coastal area in detail. In many instances no other information is available. 

 Points at which the data becomes less representative of the immediate coast 

 will be noted. Unit 6 is perhaps best representative of the corresponding 

 characterization regions (5, 6, and part of 4), since 64% of Unit 6 lies 

 within the characterization area. Forty-nine percent of Unit 7 (regions 2, 3, 

 and 4) and only 8% of Unit 8 (regions 1 and 2) lie within the characterization 

 area . 



DISTRIBUTION AND ABUNDANCE 



The abundance of each species varies regionally, due primarily to the amounts 

 of suitable habitat available. This section discusses general distribution 

 and abundance of mammals in the six regions, describes the specific habitat 

 preferences of each species, and summarizes the availability of those habitats 

 along the coast. Finally, population estimates are given for selected game 

 and furbearing species, based on habitat quantity and species densities for 

 those habitats. 



Regional Distribution 



Forty-four species (85%) of mammals are found in all six regions of the 

 characterization area (table 17-1). It is difficult to delineate the exact 

 boundaries of a species' range, particularly if the range is changing. At the 

 edge of a species' range populations are usually low and the number of 

 observations of the species, on which the range is based, is low. This is 

 confounded by the natural fluctuations that all species undergo. For species 

 with very low numbers these fluctuations may cause the population to disappear 

 altogether. The result is a constantly changing boundary, based on population 

 levels. The distributions presented in table 17-3 are based on published data 

 and, while they are the best available information to date, they should not be 

 regarded as absolute. 



Five species of mammals are found only in the southern regions and reach the 

 northern limits of their distribution within the characterization area: 

 Virginia opossum, eastern pipistrelle, New England cottontail, pine vole, and 

 gray fox. All but the pipistrelle (a bat) are expanding their ranges 

 northward. The opossum seems to be limited by cold temperatures, because its 

 fur is a poor insulator and it must remain in its den during severe winter 

 weather (Scholander et al. 1950; and Godin 1977). Populations of the New 

 England cottontail are increasing and the range is expanding, perhaps in 

 response to changes in habitat. Because the cottontail is the preferred prey 

 of the gray fox, it, too, is increasing (Palmer 1956; and Stanton 1960). 



Three other species are absent from portions of the characterization region: 

 black bear, marten, and fisher (table 17-3). The black bear is fairly 

 abundant in eastern Maine (regions 5 and 6) but is scarce in regions 3 and 4 

 and absent from regions 1 and 2. Marten were formerly found in much of Maine 

 but were reduced by trapping and habitat loss (Coulter 1959). Recently they 

 have been expanding their range eastward and southward and may be present in 

 the northern extensions of regions 4 and 5. Fishers are abundant in the mid- 

 coast area (regions 3 and 4) but have never been numerous east of the 

 Penobscot River. They may be absent from along the coast in extreme southern 

 Maine because of the lack of suitable habitat. 



17-5 



10-80 



