Date Awarded


Document Type


Degree Name

Doctor of Philosophy (Ph.D.)


Virginia Institute of Marine Science


Tidal freshwater wetlands represent a transitional wetland between tidal salt marshes and non-tidal wetlands. as such, they exhibit some of the vegetation characteristics of both systems. If the changes in the vegetation pattern favor the characteristics of one system over the other, the changes may be an indication of changes in the environmental conditions of the estuarine ecosystem that favors that system. Unfortunately, little is known of the temporal and spatial changes that occur in the vegetation patterns of tidal freshwater marshes of the mid-Atlantic coastal region. In 1987 a vegetation analysis was done on a 60 hectare section of Sweet Hall Marsh, a tidal freshwater marsh of Chesapeake Bay. The data was compared with that of a similar study completed in 1974 to determine the changes that may have occurred in the vegetation pattern of the marsh. The results found that there was no significant difference in the species diversity of the two studies. However, further analysis showed that there was a change in the plant species contributing to the diversity. Spartina cynosuroides, an oligohaline species that was not important in the 1974 study, had the fourth highest importance value in this study. The shift in species composition of Sweet Hall Marsh may reflect a shift in the marsh's environment from being historically that of tidal fresh water to one of being more transitional between oligohaline and tidal fresh water.



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