Wildlife Corridors Are Edgy

Wildlife corridors are often thought of as "hallways" connecting the "rooms" where wildlife live. We imagine furry creatures cruising along from one end to the other, arriving happily at their destinations. But this idea is misleading.

Corridors are intended to serve as linkages between wild areas, but in many cases they also serve as the wild areas themselves. They make up part of a patchwork of natural areas that provide habitat for a variety of species. Wide-ranging animals that cover a lot of ground quickly, like elk or bears, may pass through a corridor quickly, using them for dispersal, seasonal migration, or as part of a larger home range.

But other species can live their whole lives in the corridors. Animals with smaller home ranges like squirrels or foxes may take several generations to effectively cross a corridor. For them the corridor isn't merely a hallway, it's home. It's also good for these species in the larger scheme of things. It provides connectivity in the landscape that helps maintain geneflow through out the populations, preventing the negative effects of inbreeding and reduced genetic diversity that wreak havoc on isolated populations.

When we realize that corridors aren't just trails from one area to another, it can help us understand why the quality and quantity of habitat in a corridor is so important.

Corridors need to appeal to animals that shy away from human altered landscapes. They need to be far enough away from roads, artificial lighting, and human-use areas for wild animals to utilize them as they would any other part of their range. The animals don't have a birds-eye view (unless they're birds) allowing them to distinguish between a corridor and a wildland block, so for the corridor to be useful, it has to have characteristics similar to the wildland blocks.

Designing functional corridors can be challenging, especially considering that corridors are susceptible to edge effects; habitat quality along the edge of a habitat fragment is often much lower than in areas further from the habitat edge. Linear corridors have a lot of "edge". Edges are inviting to pets, lighting, noise, invasive species- all of which degrade the habitat quality in a corridor.

To address these effects, we need to ensure that wildlife corridors meet a minimum width. When I worked for the Arizona Missing Linkages project we tried to identify corridors that met a minimum width of 1 kilometer. While there is no national standard, the general consensus among biologists is, the wider the better.

That's why it's disturbing that commisioners in Pasco County are balking over the suggestion that wildlife corridors meet a minimum width. They want to alter a wildlife corridor proposal by allowing people to "reduce" the corridor's width to meet their own specifications. In Florida, the natural habitats are dwindling -and so are the wildlife- including the Florida panther. Corridors are vital in such a patchy matrix of wildland and high-density developments. Maybe the commissioners don't realize that the wildlife corridor may not serve as a corridor at all if it doesn't meet certain specifications.

It is important when protecting wildlife corridors that certain characteristics, including a minimum width, be adhered to in order to maximize the functionality of the corridor. These aren't merely hallways, they are vital wildlands. Let's not skimp on wildlife corridors.

1 comment:

  1. Hey Emily,

    I am writing a graphic panel on habitat connectivity for a new set of exhibit at the Kofa NWR. I was wondering if you would be willing to talk on the phone for a bit so I make sure to cover the relevant issues.

    You can e-mail me at mlevad(at)splitrockstudios.com