Aquatic Salamanders
We have been monitoring aquatic salamander populations in Walker Valley, where Tremont Institute is located, since 1999! To accomplish this, we have artificial salamander habitats, or Salamander Hotels, placed in five streams. Using a set protocol, students check each hotel for salamanders and identify, measure, and release any salamanders found. They also record several environmental variables, such as temperature and pH of the stream.
The objectives of this study are to:
- Gather long-term baseline data on salamander populations in Walker Valley.
- Determine species distribution along streams in the Walker Valley.
- Compare populations (snout-vent length, total length, and age distribution) in heavily used streams with populations in less visited streams.
- Compare species richness and abundance in relation to stream habitat and water quality variables in Walker Valley streams.
- Produce data that are compatible with other stream salamander research in the Smokies.
- Provide educational experience for volunteers and participants of Tremont programs, giving them a chance to learn about and participate in scientific research.
Background:
Streamside salamanders are defined as those species whose larval stages occur within 1st and 2nd order streams and springs. In the Smokies, this group is composed of the genera Desmognathus, Eurycea, Gyrinophilus, and Pseudotriton.
Stream salamanders as a group have the following attributes that make them attractive for monitoring:
- Relatively low sampling variation
- Occur in small order streams that collect and concentrate water-borne contaminants from the surrounding landscape and therefore respond to disturbances and pollutants from throughout the watershed.
- Are known to be sensitive to riparian corridor widths and stream acidity
- Are accessible for sampling throughout a lengthy period of time within the year.
- Are the top predators in streams without fish
- Good potential for incorporation into evaluations of headwater and stream habitat quality.
- High public and volunteer interest
- Fecundity is low and their life cycle lengthy. Thus, combined with a relatively low colonization ability makes the presence of all the life stages in a stream strong evidence for population stability and watershed quality.
Study Areas
In 1999, we designated stream sections for monitoring, including the Dorsey Branch, Loan Branch, Pig Pen Branch, Ashley Branch, and Spicewoods Branch. Dorsey and Loan Branches are visited by children looking for salamanders several times a week. Pig Pen, Spicewoods, and Ashley Branches are rarely visited by Tremont groups (other than for salamander monitoring) and appear to be unvisited by almost anyone. We designated one 100 m transect along each stream channel, with the exception of the Dorsey Branch, which has a second transect several hundred meters upstream of the first transect.
Collection Method
We use the leaf litter bag method designed by Tom Pauley to survey streamside salamanders (Pauley 1995). Leaf litter bags are placed at 5 m intervals along 100 m transects, for a total of 21 bags per transect. These bags should be stuffed with leaves at least two weeks before a planned visit to check the transect. We keep our leaf litter bags supplied with leaves throughout the year.
Leaf litter bags are constructed of plastic mesh (50 cm2), held together by plastic zip-ties. In the field, the bag is filled with several handfuls of leaves and a small rock to weigh it down. A 12″ piece of orange flagging tape is tied through the netting at the top of the leaf litter bag so that they are more visible in the stream. The bags are numbered with aluminum tags and tethered to a tree or root with fishing line to keep them in place. We check each transect a minimum of three times per year with no fewer than 14 days between efforts.
We monitor salamanders found inside these leaf litter bags, lovingly referred to as “salamander hotels.” By only counting the present species within the structure, we are able to ensure more consistent and reliable data across study areas.
