Temporal Analysis of Genetic Structure to Assess Population Dynamics of Reintroduced Swift Foxes

Abstract

Reintroductions are increasingly used to reestablish species, but a paucity of long-term postrelease monitoring has limited understanding of whether and when viable populations subsequently persist. We conducted temporal genetic analyses of reintroduced populations of swift foxes (Vulpes velox) in Canada (Alberta and Saskatchewan) and the United States (Montana). We used samples collected 4 years apart, 17 years from the initiation of the reintroduction, and 3 years after the conclusion of releases. To assess program success, we genotyped 304 hair samples, subsampled from the known range in 2000 and 2001, and 2005 and 2006, at 7 microsatellite loci. We compared diversity, effective population size, and genetic connectivity over time in each population. Diversity remained stable over time and there was evidence of increasing effective population size. We determined population structure in both periods after correcting for differences in sample sizes. The geographic distribution of these populations roughly corresponded with the original release locations, which suggests the release sites had residual effects on the population structure. However, given that both reintroduction sites had similar source populations, habitat fragmentation, due to cropland, may be associated with the population structure we found. Although our results indicate growing, stable populations, future connectivity analyses are warranted to ensure both populations are not subject to negative small-population effects. Our results demonstrate the importance of multiple sampling years to fully capture population dynamics of reintroduced populations. Análisis Temporal de la Estructura Genética para Evaluar la Dinámica Poblacional de Zorros (Vulpes velox) Reintroducidos.

Extreme genetic structure in a social bird species despite high dispersal capacity

“…The uncorrelated allele model was chosen as there is evidence that the correlated model may overestimate the number of populations (Guillot et al . ; Cullingham & Moehrenschlager ). The uncertainty of the coordinates was set to zero assuming that individuals have the same geographical provenance within each sampling region.…”

Monitoring a New England Cottontail Reintroduction with Noninvasive Genetic Sampling

“…Noninvasive genetic sampling provides critical insight into the viability and recovery of populations of rare or cryptic species (Waits and Paetkau 2005, Smith et al 2009, Cullingham and Moehrenschlager 2013, Woodruff et al 2016, DeMay et al 2017). In this study, we showed the value of noninvasive genetic sampling to monitor a population of a threatened habitat specialist, the New England cottontail, through 5 years of reintroduction efforts.…”

“…Successful reintroductions must overcome obstacles such as unstable demographics (Murrow et al 2009), skewed sex ratios (Tella 2001, Clout et al 2002), disease (Viggers et al 1993), inbreeding depression (Brook et al 2002, O'Grady et al 2006), stochastic events related to weather or predation (Stacey and Taper 1992), and limited habitat or population connectivity in metapopulation systems (Chandler et al 2015). Genetic monitoring is a valuable tool to evaluate the success of reintroductions and facilitate decision‐making in an adaptive management context (Schwartz et al 2007, De Barba et al 2010, Cullingham and Moehrenschlager 2013, DeMay et al 2017). Specifically, noninvasive genetic sampling of DNA extracted from hair, feathers, feces, or other shed tissues can be used to monitor populations.…”

Genetics of a reintroduced swift fox population highlights the need for integrated conservation between neighbouring countries

“…This finding has prompted a closer investigation of previously collected genetic data, where a small number of microsatellites were used to assess the genetic status of the reintroduced population. These data indicated a stable, mid‐range level of genetic diversity, and evidence of increasing effective population size (Cullingham & Moehrenschlager, ). However, there was evidence of population substructure, with two subpopulations being identified: “east” and “west”, Fig.…”

“…We used hair samples collected in 2000/01 (N = 111) and 2005/06 (N = 193) that were previously analysed at seven microsatellite loci (Cullingham & Moehrenschlager, 2013). To determine parentage among these samples, we genotyped an additional 11 microsatellite loci and a sex-determining locus (ZFX/ZFY; Morin et al, 2005).…”