| Effects of Genetic Diversity on Restoration Success |
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Human-induced changes declines in submerged aquatic vegetation (SAV) in the Chesapeake Bay have both been caused by and led to declines in water quality. The far-reaching consequences of SAV decline have focused attention on effective ways of restoring the Bay’s living resources. Resulting restoration efforts of SAV in the Chesapeake Bay have been impressive; however, success has been undeniably mixed. In collaboration with Dr. Katia Engelhardt at the University of Maryland Appalachian Laboratory, we have been funded by Maryland SeaGrant to assess the role genetic diversity and sources of restoration stock on restoring Vallisneria. Americana. At the same time, we are interested in the effect of Large-scale planting and seeding efforts on natural genetic diversity patterns. We are specifically examining three aspects of genetic diversity that have been shown to affect plant fitness and thus have important implications for restoration success: levels of inbreeding within individuals, levels of diversity among individuals), and the adaptation of individuals to local environments.
 We are interested in V. americana because it was once a dominant species in the Chesapeake Bay, it is considered an important food resource for wildfowl, it does not interfere with recreational uses of waterways, and it is used in restoring freshwater portions of the Bay by a variety of conservation groups. Changes in the distribution of SAV including Vallisneria americana are monitored using remote sensing techniques by the Virginia Institute of Marine Science. The remotely sensed locations are ground truthed by a dedicated network of agency personnel and volunteers.
Vallisneria americana is a dioecious submersed aquatic macrophyte that is capable of both clonal growth and sexual reproduction with vegetative expansion often being the dominant form of propagation. Knowledge of the distribution of genetic diversity within and among populations will enable selection of appropriate donor individuals and populations for restoration. For example, quantifying the number and spatial extent of clones within populations will contribute to generating collecting protocols that increase the potential genetic diversity in restoration stock.
 Our work focuses on populations growing in freshwater and oligohaline portions of the Chesapeake Bay. During summer 2007 Michael Lloyd (Ph.D student) and Robert Burnett (undergraduate student) are spending lots of time in waders, in boats, and in snorkeling gear sampling both natural and restored populations of V. americana.
The sampling design will allow us to assess the spatial and environmental patterns of genetic diversity in natural beds and to compare those patterns with restored beds of varying ages. Additionally, Katia will be growing the same clones we genotype in mesocosm environements, allowing us to link genetic diversity with ecological performance.
When they are not on or in the water, Mike and Robert are in the lab characterizing genetic diversity using microsatellite markers. Katia’s lab will use individuals with known genotypes to establish populations in mesocosms. These populations will be used to improve our understanding of linkages between neutral genetic diversity and fitness related characteristics such as sexual reproduction and growth rates and tolerance to adverse environmental conditions.
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