The rivers in the Los Angeles basin are brightly gleaming, curving water drains that have lost most of their ecological functions. The need to control the “killer floods” throughout the LA basin led to the fracturing of these functions til little remains of the vegetation and wildlife normally associated with riparian systems. We are involved in a year-long project to visit and record vegetation along the rights-of-way (ROW) throughout the San Gabriel River system. In addition, we recorded wildlife use and identified recreation opportunities. While much of the system will remain concreted for many years to come, the ROWs can be viewed both as potential wildlife corridors to link isolated wildlands within the urban matrix, and linear parkways for a park-poor city. The Los Angeles County Department of Public Works published the Landscaping Guidelines and Plant Palettes for the LA River to expedite the design plans and native plant choices for the ROW parks. These parks will link communities within LA and create valuable active and passive recreation opportunities.
We mapped the current vegetation and investigated the “before” use of these ROWs by wildlife. We mapped intact communities using current state protocols. We photographed each segment of the river and tributaries as well as any evidence of wildlife use: scat, droppings, dust baths, and tracks. We used a handheld Trimble GPS unit and GPS Photo-Link software to display the photographs, positions on aerial photographs, and maps on the LASGRWC website.
Results/Conclusions
Not surprising, upper watershed areas contained most of the intact native vegetation while the ROWs along the concreted main stem and major tributaries were essentially devoid of vegetation. Our investigations indicate that despite the lack of vegetation opportunistic species, such as coyote, raccoons, deer, and numerous bird species, are using the ROWs as linkages between open space areas. Some biological resources were conspicuous in their absence, reptiles, amphibians, and most insects, possibly due to a long history of pesticide use. Future investigations include: using cameras to document the use by specific wildlife species; surveying other biological resources (bats and reptiles) using accepted protocols; and testing the genetic relatedness between populations in large islands of remaining open space. Once linear parkways and pocket-parks are planted, wildlife use should change, and we would like to investigate the “after” scenario.
