Threats to connectivity from climate and land-use change can be unique to individual species even when they utilize the same habitat, such as black bears, timber rattlesnakes and Rafinesque’s big-eared bats in bottomland hardwoods of the Southeastern U.S. Credit: Thomas Fuhrmann (top), USGS (middle), USDA (bottom).
Existing habitat linkages, or connections among habitat patches, are critical for maintaining wildlife populations in their current ranges and enhancing species’ ability to adapt to future conditions. But, the amount of suitable habitat within linkages can be affected by both climate and land-use change. Knowing how future threats will affect existing habitat linkages can help inform conservation decisions in the present.
In the future, some linkages may be relatively climate stable over time compared with the surrounding landscape – these linkages are referred to as climate change refugia. They will be important for harboring threatened or vanishing habitats, so a key conservation focus will be to maintain them by managing other threats such as land-use change. Conversely, linkages in which climate is likely to change markedly might need different adaptation measures such as species relocation to new regions.
When looked at in concert with climate change, land-use change can further restrict the menu of available conservation actions by dictating which actions will be feasible. However, the degree to which threats from climate and land use change will play out similarly for different species, and thus how priority conservation actions might align for different species, is unclear.
A new study looked at climate and land-use change threats to existing habitat linkages for three species that currently occupy similar habitats in the Southeastern U.S.: timber rattlesnake (Crotalus horridus), Rafinesque’s big-eared bat (Corynorhinus rafinesquii), and American black bear (Ursus americanus). Linkages for the three species were modeled and mapped, then those maps were overlaid on maps of potential future climate and land-use change. By measuring the two threats, as well as how much of each linkage is currently protected, priority actions for each species’ linkages were identified and compared using a relatively simple framework (see below).
The key result is that even though the three species currently occupy similar habitats, changing climate and land-use conditions will affect their existing linkages differently. The timber rattlesnake, whose overall range in the Southeast is most climate-sensitive of the three species, had linkages that in fact tended to be climate refugia. So, managing other threats like land-use change within those linkages should be a priority.
On the other hand, linkages for Rafinesque’s big-eared bats and black bears will be more threatened by climate change, and in both cases, many linkages also had high land-use change. For those linkages, conservation actions that help those species adapt to changing climate and land use will be important.
The bottom line is that this study offers evidence that climate and land-use change threat will be unique even among species that use similar habitats. As a result, even species in the same habitats will require different actions to conserve their habitat networks.
Resources
Costanza, J.K., Watling, J., Sutherland, R., Belyea, C., Dilkina, B., Cayton, H., Bucklin, D., Romañach, S.S. and Haddad, N.M. 2020. Preserving connectivity under climate and land-use change: No one-size-fits-all approach for focal species in similar habitats. Biological Conservation 248: 108678.
