Genetic Structure in Elk Persists After Translocation

Muller, Lisa; Murrow, Jennifer; Lupardus, Jason; Clark, Joseph; Yarkovich, Joseph; Stiver, William; Delozier, E; Slabach, Brittany; Cox, John; Miller, Bradley

ABSTRACT: Elk (Cervus canadensis) translocation success is thought to be facilitated by high post-release herd cohesion and limited movements; both should ensure genetic mixing following release. Such mixing is important to reduce potential effects of inbreeding or genetic drift, which can be especially important in small founding populations. We had a natural experiment where we could evaluate genetic mixing of 2 distinct lineages of elk after translocation to the same area. Founding elk ultimately came from north and south of a road barrier at Elk Island National Park (EINPN or EINPS, respectively), Alberta, Canada and the 2 groups were genetically distinct. During 2000 to 2003, elk originating from Elk Island National Park were translocated to Cumberland Mountains, Tennessee (TNCM) and Great Smoky Mountains National Park, North Carolina (GSMNP), USA (some elk spent time at Land Between the Lakes Recreation Area, Kentucky, USA, before their ﬁnal translocation). At TNCM, translocated elk were hard released, whereas at GSMNP elk were held in pens up to 60 days before release (i.e., soft release). We hypothesized that associations formed in the source population would affect genetic structure in the future population. We predicted that matrilineal groups would stay closer together and have similar movements after translocation. We used 16 microsatellite markers to analyze genetic composition and structure of translocated elk and their offspring in the years after release. Most source elk used for translocation strongly assigned to either EINPN or EINPS (93.2%, n ¼ 204). Evaluating the genetic structure of offspring after translocation, we found the 2 genetic groups mostly persisted 1 year. Mean Euclidean distances between pairwise locations of female elk were similar for each genetic cluster for each area. The mean distances for all paired locations (genetic clusters combined) in TNCM were 14.67 km (n = 4,576 +- 13.23 [SD]) and in GSMNP were 9.30 km (n ¼ 1,468  9.75). However, when looking at only simultaneous locations <50 m apart, the frequency of occurrence was higher (P < 0.001) for elk with the same genetic structure (71.1%) compared with those with different structure (28.9%). The maximum distance travelled from the release site was not different for the 2 genetic groups, but EINPN females tended to travel farther. Pairwise female distances were lower in GSMNP where we used a soft release. Release methodology and social structure appear to affect movements and possibly genetic mixing after translocation. Given that restoration success can depend on maintaining genetic diversity and number of founders, our analyses suggest that within-cluster breeding bias can result in lower genetic variability and a smaller effective population size than previously assumed.