Environment : Notes about your surroundings.

Disappearing Plants--Endangered individual species often get more attention, but the fact is that entire plant communities are disappearing all over Southern California. Differing climactic and geographic zones create a number of distinct plant communities in Orange County and elsewhere; each community is typified by one or more dominant plant species and each supports a distinct array of animal life.

The annual symposium of Southern California Botanists, to be held all day Saturday at Cal State Fullerton, will focus on five endangered plant communities in Southern California, all of which occur to some extent in Orange County. The following is a description of each, along with the names of the scheduled speakers.

California Grassland and Vernal Pools--Much grassland, of course, has been developed. On most of the remaining acreage, native grasses have long since been replaced by non-native annual grasses accidentally introduced during the Spanish Mission era. Some flat grasslands contain temporary vernal pools that support a number of rare and endangered plant species. Few of these remain in Orange County.

The speaker will be Jon E. Keeley of Occidental College in Los Angeles.

California Coastal Sage Scrub--The community, found on coastal ranges through much of California, is characterized by small, soft-leaved shrubs including California sagebrush, several species of sage and California buckwheat. Much of the community has been displaced by agriculture and urbanization, with as little as 10% to 25% of the former habitat remaining.

The speaker is John F. O'Leary of San Diego State University.

Walnut Woodlands--The California walnut, one of two endemic walnut species in the state, is found only in inland valleys of Ventura, Los Angeles and North Orange counties. The trees probably once occurred on coastal plains, where natural stands are long since gone. Once again, remaining stands are threatened by development.

Ronald D. Quinn of Cal Poly Pomona will speak on the status of remaining stands.

Estuarine Wetlands--These intertidal bays receive at least occasional freshwater runoff. It is estimated that at least 75% of Southern California's historical estuarine wetlands have been destroyed and much of the remaining acreage is seriously degraded. Two local examples of estuarine wetlands include Upper Newport Bay and Anaheim Bay.

Wayne R. Ferren Jr. of UC Santa Barbara will speak on recent research and new management issues, including the potentially disastrous effects of predicted global warming.

Riparian Habitat and Woodland--Natural plant and animal communities along rivers have been largely decimated by flood-control efforts. Peter Bowler of UC Irvine and Richard Zembal of the U.S. Fish and Wildlife Service office in Laguna Niguel will discuss remaining riparian areas along the Santa Margarita River, south of Orange County, and along sections of the Santa Ana River.

Registration for Saturday's workshop will begin at 8 a.m., with the program running from 9 a.m. to 4 p.m. in Room 121 of McCarthy Hall. Admission is $7 for members of Southern California Botanists, $8 for students and $10 for the general public. Admission plus membership is $15.

Reminder--The Natural History Foundation of Orange County will offer its annual symposium Nov. 19 in the Nelson Research Building at UC Irvine. The topic is "Global Pollution and Local Action." Among the scheduled speakers is UCI's F. Sherwood Rowland, who will talk about a subject he helped pioneer, stratospheric ozone depletion. Hours are 1 to 6 p.m.; admission is $6 general and $3 for students.

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