Relating the population genetic structure of woodland caribou to landscape connectivity.
Pither, Richard*,1, 2, Manseau, Micheline1, 2, Clark, Jeff2, Ball, Mark3, Wilson, Paul3, Arsenault, Alan4, 1 Parks Canada, Winnipeg, Manitoba, Canada2 University of Manitoba, Winnipeg, Manitoba, Canada3 Trent University, Peterborough, Ontario, Canada4 Saskatchewan Fish & Wildlife Branch, Regina, Saskatchewan, Canada
ABSTRACT- We examined the relationship between the genetic structure of woodland caribou (Rangifer tarandus caribou) populations and landscape connectivity at the regional and local scales. Research was conducted on ten populations in Saskatchewan and Manitoba, Canada. Fecal pellets were collected in winter from more than 300 individuals. DNA was extracted from the pellets and amplified with six microsatellite markers, a mtDNA control region marker, and a high molecular weight, sex-linked marker. Landscape analyses were based on spatial graph theory. Landscapes are represented by a mathematical graph, consisting of nodes representing high quality habitat patches and links representing the shortest or least-cost path connecting patches. The links are based on movement costs and reflect the functional connectivity of the landscape. Digital land cover maps were created using forest inventory data from government and industry sources. Land cover classes and movement cost data were derived from telemetry data collected from woodland caribou fitted with GPS collars in Manitoba. Preliminary results indicate that levels of population genetic differentiation (FST) were higher among Manitoba populations than among populations in Saskatchewan. This pattern corresponds to a lower level of landscape connectivity arising from natural physiographical barriers in Manitoba. At the local scale, the levels of expected heterozygosity (mean HE = 0.711) for most populations were comparable to those of woodland caribou in other provinces. However, one population, at the southern edge of the species′ range in Manitoba, had significantly lower (p < 0.001) genetic variation than other populations. Limited landscape connectivity appears to be exacerbating uni-directional gene flow for this population. Our findings reveal potential genetic consequences of reduced landscape connectivity arising from the expansion of industrial activities and highlights the challenge of protecting this threatened species, especially at the southern edge of its range.
Key words: Rangifer tarandus, population genetic structure, landscape connectivity, threatened species
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