Devil's River Minnow - Anthropogenic Effects

Anthropogenic Effects

The fragile status of this species is due to the culmination of many factors. Human activity has caused a large amount of habitat loss and/or degradation. The Devils River Minnow depends on clean, constantly flowing spring waters in order to survive. However, due to both the construction and agricultural industries, the supply of these waters has been dramatically reduced. Agricultural runoff is responsible for most of the pollutants in the minnows’ habitat, many of which they cannot tolerate at even slightly increased levels. Dam construction, particularly that of the Amistad Dam, has greatly contributed to spring inundation. Spring flow has also been reduced due to well pumping and overgrazed soil, which lowers the amount of water that can normally be found in natural aquifers. The reduction of these springs has caused the overall quantity and length of the Devils River to dramatically decline. The exact extent of this decline is not known, however, according to United States Geological Survey (USGS) data from the Paffords Crossing gauging station on the Devils River, the daily mean discharge has “generally decreased between 1978 and 1992.” Once established populations of the species have now been decimated, primarily in Texas where droughts reduce the supply of groundwater even further. Anthropogenic sources, while some of the major contributors to the Dionda diaboli’s decline, are not entirely responsible for its current circumstances.