Misunderstanding abounds about land use in the United States.

By far the greatest impact on the American landscape comes not from urbanization but rather from agriculture. According to the U.S. Department of Agriculture, farming and ranching are responsible for 68 percent of all species endangerment in the United States.

Agriculture is the largest consumer of water, particularly in the West. Most water developments would not exist were it not for the demand created by irrigated agriculture.

If ultimate causes and not proximate causes for species extinction are considered, agricultural impacts would even be higher. Yet scant attention is paid by academicians, environmentalists, recreationists and the general public to agriculture's role in habitat fragmentation, species endangerment and declining water quality.

The ironic aspect of this head-in-the sand approach to land use is that most agriculture is completely unnecessary to feed the nation. The great bulk of agricultural production goes toward forage production used primarily by livestock. A small shift in our diet away from meat could have a tremendous impact on the ground in terms of freeing up lands for restoration and wildlife habitat. It would also reduce the poisoning of our streams and groundwater with pesticides and other residue of modern agricultural practices.

Most of the information in the following summary is available from the USDA Economic Research Service publication "Major Uses of Land in the United States 1997." (To order, call 1-800-9996779). The numbers do not change appreciably from year to year.

Overview of Land Use in the United States-The U.S. has 2.3 billion acres of land. However, 375 million acres are in Alaska and not suitable for agricultural production. The land area of the lower 48 states is approximately 1.9 billion acres.

To put things in perspective, keep in mind that California is 103 million acres, Montana 94 million acres, Oregon 60 million acres and Maine 20 million acres.

Developed Land- Despite all the hand wringing over sprawl and urbanization, only 66 million acres are considered developed lands. This amounts to 3 percent of the land area in the U.S., yet this small land base is home to 75 percent of the population. In general, urban lands are nearly useless for biodiversity preservation. Furthermore, urbanized lands, once converted, usually do not shift to another use.

Rural Residential Land-This category comprises nearly all sprawl and subdivisions along with farmhouses scattered across the country The total acreage for rural residential is 73 million acres. Of this total, 44 million acres are lots of 10 or more acres.

Developed and rural residential make up 139 million acres, or 6.1 percent of total land area in the U.S. This amount of land is not insignificant until you consider that we planted more than 80 million acres of feeder corn and another 75 million acres of soybeans (95 percent of which are consumed by livestock, not tofu eaters) last year alone. These two crops affect more of the land area of the U.S. than all the urbanization, rural residential, highways, railroads, commercial centers, malls, industrial parks and golf courses combined.

Cropland- About 349 million acres in the U.S. are planted for crops. This is the equivalent of about four states the size of Montana. Four crops -- feeder corn (80 million acres), soybeans (75 million acres), alfalfa hay (61 million acres) and wheat (62 million acres) -- make up 80 percent of total crop acreage. All but wheat are primarily used to feed livestock.

The amount of land used to produce all vegetables in the U.S. is less than 3 million acres.

Range and Pasture Land- Some 788 million acres, or 41.4 percent of the U. S. excluding Alaska, are grazed by livestock. This is an area the size of 8.3 states the size of Montana. Grazed lands include rangeland, pasture and cropland pasture. More than 309 million acres of federal, state and other public lands are grazed by domestic livestock. Another 140 million acres are forested lands that are grazed.

Forest Land- Forest lands comprise 747 million acres. Of these lands, some 501 million acres are primarily forest (minus lands used for grazed forest and other special categories).

The USDA report concludes that urbanization and rural residences (subdivisions) "do not threaten the U.S. cropland base or the level of agricultural production." This does not mean sprawl doesn't have impacts where it occurs. But the notion that sprawl is the greatest threat to biodiversity is absolutely false.

Conclusions that place sprawl ahead of agriculture in terms of biodiversity impacts are due to faulty accounting methods and a general bias that favors agriculture as a "good" use of the land.

Furthermore, there are viable means of controlling sprawl. They include land-use planning, zoning, fee purchase and conservation easements.

Despite acreage being paved over, malled over or overbuilt with condos, developed land is generally concentrated in and near cities. The loss of farm or ranch land is insignificant compared to the total acreage available in the U.S.

The real message here is that we can afford to restore hundreds of millions of acres in the U.S. if we simply shift our diets away from meat. Many organizations spend their time fighting sprawl and championing agriculture as a benign use of the land. If a similar amount of effort were directed toward reducing agricultural production, we would produce far greater protection and restoration for declining species, endangered ecosystems and ecological processes.

When critics suggest that we don't have the money to buy land for wildlands restoration, they are forgetting agricultural subsidies, which amount to hundreds of billions of dollars. For what we spend to prop up marginal agricultural producers, we could easily buy most of the private farm and ranch land in the country This would be a far more effective way to contain sprawl, restore wildlands, bring back endangered species, clean up water, slow the spread of exotic species and reduce soil erosion.

George Wuerthner is a Western Watersheds Project advisory board member who lives in Eugene, Oregon.