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Russian River Notes >*• March 1994 



Riparian Habitat 



an the Russian River ** 



A Russian River Enhancement Plan status report completed in January 1994 documents die extent and 

 quality of riparian forest along the Russian River. Riparian (streamside) forest is rare in California; more than 

 90 percent has been lost to development, agriculture, and other uses. On the Russian River, 40 percent of the 

 riparian forest was lost between 1940 and 1992. Riparian habitat is the most highly productive wildlife habitat, 

 supporting the greatest diversity of animal species. Half of the reptiles and three fourths of the amphibians in 

 California, as well as many bird species, depend upon streamside forest. The thick and fertile tangle of 

 riparian forest is California's version of the tropical rainforest 



Not only does riparian forest 

 provide for a broad diversity of 

 animal species, it also stabilizes 

 river banks and protects agricul- 

 tural lands; It catches large woody 

 debris during floods, protecting 

 vineyards and orchards from log 

 jams; it creates and shades stream- 

 side pools and contributes a 

 diversity of aquatic habitat for fish 

 by providing woody debris, root 

 masses, and undercut banks. 



The extent and quality of 

 riparian forest is controlled by the 

 physical processes of the river. A 

 healthy forest consists of many 

 tree and shrub species and a 

 mixture of tall, mature trees, mid- 

 range trees, and seedlings. This 

 mixture is dynamic, shifting as the 

 river changes. Por example, 



channel scour and bank erosion 

 remove mature trees along the 

 river's edge and add woody 

 debris to the channel. The seeds of 

 "pioneer" species, such as willow, 

 germinate on newly lald-down 

 sediment on gravel bars. 



Willows are among the 

 hardiest of riparian trees and are 

 able to withstand the force of river 

 flows; therefore, they grow dosest 

 to the active channel. As the 

 willows mature, their dense root 

 and branch systems catch more 

 sediment, building hummocks of 

 higher ground along gravel bars. 

 These hummocks diversify as 

 other tree spedes invade, and over 

 time a mature forest may develop, 

 replacing other areas of mature 

 forest scoured out by the river. 



This process of scouring, loss 

 and regrowth of habitat is termed 

 succession. It occurs at the mercy 

 of the river's channel process. To 

 maintain the health of the riparian 

 habitat, the river's physical 

 processes must allow for these 

 successional changes. The mature 

 habitat that exists today could 

 easily be lost next winter. Unless 

 mere are middle-aged and new 

 trees to replace the mature trees, 

 over rime the system will score a 

 net loss. 



The enhancement plan alms 

 to improve riparian habitat by 

 focusing on the river's equilibrium 

 and recommends measures to 

 restore a greater level of balance to 

 allow natural riparian habitat 

 succession to occur. 



—KartnGaffnty 



This cross-section of the middle rtachcfthe 



Russian River depict* the doumcut charmd 

 and its effects on groundwater levels. 



A meandering channel slaws the force 

 of the water, depositing sediment on 

 one bank while cutting into the 

 opposite bank. Courtesy of Philip 

 Williams & Associates. 



