California Sea Grant College Program

In California’s Central Valley, freshwater diversions and land development have greatly reduced the extent and sustainability of native cottonwood and willow riparian forests, which provide critical habitats for many species of wildlife and offer other environmental benefits such as slowing erosion, maintaining soil quality and filtering pollutants.

The cumulative result of human activity in the region over the last century and a half has been the loss of about 90 percent of all riparian forests. Efforts are underway to protect and restore remaining forested areas, which are often fragmented and vulnerable to replacement by less ecologically beneficial vegetation.