work (by Ken Popper, Mark Stern, and Susan Lundsten) has yielded good information on habitat requirements of Yellow Rails which will help in their management, but little is known about where they winter, their needs during migration, and their relatedness to other breeding populations.
Historical records suggest that Yellow Rails have long occupied marshes in the western U.S. There are breeding records from Mono Co., CA from the 1920’s to 1950, and breeding in OR was confirmed at Aspen Lake, Klamath Co. in 1926. Inventories beginning in 1982 confirmed a more extensive distribution in the Klamath region. Historical and a few recent records suggest that these rails winter in California’s bay-delta, the Central Valley, and possibly in Humboldt Bay marshes. All this suggests that a disjunct breeding population has existed for some time along the eastern margin of the Cascade-Sierra crest, and that they migrate to coastal regions in the winter. Traditional taxonomic treatment has distinguished only two subspecies in North America, Coturnicops noveboracensis noveboracensis in the U.S., and C. n. goldmani in Mexico (not seen since 1964), but western birds have not received careful scrutiny to date. Banding studies over the last 10 years throughout their range show no evidence of interaction between the eastern and western populations. Genetic analyses are the next step to help us confirm the supposition that this very small and geographically isolated population is also genetically unique.
This project comprises two stages; this first stage in FY05 will develop genetic markers (control region mitochondrial and microsatellite DNA) necessary to carry out later analyses using other funds. In the second stage we will use mitochondrial and microsatellite DNA to test the hypothesis that the genetic structure of western Yellow Rails is no different from birds breeding east of the Rockies in FY06
In 2005 we will collect 15-20 samples from each of at least 5 to 10 distinct breeding areas, including Oregon. Considerable material likely already exists in museum collections and universities from studies on Yellow Rails carried out in the Great Lakes area, in Canada. Forty or more specimens from California reside in various California collections. Samples will be feathers or blood, although other material might be available from which DNA could be extracted. Field sampling protocol can be seen at the Haig Lab Conservation Genetics website (http://fresc.usgs.gov/staff/haig/conservation/).
Microsatellite DNA- Microsatellite markers will be developed for Yellow Rails from Sterptaviden M-280 enriched libraries. A minimum of 10 polymorphic loci will selected as per Waits et al. (2001). Statistical tests for microsatellite genetic analyses will be performed using genetic analysis software GENEPOP and F-STAT. Multi-scale genetic diversity will be measured and deviations from Hardy-Weinberg equilibrium (HWE) and linkage disquilibria over all and within populations will be tested. Evidence of recent small effective population size will be evaluated using program BOTTLENECK. Molecular variance analysis will be performed using (AMOVA) at different hierarchical levels (within, among population and regions). 0 will be used to estimate geneflow. Association between population Euclidean, geographical and pairwise genetic distances will be assessed by nonparametric Mantel tests.
Mitochondrial DNA (mtDNA) - An 800 bp portion of region I and II of the mtDNA control region will be sequenced using universal primers. ARLEQUIN version 2.0 will be used to determine total number of haplotypes, polymorphic sites, haplotype diversity (h), nucleotide diversity (pi), and tests of assumptions of neutrality for mtDNA mutations by Tajima’s D will be performed. Population differentiation will be calculated between populations and subspecies and molecular variance analysis will be performed using (AMOVA) at different hierarchical levels (within, among population, regions and subspecies). Mitochondrial DNA population structuring will be assessed by calculating pairwise FST values. Associations between population Euclidean geographical and pairwise genetic distances will be assessed by nonparametric Mantel tests. To discriminate between recurrent and historical gene flow nested clade analysis will be performed using the programs TCS 1.13 and GeoDis 2.0.
Haig, Susan M. - Supervisory Research Wildlife Biologist
Phone: 541-750-7482
Email: susan_haig@usgs.gov
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