A river turtle species, once one of the most wide-ranging in the United States, still suffers from past harvesting and declining water quality, researchers say. University of Florida researchers studying river turtles in Missouri found populations of the northern map turtle have not recovered from harvesting, mostly for food, that caused a 50 percent population loss between 1969 and 1980, the university reported Tuesday. River turtles are vital to ecosystem functions by cycling nutrients and maintaining food web dynamics, the researchers said. \"The importance of river turtles is really underplayed,\" said lead author Amber Pitt, a Clemson University postdoctoral research fellow who conducted research for the study as a UF graduate student. \"River turtles are long-lived, rely on the same water resources that we do and can serve as indicators of water quality,\" Pitt said. \"People should be concerned if turtles are impacted by poor water quality because we are likely being affected, too.\" The northern map turtle, Graptemys geographica, inhabits river systems from southern Arkansas to Quebec in Canada. \"Oftentimes with conservation, you have the charismatic mega fauna that people care about, such as sea turtles -- everybody cares about sea turtles, including me,\" Pitt said. \"But river turtles are facing just as many threats as sea turtles. People are also harvesting river turtles and there are very few laws in place to stop this harvest -- it\'s a global epidemic that is causing turtle populations to be wiped out.\"