99th ESA Annual Meeting (August 10 -- 15, 2014)

OOS 12

Biota of the Los Angeles River, New Studies and Insights in 2014

The Los Angeles River (LAR) system is a gleaming river of (mostly) concrete from the base of the mountains to Long Beach harbor. Though seasonal, it was at times a “killer river” (responsible for 113 deaths in 1938 floods), prompting the ACOE and Public Works Department (DPW) to permanently contain its course. During the 70+ years of river confinement most functions normally associated with riparian systems were lost, most notably support of wildlife. Gone are the fens, tall gallery forests, sandy washes, cienegas, and adjacent scrublands, replaced by an armored concrete channel with fenced/gated rights-of-way (ROW) that exclude the public contact while protecting it from seasonal danger. In 1991 the County Board of Supervisors directed the DPW to begin a master planning effort to revitalize the public ROWs into urban amenities. Progress was slow at first but in 2004 the LAR Landscaping Guidelines outlined the development of linear parks within ROWs that could link communities and ecological processes along the river. In 2005 the City of L.A. adopted a Revitalization Plan emphasizing community connections and water conservation. Despite a perception of the river as a giant stormdrain, in 2010 the US EPA asserted the entire river as navigable, so granting full protection of the Clean Water Act. Kayakers, bicyclists, joggers, fishermen, and birders enjoy limited areas within a very urban river. The pending ACOE LAR Revitalization Plan provides a project framework to restore riparian/aquatic habitats along 11 miles of the river. However, recent most revitalization efforts emphasize human habitat, despite long stretches of natural habitat between cement portions, and high wildlife usage of completely artificial river portions. While generally ignored by large research institutions, many consulting biologists collect data on its flora and fauna for various projects, resulting in a considerable amount of ecological investigation scattered in unpublished reports. In 1993, the Natural History Museum of Los Angeles County (NHMLAC) published The Biota of the Los Angeles River, still the only comprehensive study of the river’s natural resources. Surveyed resources included algae, vascular plants, freshwater mollusks, fish, amphibians and reptiles, birds, and mammals. This proposed session will examine the river’s background, its drastic change over the last 200 years from a seasonally free-flowing river to an armored flood control channel, and the grassroots efforts that eventually refocused public attention. We present new studies and insights gained by local researchers since 1993 and identify data gaps and areas for future study.