Coastal & Marine Ecosystems 



Overview 



The quantity and health of 

 the nation's coastal and 

 marine resources have declined over historical 

 time at the species, community, and ecosystem 

 levels. All articles in this section implicate 

 human activities as contributing to these 

 declines. Human impacts on the coastal and 

 nearshore marine zone include urbanization 

 (direct loss of habitat, lowered water quality), 

 shoreline modification (dredging and filling, 

 diking and impoundments), overfishing, and 

 high-density recreational use. 



Some portion of the overall downward trend 

 is directly attributable to natural processes. 

 Hurricanes and coastal storms can have signifi- 

 cant negative impacts on both barrier islands 

 (Williams and Johnston) and seagrass beds 

 (Handley, Onuf). Rising sea level and coastal 

 subsidence — natural processes that are likely 

 being accelerated by anthropogenic (human- 

 cau.sed) activities — are responsible for coastal 

 wetland loss in Louisiana (Johnston et al.). 

 Rising sea level is also implicated in the erosion 

 of barrier islands (Williams and Johnston). The 

 inescapable conclusion is, however, that even 

 where natural processes play a role, human 

 impact is of equal or greater importance to the 

 long-term health of these resources. 



Despite overall declines in coastal and 

 marine resources, there is some room for cau- 



tious optimism. Some coral reefs are far enough 

 from human habitation that they are probably 

 stable and not declining (Jameson). Despite 

 changes in the relative abundances of native fish 

 species and the introduction of exotic species in 

 the tidal portion of the Hudson River, no native 

 fish species have beeen extiipated within the 

 period of record (1936 to 1990) (Daniels). The 

 population trend for manatee {Triclwcluis man- 

 atus) in Florida appears stable and perhaps 

 slightly increasing (Lefebvre and O'Shea). 

 Recent local reversals in the decline of sea- 

 grasses have occurred in Chesapeake Bay 

 (Pendleton) and in lower Tampa and Little 

 Sarasota bays (Handley). These successes, how- 

 ever, are tempered by the realization that human 

 populations in coastal states are projected to 

 substantially increase soon. 



It is clear from these articles that the quality 

 and extent of our information bases forjudging 

 status and trends of our coastal and marine 

 resources are often inadequate. Whereas the 

 areal coverage of some ecosystems can be 

 judged by comparison of remotely sensed data 

 (e.g., coastal wetlands), gathering analogous 

 information on other ecosystems or components 

 (e.g., fishes on coral reefs) requires much small- 

 er scale, more labor-intensive efforts. In their 

 review of Florida Keys reef fishes. Smith- Vaniz 

 et al. were forced to rely on a combination of 



by 



Science Editor 



Carole C. Mclvor 



National Biological 



Service 



Arizona Cooperative Fish 



and Wildlife Research Unit 



University of Arizona 



Tucson, AZ 85721 



