American Entomological Society Meeting and News Society Meeting of April 23, 2014

Abstract

Human activities have affected all aquatic and wetland habitats on the Del mar va Peninsula, sometimes degrading or destroying them, and at other times creating them. Dragonflies and damselflies (Odonata) spend most of their lives as larvae under water. As a consequence of habitat alterations, some species have thrived and others have become rare or have disappeared. By constructing dams, early settlers converted free-flowing Piedmont streams into a series of ponds to power their mills. Soil eroded from farmland where forests once stood and washed into the valleys filling the mill ponds. Later removal of the dams allowed streams to erode back to their original beds forming canyons in the now elevated flood plain. Abundant vernal ponds on the Coast al Plain were drained for agriculture. Runoff of fertilizers resulted in eutro phication of streams and ponds. Rising sea level allowed salt infiltration into and loss of rare sea level fens. Storm water detention basins and sand mining operations have created new and sometimes favorable habitats for different species of Odonata. In a particular example, the proliferation of storm water retention basins and eutrophication of ponds has favored large populations of Erythemis simplicicollis (Eastern Pondhawk), a species that dines on other dragonflies and especially damselflies. Their abundance has been linked to the near absence of pond damselflies in the summer at habitats where they were once common.