A Focus on Vallisneria

Vallisneria americana and V. neotropicalis, commonly known as American eelgrass or tape grass, are native, rooted aquatic plants with strap-like leaves that can grow to several feet in length. Eelgrass is found throughout the United States and is an important component of Florida’s freshwater ecosystems. This plant can form large meadows in aquatic environments and provides ecosystem benefits such as improving water quality, oxygenating and stabilizing sediments, and serving as a carbon sink for carbon dioxide. Healthy eelgrass patches also provide nursery areas, forage, and habitat for a wide range of vertebrate and invertebrate species including certain imperiled species of Florida, such as the Suwannee cooter, the Florida sandhill crane, the tessellated darter, and the Florida manatee.

This important plant has been lost from many of its historical locations across Florida, including the Everglades, the Caloosahatchee River, the St. Johns River, and the Springs Coast. Because eelgrass is often a primary provider of habitat and food in many freshwater systems, it is the subject of multiple restoration efforts throughout the state. While eelgrass is a resilient species in many instances, often found growing in ditches and canals and other non-pristine waterways, restoration at historical sites has proved to be challenging. Personnel from the Freshwater Plants research project are working with managers from FWC’s Aquatic Habitat Restoration and Enhancement Subsection to develop or improve methods of restoring eelgrass in the St Johns River, Lake George, and Silver Glen Run.

While conducting studies of eelgrass in 2018-2019, Freshwater Plants researchers and geneticists at FWRI discovered the presence of a novel, non-native hybrid eelgrass species (Vallisneria spiralis x V. denseserrulata) in Florida and Alabama. Continuing research during 2021-2023, funded by FWC’s Invasive Plant Management Section, examined the statewide distribution and potential invasiveness of the hybrid. Additionally, Freshwater Plants researchers identified morphological traits that may aid managers in visually distinguishing native from non-native eelgrass.