Effects of urbanization on streams and salamanders

The following is guest post by Bonnie Miller, a junior at Clemson University enrolled in Dr. Barrett's Creative Inquiry course focused on amphibian conservation.

My name is Bonnie Miller and I am currently a Junior at Clemson University. I recently switched my major from Biosystems Engineering to Conservation Biology. After this switch I wanted to make connections within my new field and also figure out what real-world situations I might be interested in. At the recommendation of my advisor, I registered for a Creative Inquiry called “Landscape Ecology of Appalachia” which focuses on the effect of urbanization on streams and more specifically how salamander abundance and diversity may be affected.

A large portion of the class consists of excursions out in the field to gather data. Besides sampling a variety of streams for salamanders, we take other data such as the salinity, temperature, dissolved oxygen content, and pH of the stream water. We take note of the canopy cover and streambank vegetation among many other pieces of data.

While a large part of the course is field work, there is also a personal project component. My project is on Basal Area and how it might be related to the salamander diversity of streams. Basal Area is an estimate of the amount of an area that is occupied by trees. With this information, you can get an idea of the canopy cover, light levels, and overall composition of the forest surrounding a stream. Typically the higher the Basal Area, the more adult trees there are in the area and the more shade present.

At every site we visit, we use a wedge prism tool to calculate the Basal Area for the land surrounding the stream. Along with this data, I am also looking at the diversity of salamanders we catch when we sample the stream. We identify each salamander and note whether it is an adult or larvae. I’d like to compare the Basal Area to the number of species of salamanders that were caught and also the number of Southern Two Lined salamander larvae that were found.

What can be learned from this? Well, salamanders have long been used a indicators of stream health. If the natural state of a stream has been altered (as it often is by urban development) salamander populations can show that. Salamanders are sensitive to disturbances in their ecosystem and have a large role that they play. Through looking at the number of species and which specific species are present, you can gather information on the overall health of the stream.

Basal Area is a good indicator of the health of the land directly surrounding the stream. Within areas of urbanization, the forest usually has been disturbed, which would result in a lower Basal Area. Though the urbanization may have initially occurred many years ago, it takes an immense amount of time for a forest to reach the same level health-wise as it was before the disturbance of urbanization.

Luckily, there has been a recent movement to pay more attention to the environment and reduce the negative effect that humans may impose on their surroundings. This Creative Inquiry and my personal project relate directly to those issues. The first step to solving these problems that humans may be creating in nature is figuring out what those problems are. Through research we can see what human or natural factors are altering the ecosystem and what we can do to maintain the balance. This balance is so very precarious and tweaking one small factor may tip the entire scale. Overall urbanization is spreading rapidly and the effects of this development may not be considered before it occurs. It is tremendously important to be aware of the delicate balance that is our natural world and to do what we can to prevent a negative impact on our precious planet.