Density‐dependent dispersal suggests a genetic measure of habitat suitability

Abstract

Recent research shows that density dependence should result in predictable movements between habitats of different suitability, depending on whether population densities are increasing or decreasing. When population densities are increasing, habitats become filled in order of their suitability, resulting in a net flow from high suitability to low suitability. When populations decrease in density, the reverse can happen. These patterns suggest that genetic information can be used to infer habitat suitability since individual-based genetic assignment tests permit high resolution assessments of migration. We used replicated landscapes to study fishers (Martes pennanti ) during a population increase and predicted that there should be a net flow of individuals from areas of shallow to deep snow, since snow depth has previously been linked to fisher fitness. A total of 769 fishers were sampled from 35 different landscapes and profiled at 16 microsatellite loci. From assignment tests, we inferred five genetic populations. By assigning each of the 35 landscapes to one of these five populations, we were able to determine the proportion of immigrants to each. Consistent with our prediction, there was a positive relationship between the proportion of immigrants and snow depth. The best model of fisher habitat suitability was one with both snow depth and the proportion of coniferous forest in landscapes. Our findings suggest that where population trend is known, genetic information can be used to measure habitat suitability.

Dispersal promotes high gene flow among Canada lynx populations across mainland North America

“…Number of clusters (k) set to two (a) and three (b) Atlantic Oscillations, resulting in different population dynamics on either side of the barrier (Stenseth et al 1999(Stenseth et al , 2004a. Given the importance of snow conditions for prey capture by lynx (Stenseth et al 2004b) and its importance for other species (Carr et al 2007) it is possible that population dynamics differ on either side of the putative climate barrier. Direct tests of association between genetic data and landscape or environmental data (e.g.…”

Fine-scale landscape genetics of the American badger (Taxidea taxus): disentangling landscape effects and sampling artifacts in a poorly understood species

“…In southern Wisconsin, Native Open habitats were often interspersed with Agriculture, but spatial data may have lacked the resolution to capture fine-scale habitats necessary for dispersal (Anderson et al, 2010) similar to native habitat along fencerows (Duquette and Gehrt, 2014). Alternatively, dispersal through sub-optimal habitats via density-dependent dispersal (for example, Martes pennanti; Carr et al, 2007) or compensatory movements (Rosenberg et al, 1998) could also explain why Agriculture enhanced gene flow. For badgers, unavailable Native Open habitats (Carr et al, 2007) and/or faster movements through Agriculture during dispersal (for example, Schultz and Crone, 2001;Dickson et al, 2005;Rizkalla and Swihart, 2007) could produce high genetic similarity among individuals within agricultural habitats and surrounding suitable habitats (for example, Native Open or pasturelands in central and southwestern Wisconsin, respectively).…”

“…Alternatively, dispersal through sub-optimal habitats via density-dependent dispersal (for example, Martes pennanti; Carr et al, 2007) or compensatory movements (Rosenberg et al, 1998) could also explain why Agriculture enhanced gene flow. For badgers, unavailable Native Open habitats (Carr et al, 2007) and/or faster movements through Agriculture during dispersal (for example, Schultz and Crone, 2001;Dickson et al, 2005;Rizkalla and Swihart, 2007) could produce high genetic similarity among individuals within agricultural habitats and surrounding suitable habitats (for example, Native Open or pasturelands in central and southwestern Wisconsin, respectively). Under this scenario, we would also expect elevated F IS values in badgers in agricultural habitat relative to other habitats, a pattern that was present in our study but not significant.…”

Using a genetic network to parameterize a landscape resistance surface for fishers, Martes pennanti

“…High‐quality fisher habitat is characterized by low snow depth, which likely reduces the cost of locomotion, and the extent of coniferous forest cover, which is likely related to food availability (Krohn et al. 1995; Carr et al. 2007b; Garroway et al.…”