Off-Campus Hollins Users:
To access this document, please click here to log in to our proxy server with your campus network user name/password (the same one you use to log into the campus network and your e-mail).
Event Type
Research Presentation
Academic Department
Biology
Location
Dana Science Building, 2nd floor
Start Date
14-4-2023 1:30 PM
End Date
14-4-2023 3:00 PM
Description
Under the direction of Dr. Renee Godard
An invasive sea grass species, Halophila stipulacea, was introduced to the Caribbean in 2002 and first appeared in St John (STJ), USVI in 2010. To understand the invasion dynamics of this species, five bays in STJ were sampled with 25 cm2 photo transects across each bay (grassbed transects) in January 2020 and again in June 2022. In addition, photo transects were taken at the exact foraging locations of green turtles Chelonia mydas in both years. Individual grass blades were identified and counted in each of the photo transects separately by 3 individuals and an average abundance of each species was calculated per transect over both years. Halophila stipulacea showed a significant increase in grassbed transects between 2020 and 2022. While an increase in H. stipulacea was noted in foraging transects, this increase was not significant. However, there was an increase noted in the abundance of turtle grass (Thalassia testudinum) in turtle foraging transect sites between the two years. H. stipulacea increased in abundance in grassbed transects in all 5 bays sampled but only increased in foraging transects in one bay. It appears that H. stipulacea has been increasing in abundance in St. John and that the foraging preferences of turtles may act as an agent for the increase in the non-native species.
Two years in the life of an invader: Halophila stipulacea Increases in Abundance only in Grassbeds Transects
Dana Science Building, 2nd floor
Under the direction of Dr. Renee Godard
An invasive sea grass species, Halophila stipulacea, was introduced to the Caribbean in 2002 and first appeared in St John (STJ), USVI in 2010. To understand the invasion dynamics of this species, five bays in STJ were sampled with 25 cm2 photo transects across each bay (grassbed transects) in January 2020 and again in June 2022. In addition, photo transects were taken at the exact foraging locations of green turtles Chelonia mydas in both years. Individual grass blades were identified and counted in each of the photo transects separately by 3 individuals and an average abundance of each species was calculated per transect over both years. Halophila stipulacea showed a significant increase in grassbed transects between 2020 and 2022. While an increase in H. stipulacea was noted in foraging transects, this increase was not significant. However, there was an increase noted in the abundance of turtle grass (Thalassia testudinum) in turtle foraging transect sites between the two years. H. stipulacea increased in abundance in grassbed transects in all 5 bays sampled but only increased in foraging transects in one bay. It appears that H. stipulacea has been increasing in abundance in St. John and that the foraging preferences of turtles may act as an agent for the increase in the non-native species.