plant and animal tissue, releasing compounds for reuse by plants, and convert 

 and store pollutants. Insects and certain aquatic invertebrates process 

 detritus and are themselves utilized as food in the system. 



People affect the biota directly through activities that (1) alter the habitat 

 in which a species lives thereby impacting its population; (2) impact food 

 webs (through input into the ecosystem of heavy metals, biocides, and oil), 

 energy flows (e.g., siltation and obstruction of water flow), and biogeochemi- 

 cal cycles (nutrient depletion and eutrophication) ; and (3) result in the har- 

 vest of certain species (commercial fishing and shellfish harvest, sport 

 fishing, hunting, trapping, and timber harvesting). 



The composition, distribution, and functional requirements of biota are 

 discussed by system in this characterization and detailed information can be 

 found in the chapters on the various systems (chapters 4 through 10). In 

 addition, chapters 11 through 20 present information on commercially and 

 ecologically important groups of species. Common names of species are used in 

 the text except where more than one or no common name exists. Taxonomic names 

 of most plants and invertebrates are given in the text to avoid ambiguity. 

 The taxonomic names of all species mentioned in the text are listed in the 

 appendix. 



Abiota 



The ecosystem of the Maine coast is dominated by its physical components, for 

 example, geology, climate, and hydrology. The geological and hydrological 

 forces form the physical structure to which the biotic components must adapt. 

 Geology and hydrology interact to determine the distribution and chemistry of 

 surface and ground waters (figure 1-8). Water circulates from the oceans to 

 the atmosphere and back to the oceans, either directly or via terrestrial 

 and/or aquatic systems, and transports life-supporting elements that are 

 released from rocks and soils by weathering. 



Climate interfaces with both geology and hydrology and is a dominant forcing 

 function in Maine. The climatic factors of precipitation, temperature, 

 insolation, fog, storms, wind, humidity, and ice all affect the abundance and 

 distribution of biota. 



People place stress on the abiotic aspects of the ecosystem through socioec- 

 onomic activities. The characteristic features of these forcing functions in 

 coastal Maine are detailed in chapter 2, "The Maine Coast Ecosystem." 



THE SPECIES POPULATIONS 



Major groups of species on the Maine coast are listed in figure 1-9. Species 

 populations, including those of commercially and ecologically important 

 species, and their interrelationships are discussed in chapters 11 through 20. 

 The seasonal status and distribution of groups of species, uses of habitat, 

 various life stages, reproduction, feeding habits, importance to humanity, 

 factors of abundance (natural and artificial), and management are examined. 

 Detailed studies of important species are included. 



1-14 



