Using Genetic Diversity of Vallisneria americana Across a Latitudinal Gradient To Inform Submersed Aquatic Vegetation Restoration Strategies

EPA Grant Number: FP917113
Title: Using Genetic Diversity of Vallisneria americana Across a Latitudinal Gradient To Inform Submersed Aquatic Vegetation Restoration Strategies
Investigators: West, Brittany Elizabeth
Institution: University of Maryland - College Park
EPA Project Officer: Lee, Sonja
Project Period: August 30, 2010 through August 29, 2012
Project Amount: $74,000
RFA: STAR Graduate Fellowships (2010) RFA Text |  Recipients Lists
Research Category: Academic Fellowships , Fellowship - Ecosystem Services: Aquatic Systems Ecology


Submersed aquatic vegetation (SAV) is an important component of aquatic ecosystems that has experienced large-scale losses over relatively short time periods. In addition to the intensifying threats SAV encounters as human population size increases, the effects of global climate change are not well understood, but anticipated to dramatically alter SAV abundance and distribution. To contribute to the understanding of these potential effects I will describe the structure of genetic diversity in the SAV species Vallisneria americana (wild celery) at local, regional, and macrogeographic scales across a broad latitudinal gradient along the western Atlantic coast. I also will investigate the phenotypic responses of different genotypes from across that gradient to environmental stressors. The research results will provide information on how current stressors have affected diversity within and connectivity among V. americana occurrences and will provide insight into potential for adaptation to future conditions anticipated under climate change.


Efforts to restore submersed aquatic vegetation (SAV) have been marginally successful, and threats of climate change present more challenges. This research analyzes the relationships between genetic diversity and plant growth responses of Vallisneria americana (wild celery) collected along the Atlantic Coast. The results will provide insight into conservation/restoration efforts regarding the potential of individuals from different regions to tolerate or adapt to novel environmental conditions.


I will use developed microsatellite markers to compare the population genetic diversity and structure of V. americana among sites within regions and among regions spanning the latitudinal gradient along the western edge of the Atlantic Ocean. Samples of V. americana will be collected along the latitudinal gradient from Florida to Maine for this analysis. Collected samples will then be propagated at the University of Maryland under common conditions, and additional environmental stress experiments will be performed in controlled growth chamber or greenhouse environments. Two sets of growth experiments will specifically focus on the effects of temperature and light availability, environmental factors that are expected to vary over a latitudinal gradient and under altered climate conditions, on the growth and survival of V. americana collected from these different regions. The data from this research will quantify the genetic diversity in V. americana along the Atlantic coast of the United States, identify areas of high genetic diversity or areas with large discrepancies in regional allele composition along a latitudinal gradient, as well as quantify the vegetative growth differences among individuals within sites, among sites within regions, and among regions across the latitudinal gradient that arise from environmental stresses.

Expected Results:

This research aims to describe the structure of V. americana genetic diversity at local, regional, and macrogeographic scales across a latitudinal gradient and to link genetic variation with phenotypic variation to understand potential for persistence in the presence of environmental stressors. The local and regional genetic structuring in V. americana may vary across a latitudinal gradient, and different genotypes of V. americana may exhibit varying phenotypic responses to environmental stressors. It is important to understand these dynamics because a species’ capacity to adapt to a changing environment (i.e., its evolutionary potential) is determined by the amount of genetic variance on which natural selection can act. A thorough understanding of how SAV genetic diversity is structured at multiple spatial scales across the latitudinal gradient, and how the breadth of environmental tolerance varies among individuals, sites, and regions will provide insight into the degree of phenotypic variation available and the potential for adaptation under anticipated future conditions. These data will provide a scientifically sound basis for choosing among management options aimed at slowing and reversing declines in submersed aquatic vegetation.

Potential to Further Environmental/Human Health Protection:

The results of this research will enhance the protection and restoration of valuable SAV habitat by applying molecular genetic techniques to augment current conservation and restoration practices and to shape future restoration initiatives. Characterizing the genetic structuring of V. americana across a latitudinal gradient will allow managers to identify populations that show signs of isolation or inbreeding, and to prioritize preservation of areas with high genetic diversity or unique allelic composition. The data linking genetic variation with phenotypic response also will inform current restoration efforts by enhancing the selection of suitable restoration stock. Moreover, this project can inform future restoration initiatives by providing information necessary to anticipate future conditions in V. americana beds along the Atlantic coast. With the continued threats of climate change, new restoration strategies like managed relocation (MR) are rapidly being developed to address biodiversity management and restoration when both persistence and recolonization are not possible. Data from this research could evaluate the necessity of drastic actions like MR by assessing the tolerance of V. americana individuals across a broad latitudinal gradient to current and projected future conditions.

Supplemental Keywords:

Vallisneria americana, SAV restoration, genetic structure, phenotypic plasticity, latitudinal gradient, climate change, managed relocation,

Progress and Final Reports:

  • 2011
  • Final