Community and Ecosystem Effects

The difficulty of measuring community and ecosystem effects has been extensively discussed in the literature (Suter 1993). Ecological systems can be perceived as mechanisms for energy flow, for materials cycling, and also as assemblages of species. Ecosystem properties may also be examined. 

Ecosystems are multidimensional constructs, and they have been seen in that fashion for a number of years. An example is the Hutchinsonian idea of organisms and populations residing in an n-dimensional hypervolume, which is the basis of current niche theory (Hutchinson 1959). The n-dimensional hypervolume is the ecosystem with all its components as perceived by the population. The variability of these parameters over time as well as the quantity and quality of nutrient inputs to the system are used to account for the diversity of species within this system (Hutchinson 1961 Richerson et al. 1970 Tilman 1976). An accurate description of an ecosystem should, in some way, correspond to its multidimensional nature. 

impacts are quantified using a reference site as a negative control for comparison to other sites under question. Similarly, multispecies toxicity tests, microcosms, and mesocosms attempt to detect differences between the control treatment and the dosed treatment groups. 

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