Effects of a Polluted Environment Research and Development Needs (1977) / Chapter Skim
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EFFECTS ON BIOLOGICAL COMMUNITIES AND ECOSYSTEMS
EFFECTS ON BIOLOGICAL COMMUNITIES AND ECOSYSTEMS
Pages 81-91
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From page 81... ...
To protect these largely irreplaceable values, it is very important to know the effects of human activities on ecosystems. Evaluation of the potential ecological impact of a given environmental change requires information on effects on units of biological organization above the level of the population or species, we need to examine structural features of biological communities, such as diversity and abundance of species and interactions among populations, and functional characteristics of ecosystems, such as the transfer of energy, production of biomass, and cycling of oxygen, water, and mineral elements.
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From page 82... ...
The predictive accuracy of each approach alone is distinctly limited; taken together, they can produce research results that may approximate measurements of eccsystcm effects. LABOPATOFX MICFCCCSKS cpsms should be refined and acclied, but the limited ut ility^of _suchL- systems for A number of bioassay techniques have recently been developed that employ simplified microcosms of biological communities.
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From page 83... ...
In short, while microcosm studies may be useful to screen substances for further study, reliable predictions of effects on ecosystems require more elaborate tests. EXPERIMENTAL PERTURBATIONS OF COMMUNITIES Experimental perturbations of ecosystems are a very useful tool for producing important information about ecological effects of environmental changes.
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From page 84... ...
Eecause of seasonal and annual variability, the resilience of natural systems, and the time scales of many ecological processes, several years of observations may be required before reliable evidence of ecological effects can be obtained. The substantial costs cf long-term field ecological research make it important to develop a relatively small number of sites that can be sustained until useful results are derived.
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From page 85... ...
Carefully chosen indicators of critical structural or functional elements of ecosystems (such as species diversity, nutrient cycling, erergy flows, or primary productivity) should be monitored.
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From page 86... ...
The usefulness cf collected data will depend on the soundness of the theoretical basis for choosing particular indicators. If the status of selected organisms is to be used to assess effects on ecosystems, the crganisms chosen should be valid representatives of critical functional guilds, such as primary producers, decomposers, herbivores, predators, and the like.
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From page 87... ...
Most investigations of ecological effects cf pollution have not examined impacts on biogeochemical cycles or underlying microbial processes. One exception is the extensive body cf research on effects cf fertilizers and pesticides on soil organisms; but even in this well-studied field, systematic understanding of impacts cn ccmplex elemental cycles has proved to be elusive.
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From page 88... ...
Some environmental perturbations that might be investigated include acid rainfall, heavy fertilizer use, pesticide applications, fly ash fallout, fluoride and heavy metal pollution, and .sludge disposal. Some unstressed ecosystems should also be examined, as controls.
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From page 89... ...
This category includes screening chemicals with laboratory microcosms, and using the most recent data and best available modeling techniques to evaluate potential ecological impacts of particular actions. Other work, such as studies of experimental perturbations of ecosystems or monitcring of nutrient cycles, will produce information of great value to a wider group of federal and state agencies, but only after a number of years.
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From page 90... ...
Rational Science Foundation Directorate for Research Applications, RANN Division of Advanced Environmental Research and Technology. Washington, D.C.: U.S.
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From page 91... ...
(1966) Food web complexity ard species diversity, American Naturalist 100:65-75.
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