Human Influences | |
| Overview | | |
| The following articles are directed at neither a specific species nor an ecosystem, but at human activities that affect living resources nationally and internationally. These broad-scale effects on, and changes in, ecosystem health are frequently the result of local or regional actions and land-use practices that collectively have effects across the nation. |
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| The first article (Stein et al.) examines the significance of federal lands as refugia for the protection and conservation of endangered species. Stein et al. (box) then describe a system used to rank species by their need for conservation measures to prevent their endangerment and future extinction. In the article by Friend, we learn about the history of diseases in waterfowl, the trends in disease outbreak, and how the loss of wetlands and the discharge of water can be associated with these disease outbreaks. Dein et al. describe the use of propagation and translocation (transplanting species to a certain area) to recover or augment threatened or endangered species as well as recreational species. Dein et al. also examine the secondary consequences of such efforts on the transfer and spread of disease to wildlife, domestic animals, and humans. Cumulatively, these articles broaden the focus of status and trends assessments beyond individual species and ecosystems, and begin to reveal the interrelatedness between species, ecosystems, and human activities. |
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| The remainder of the articles focus on the effects of pollution that results from human activities such as agricultural, industrial, and municipal development. The articles pay special attention to monitoring of pollution because the effects of pollution are excellent examples of the links between ecosystem health and the health of organisms, including humans, that depend on those systems. |
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| The first article on pollution (Turgeon and Robertson) describes toxic contaminants in fish and mollusks from U.S. coastal waters. Next, Schmitt and Bunck describe the trends of chemical residues in fish and wildlife from across the nation during the past 25 years. The note by Glaser emphasizes how birds are being affected by the "new family" of pesticides in use across the United States. |
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| Schreiber discusses the adverse impacts of acid deposition (acid rain) on sensitive species and ecosystems and the influence of recent regulatory efforts to control this form of pollution. Everson and Graber describe the results of a long-term study on the effects of acid rain on forest watersheds, the secondary impacts on water chemistry because of leaching of nutrients from soils, and the influence of a forest fire on the process. Allen discusses the agricultural effects on wildlife habitat. |
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| Overall, these varied articles introduce the ways in which large-scale assessments of status and trends in the health and condition of biota also provide an excellent indication of overall ecosystem health, particularly in relation to the less visible effects such as long-term, subtle declines due to diseases and pollution. |
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