Where are stable 50-year-old landscapes with patches and long, wide corridors?

Do conservation corridors work? Examples sought in Europe.

Dr. Paul Beier and Dr. Andrew J. Gregory of the School of Forestry and Merriam-Powell Center for Environmental Research, Northern Arizona University, Flagstaff, U.S.A. initiated a study to determine if conservation corridors work. The goal of their study is to measure the ability of long, wide corridors to promote gene flow and long-term patch occupancy among habitat blocks that are embedded in a human dominated (row crop ag, industrial forest, urban matrix).

Conservation corridors are an intervention intended to promote demographic and genetic exchange at levels sufficient to sustain plants and animals in the linked natural landscapes after the surrounding matrix has been converted for urban or agricultural use. Unfortunately, rather than assessing species’ demographic persistence or gene flow attributable to corridors, most research on the effectiveness of corridors has assessed species’ presence and movement along relatively short (< 150 m) corridors in landscapes where the matrix is not dominated by human land uses.

Little evidence that conservation corridors work

Thus, despite much research on corridors, there is little evidence that conservation corridors work. They describe a research project to determine if conservation corridors work and determine what conditions (such as width, severity of constrictions, or adjacent land uses) are associated with successful conservation corridors.

Because conservation corridors are too young for genetic and demographic effects to be evaluated, they:

• will study landscapes with “de facto” conservation corridors (i.e., corridors > 500 m long, in a human-dominated matrix). In each landscape (n > 50),
• will collect DNA samples from focal species in patches connected by corridors, isolated patches, and sampling locations within an intact natural area.

A corridor will be deemed successful if genetic distances between connected patches are smaller than genetic distances between isolated patches and similar to genetic distances between sampling sites in intact habitat. Focal species will vary among landscapes and may include any reptile, amphibian, mammal, flightless arthropod, or sedentary bird associated with the patches and corridors, but not the human-dominated matrix.

Do you know any good examples?

In each landscape, the configuration of patches and corridors must have been stable for at least 20-50 years, so that genetic structure is likely reflective of landscape pattern.

Paul and Andrew ask readers to suggest appropriate landscapes for this study.