Right-of-way corridors serve as habitat for a number of plants and birds. 

 They are also utilized frequently by deer, foxes, and coyotes. The density of 

 breeding birds in rights-of-way is usually less than it is in surrounding 

 woodland and shrub habitats. The effects of rights-of-way on terrestrial bird 

 populations is discussed further in chapter 16, "Terrestrial Birds." 



Causeways builts on or over tidal areas restrict tidal flow to areas landward 

 of the causeways. Causeways may act as barriers; most culverts do not allow a 

 sufficient exchange of water. The alteration in drainage patterns may result 

 in changes in water temperature, salinity, sedimentation, and flushing rates. 

 These changes may affect primary production, benthic biota, and other 

 organisms such as migratory birds and fishes. The passage of migratory fishes 

 may be restricted by culverts. In extreme cases, the stagnation of water 

 along a causeway may cause low dissolved oxygen levels, which stress aquatic 

 fauna. Roads have caused siltation in lakes in coastal Maine (e.g., Upper 

 Hadlock Pond, region 5). An impact associated with dirt roads, logging roads, 

 and skid trails is soil erosion, which produces effects similar to those of 

 agriculture and construction activities. 



Roads constructed in dune areas also may have harmful ecological impacts. 

 Construction of roads may prevent sediment from being naturally utilized as 

 beach sediment. Roads constructed on beach ridges conflict with the natural 

 landward migration of beach ridge material. Storms from the northeast, which 

 occur frequently in Maine during winter, cover the road surfaces with gravel 

 from beaches. Since the natural movement of sand is interrupted, the profile 

 of the beach as well as the habitat for many organisms will be altered. 



Airports pose a unique problem for birds, primarily gulls and waterfowl. 

 Airports situated near dumps or along flight lines between dumps and rivers, 

 dumps and shopping centers, or near sources of solid waste can pose a serious 

 aircraft-bird collision hazard. Airports situated near waterbird 

 concentration areas pose similar collision problems. Herring and great black- 

 backed gulls, which feed and rest in open grassy habitats, are attracted to 

 some airports. Collisions between aircraft and birds are uncommon in most 

 areas in Maine. 



Herbicides, used to control woody and herbaceous plants along rights-of-way 

 (especially railroads), may cause problems, especially if improperly handled. 

 Improper formulation of the herbicide and improper disposal of herbicide 

 containers may result in locally high herbicide concentrations. These 

 contaminants may, in turn, enter ground and surface waters. The long-term 

 effects of herbicides on plants and animals is uncertain (see "Forestry" 

 above) . 



TOURISM AND RECREATION 



Tourism and recreation in coastal Maine have a significant impact on the 

 environment, through (1) the discharge of wastes, (2) the disturbance of and 

 encroachment on sensitive species of wildlife, and (3) the alteration of 

 natural ecosystems. Seasonal residences and tourist facilities (motels, 

 hotels, and restaurants) add to the pressures of development on lands. Their 

 waste water and domestic sewage contribute to the seasonal and permanent 

 closings of clam and worm flats. The sanitary survey reports prepared for 

 each municipality by the DEP summarize the number of residential discharges 



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