Healthy creekside vegetation |
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Disturbed creekside vegetation |
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On the banks of many creeks of the San Francisquito watershed, native creekside (riparian) vegetation has been degraded or removed as the area has been developed. This native vegetation fulfills a diverse set of functions in creek ecology, and its removal has created a number of problems. |
Creekside vegetation is important because it:
 Provides food and shelter for many organisms including insects, amphibians, reptiles, birds, and small mammals.
Shades the creek, keeping the water cool. Removal of this vegetation raises water temperatures, leading to reduced dissolved oxygen levels and encouraging algae growth. In addition, vegetation provides shadowy areas where aquatic wildlife hide from predators.
Connects disjointed islands of natural habitat in the watershed by creating a line of semi-wild area, known as a "riparian corridor." Preventing habitat fragmentation is of vital importance to many species that migrate at various stages of their life cycle, among them steelhead and many amphibians. Connecting natural habitat areas also helps maintain the genetic diversity of local wildlife and its resistance to disease.
Filters pollutants, including pesticides and fertilizers, out of water that washes into to the creek from the surrounding landscape.
Stabilizes the banks of the creek, preventing erosion and siltation that degrades water quality and clogs the gravel where steelhead spawn.
Removal or disturbance of native creekside vegetation opens the door to infestation of nonnative invasive plants, such as arundo donax, Cape ivy, and French broom. Once established, these plants often outcompete native plants and dominate the landscape, which can cause drastic habitat changes. |
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