Coastal Sage: A Vanishing Habitat

The California gnatcatcher is likely to be added this week to the nation’s list of endangered and threatened species. The songbird lives and breeds in a fragile ecosystem called coastal sage scrub. This fragrant, arid mix of native plants has three main components: California sagebrush, black sage and California buckwheat. About 75 other rare plants and animals make their homes there, and many are candidates for endangered species status.

Sage Scrub, Development Collide Before the development boom, about 2.5 million acres of coastal sage scrub existed between Ventura and San Diego.

A Few Scrub Inhabitants

Sage scrub is home to an array of creatures and plants that could become endangered:

California gnatcatcher: Tiny, sedentary, insect-eating songbird; mews like a kitten. About 3,000 pairs exist. In Orange County, 605 pairs were found in spring, 1992. Status: Proposed as federal endangered species; decision due Wednesday.

Cactus wren: The 8 1/2-inch-long bird nests in protective spines of cholla or prickly pear cactus. Feeds on insects, fruit. Status: U.S. Fish and Wildlife Service was petitioned to list it in 1990. Decision is past due.

Orange-throated whiptail: Seven-inch-long lizard; associated with open areas in coastal sage scrub. Feeds on insects. Status: Candidate for federal listing.

Red diamond rattlesnake: Up to six feet long; found on rocks. Feeds on rodents, squirrels, lizards and birds including gnatcatcher and cactus wren. Status: Candidate for federal listing.

Foothill Mariposa lily: About one to two feet high, yellow flowers; blooms in late spring or summer. Grows only in Orange County coastal sage. Status: State candidate for endangered listing.

California buckwheat: About two to three feet high, puffy ball-shaped white flowers bloom in spring, summer. Used by gnatcatchers for nesting and foraging. Status: No protected status.

Black sage: About three to four feet high, white or purplish flowers, strongly scented. Used by gnatcatchers and other birds. Status: No protected status.

California sagebrush: About three to four feet high; aromatic foliage; blooms in fall. Used by gnatcatchers for nesting and foraging. Status: No protected status.

Prickly pear: About three to six feet high, yellow, orange or salmon flowers, 1 1/2-inch spines. Blooms in late spring, early summer. Used by cactus wren. Status: No protected status.

Many-stemmed dudleya: Seven inches high, tiny yellow flowers; dies during dry months. Status: Being considered for state listing; federal studies underway.

Quino checkerspot butterfly: A two-inch wingspan and half-inch body. Is yellow and rust colored with black grid-like veins on wings. Status: Being considered for state endangered list.

Point--Counterpoint: The Gnatcatcher Debate

The U.S. Fish and Wildlife Service must decide whether to name the California gnatcatcher an endangered species solely on the basis of scientific evidence. Under the law, economics and politics cannot be considered. But the battle over the bird is so contentious that even the science and facts are being debated. Supporters of listing the bird as endangered include environmental groups and biologists, while opponents include Southern California’s developers and local government planners. The two sides have faced off on several key points about the gnatcatcher.

PAST HABITAT DESTRUCTION

Supporters: A century ago, Southern California had 2.5 million acres of coastal sage scrub, the vegetation the bird uses for nesting and foraging. Now as little as 10%, an estimated 250,000 acres, remains, making it one of the United State’s most depleted wildlife habitats. Of 56 sites where gnatcatchers nested in 1980, 33 (or 59%) were completely or partially destroyed by 1990.

Opponents: Federal officials made a mathematical error, so the remaining 250,000 acres are about 34% of the acreage that existed a century ago--not 10%. That loss is about the same as any other natural habitat in California, so it is not enough to be considered an imminent threat to the species’ long-term survival. Also, as much as 400,000 acres may be left, not 250,000.

FUTURE HABITAT LOSSES

Supporters: Nearly all gnatcatcher habitat will be gone in 20 years. About three dozen developments that would grade 28,000 acres of its habitat are approved or in advanced stages. Much of the remaining scrub is unsuitable because it is fragmented, in poor condition or too high in elevation. Further losses will cause extinction by isolating the birds and preventing genetic diversity.

Opponents: About 100 square miles of sage scrub is already protected in parks, preserves or other public areas, and much of that is high-quality habitat suitable for gnatcatchers. Building has slowed considerably due to the economy, and many local governments are now more protective of the bird. Other lands can be voluntarily preserved or restored without listing the species.

BAJA BIRDS

Supporters: The nation’s leading experts in the American Ornithologists Union say Southern California’s gnatcatchers are a distinct subspecies from similar gnatcatchers in Mexico. The Baja gnatcatchers are different in 31 ways, from tail size to color, which indicates the California ones are different genetically and worthy of protection. Also, Mexico has no laws protecting wildlife.

Opponents: Those Mexico birds are not necessarily a different subspecies since the data used by the ornithologists seems flawed. The raw calculations have not been released to the public, and there has been no independent review or genetic testing, so the accuracy of their conclusion is in doubt. If they are the same birds, they are not endangered, since an estimated 2.5 million gnatcatchers exist in Baja.

GNATCATCHER POPULATION

Supporters: No one knows how many existed in the past, but it’s clear that in the 1940s, the birds were much more common throughout six counties from Ventura to San Diego. Its population last year was about 3,000 pairs--about the same number of spotted owls that existed when that species was listed. Population counts fluctuate greatly depending on weather, and the bird’s numbers can drop by half in a single year.

Opponents: About 2,000 birds were counted in Orange and San Diego counties in 1992, bringing its total population to about 3,000 pairs. That is 2 1/2 times more than what was originally estimated in 1990, when federal biologists began their review. The numbers seem to be going up, or at least are higher than estimated two years ago, so the birds’ long-term survival does not seem to be at risk.

Projects Scrubbed?

These are some of the proposed projects that would damage the most coastal sage scrub and might be altered if the gnatcatcher is declared an endangered species.

Project Acres of scrub East Orange/Irvine Co. 1,400 Newport Coast/Irvine Co. 536 Mountain Park/Irvine Co. 500 West Coyote Hills/Chevron 280 Eastern tollway/Orange County 200-300 Foothill tollway/Orange County 200 Shell Yorba Linda/Shell Oil Co. 200 San Joaquin Hills tollway/Orange County 155 East Tustin development/Irvine Co. 90

Sources: U.S. Fish and Wildlife Service, National Geographic Society Field Guide to the Birds of North America, Peterson Field Guide to Mammals