We started the 2018 season by chopping wood, and lots of it. Slab wood left over from the milling process has been piling up on White Memorial’s property, and we knew exactly who could use it- Amphibians. This summer started out with hauling this wood out into the woods to increase the number of amphibian cover board grids. These grids get surveyed every year to get an idea of amphibian diversity and abundance at White Memorial. This year, it got taken to the next level.
|Shannon shown here excitedly showing off a Four-Toed|
Salamander she found at one of the grids
Shannon Smith, Litchfield native and Trinity College student, completed her Master’s thesis on White Memorial’s salamanders. Specifically, how Red-Backed salamanders are affected by invasive non-native earthworms. To help Shannon get data for this project, we doubled the amount of cover board grids present on the property, and aided her in field work whenever we could.
|Shannon is shown here surrounded by her research|
materials. 4 1-Gallons jugs of water mixed with mustard
were brought to each plot, no matter how remote
Her methods required sampling of salamanders, earthworms, leaf litter, and soil invertebrates for each of the 40 grids. Each grid took about 2 hours, a lot of grit, a good sense of direction, and tons of Tecnu to complete.
|Some of the research materials on top of a cover board.|
Each grid had 25 of these cover boards that needed
to individually be flipped and analyzed for salamanders
Her research questions evolved as time went on, as is normal for research in this field; so little is known about the earthworm invasion and its implications. Because about half of the cover board grids she sampled had been present for years prior to her project, and the other half had just been dealt out only a few months prior, she had to account for the dispersal rate of these animals to the new grids.
She found that the strongest influences on salamander abundance were leaf litter quality, soil temperature, and invertebrate community diversity.
|Red-Backed Salamander found in Shannon's|
Red-Backed Salamanders are Connecticut's most abundant amphibian. By consuming large numbers of soil invertebrates which are otherwise unavailable as food for larger animals, Red-Backed Salamanders play a key role in moving nutrients up the food web. They are eaten mainly by songbirds, but also mammals of many sizes and also larger amphibians.
This study is showing that earthworms may be negatively affecting these amphibian's ability to play that key role in the food web. Earthworms are altering the soil environment for these important amphibians by decreasing the amount/diversity of soil invertebrates and influencing the leaf litter layers. This could have serious ecological effects reaching far up the food web. More research is needed to understand the role that non-native earthworms play in our soil, and how they are affecting other soil invertebrates.
You can help limit the earthworm invasion by not dumping unused "night crawlers" or other worms in the forest but rather the trash bin. Recognize that earthworms are having huge impacts on forest health, and try not to spread them around.
|Four-Toed Salamander, a species much less|
common than the Red-Backed