Is the United States connected enough for plants and animals to respond to climate change?
High levels of fragmentation throughout the country mean more barriers to movement if ranges shift under warming temperatures. The extent to which suitable habitats are connected, and the measures we take to ensure that they are, may mean the difference in whether many species can persist.
New research by McGuire et al. examines more closely the idea of “climate connectivity” at a nationwide scale and evaluates how well corridors may help achieve it. They show striking results not only in how well the country has (or has not) achieved climate connectivity, but how effective corridors may be in helping to mitigate the current lack of connectivity in many ecoregions.
Their results show that only 41% of the natural areas in the United States are connected enough for species to be able to track changes in climate. While just over half (51%) of the western U.S. achieves climate connectivity, only 2% of the eastern U.S. does. The Midwest in particular shows large gaps in connectivity.
Although these are sobering numbers, they present a great opportunity to mitigate fragmentation through the use of corridors, which the authors calculate could increase nationwide climate connectivity by 65% of natural land area. Even short corridors (≤ 10 km) would still achieve climate connectivity for 60% of natural land areas. Corridors would have the most impact in the southeastern US, particularly along the coastal plains and west and southcentral semiarid prairies. Ensuring that these pathways exist will be critical in maintaining biodiversity throughout the country.
McGuire, J. L., J. J. Lawler, B. H. McRae, T. A. Nuñez, and D. M. Theobald. 2016. Achieving climate connectivity in a fragmented landscape. Proceedings of the National Academy of Sciences 113 (26): 7195-7200.