Riparian Forest

Riparian forests are sometimes called the rainforests of California—not because they receive more precipitation than other areas, but because of the incredible diversity of plants, fish, and wildlife that they support. Riparian forest habitat is dominated by woody vegetation growing adjacent to a river, stream, or other flowing body of water. With Sacramento located at the confluence of two major rivers, riparian forest habitat is a major influence in our local ecology.

Fascinating Features

  • The blue elderberry (Sambucus nigra ssp. caerulea), which grows in riparian forests, is an important plant for many indigenous people. The berries are used as a nutritious food source and provide dye for basketry materials, elder flowers are used medicinally, and the straight-growing branches can be used to make game pieces, flutes, and arrow shafts.
  • Many riparian plant species exhibit special adaptations for growing in areas that are prone to flooding. They may have flexible branches to withstand high flows, the ability to grow roots from above-ground parts of the plant that help the plant absorb oxygen when water-saturated soil becomes anaerobic, or fruits or seeds that float on water to aid in dispersal.
  • Only 5 to 10 percent of California’s riparian habitat remains today, and much of that is in a state of degradation. The majority of this loss is due to stream channelization, urban and suburban development, logging, grazing, and water diversion.

Habitat Values

This habitat’s dense vegetative cover and availability of year-round water provide shelter and abundant food for both terrestrial and aquatic wildlife and fish. Common tree and shrub species such as Fremont’s cottonwood (Populus fremontii), willows (Salix spp.), red osier dogwood (Cornus sericea), and California wild rose (Rosa californica) create a multilayered canopy.

Water quality and erosion control

Roots of native riparian trees and shrubs trap sediment that stabilizes river and stream banks, reduces erosion, and improves water quality. Structure provided by the root systems, as well as by fallen logs and branches, maintains habitat for aquatic invertebrates and healthy fish populations.

Native aquatic habitat

Riparian tree canopies provide shade over critical stream edge habitat, which helps to maintain cooler water temperatures, an important feature for cold water fish species such as Chinook salmon (Oncorhynchus tshawytscha) and steelhead (Oncorhynchus mykiss).

Native bird habitat

Over 135 species of birds native to California use riparian forest habitat. Some, like the Least Bell’s Vireo (Vireo bellii pusillus) and Yellow-billed Cuckoo (Coccyzus americanus), rely exclusively on riparian habitats, where native trees and shrubs support the high numbers of insects these birds need as food.