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H umans have long been fascinated by the dynamism of free-flowing waters. Yet we have expended great effort to tame i rivers for transportation, water supply , flood control, agriculture, and ; f power generation. It is now recognized that harnessing of streams and rivers comes at great cost: Many. rivers no longer support socially valued native species or(More)
  • James R Karr
  • 1991
Water of sufficient quality and quantity is critical to all life. Increasing human population and growth of technology require human society to devote more and more attention to protection of adequate supplies of water. Although perception of biological degradation stimulated current state and federal legislation on the quality of water resources, that(More)
Climate change affects public land ecosystems and services throughout the American West and these effects are projected to intensify. Even if greenhouse gas emissions are reduced, adaptation strategies for public lands are needed to reduce anthropogenic stressors of terrestrial and aquatic ecosystems and to help native species and ecosystems survive in an(More)
SUMMARY 1. Society benefits immeasurably from rivers. Yet over the past century, humans have changed rivers dramatically, threatening river health. As a result, societal well-being is also threatened because goods and services critical to human society are being depleted. 2. `Health' Ð shorthand for good condition (e.g. healthy economy, healthy communities)(More)
Dramatic declines in both taxonomic diversity and abundances of reef taxa from bacteria to stony corals to sharks provide ample evidence that coral reef ecosystems are at risk globally (Knowlton and Jackson, 2008; Mora, 2008; Sandin et al., 2008). Climate-related factors such as rising temperatures and ocean acidification are frequently cited as primary(More)
members of the committee responsible for the report were chosen for their special competencies and with regard for appropriate balance. The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to(More)