Environmental contaminants . Humans also affect mammals by applying 

 chemical pesticides to control agricultural and forest insect pests. Some of 

 the chemicals sprayed on agricultural lands in the characterization area 

 include Guthion, Diazinon, Benlate, Ferbam, Thrithion, Sevin, Systox, 

 Disyston, Dithane, Monitor, Bladex, and Lasso. Chemicals sprayed for control 

 of forest insect pests (primarily spruce budworm) include Sevin, Orthene , and 

 Dylox, as well as experimental sprayings of Matacil and Lannate. Bacillus 

 thuringiensis , a biological control bacteria, is also used. The persistent 

 pesticides, such as DDT, have not been used since the early 1970s. The extent 

 of pesticide use in the coastal zone and known impacts are discussed in 

 chapter 3, "Human Impacts on the Ecosystem." The effects on mammals of the 

 chemicals currently used seem to be minor. They break down rapidly (within a 

 few days or weeks) and are not concentrated in animal tissues. Populations of 

 nontarget insects may be reduced temporarily but this has not seemed to affect 

 small mammal populations and no acute toxic effects have been noted (Conner 

 1960; Barrett 1968; Buckner et al. 1973, 1974, andl975; Caslick and Smith 

 1973; Buckner and Sarrazin 1975; and Stehn and Stone 1975). 



Residues of DDT and its metabolites may still be present in some species of 

 terrestrial mammals, as Dimond and Sherburne (1969) reported residues of DDT 

 in shrews 9 years after application. The pattern of accumulation in mammal 

 species was based on the food habits, as expected. Voles and mice (mainly 

 herbivores) had low levels and were approaching pretreatment levels after 9 

 years. Shrews had 10 to 40 times as much as mice and voles and were still 

 well above pre-spray levels after 9 years. The highest levels, 41 ppm, were 

 high enough to cause acute mortality, which could result in local extinctions. 

 Sherburne and Dimond (1969) also examined residues in snowshoe hares and mink. 

 Hares had low levels which did not differ from hares on untreated areas. Mink 

 had levels 10 to 90 times those found in hares and levels were still above 

 pretreatment concentrations after 7 to 9 years. 



IMPORTANCE TO HUMANITY 



Mammals are valuable for recreational, economic, aesthetic, and scientific 

 reasons. The most obvious values are those associated with recreation, i.e. 

 hunting and trapping. There were over 218,000 licensed hunters in Maine in 

 1977, of which about 30,000 were nonresidents. While some of these may have 

 been interested only in hunting game birds, it is estimated that over 80% of 

 those holding hunting licenses hunted deer. The recreational importance of 

 seven of the ten game species hunted for sport (no data for cottontail, 

 woodchuck, or coyote) is indicated by the number of man-days effort expended 

 in pursuit of these species (table 17-9). Deer provide the greatest amount of 

 recreational value, with approximately 580,000 man-days of effort expended in 

 Wildlife Management Units 6, 7, and 8. Following deer, in decreasing order of 

 effort, are snowshoe hare (222,000), gray squirrel (38,000), black bear 

 (32,000), raccoon (27,000), fox (21,000), and bobcat (13,000). The three 

 Wilflife Management Units along the coast provide a large share of the total 

 recreational value in hunting in the State. This proportion is highest for 

 gray squirrel (69% of total man-days for the State), followed by snowshoe hare 

 (57%), raccoon (51%), fox (46%), deer (45%), bobcat (31%), and bear (16%). 



Furbearing mammals also provide recreational opportunity. The number of 

 trappers pursuing each species of furbearers in WMUs 6, 7, and 8 is shown in 

 table 17-10. Also shown is the number of trap-days effort (number of traps x 



17-28 



