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Impacts on Fauna Sand is often dredged out of the subtidal environment for deposition on the beach. Beach renourishment may have both direct and indirect effects upon flora and fauna of the sandy shore. The direct effects of beach renourishment include impacts that occur during dredging of subtidal materials, as well as those that occur during emplacement. Many coastal dredging operations which obtain sand material for beach renourishment impact species in the process. Certain types of dredges can cause high mortalities of female sea turtles during the nesting season. Many of the subtidal invertebrate organisms collected in the dredge material die after emplacement into the intertidal environment. Among the impacts which occur after emplacement are changes in the food webs inhabiting the beach sands, as well as influences upon temperature and humidity of sand in the high intertidal region of the beach where sea turtles often lay their nests. Cinde Donoghue, a graduate from the University of Virginia Environmental Science program, has recently studied renourishment effects on Pea Island (near Nags Head, North Carolina). She discovered that renourishment caused an immediate decrease of at least 40 percent in mole crabs, coquina clams, and ghost crabs. This reduction lasted between 2 to 5 months. However, even longer recovery (up to 8 months) occurred if the dredged material was placed on the beach during peak larval recruitment times ("recruitment" refers to the time when larvae mature and enter the adult population). Many shorebirds are dependent upon these common beach invertebrates for food. The concern that exists for sea turtles is based on the impacts that altering the grain size, organic matter content, and sediment color have upon the processes that take place during egg incubation. Sea turtles have been shown to select certain regions of the beach to lay their eggs. Critical to nesting is their ability to excavate the sand to produce an egg chamber into which the eggs are delivered. The success of hatching of eggs is dependent upon a narrow range of temperature and humidity conditions within the nesting sand. Changes in grain size and color influence these factors and may deter nesting or reduce hatching success. Renourishing beaches with inland sand sources often results in mismatched grain size, color and organic matter content. Regarding organic matter content, bacterial and fungal spores from terrestrial sand sources may have more pathogenic components than subtidally-obtained renourishment sources. The process of renourishment probably has even more severe indirect effects, namely promoting an attitude that beachfront development can be pursued anywhere and everywhere. A variety of species of animal and plants that used to inhabit the coasts are now endangered or threatened because of elimination of their habitat. For example, the threatened loggerhead sea turtle (Caretta caretta) has experienced a significant population decline in the southeastern states of South Carolina and Georgia in part due to beachfront development. Many species of shore birds like the Piping plover (Charadrius melodus) are sensitive to dune development. The decline in this species (a loss of 1,240 breeding pairs along U.S. Atlantic coast as of 1990) caused it to be added to the federal list of "Threatened and Endangered Species" in 1985, and it is protected under the "Endangered Species Act." Now read the New York Times article, and answer the following questions.(You may need to register for access to this free site.)
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