Isolation of peripheral populations of Canada lynx (Lynx canadensis)

Abstract

Landscape barriers to gene flow, such as rivers, can affect animal populations by limiting the potential for rescue of these isolated populations. We tested the riverine barrier hypothesis, predicting that the St. Lawrence River in eastern Canada would cause genetic divergence of Canada lynx (Lynx canadensis Kerr, 1792) populations by restricting dispersal and gene flow. We sampled 558 lynx from eastern Canada and genotyped these at 14 microsatellite loci. We found three genetic clusters, defined by the St. Lawrence River and the Strait of Belle Isle, a waterway separating Newfoundland from mainland Canada. However, these waterways were not absolute barriers, as we found 24 individuals that appeared to have crossed them. Peripheral populations of lynx are threatened in parts of Canada and the USA, and it is thought that these populations are maintained by immigration from the core. Our findings suggest that in eastern North America, rescue might be less likely because the St. Lawrence River restricts dispersal. We found that ice cover was often sufficient to allow lynx to walk across the ice in winter. If lynx used ice bridges in winter, then climate warming could cause a reduction in the extent and longevity of river and sea ice, further isolating these peripheral lynx populations.

Genome‐scale sampling suggests cryptic epigenetic structuring and insular divergence in Canada lynx

“…Our covariates included a binary variable of insularity, which identified the Newfoundland population against mainland populations and was used to describe the largely impassable barrier of the Strait of Belle Isle between Newfoundland and mainland Labrador (Koen, Bowman, & Wilson, ). Although the strait is only 17.6 km at its narrowest (South, ) and is covered with an ice bridge for portions of the year, lynx avoid unforested habitats (Murray, Boutin, & O'Donoghue, ) and microsatellite analyses have identified only minimal rates of migration between Newfoundland and the mainland (Koen et al, ). A variable of geographic distance was included which was simply the first axis of a principal coordinates analysis (PCoA) on a Euclidean distance matrix of latitude and longitude (PCo1 = 99.7% of the variation, Figure ).…”

Selection and drift influence genetic differentiation of insular Canada lynx (Lynx canadensis) on Newfoundland and Cape Breton Island

“…With the exception of Cape Breton Island, the samples we used in this study were the same as those in Koen et al. (), with some small changes in sample size. We collected hide samples from lynx that were harvested for their fur in Quebec ( N = 493), Labrador ( N = 21), and Newfoundland ( N = 27) between 2008 and 2011.…”

“…We used manual scores from Koen et al. () for all other samples. We omitted samples that were missing alleles at more than 2 of the 14 microsatellite loci.…”

Climate connectivity of the bobcat in the Great Lakes region

“…A species’ dispersal capability might depend on its physiological limitations (Travis et al, ), its demography (Clark, Lewis, & Horvath, ), or its behavior (Ehrlich, ; Pusey, ; Warren et al, ). Large physical barriers such as mountains, oceans, lakes, and rivers can impede movement of individuals, disrupting gene flow (Grant & Grant, ; Koen, Bowman, & Wilson, ; Stebbins, ; Steeves, Anderson, McNally, Kim, & Friesen, ).…”

“…The Great Lakes are visibly the largest natural barrier to terrestrial species migration in eastern North America. Currently, we do not know for many species to what extent the Great Lakes have influenced movement and consequently gene flow, although the impacts are likely profound; much smaller barriers such as canals, highways, mountains, rivers, roads, sea lochs, and urban development have been shown to restrict the gene flow of many terrestrial vagile species (Blanchong et al, ; Coulon et al, ; Cushman & Lewis, ; Epps et al, ; Koen et al, ; Kuehn et al, ; Pérez‐Espona et al, ; Proctor, McLellan, Strobeck, & Barclay, ; Riley et al, ; Robinson, Samuel, Lopez, & Shelton, ; Robinson, Samuel, Rolley, & Shelton, ; Vander Wal, Paquet, & Andraés, ). Unfortunately, the additive influence of anthropogenic disturbance between and within the vicinity of the Great Lakes will likely further restrict gene flow through these large natural barriers for many species.…”