Do conservation corridors work?

Habitat loss and fragmentation are leading threats to wildlife. About 14 percent of the earth’s land surface has been set aside to conserve biodiversity. Unfortunately, these natural areas by themselves are inadequate for conserving biodiversity, especially if they become “islands” of habitat within a sea of disturbed or converted land. Thus, recent conservation efforts — costing millions of dollars — have focused on establishing conservation corridors, typically 500 m to 50 km long, between habitat preserves. Many studies have documented that animals move through short (~100 m) corridors passing through a contrasting natural land cover type. However, few studies have tested whether conservation corridors (long, wide swaths passing through human-dominated land uses) provide long-term functional connectivity for wildlife.

We intend to test, on a global scale, two questions:

Do conservation corridors work?
What are the characteristics of corridors that do work?

To do this, we need your help to find study sites at which we can assess the ability of big corridors (the sort of corridors typically proposed as conservation interventions) to promote long-term gene flow. Many studies have demonstrated that short linear features promote animal movement over short distances when the area outside the corridor is relatively natural, but we are interested in corridors over a half-mile long embedded in urban, row crop, or industrial areas. And we don’t want to measure success in terms of movement of individual animals; instead we will measure success in terms of long-term gene flow. Thus we need landscapes that have been stable for 20 to 50 years – long enough that the pattern of corridors and patches will have affected genetic patterns. We seek about 100 landscapes (each with 1 or more corridors) for our study, and we will study landscapes on all continents. We need many landscapes because doubtless some corridors provide gene flow across human-dominated areas, and other corridors fail to do so. With a large sample, we can identify what traits are associated with successful corridors.

Although we are highly selective about what landscapes we will study, we will study any reptile, amphibian, mammal, flightless arthropod, or sedentary bird that is likely to be found in the corridor, but not in the human-dominated matrix.

Please suggest appropriate landscapes for this study (and learn more about the study design and rationale) at docorridorswork.org. We are offering finders a small finder’s fee, and immediate access to the genetic data from your site. Please tell anyone you think may be able to help!

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Andrew J. Gregory, PhD.

Northern Arizona University, School of Forestry, Flagstaff AZ 86011-5018

EM: Andrew.Gregory@nau.edu