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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)
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)
Fish community structure was examined in 9 forested streams (1–6 m wide) in central Panama during dry seasons over a 3 year period. Study regions varied in annual rainfall, degree of canopy shading, and topographical relief. Benthic invertebrates were more abundant in riffles than in pools and more abundant in early (January) than late (March) dry season.(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)
Rivers cannot continue to meet society's needs, or the needs of living things, if humans continue to regard river management as a purely political or engineering challenge. The flow of rivers is part of a greater flow, the planet's water cycle, which sustains not only the flow of water but the entire web of life. Ultimately, the condition, or health, of the(More)