Think in Reverse

Corridors for a Healthier Environment- Part 2 September 27, 2011

Filed under: Uncategorized — clairelester @ 12:00 pm

In my last post I talked about the importance of natural corridors and how the need to protect them is a serious matter. I learned from the previous article that corridors help to create genetic diversity within a certain species and broken corridors isolate patches of a species who must then survive reproducing only among themselves with the smaller amount of resources they have been limited too. As we have learned in class, less diversity equals less resilience in a system. Sally Elminger proposes in this article that in response to fragmenting these natural habitats we need to begin to start re connecting them.
Elminger goes on to describe the difference between natural and human corridors, and some different types of each. Two types of natural corridors are a river or stream corridor (also called a riparian corridor), and a tree line or hedgerow corridor. Stream corridors are easy to observe and are often times left underdeveloped. The stream/river corridor also most commonly includes both the flood plains on either side of the river and upland vegetation. Looking back to my last blog post and the example of the frogs reproduction cycle that I used, this species would be able to carry out all of its life processes if the entirety of the riparian corridor was preserved. Although, most species do not require such a large variety of habitat as the frog, the upland vegetation and flood plains can be just as important to a species that lives its whole life in the water. For example, Elminger tells us: “A major threat to water quality is sediments and pollutants that are washed off surfaces such as parking lots and lawns (fertilizers/pesticides) and into streams. But if the storm water must first cross a vegetated “buffer,” then the stems and detritus from the plants help to slow the water down, allowing the water to infiltrate the soil and be taken up by the plants.” Another benefit of this vegetation is that larger plants help provide essential nutrients to the water through the dropping of their leaves and branches that biodegrade and provide food for some stream organisms; while their roots help to hold the sediment of the stream bottom and its floodplains in place by preventing erosion. Lastly, it may seem obvious but the shade of larger vegetation can also help to make the habitat a much more appealing place to be for certain organisms by helping to lower the temperature.
The second example Elminger gives of a natural corridor is a tree row. This type of corridor is identified by narrow rows of trees, shrubs, and herbaceous plants, and they are often used in agricultural landscapes to designate property lines or to separate different fields of crops. Tree rows can be composed of native vegetation, non-native vegetation, or a mix of both. Native vegetation can provide an essential “source of seed.” Elminger mentions that this type of natural corridor can be continuous, or can be a “stepping stone” corridor, like the images we looked at in the Forman reading and that I posted in my most recent blog post.
Sally Elminger closes with describing some types of human corridors. Before reading this article I had assumed that manmade corridors were a large threat to natural habitat connections and unless intentional could not provide much benefit to our natural species. However, Elminger talks about how the extended corridors we sometimes produce, such as railways and utility line stretches can not only help to preserve wildlife corridors but can even enhance or create them. For example, “In the Midwest, many railroad lines traversed fire-dependent plant communities, such as prairies and oak openings. The sparks from the rail cars often started fires next to the tracks, which, in turn, sustained the plants within the railway corridor.” At the end of the article, we are encouraged to look in our community to identify how certain natural areas are linked. Can you think of any manmade or natural corridors that seem to be important in preserving certain types of plants or animals in Charlottesville?



One Response to “Corridors for a Healthier Environment- Part 2”

  1. Evan Says:

    Claire, this is a really interesting article that you talked about because, like you, I assumed that most man-made connections and corridors weren’t actually helping the ecological health of an area. Elminger’s comments about how artificially made corridors like railroads and utility lines and even tree lines which were created to designate property boundaries are really eye-opening and I hope will influence a bit more design in terms of creating corridors which might be bother aesthetically pleasing and effective in maintaining ecological diversity and therefore resilience. Additionally, I think it’s important for engineers to acknowledge the ecological impact of their decisions because the comment on railroads and utility corridors made me realize that architects and designers almost never have any influence or part in the construction of such structures.

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