Foster discusses the difficulties of imputing dollar values to wetlands 

 preservation benefits. In particular, he discusses the work of Larson, Gupta, 

 and Foster (see [11] for a discussion of the work of Gupta and Foster, and [12] 

 for a discussion of the work of Larson); Gosselink, Odum, and Pope ([9]); and 

 Batie and Wilson ([23]). The innovative work of Larson, Gupta, and Foster uses 

 the collective expertise of a group of wildlife biologists, hydrologists, 

 landscape architects, and economists to impute dollar values to four types of 

 inland freshwater benefits, including the provision of wildlife habitat, 

 municipal water supply, visual -cultural benefits, and flood control benefits. 



Foster argues that economists and ecologists who estimate wetlands 

 preservations benefits do not make sufficient allowance for variations among 

 wetlands in terms of the functions they perform. Nor do they allow for the wide 

 variation in the physical productivity of wetlands performing the same beneficial 

 functions. In particular, Foster is very concerned with valuing "unique" 

 wetlands. 



26. Jaworski, E. and N. Raphael. 1978. Fish, wildlife, and recreational 

 values of Michigan's coastal wetlands. Phase I. Michigan Department of 

 Natural Resources Report, Land Resources Program, Lansing. 225 pp. 



Jaworski and Raphael make a thorough inventory of the distribution of 

 Michigan's coastal wetlands resources. Not only do they estimate the areal 

 extent of the remaining wetlands, they also provide extensive data on the rate 

 of loss of coastal wetlands. They also inventory the social benefits and values 

 provided by these wetlands. The technique used to impute value to wetland 

 acreage is, unfortunately, simply that of estimating total expenditures for the 

 activity in question, then dividing the expenditure by the areal extent of the 

 wetlands type providing the amenity value of social output. Thus net values of 

 the expenditures are imputed to the wetlands, and there is no distinction between 

 average and marginal social product. This is tantamount to a single factor 

 theory of value, though the figures are offered as a surrogate for the estimation 

 of the true social surplus values. Jaworski and Raphael have none of the 

 evangelical zeal of Pope and Gosselink ([8]) in espousing this interpretation 

 of the data; this is the best they could do at the time. 



A great deal of effort was needed for the estimation of the various types 

 of per acre benefit values. To calculate the per acre value of the duck habitat, 

 they first estimated the areal extent of waterfowl habitat by types (spring 

 migration or fall migration) and geographic locale. Then Jaworski and Raphael 

 estimated the average physical product of the existing total migratory waterfall 

 habitat. The numerous detailed areal extent estimates require a good deal of 

 expertise in applied geography (in fact, Jaworski and Raphael were members of 

 the Geography-Geology Department of Eastern Michigan University when they wrote 

 this monograph) . 



A 1972 inventory estimated the areal extent of Michigan's coastal wetlands 

 to be 105,855 acres (165.4 square miles). These coastal wetlands produced 21% 

 of the waterfowl harvest, 14% of the duck production, 11% of the muskrat harvest, 

 and 15% (by value) of the commercial fisheries harvest for Michigan. The sum 

 of the average per acre commercial harvest and the total per acre expenditures 

 for recreational activities is $489.69 per acre per year. The total value of 



26 



