Most coastal zone lakes have extensive shallows with abundant growth of 

 macrophytes . However, the abundance of macrophytes and associated animal life 

 is greately reduced in the more oligotrophic Maine lakes (e.g., Jordan Pond in 

 region 5), which often have rocky and gravelly bottoms in their shallow areas. 

 The diversity of invertebrates (as shown in figure 7-7) is much greater in 

 littoral zones (especially those associated with macrophytes) than in pelagial 

 zones . 



Lake food webs are closely integrated with lands or waters adjacent to lake 

 systems. Food-chain energy and materials are lost by lakes in the emergence 

 of insects and the departure of vertebrates that temporarily occupy the lake, 

 and much food energy is gained from the influx of organic matter from 

 terrestrial ecosystems. Terrestrial and wetland vertebrates (e.g., swallows, 

 mink, and some waterfowl) may obtain much of their food from lakes and 

 associated wetlands. 



LACUSTRINE SUCCESSION 



Lake basins gradually become shallow through accumulation of biotic (plant and 



animal remains) and abiotic (mineral) sediments. The accumulation of 



sediments is often accompanied by the encroachment of palustrine areas on the 



original basin. Eventually, lacustrine systems pass through the process of 

 palustrine succession (see chapter 8, "The Palustrine System," page 8-6). 



LAND USE 



Landcover maps published by the Maine State Planning Office (1977) were used 

 to identify land use practices adjacent to the lakes named on U.S. Geological 

 Survey maps. The land-use survey included all lands within 0.5 km of the 

 shorelines . 



A large proportion of the area surrounding the named lakes and ponds in the 

 coastal zone is dominated by forests. They give stability to the physical 

 and biological characteristics of lakes and contribute significantly to lake 

 energy cycles. 



Recreational and Municipal Use 



Except among some of the larger lakes in the coastal zone, recreational 

 opportunities are limited largely to shoreline residents; consequently, few 

 are managed in the public interest. Recreational uses include swimming, 

 boating, fishing, picnicking, camping, hunting, and golf. Parks, campgrounds, 

 playing fields, and playgrounds are associated with only 9% (about 15% in 

 regions 3 and 4) of the lakes named in USGS maps, according to the Maine State 

 Planning Office (1977). Swimming beaches exist on only 4% of the lakes, and 

 marinas, boat harbors, or docks on only 9% of the lakes. 



Summer cottages occupy much of the shoreline on a large percentage of the 

 coastal zone lakes. Although lakes of 10 acres (4 ha) and larger are 

 considered public waters in Maine, only a small percentage of the lakes have 

 public access. Public access to coastal zone lakes is greatest in Acadia 

 National Park. 



7-32 



