There are several ways to identify wildlife corridors. One method is to ask reserve managers and wildlife researchers where corridors exist. This can be an accurate and cost-effective method in places where people live or work, but may miss corridors where people simply are not looking. Another way is to use GPS and/or VHF-collars. This is often cost-prohibitive and limited to local, or regional scales.

As connectivity between protected areas rapidly erodes, novel methods must be developed to quickly and cheaply assess where wildlife corridors still exist. Interviews with people living within or adjacent to wildlife corridors can provide accurate information on wildlife movements that can be obtained fairly easily. These data can then be used to validate connectivity models.

Using these complementary methods, researchers at the University of California, Davis have identified 52 structural wildlife corridors linking protected areas across Tanzania. Using a highly cost-effective combination of interviews and a land conversion dataset for East Africa, they found an additional 23 corridors beyond those previously identified in Tanzanian Government reports.

However, according to their publication in the journal PLoS ONE, nearly one-sixth of all the wildlife corridors previously identified in Tanzania in 2009 potentially have been separated by land conversion, and one-third now pass across lands likely to be converted to human use in the near future.

Tanzania is an ideal country to test methods for delineating wildlife corridors because it is the only country in Africa to have assessed its wildlife corridors at the national scale. The researchers compared the output of 60 corridor models to their interview data to determine which model most accurately captured connectivity between protected areas across the country.

Encouragingly, structural wildlife corridors still connect protected areas from east to west across the nation – but only just.  No open wildlife corridors remain to link protected areas between northern and southern Tanzania, however, and two reserves (Gombe Stream National Park and Pande Game Reserve) are completely isolated from all others in the country.

The findings from this research are optimistic: there might be a far greater potential for large mammals to move between protected areas in Tanzania than was previously supposed. Whether or not mammals use these corridors is, of course, an open question.  More research is needed to document the movements of mammals along these potential corridors via interviews, ground surveys and GPS collaring of target species to determine actual on-the-ground use.

Resources

Riggio J. and T. Caro. 2017. Structural connectivity at a national scale: Wildlife corridors in Tanzania. PLoS ONE12(11): e0187407.

Urban corridors: research updates around the globe (April 2017)

Wildlife corridors on three continents (April 2013)