CRS-145 



2. Change in wetland species composition — almost any change in hydro- 

 logic or water quality conditions may alter the vegetative community; 

 biological effects include changes in wetland composition, changes in 

 wetland primary productivity, and changes in plant species diversity. 



3. Change in wetland class composition — altered water levels may affect 

 the distribution and abundance of wetland classes, which are a major 

 determinant of wildlife values. 



4. Change in wetland primary productivity — energy capture by green 

 plants, primary productivity, may be reduced by all phases of high- 

 way construction and use. Primary productivity is important because 

 of its effects on secondary productivity and the rate of plant suc- 

 cession. 



5. Sudden mortality of wetland species — creation of temporary but 

 extreme environment conditions can substantially affect existing 

 biota. 



6. Barrier to animal movement — barriers can inhibit the normal peri- 

 odic movement of animal populations, essential for their survival 

 and productivity. 



7 . Rare and endangered species — all Federal agencies are required to 

 ensure that actions, authorized, funded, regulated or administered 

 by them do not jeopardize continued existence of a species identi- 

 fied as endangered, or destroy or alter critical habitat of the 

 species . 



Source: National Research Council, Transportation Research Board. Ecological 

 Effects of Highway Fills on Wetlands. Report 218B. Prepared by P. W. 

 Schuldiner, D. F. Cope and R. B. Newton. Washington, 1979. p. 14-38. 



