illustrate the same processes, components, and interrelationships. The energy circuit 

 diagram is more academic, but the sketch is more easily understood. Characterization 

 studies include both types of graphics and combinations of them with narrative 

 explanations. 



In summary, the models with accompanying narrative and graphics are designed 

 to delineate functional system boundaries, forcing functions (such as climate, tides, 

 and currents); components (such as habitats, populations, and species); processes 

 (such as energy transfer, sedimentation, and food webs); and economic productivity 

 (such as commercial fishing, hunting, oil and gas production, and industrial 

 development). 



Narrative Report 



The narrative report of a characterization study complements the ecosystem 

 (conceptual) models by more fully explaining the cause and effect relationships of 

 human activities, natural changes, and their controlling influences. The report 

 contains a narrative, figures, tables, and diagrams. It also includes a user's guide to 

 assist the reader in understanding how to obtain maximum benefits from the report. 

 Examples of the type of data presentations used in the report are shown in Figures 3 

 and 4. Figure 3 illustrates a generalized secondary plant succession in white pine and 

 shrub pine forests and its associated bird species for coastal Maine. ^ Figure 4 depicts 

 a typical coastal ecosystem trophic structure and food web.' 



Ecological Atlas 



The ecological atlas consists of maps with supporting narrative and tabular data 

 that depict biological resources, coastal processes, socioeconomic activities, physical 

 features, and hydrologic information. Map scales vary from 1:24,000 to 1:1,000,000, 

 depending upon the topic portrayed. The standard mapping scales are 1 :24,000 and 

 1:100,000, using U.S. Geological Survey topographic series as base maps. The types 

 of information used, topics portrayed, and uses of maps are shown in Figure 5. 



The maps show biological resources, including oyster and clam beds, fish 

 spawning and nursery areas, submerged vegetation, nesting and high density areas 

 for birds and sea turtles, high density areas of waterfowl and furbearers, critical 

 habitats for endangered and threatened species, natural or artificial fishing reefs, and 

 habitats. For some study areas, habitats (wetland and upland) are portrayed at a 

 scale of 1:24,000 for both past (1950s) and present (late 1970s) distribution. 



For example, data for the habitat maps of the Mississippi Deltaic Plain Region 

 study indicate that over 500,000 acres, or 800 square miles of southeastern Louisiana 

 coastal wetlands were lost or altered from the mid-1950s to 1978. This represents an 

 approximate rate of about 25,000 acres, or 39 square miles, per year. The majority of 

 the wetland changes was from marsh to open water. The loss or alteration in 

 Mississippi, which has less wetland area, was estimated at 5,500 acres, or less than 

 nine miles, during the two decades. 



Physical features that have been mapped are shoreline changes, high and low wave 

 energies, and inundations by major hurricanes and storms. Boundaries of fresh and 

 nonfresh (saline) marshes in the 1950s, 1960s, and 1970s and water control structures, 

 including dams, locks, and weirs, have also been mapped. 



Socioeconomic features that have been portrayed are conservation, preservation, 

 and recreation areas, point source discharges, energy developments such as oil and 

 gas infrastructure including pipelines, mineral resources, dredge spoil disposal sites, 

 and historical and archaeological sites. 



Some maps also show geological features, spoil areas, active dunes, currents, 

 seasonal wind patterns, and estuarine circulation patterns. 



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