Keystone College Wildlife Biology Graduate Students Studying Invasiveness of Earthworms
Keystone College Wildlife Biology Graduate Students in Assistant Professor Linda Tucker Serniak’s Forest Ecology Lab are learning how invasive earthworms are affecting the plants, arthropods, and salamanders on the Woodlands Campus. Earthworms consume leaf litter, which can decrease the habitat available for salamanders as well as affect what types of arthropods live there. Because many forest soil nutrients come from leaf litter, invasive earthworms have the potential to modify nutrient cycles and change which plants can survive.
The students in the course are Abigail Hayford, Shanon Hornung, Summer Price, Kai Lydon, Zachary Hemond, Alyson Grindall, and Christina DeCresenza.
They have been setting up random 5-m diameter plots and collecting the earthworms using mustard extraction. The mustard powder is mixed with water and poured over a defined area, and the earthworms will rise to the surface. Students identify and weigh the earthworms, most of which are jumping worms (Amynthas spp.), a relatively new invasive earthworm in the northeast. These worms have not been studied as well as other earthworm species.
The students will work in two teams for the rest of the project. The first team will study how earthworms affect understory plant diversity, such as shrubs and ferns, as well as the arthropods (insects, spiders, etc.) that live on those plants. They identify all of the plants in the plot and estimate the cover of each species. Then to collect arthropods, they beat the plants and catch the falling arthropods in an upside-down umbrella, and then they are placed into a bag to be IDed later in the lab.
The second team will study how earthworms affect salamanders and arthropods that live in the leaf litter – these would serve as food for the salamanders! They search the leaf litter as well as under cover objects like rocks and fallen logs and gather all of the salamanders they find. Then they identify and weigh the salamanders. They collect a leaf litter sample to take back to the lab to ID the arthropods present. The students are also measuring soil pH and leaf litter depth in case that influences their findings.
