The Status and Trends of Our Nation's Biological Resources is a report that synthesizes current information on status and trends of biological resources with a historical perspective of ecosystems across the country to assess how the nation's resources are changing. The report was produced by the U.S. Geological Survey's Biological Resources Division with contributions from nearly 200 experts from federal government, academic, and nongovernmental communities, including a section on Marine Resources written by the National Marine Fisheries Service. The 1,000-page, peer-reviewed, full-color, two-volume report is written in non-technical language to be usable by policy makers and interested citizens as well as natural resource professionals.

The report is organized into two parts. Part One details seven major factors affecting biological resources nationwide: Natural Processes, Land Use, Water Use, Climate Change, Nonindigenous Species, Environmental Contaminants, and Harvest. Part Two describes the status and trends of biological resources in different regions of the country, the ecosystems in that region, and how these resources have been affected by the factors described in Part One. The regions covered are the Northeast, Great Lakes, Southeast, Caribbean Islands, Mississippi River, Coastal Louisiana, Grasslands, Rocky Mountains, Great Basin-Mojave Desert, Southwest, California, Pacific Northwest, Alaska, Hawaii and the Pacific Islands, and Marine Resources.

Part 1: Factors Affecting Biological Resources

Of the seven factors detailed in the report, six are human-induced and one, natural processes, covers natural events such as fire, hurricanes, and even precipitation extremes that induce changes in physical habitat. These natural processes, when not extremely severe or highly regular in their occurrence, can promote biodiversity by varying physical habitat. Hurricanes can provide some benefits to ecosystems by distributing sediment to coastal wetlands. Similarly, biological populations can respond surprisingly fast in areas devastated by volcanos (Fig. 1).

Fig 1. (Click to enlarge)

Land use, water use, and nonindigenous species are the three factors that have had the greatest broad-scale effects on biological resources. Urbanization, conversion of lands to agriculture, draining of wetlands, and the fragmentation of forests are some of the land-use changes repeatedly cited in Part Two as major forces negatively affecting the health of biological resources. Changes in our nation's waterways to accommodate navigation, irrigation, hydroelectric power generation, and municipal use have drastically altered the biological integrity of aquatic environments. Consequently, aquatic organisms now dominate lists of imperiled species. Changes in land and water use have altered habitats so that they are more favorable for the establishment of nonindigenous species, which are posing increasing threats because of our more global economy and increased international travel. The invading species become established in habitats that have no natural competitors or predators, and thus, these species can thrive to the extent that they may significantly harm the habitat (Fig. 2).

Fig 2. (Click to enlarge)

The impacts on biological resources due to environmental contaminants and climate change are often not as obvious as the effects of a dammed river or a drained wetland, but potential effects can be severe. Birds, for example, accumulate selenium from used irrigation water, which decreases their reproductive success, and acid drainage from abandoned mines reduces the diversity of thousands of miles of freshwater streams. Climate change also has the potential to alter the geographic ranges of species and to possibly change habitats significantly enough to cause species endangerment.

The effects of harvest, both economically and biologically, are most apparent in the depletion of marine resources (Fig. 3). Harvest also affects genetic diversity when population size is reduced, but the relation between diminished genetic diversity and the ability of a population to sustain harvest is not well understood. Consideration of harvest effects must go beyond focusing on the single harvested population and toward considering all related members of the community.

Fig 3. (Click to enlarge)

This report articulates the status and trends of individual species and particular habitats, which, if lost, can threaten the ecosystem functions on which humans depend. In the face of environmental change, biodivesity may provide the stability that buffers ecosystems against the collapse of ecological function.