increasing biological activity in surface litter and soil, balancing the 

 soil nutrient status, and reducing mobility of toxic elements. Fertili- 

 zers may speed cycling of nutrients by mobilizing anions and cations if 

 biomass exists that can capture them. However, if not captured, the more 

 mobile ions may leak to shallow groundwater aquifers, drainage ditches, 

 streams, and marshes. 



Artificial revegetation facilititates rapid reintroduction of producer 

 biomass on denuded areas, thus speeding the return to initial site condi- 

 tions. Biotic feedback mechanisms which regulate soil structure, soil 

 heat, nutrient availability, soil moisture, and surface-water runoff con- 

 tinually enhance site micro-environmental quality, thereby facilitating 

 reestablishment of more stable plant assemblages. Native plant species 

 provide food and cover resources most compatible with requirements of near- 

 by consumer groups. Although the selection of suitable plant species is 

 limited in salt and brackish marsh systems, many diverse grasses, sedges, 

 forbs, and a few select shrub species are available for levee revegetation 

 in fresh and delta marsh systems. Climax species ecotypes are desirable 

 if site soil characteristics are not greatly altered, particulary if 

 reestablishment to original site conditions is preferred. On more adver- 

 sely disturbed sites (dry, infertile), pioneer or serai species can be 

 utilized as site conditioners to aid in the natural succession to climax 

 species. Land management objectives, however, regulate what cover type 

 is planted and, thus, which specific consumer groups are encouraged by 

 habitat expansions. 



Mulch, a temporary surface covering of straw, wood chips, asphalt emulsion, 

 jute matting, or similar materials, moderates several important surface 

 soil aspects that regulate plant germination and growth. Mulch applica- 

 tion on disturbed sites moderates soil temperature fluctuations, retains 

 soil moisture, contributes to soil fertility, and, in conjunction with 

 soil structure, increases surface-water infiltration. 



Restoration typically occurs on sites which previously supported various 

 types of displacement-producing activities. Displacement, if it were to 

 occur, has already been effected by such prior processes. Additional 

 effects are probably minor and short term in nature. Site shutdown and 

 restoration should encourage the return of sensitive wildlife species. 



4. Key attribute alterations 



Restoration of soil structure is the pivotal aspect of site rehabilita- 

 tion which controls other regulatory parameters that determine the 

 suitability of the edaphic environment for plant growth. Soil structure 

 regulates the infiltration of soil air and soil moisture, surface-water 

 runoff, water permeability, and water-holding capacity. Second-order 

 effects include regulation of soil erosion, nutrient availability, and 

 soil salinity. Several management techniques are available which 

 accelerate site recovery and allow selection of specific plant assem- 

 blages for reestablishment. 



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