The Impact Of Varying Densities Of The Exotic Vegetation Hydrilla On Fish Communities Of The Potomac River PDF Download

In an attempt to objectively evaluate the ecological role of hydrilla in the Potomac River, a qualitative study was conducted on the use of the plant by waterfowl species. Three study areas were selected along the river where hydrilla was known to grow profusely, and observations were made of waterfowl feeding on the hydrilla or otherwise using the areas. In addition, a small population of captive waterfowl was used in a simplistic study of feeding preference on hydrilla plant material collected along the river. This report gives the results of these studies. In general, from the observations in these studies, it is apparent that hydrilla does provide ecological values important to waterfowl and other water-associated birds. The most obvious use of hydrilla by ducks and geese is direct consumption as food. Some duck species and other birds are no doubt obtaining adequate fish and invertebrate food items from the hydrilla stems, leaves, and interfoliar spaces. These studies, although qualitative for the most part, indicate that the ecological value of hydrilla is probably very well worth further consideration. The potential positive scientific information to be gained is obvious. Keywords: Aquatic weeds; Aquatic plants; Weed control.