We may not always realize it at first glance, but the natural world is always changing; little by little, and over long periods of time, but it is changing nonetheless, and a lot of that is completely natural. However, as people with growing needs, desires, and technological advancements, we are changing the land around us faster than ever before and some of the first places affected by these changes are streams.
My name is Maddy Feiste and I am a freshman student at Clemson University participating in the creative inquiry Landscape Ecology of the Appalachia. In this program, a handful of us undergraduate students are working under graduate student Nathan Weaver to study the effects of urban development on stream health. More specifically, we’re looking at the populations of salamanders that live in those streams. Salamanders are an important part of the ecosystem in that they are the main predators of insect larvae that grow and mature in streams. They’re very effective keep insect populations under control by reducing the number of larvae that survive to adulthood. Salamanders are also important to us because many species serve as indicators of water pollution. For example, a healthy stream will show many different species of salamanders, while a polluted stream may only show one species of a highly tolerant salamander, or even no salamanders at all. By surveying salamanders in various streams, we can develop a good understanding of the stream’s overall health and the effects that nearby exurbanization may be having on the water quality.
Fortunately for us, the southern Appalachian Mountains are a biodiversity hotspot for salamanders, making it the perfect place for us to study these valuable organisms. The same mountains, however, have been an increasingly popular tourist destination spot for people seeking what they consider to be the ideal getaway that brings them closer to nature. This idea of the peaceful mountain getaway may at first seem harmless or even beneficial, but the development involved brings us right to the problem of exurbanization. Exurbanization is a form of low-density development similar to urban sprawl. In exurbanization, houses and businesses are built farther apart in order to provide a more secluded feeling for the people living there, while still providing the services and amenities that would be available to them in a larger city. All of this widespread development can seriously endanger streams in the region by filling them with sediment from construction, as well as runoff from roads and fertilized landscaping. This semester we went on multiple sampling trips locally in order to assess how this type of development affected the streams in and around Clemson.
When gathering our data we began by testing the water quality in the streams, measuring dissolved oxygen, salinity, pH, temperature, and conductivity. We then moved on to survey the stream morphology, noting what percent of streambed was rock, gravel, pebbles, or sediment. This data became especially important to me as we developed our own personal projects. My particular topic has come to be streambed morphology and how salamander species abundance varies according to substrate differences between streams. As we continued to sample this semester, two important differences became clear in urban versus control streams, and that was that the urban streams had a high percentage of sediment, while our control streams located in the Clemson experimental forest almost always contained less sediment and more rock and gravel. The control streams also exhibited higher diversity of salamander species than the urban streams, as opposed to the urban streams, where we only ever found the very hardy southern two-lined salamander. Knowing this, I wanted to investigate more into why sediment bottom streams harbor fewer salamanders than rocky-bottomed ones. It may be that the more uniform sediment provides less habitat for salamanders and their prey than layered pebbles and rocks would, but only more research will tell for sure.
I’m very excited to continue this creative inquiry into next semester and gain a greater understanding of the relationships that salamanders share with their physical environment. Sedimentation is a well-known problem for streams and in many cases has been known to completely fill in streams so that they no longer exist. Runoff and storm water management are both environmental issues that I am passionate about and that I would like to continue to investigate further with this project. I think that next I would like to compare a stream near a town using conventional storm water management practices to a stream from an area using more sustainable practices. It would be interesting to see if there are very significant differences in the salamander diversity of the different locations. I look forward to writing about more of my findings in the coming spring!