In today’s Academic Minute, Dr. Paul Beier of Northern Arizona University examines how wildlife corridors can help populations of animals deal with increasing urban sprawl.
Paul Beier is a professor in the School of Forestry at Northern Arizona University in Flagstaff, Arizona, where his research interests include wildlife ecology and conservation biology. His current work is focused on the design of wildlife corridors, with corridor projects ongoing in urban southern California, diverse landscapes in Arizona, and in the transborder area of Ghana, Togo, and Burkina Faso. He holds a Ph.D. from the University of California Berkeley.
Dr. Paul Beier – Wildlife Corridors and Genetic Diversity
In the last century, large natural areas have been split into smaller fragments embedded in a matrix of cities, farms, and highways. Although many fragments are protected as parks, wildlife populations in isolated parks lose genetic diversity and eventually become extinct. And if a fire or other disaster destroys a population in an isolated park, the species can’t re-colonize it.
Wildlife corridors can connect our existing parks before they become isolated. After the natural land on either side of the corridor is lost, the corridor should support gene flow and recolonization. A typical corridor design is ambitious – over a mile long and a quarter mile wide.
As a conservationist, I am excited that these corridor designs are being implemented. As a scientist, however, I worry whether these long corridors will work once the surrounding natural land has been lost. Although there have been many studies of corridors, these studies have documented only that corridors increase animal movement between patches about 100 yards apart. Moreover most of these studies have involved a corridor of one natural land cover, for example a grassland corridor, through a matrix of another natural land cover, such as forest.
These studies of tiny corridors in natural landscapes suggest that corridors are a good conservation strategy. But we need stronger evidence.
Because no conservation corridor has existed long enough to assess how well it provides long term gene flow and patch occupancy, my research lab has launched an effort to identify and study landscapes where long corridors through farms and cities have “accidentally” connected parks for at least 50 years. Colleagues from around the world are suggesting potential landscapes through docorridorswork.org. We are finding many of these corridors – for instance in forest swaths along the former Iron Curtain, in remnant grasslands in the farmlands of California’s San Joaquin Valley, and along cattle drive routes in Australia.
We expect to confirm that at least some long corridors through human-dominated lands do indeed “work.” More important, by studying many such landscapes, we will learn why some corridors are better than others at ensuring genetic diversity and long-term survival of species.