As Gnatcatcher Goes, So Goes Nature : Environment: Studying well-being of the bird species could tell researchers a lot about the state of the North County natural habitat.

The San Diego County landscape has changed so much that no one has a clear picture of what is left of nature, hindering the development of long-range plans to save it, environmental researchers said at a conference Friday.

At the heart of the Southern California Wildlife Habitat Conservation Discussion, which attracted more than 100 biologists, government planners and landowners to Carlsbad, was the need to save the California gnatcatcher and its habitat, mainly the California coastal sage shrubs. The bird is a candidate for the Endangered Species List, but how much endangered is unknown.

“Like just about any species, what we really understand is usually pretty minimal,” said Barry Jones, a biologist for Environmental and Energy Services, a San Diego environmental research company. “This bird is not any different. We’re still getting started on the research.”

The latest figures show 1,000 to 1,500 pairs of gnatcatchers in California and Mexico, but that figure is 10 years old.

“San Diego isn’t the same place any more,” Jones said.

Jones and other wildlife experts said that the rapid growth of housing and roads in North County during the past decade has left them without an idea of how much wild habitat remains and where it might be situated. As a result, they said, they are in the dark about the well-being of possibly endangered plants and animals in those areas.

The first step, they said, is to take a census of nature in the region. And the second is to develop a cooperative, regional--and immediate--plan to stall the demise of the gnatcatcher and other species.

Rick Alexander, director of land-use planning for the San Diego Assn. of Governments, said local governments need a regional plan to make land-use decisions so that they understand how the decisions of one city affect the environment of the region.

“We hope to get a complete look at where the major habitat types are and what must be done to preserve them,” Alexander said. “We want to make sure that we’re looking at not only the region of San Diego, but all of Southern California, if necessary.”

“The biological data is critical, but it is being developed,” Alexander said.

Biologists stress that it is not just the gnatcatcher that is at stake, but whole ecosystems. They tend to focus on the gnatcatcher because it is what they call an indicator species: the rise or fall in its population signals the health or illness of its environment.

“It’s part of the web of the whole wildlife network, and when one species dies, others associated with it die,” said Linda Michael of the San Diego chapter of the Sierra Club. “As you have fewer birds, the insect population goes up, and those animals that try to feed on the birds will also suffer.”

But traditional environmental preservation groups were not the only ones supporting the effort to develop a regional habitat preservation plan.

The Alliance for Habitat Conservation, a corps of 20 San Diego landowners and developers who organized last year in response to concern over the gnatcatcher’s state, received praise for its interest in the matter.

“Our concern was that some of the other planning efforts have been done in the mode of crisis planning rather than pro-active planning,” said John Barone, project manager of the Fieldstone Co., one of the largest developers in Carlsbad, which plans to build 3,400 homes during the next 12 to 15 years in the city.

The alliance has begun research into the California gnatcatcher and its habitat in an effort to work with others to develop a regional plan, Barone said.

“We are always better off to be able to plan from an understanding of all the constraints involved,” Barone said.