Corridors, Highways, and Habitat (Oh My!)

(Right) Wildlife movement around a corridor - in this illustration birds fly along the interior of the corridor, deer munch on plants found on the corridor edge, and a bear meanders across the corridor. (Left) The illustration on the left shows more than one type of corridor. This image illustrates a portion of a network of forest corridors. It also shows a network of a human transportation corridors, or roads. Often times natural corridors are more curvy, while human-built corridors are composed of rigid geometries. These corridors cross each other on the right side of the illustration - below, I touch on how that crossing can work well and how it cannot work well.

“Highways, new plantations, the fencing-off of certain areas, the damming of water sources, and similar developments, crowd out natural habitats and, at times, break them up in such a way that animal populations can no longer migrate or roam freely. As a result, some species face extinction. Alternatives exist which at least lessen the impact of these projects, like the creation of biological corridors, but few countries demonstrate such concern and foresight."

-Pope Francis I, Laudato Si', par. 35

The biological corridor Pope Francis is discussing is simply a linear strip of habitat that differs from the land on either side of it. An animal's habitat is an area with the necessary conditions to support its survival. My habitat is where I live, and it can be described by what and who enters and leaves that space regularly and provides something necessary for me to function in that space. I have a daily range of motion that is included in that habitat, and, on occasion, I go beyond that daily range. However, there are places on this earth I simply cannot, nature willing, go to and thrive—like the bottom of the Mariana Trench or the inside of Mt. St. Helens. I tend to avoid those places. Animals in the wild are much the same - they live in areas defined by the habitat requirements of their species, and each species has a certain set of requirements for an area to be considered suitable habitat. Some species are more sensitive than others and they can rarely exist outside their habitat without pressing mortal danger, like some arboreal bird species. Some species are "multihabitat," and they are fine meandering through the landscape, whether in a field or a forest.

 

Wildlife corridor movement

Land bridge in NJ, USA. wikipedia.org, user: Doug Kerr

Corridors serve three primary functions. They provide a conduit for organisms and other non-living things (such as soil particles), they provide habitat for creatures and other life forms that live within them and along their edges, and they create a barrier or filter for anything in an area that is moving towards the corridor at an oblique or perpendicular angle, like the bear to the right. A corridor of high-quality habitat that is contiguous is ideal for the connection, dispersal, and migration of species populations, and it is vital for those species that are not "multihabitat." The continuity of corridors is often broken up by “Highways, new plantations, the fencing-off of certain areas, the damming of water sources…” to quote the Pope. In the United States, every day, 1,000,000 vertebrates traversing across the landscape are hit by cars (Forman). This incredibly large number is indicative of a serious problem of habitat fragmentation. Vulnerable animal populations attempting to obtain resources missing from their current habitat, to migrate, or to reach other populations of the same species in a fragmented landscape are more likely to meet a fatal end. It is not realistic to propose getting rid of all roads and vehicular transportation, but design solutions, such as wildlife underpasses and bridges, can make a significant difference in the survival of these creatures.

Church lands could be assessed for their spatial relationship to various corridors using mapping analysis. Where there is a lack of continuity, perhaps the land could serve as an auxiliary patch. This is why a major focus of the Good Land Project is to create a map of church properties, which will reveal ways that the land could do much more for the environment - and it may also reveal where land is already playing a critical role in the landscape and may be, at the least, helps increase the connectivity of a vital corridor by providing a habitat patch. Existing Church lands could be serving as crucial pieces of corridors and should be carefully approached with regard to land-use planning if they are. However, without a comprehensive map of the Church’s properties, we cannot know if this is the case.

Molly Burhans
catholicgeo.org

Sources:

[1] Pope Francis I. “Laudato Si’ - Encyclical Letter, On Care for Our Common Home, Pope Franci I.” Vatican: the Holy See. Vatican Website. Libreria Editrice Vaticana, 2015. Web. July. 2015.

This whole post is heavily influenced by:

[2] Forman, Richard T. T. Land Mosaics. Cambridge, UK: Cambridge University Press, 1995. Print.