Evaluation of genetic change from translocation among Gunnison Sage-Grouse (Centrocercus minimus) populations

Abstract

Maintenance of genetic diversity is important for conserving species, especially those with fragmented habitats or ranges. In the absence of natural dispersal, translocation can be used to achieve this goal, although the success of translocation can be difficult to measure. Here we evaluate genetic change following translocation in Gunnison Sage-Grouse (Centrocercus minimus), a species reduced to 7 discrete populations with low levels of gene flow and high levels of genetic differentiation. Between 2000 and 2014, 306 birds from the largest and most genetically diverse population (Gunnison Basin) were translocated to 5 much smaller satellite populations to augment local population size and increase genetic diversity. Although the magnitude of the effect varied by population, we found evidence of increased genetic variation, decreased genetic differentiation from Gunnison Basin, and reproduction between translocated individuals and resident birds. These results suggest that translocations are impacting satellite populations, with current data providing a new baseline for genetic diversity among populations of this imperiled species.

Survival rates of translocated Gunnison sage‐grouse

“…Previous research has noted differences in survival between sexes from fall to spring resident juvenile greater Although we observed the survival of GUSG into subsequent breeding seasons, our translocations did not appear to have a sustained effect on lek counts, even though there is genetic evidence that suggest translocated birds successfully bred (Zimmerman et al 2019). Translocations likely contributed to short-term increases in lek counts, and lek trends may have declined more quickly in these satellite populations if translocations had not occurred.…”

U.S. conservation translocations: Over a century of intended consequences

“…Several key points that shaped the history of biological control programs and invasive species management are plotted below the timeline (Heimpel & Cock, 2018;Johnson, Crafton, & Upton, 2017;Vail, Coulson, Kauffman, & Dix, 2001) Genetic swamping is a potential negative consequence specific to reinforcements. We found no reports of genetic swamping adversely impacting reinforced populations, though it was only explicitly monitored in a few cases (Bouzat et al, 2009;Hogg, Forbes, Steele, & Luikart, 2006;Jahner et al, 2019;Olson, Whittaker, & Rhodes, 2012;Zimmerman, Aldridge, Apa, & Oyler-Mccance, 2019). It is general practice to perform reinforcements of small numbers to avoid swamping.…”

“…Genetic swamping is a potential negative consequence specific to reinforcements. We found no reports of genetic swamping adversely impacting reinforced populations, though it was only explicitly monitored in a few cases (Bouzat et al, 2009; Hogg, Forbes, Steele, & Luikart, 2006; Jahner et al, 2019; Olson, Whittaker, & Rhodes, 2012; Zimmerman, Aldridge, Apa, & Oyler‐Mccance, 2019). It is general practice to perform reinforcements of small numbers to avoid swamping.…”

Scale‐dependent influence of the sagebrush community on genetic connectivity of the sagebrush obligate Gunnison sage‐grouse

“…We excluded the recently re‐established Poncha Pass population (Nehring & Apa, 2000). Our Gunnison Basin data set was composed of 624 unique samples representing 49 of the 70 leks considered active between 2006 and 2014 (92% of samples collected after 2010), also as part of a previous study (Zimmerman et al, 2019). In brief, samples were primarily noninvasively collected feathers, but also included mortalities, and blood samples collected from captured individuals.…”