There are five main drivers for habitat loss in the U.S. agriculture, land conversion for development, water development, pollution, and global warming. Much of the habitat loss from agriculture was done long ago when settlers converted forests and prairies to cropland. Today, there is increasing pressure to redevelop conservation lands for high-priced food and bio-fuel crops. The conversion of lands that once provided wildlife habitat to housing developments, roads, office parks, strip malls, parking lots and industrial sites continues, even during the current economic crisis. Dams and other water diversions siphon off and disconnect waters, changing hydrology and water chemistry (when nutrients are not able to flow downstream). During the dry season, the Colorado River has little to no water in it by the time it reaches the Sea of Cortez. Freshwater wildlife are most impacted by pollution. Pollutants such as untreated sewage, mining waste, acid rain, fertilizers and pesticides concentrate in rivers, lakes and wetlands and eventually end up in estuaries and the food web. Global warming is the emerging driver of habitat loss. Wildlife that need the cool temperatures of high elevations, such as the American pika, may soon run out of habitat. Coastal wildlife may find their habitat underwater as sea levels rise.
