U.S. biosurvey reveals worrisome trends.

As in legal contracts and cake decorating, the devil is the details of the U.S. Geological Survey's first large-scale assessment of the country's living wealth.

The two-volume "Status and Trends of the Nation's Biological Resources," released last week, doesn't assign an overall grade for ecological health. However, its discussion of major forces affecting U.S. flora and fauna and its regional summaries pile up facts for a significant heap of concern.

"I truly hope the reading public will sit back and say, `We need a new environmental conscience,'" says the project's director, Michael J. Mac of USGS in Reston, Va. Some 200 researchers labored for 4 years to write a nontechnical accounting more comprehensive than the USGS 1995 report, "Our Living Resources."

"To me, the big revelation was nonindigenous species," says USGS Director Charles G. Groat. According to the report, more than 6,500 interlopers have established themselves in the United States, including 91 mollusks, more than 2,000 insects and arachnids, and 239 plant pathogens. These pushy newcomers have wiped out some of the country's former residents and helped edge 315 natives onto lists of threatened and endangered species.

Even a mild-mannered invader may carry dangerous hitchhikers, warns Peter S. White, director of the North Carolina Botanical Garden in Chapel Hill and author of the report's Southeastern section. Nursery stock transported both American chestnut blight and the woolly adelgid aphid, which thinned conifer forests.

At the mention of invasive species, White whips out a manifesto--which he recently nailed to a tree for dramatic effect--urging horticulturists to greater vigilance. Overall, however, the report concludes, "little attention has been paid--and almost no progress has been made--in addressing the problem of nonindigenous species."

The report also highlights water use as a major shaper of U.S. ecological resources. As early as 1965, the daily water withdrawals from the environment for human use, totaling 1.3 billion cubic meters per day, already exceeded the dependable supply by 13 percent, the authors say. "Trends clearly show that our present water-development and use practices cannot continue," they conclude.

The land-use chapter notes that housing lots are getting bigger, exaggerating suburban sprawl. In seven states once covered with grasslands, less than 1 percent of tall-grass prairie remains.

What researchers don't know emerges as a major theme. "The gaps tend to be in the less cuddly things: mollusks, aquatic plants," Groat laments. Consider even the most beloved invertebrates. Coauthor Paul A. Opler in Fort Collins, Colo., says, "We don't have any good objective data on our nation's butterflies."

Janet N. Abramovitz, who heads the biodiversity group at the Worldwatch Institute in Washington, D.C., calls the report "the kind of thing the government should do more of. Otherwise, there isn't a compendium of this kind of information."

The next major environmental-status report due out takes a different approach, says Robin O'Malley of the Heinz Center in Washington. Its report, to be released in November, quantifies 12 aspects of ecosystems. "We are attempting to identify a few things that tell you a lot about the condition of ecosystems--the equivalent of the inflation rate and the gross national product," he says.

As to when the USGS report might get updated, Mac has not recovered sufficiently from preparing this one to do more than wince at the question.