Of the threatened or endangered wildlife and plants currently listed by the United States Fish and Wildlife Service an estimated fifty percent of the wildlife and over thirty percent of the plants depend on wetlands for survival. Numbered among these are the Swainson's Hawk, California Red-legged Frog, and Western Pond Turtle. Wetlands support one of the most productive and biologically diverse natural ecosystems in the world. They offer both aquatic and land-based habitat. Many plants and animals have adapted specifically to life within the wetlands including forty-one of California's rare and endangered species.
Wetlands protect and improve the quality of water.
The water passing through wetlands carries organisms, sediments, nutrients, and pollutants. The vegetation and soil in the wetland form a kind of sieve, trapping those materials and filtering the water. Wetlands help to control soil erosion. They act as natural tubs or sponges. Floodwater or surface waters collect in isolated depressions where they are stored and slowly released.