Small Crustaceans, Big Implications: Anthropogenic Impacts of Propeller Scars on Floridian Seagrass Ecosystems

Faith James, Ingrid Jacobson, and Dr. Jenn Sweatman, Biology Department, Concordia College, 901 8th St S, Moorhead MN 56562

Seagrass meadows on the Florida coastline provide optimal habitats for many keystone species but are being threatened by increasing anthropogenic activity. This ecosystem is vulnerable to boat propeller scarring that fragments natural habitats and disrupts typical species movements. Long-term impacts of habitat fragmentation are monitored by analyzing seagrass nutrient content, which reflects ecosystem-wide nutrient availability. Communities of amphipods may be useful for analyzing the effects of habitat fragmentation on higher trophic levels. Studies have explored how older seagrass scars affect other crustaceans like crabs and mollusks, as well as the influence of new scars on amphipod communities, but no study has examined the effects of older seagrass scars on amphipods. Our lab is investigating how older propeller scars affect seagrass nutrient content and amphipod communities. Our lab collected samples from three randomly selected propeller scars in Lignumvitae State Park, Florida, at four distances: 0 m (at the seagrass-scar interface), 1 m, 2 m, and 5 m. Samples were collected using a Virnstein Grabber, which collects aboveground seagrass biomass and associated epifauna. Seagrass samples are currently being dried, homogenized, and analyzed for total phosphorus, carbon, and nitrogen content. Amphipods are being identified to the species level where possible. Species diversity and frequency will be calculated across sampling plots for univariate statistical analysis. We will also conduct a multivariate analysis of amphipod communities across the sampling plots to potentially identify community-level changes. We expect to find reduced nutrient content in the seagrass, as well as low amphipod population density and diversity, due to habitat fragmentation and destruction. The findings of this project would advance our understanding of fragmentation effects on seagrass ecosystems. Data will be reported to the Florida State Parks department, further contributing to conservation management practices in the Florida Keys.

Additional Abstract Information

Presenters: Faith James, Faith James, Ingrid Jacobson

Institution: Concordia College - Moorhead

Type: Poster

Subject: Ecology

Status: Approved

Time and Location

Session: Poster 5
Date/Time: Tue 12:30pm-1:30pm
Session Number: 4103