Implications of recurrent disturbance for genetic diversity

Abstract

Exploring interactions between ecological disturbance, species’ abundances and community composition provides critical insights for ecological dynamics. While disturbance is also potentially an important driver of landscape genetic patterns, the mechanisms by which these patterns may arise by selective and neutral processes are not well‐understood. We used simulation to evaluate the relative importance of disturbance regime components, and their interaction with demographic and dispersal processes, on the distribution of genetic diversity across landscapes. We investigated genetic impacts of variation in key components of disturbance regimes and spatial patterns that are likely to respond to climate change and land management, including disturbance size, frequency, and severity. The influence of disturbance was mediated by dispersal distance and, to a limited extent, by birth rate. Nevertheless, all three disturbance regime components strongly influenced spatial and temporal patterns of genetic diversity within subpopulations, and were associated with changes in genetic structure. Furthermore, disturbance‐induced changes in temporal population dynamics and the spatial distribution of populations across the landscape resulted in disrupted isolation by distance patterns among populations. Our results show that forecast changes in disturbance regimes have the potential to cause major changes to the distribution of genetic diversity within and among populations. We highlight likely scenarios under which future changes to disturbance size, severity, or frequency will have the strongest impacts on population genetic patterns. In addition, our results have implications for the inference of biological processes from genetic data, because the effects of dispersal on genetic patterns were strongly mediated by disturbance regimes.

Novel insights into the genetic diversity and clonal structure of natural trembling aspen (Populus tremuloidesMichx.) populations: A transcontinental study

“…However, ecological disturbances, especially high‐severity disturbances, often have long‐lasting effects on neutral genetic diversity (Banks et al., ; Davies, Cary, Landguth, Lindenmayer, & Banks, ). In our survey, genetic diversity varied among sites ( H o , N a , Trip) and was partly explained by the surrounding site conditions.…”

Population-level genetic variation and climate change in a biodiversity hotspot

“…High levels of heterozygosity have been repeatedly shown to confer resistance to environmental change (Hanski et al, 2006;Willi et al, 2006;Bonin et al, 2007). Model simulations suggest that species with low heterozygosity but large ranges will suffer a spatial redistribution of heterozygosity, depending on the level and length of the disturbance, whereas taxa with limited distributions with severe and frequent disturbance will suffer dramatic declines in heterozygosity regardless of initial levels of heterozygosity (Davies et al, 2016).…”

“…The extent to which high levels of genetic variation within and among populations are associated with the ability of a species to persist in the face of both short-and long-term disturbance regimes has long been deliberated (Lowe and Allendorf, 2010;Davies et al, 2016). Understanding the distribution of genetic variation on the landscape and the life history or ecological parameters that influence this variation will be important in identifying the taxa most vulnerable to anthropogenic change (Peter and Slatkin, 2013;Brandvain et al, 2014).…”

“…xantiana (Moeller et al, 2011;Davies et al, 2016). Population differentiation is easier to resolve in species with low rates of dispersal due to high genetic structuring (high F ST values), whereas high levels of gene flow (high N m ) can increase the difficulty of interpretation and will be reflected by low F ST values.…”

Where do animals come from during post‐fire population recovery? Implications for ecological and genetic patterns in post‐fire landscapes

“…Likewise, gradients in genetic diversity with distance from unburnt habitat are not expected where recovery is driven by in situ residual populations. Population distribution and genetic patterns are largely insensitive to long‐term variation in disturbance size and frequency under this model of recovery, unless rates of survival or population recovery are very low (Davies et al ). In the latter scenario, increases in the magnitude or duration of post‐fire genetic drift may lead to increased genetic structure within burnt landscapes.…”