Environment : Notes about your surroundings.

BRINGING IT BACK: Habitat restoration is a hot topic in Orange County environmental circles. Several projects are under way, including the planned restoration of tidal access to 17 acres of wetlands in Huntington Beach and the reintroduction of native plants to areas of Irvine Park. Also, this year marks the 10th anniversary of the restoration of 150 acres of wetlands in what is now the Bolsa Chica Ecological Reserve.

“Habitat and Wildlife Restoration in Southern California” is the theme of the second all-day symposium sponsored by the Natural History Foundation of Orange County, recently announced for Oct. 29 in the Nelson Research Building at UC Irvine.

Jeff Froke, former head of the National Audubon Society’s Starr Ranch preserve near Caspers Regional Park and now president of the Roger Tory Peterson Institute of Natural History in New York, will open the symposium with a presentation on evolution of the Orange County landscape and prospects for restoration.

Other topics include the Orange County Wildlife Plan; landscaping with native plants; coastal sage scrub restoration projects in two local state parks; the ecological history of the San Joaquin Marsh wetlands and San Diego Creek watershed; habitat fragmentation in the Laguna Greenbelt, and enhancing the lower Santa Ana River wetlands. Field trips to the Crystal Cove State Park and San Joaquin Freshwater Marsh restoration sites will be offered the morning after the symposium.

General admission to the event is $5, $2 for students. Call (714) 640-7120 for information.

EXOTIC INVADERS: Local residents who would like to take an active role in habitat enhancement are being sought for a project in Upper Newport Bay. The important wetlands reserve is facing a threat from several species of weedy exotic plants that have escaped from cultivation, including Pampas grass, castor bean and ice plant. The invaders, which are of little or no use to local wildlife, are displacing native plant species along the shores of the bay itself and in the surrounding riparian and coastal sage scrub communities.

Volunteer work crews are being recruited to remove weeds and for mapping and photographic documentation of the work. Donations or loans of equipment are also being solicited. For information, write to state Fish and Game biologist Greg Gerstenberg, 615 S. Grand Ave., Orange, Calif. 92666.

CENTENNIAL BASH: A final note from the Natural History Foundation of Orange County: The group, as part of the county’s centennial celebration, will offer a natural history festival on Oct. 15 from 10 a.m. to 4 p.m. at the Museum of Natural History and Science, 2627 Vista del Oro in Newport Beach.

The event will feature nature walks in Upper Newport Bay, demonstrations of Indian skills, programs on earthquakes, birds, insects and fossils, and a variety of activities for children. Admission to the event is $2 for adults and $1 for children. Foundation members will be admitted free.