Parentage assignment detects frequent and large‐scale dispersal in water voles

Abstract

Estimating the rate and scale of dispersal is essential for predicting the dynamics of fragmented populations, yet empirical estimates are typically imprecise and often negatively biased. We maximized detection of dispersal events between small, subdivided populations of water voles (Arvicola terrestris) using a novel method that combined direct capture-mark-recapture with microsatellite genotyping to identify parents and offspring in different populations and hence infer dispersal. We validated the method using individuals known from trapping data to have dispersed between populations. Local populations were linked by high rates of juvenile dispersal but much lower levels of adult dispersal. In the spring breeding population, 19% of females and 33% of males had left their natal population of the previous year. The average interpopulation dispersal distance was 1.8 km (range 0.3-5.2 km). Overall, patterns of dispersal fitted a negative exponential function. Information from genotyping increased the estimated rate and scale of dispersal by three- and twofold, respectively, and hence represents a powerful tool to provide more realistic estimates of dispersal parameters.

Challenges to assessing connectivity between massive populations of the Australian plague locust

“…Assessing dispersal is of obvious importance in disciplines such as conservation biology, in which informed management decisions based on an understanding of population structure and movement, or lack thereof, must be made to help preserve species threatened by small population sizes (e.g. [2]). At the opposite end of the spectrum are pest and invasive species whose large population sizes and dispersal ability can threaten both ecological and agricultural systems.…”

Estimating offspring production using capture‐mark‐recapture and genetic methods in red squirrels

“…The type of samples obtained from natural populations has great implications for the reconstruction of parentage in studies using a combination of polymorphic molecular markers (DNA microsatellites), parentage analysis methods based on maximum likelihood estimators, and exclusion of individuals as potential parents (Jones and Ardren 2003;Telfer et al 2003;Koch et al 2008). Although the joint combination of these methods greatly increases the correct parentage assignment, the risk of two types of errors remains: false parentage assignment and the nondetection of true parents, in our case mothers (e.g., Oddou-Muratorio et al 2003;Shurtliff et al 2005).…”

“…In several studies only parents assigned with a 95% probability were considered (e.g., Aars et al 2006;Dugdale et al 2007;Lane et al 2008). In our study system it was impossible to exclude the candidate mothers (CPs) assigned with a 80% confidence (see also Telfer et al 2003). Our choice of retaining these CPs was supported by the simulations of candidate offspring-'false', non-reproducing, CPs, that demonstrated that only in 1% of cases (n = 787 offspring-CP combinations) a false CP was assigned as the mother with an 80% confidence.…”

Gene Flow in an Invasive Species of Grass, Brachypodium Sylvaticum

“…The mode of dispersal can, to a large degree, be determined by the genetic diversity seen within populations and the differentiation between populations: If gene flow can be observed between two relatively isolated populations, conclusions can be drawn that long-distance seed (or pollen) dispersal is taking place, or that the populations share a common source (Nichols and Hewitt 1994;Cain, Milligan et al 2000;Muller-Landau, Levin et al 2003;Walker, Hulme et al 2003;Paetkau, Slade et al 2004). Genetic diversity can also provide clues as to how long populations have been established (the more diverse a population is, the older it is likely to be), as well as the relative ages of populations (more genetically diverse populations may be older than the less diverse ones) (Gautschi, Jacob et al 2003;Telfer, Piertney et al 2003). Because microsatellites do not code for any proteins, most are under no selective pressure and enjoy relatively high rates of mutation (around one mutation per fifty generations).…”