Genetic connectivity in 10 North American mammals
Landscape connectivity is a core component of ecosystem integrity, which is something that National Forests and Grasslands are required to promote and restore under current regulations. The problem is that there are many different ways to map connectivity, and it is not clear which approaches best represent the way that wildlife experience and move across the landscape. One way to address this is with an approach called “landscape genetics,” in which scientists compare maps of landscape features (e.g. vegetation types, waterways etc.) with patterns of genetic similarities and differences between individuals of a species to understand where gene flow – and thus connectivity – is occurring. Alternatively, some researchers and managers use generalized connectivity maps, i.e. not tailored to specific species’ movement patterns or gene flow, for making decisions about where to improve connectivity by building wildlife overpasses, installing culverts, and enhancing habitat.
A bobcat walks next to the Madison River in Yellowstone.
Scientists at the Rocky Mountain Research Station and the National Genomics Center for Wildlife and Fish Conservation partnered with managers at the New Jersey Department of Environmental Protection to test different ways of modelling and mapping connectivity across 10 different mammal species in the state. They found that while human development often impeded species’ genetic connectivity, forests, shrubs, and herbaceous vegetation often facilitated it. In general, patterns of genetic connectivity differed across species and were usually best explained by different combinations of landscape features. This suggests that managers should exercise caution when developing generalized connectivity maps for land management planning. Species may have unique responses to landscape features, and factors that facilitate genetic connectivity for one species may impede it for others.
Additionally, the project aimed to provide land and resource managers with information about how certain landscape features might facilitate or impede the movement of bobcats, a state threatened species currently restricted to the northern forested portions of the state. Genetic connectivity for bobcats was impeded by human infrastructure on the landscape, which may become important as bobcats expand their range closer to the heavily developed central portion of New Jersey.
This project is just one of many collaborations between scientists at Rocky Mountain Research Station and state partners. Collaborations like these help land management agencies address local research needs while efficiently leveraging expertise provided by scientists at the station.