ABSTRACT
“An Evaluation System for Wetlands of Ontario South of the Precambrian Shield” was produced jointly by Environment Canada and the Ontario Ministry of Natural Resources (EC/OMNR, 1983). The evaluation system is designed to numerically quantify wetland values to permit comparison of wetlands relative to each other. The evaluation system is broad in perspective: it can be applied to four wetland types–marshes, swamps, fens and bogs–and it encompasses four categories of wetland values–biological, social, hydrological and special features.
Vigorous field testing and statistical analysis of evaluation results showed that the system is reproducible, and it appears to produce a fairly accurate ranking of wetlands. Marshes, swamps and bogs scored fairly highly for the Biological Component; Social Component scores covered a range of values for all wetland types; Hydrological Component scores for marshes were consistently low whereas bogs obtained much higher scores; and Special Features Component scores were high for many wetlands including a large number of marshes.
Wetlands are grouped into seven classes on the basis of evaluation scores, with Class 1 and 2 wetlands being the most valuable. Of the 30 Great Lakes coastal wetlands evaluated on Lakes Ontario, Erie and St. Clair, 19 (63%) were Class 1 and 2 wetlands, and 90 percent were Class 1763, 2 or 1. The high performance of these coastal wetlands derives from their strengths in the Biological and Special Features Components; Hydrological Component scores were very low. Details of the scoring system are illustrated using Second Marsh (Oshawa, Ontario) as an example.
