Note that the data published in the 2002 State of the Nation’s Ecosystems Report as well as the 2003 and 2005 Web-Only Updates have been superseded by the 2008 Report and thus should be used with caution. For the most recent data, purchase the 2008 Report from Island Press.

View Data on "Natural" Area in Patches of Different Sizes, Nationally View Data on "Natural" Area in Patches of Different Sizes, 1992, (by region)

What Is This Indicator, and Why Is It Important? This indicator reports how much of the “natural” area within urban and suburban lands is in patches of varying size, from less than 10 acres to greater than 10,000 acres. Natural areas include forests, grasslands and shrublands (including most pasturelands—especially in the west), and wetlands.

Smaller patches of natural habitat generally provide lower-quality habitat for plants and animals (although this is not necessarily true for wetlands) and provide less solitude and fewer recreational opportunities for people. Smaller patches of habitat favor common, human-tolerant species like squirrels, white-tailed deer, starlings, and sparrows, over less common species that require larger areas, such as some birds (pileated woodpeckers, broadwinged hawks, and many warblers), mammals (bears, mountain lions, wolves, coyotes, mink, otters, and weasels), and amphibians.

What Do the Data Show? About half of all natural lands in urban and suburban areas are in patches smaller than 10 acres. A progressively smaller percentage of natural areas are found in larger patches, so that, nationally, less than 5% of the total is found in patches of 1,000 acres or more. The Northeast has a higher percentage of large “natural” patches (100 to less than 1,000 acres and 1,000 to less than 10,000 acres) than the other regions, while very large patches (greater than 10,000 acres) are found only in the West; these patches account for 0.3% of all natural lands in urban and suburban areas.

Discussion In addition to size (shown here), the quality of habitat and recreational value of natural areas is influenced by other factors, such as the shape of patches and how isolated they are from other natural areas.