COS 10-6
Traffic infrastructure and other land-use elements affect genetic population structure of water frogs
Traffic infrastructure has been recognized as a major challenge for the movement of wildlife in human-dominated landscapes. Highly frequented roads may increase the mortality of individuals, resulting in a barrier effect for dispersal and migration, thus reducing the genetic exchange between populations. However, the long-term effects of traffic infrastructure on the genetic exchange in relation to other land-use types are not well understood. Here, we identify whether different types of traffic infrastructure and other land-use elements affect gene flow between populations of water frogs (Pelophylaxspp.). 999 frogs were captured at 58 ponds in 2013 to retrieve DNA samples for nuclear microsatellite analyses by buccal swabs. The ponds were distributed along three highway segments in the Swiss lowlands, a densely settled area with intensely managed agricultural land.
Results/Conclusions
Partial Mantel tests and multiple regression analysis on distance matrices indicated that the genetic distance between populations was increased when separated by a highway segment. In addition, genetic distance between populations increased with the number of main roads between them, whereas railways did not have any effect. Thus, an expected barrier effect of highways on the genetic exchange could be confirmed. Results from corridor analysis showed that the genetic structure was also significantly affected by land-use elements other than traffic infrastructure, as the genetic exchange between pairs of populations increased with increasing proportion of the area covered by agricultural land. In contrast, gene flow decreased with the proportion of the area covered water bodies and wetlands between populations.Therefore, we suggest increased mobility of individuals in agricultural landscapes, whereas a high density of wetlands restricts dispersal distances, thus likely reducing mortality caused by traffic infrastructure.