Each regional chapter describes the geologic and climatic changes that formed the region and the recent history of settlement; describes the ecosystems in the region; provides status and trends of populations; and identifies information gaps.
The final chapter of Part Two, produced by the National Marine Fisheries Service, describes the status and trends of marine resources by region.
The report also identifies scientific information gaps and points to needed research, monitoring and restoration--from Alaska to Hawaii to Florida and the Caribbean Islands, encompassing endangered and at-risk species, coral reefs and the rivers and streams of the nation.
There is some good news in the report. Severe events such as hurricanes can provide some benefits to ecosystems. Biological populations can respond surprisingly fast in devastated areas; such is the case of amphibians that recolonized in areas devastated by the Mount St. Helens' eruption.
Land use, water use and nonindigenous, or nonnative, species are the three factors having the greatest broad-scale effects on biological resources.
Some land use changes repeatedly cited as major forces affecting biological resources are urbanization, conversion of lands to agriculture, draining of wetlands and the fragmentation of forests.
Changes in the nation's waterways to accommodate navigation, irrigation, hydroelectric power generation and municipal use have drastically altered the biological integrity of aquatic environments. Aquatic organisms now dominate lists of imperiled species.