Wetlands are destroyed by agriculture due to infilling, grazing and chemicals. Buildings and roads block normal flooding and drainage. Stream Channelization - Streams are moved by modifying the land around them. Water no longer collects in wetlands, but rushes through a stream, bringing along pollutants and causing flooding. Grazing removes virtually all of the vegetative cover except for short grasses, which provides little cover or food for wildlife.
Livestock waste pollutes wetlands with too much organic material.
Mining - Mining seeps toxic chemicals into the water system. Strip mining produces acid mine drainage and physically destroys streams and wetlands. Hard rock mining leaves toxic waste and can lower water tables, drying up groundwater- fed wetlands. However, the native species were there for a reason, whether to prevent flooding or as a food source. When the natural species disappear, the wetland cannot function.