of this study because the elemental units in some- 

 cases are of inconvenient size for the purpose of 

 characterization. A great deal of information ob- 

 tained from Dolan et al. (1972) was used in 

 preparing this document. 



A limitation of classification of coastal areas 

 which should be briefly mentioned is the restric- 

 tion to that which specifically is being classified. 

 Classifications have addressed only beaches 

 (Shepard 1937), estuaries (Hansen and Rattray 

 1966), coastal waters including or excluding 

 estuaries (Lynch et al. 1976), coastal ecosystems 

 (Odum et al. 1974), or coastal and estuarine spe- 

 cies associations (Briggs 1974). Only one example 

 of each is cited for the sake of brevity, although 

 many more exist. As mentioned previously, the 

 classification presented in this paper is concerned 

 with coastal ecosystems in estuarine and coastal 

 waters and associated wetlands. 



The major problem with this proposed scheme 

 or any other classification scheme is that of draw- 

 ing boundaries somewhere along what is all too 

 frequently a continuum. All natural ecosystems 

 are "open ended" and have no fixed boundaries. 

 Where there may be a distinct boundary between 

 geological units along a coast, climate may well 

 be continuous. When geology intergrades, climate 

 may fall into distinct units. No clear boundary 

 may be definable. Compounding this problem 

 are those of shifting current, rainfall, and tem- 

 perature patterns during the year, and the very 

 nature of the coastal zone itself as an ecotone 

 between the land and sea. Thus, while some of 

 the different divisions specified may represent 

 fairly distinctive ecosystems or clusters of similar 

 ecosystems, others may be less distinctive. Some 

 divisions may be different from other divisions 

 only because they are intermediate. This paper 

 presents an attempt to regionalize and separate 

 into similarly functioning ecosystems the coastal 

 areas of the United States, using the available 

 ecological information and the expert opinion of 

 numerous resource managers who work along the 

 coast. 



METHODS 



In order to formulate a hierarchical regional 

 classification scheme for coastal ecosystems, cri- 

 teria were established which allow inspection of 

 the characteristics of coastal ecosystems or clus- 

 ters of ecosystems at various levels of resolu- 

 tion. Those criteria are: 



Level I: These divisions are the largest in 

 geographical area and represent clusters of 

 similarly functioning ecosystems. The main 

 criteria for separating the different divisions 

 of Level I arc ocean or lake systems upon 

 which the coastline abuts, or the major ocean 

 current or currents which wash the shore, 

 or major differences in climate. Ocean currents 

 and climate are the main forcing functions of 

 ecosystems along the coastline and arc appro- 

 priate criteria for separating these ecosystems. 



Level II: These divisions are geographically 

 smaller than Level I divisions, and represent 

 a small number of interrelated and similarly 

 functioning ecosystems. They are separated 

 chiefly by geological structural properties of 

 the coast, both above and below the water- 

 line, with consideration given to hydrological, 

 physical, and chemical properties. The struc- 

 tural geology of the coastal area is a major 

 constraining factor on ecosystems and thus is 

 an appropriate second level criterion for 

 separation of these ecosystems. 



Level III: For the purposes of this study, 

 Level III divisions have not been delineated, 

 but may be required in the future. A detailed 

 study would be required to properly delineate 

 Level III divisions. The following are the 

 recommended methods for determining such 

 divisions. Level III divisions would be the 

 smallest divisions of the classification. Each 

 should represent a logical unit or ecosystem. 

 The primary criterion for separation should 

 be the homogeneity of response, considering 

 the forcing functions and constraints, of the 

 division to perturbation. 



At the first, most general level, the forcing 

 functions of the systems are the chief criteria. 

 At the second level, the major constraints on 

 the system are the chief criteria. At the third, 

 most specific level, the homogeneity of the 

 response of the system to the forcing functions 

 and constraints is suggested as the criterion for 

 separation. Thus the criteria are: what makes 

 the system work, what determines how the 

 system can work, and how does the system 

 respond. 



To separate divisions, boundary lines were 

 drawn perpendicular to the coast using the listed 

 criteria and manual overlay of maps exhibiting the 



