Hunt et al. (1978a) discussed three methods of vegetation establishment: 

 (a) allow natural plant invasion and establishment, (b) plant selected spe- 

 cies, and (c) combine natural establishment and planned propagation. 



The ability of propagules to reach the site is the most important factor 

 determining the potential for natural colonization. Sources, distances, and 

 modes of transportation are important. Physical and biological factors at the 

 site, such as site size, soil type, and moisture, are also important determi- 

 nants of establishment success. 



Vegetation can usually be established within a year through planting and 

 other standard agronomic practices. Advantages and disadvantages of natural 

 establishment and planting are discussed in Hunt et al. (1978a). 



Plant species are selected by first looking at vegetational needs of the 

 target species. Candidate species can then be evaluated in light of adaptabi- 

 lity to climate and substrate, growth requirements, availability, ease of 

 propagation, management requirements, and costs (Hunt et al. 1978a). Summariz- 

 ed data is available on plants known to grow on dredged material sites (Landin 

 1978a, Ocean Data Systems, Inc. 1978). Also available is a study of succes- 

 sional patterns of plants and animals at terrestrial disposal areas (Coastal 

 Zone Resources Corporation 1977). 



As a general rule, native plant species should be used for habitat devel- 

 opment (Ocean Data Systems, Inc. 1978) because: (a) the wildlife of the area 

 normally depends on these plants and (b) the plants are adapted to the climate 

 and to the physical and chemical properties of the local sediments. An excep- 

 tion to (b) is domesticated species of plants that are of greater value to 

 feeding waterfowl (Crawford and Edwards 1978, Hunt et al. 1978b). 



There are a number of engineering considerations that effect the ecology 

 of a site and its value to wildlife. The size, configuration, elevation, and 

 topography all affect wildlife use and suitability (Hunt et al. 1978a). Like- 

 wise, the presence or abundance and patterns of vegetation affect wildlife, 

 e.g., greater vegetative diversity generally leads to greater animal diversity. 



Long-term site maintenance and management could range from simple moni- 

 toring of the presence of vegetation and wildlife use to intensive management 

 of the site. Management activities can consist of the repair or removal of 

 dikes or protective structures, erosion control, or vegetation management. 

 Vegetation management may consist of fertilization, liming, cultivation, mow- 

 ing, burning, pruning, and herbicide application (Hunt et al. 1978a). 



Island development . Islands developed from dredged material have often 

 been valuable to colonial nesting waterbirds, e.g., gulls, terns, skimmers, 

 herons, egrets, ibises, cormorants, pelicans, and spoonbills (Figure 5). Some 

 of these bird species are threatened or endangered. However, the establishment 

 of islands has often eliminated valuable fishery habitat. The trade off of 

 habitats must be clearly recognized. Additional impacts may include changes 

 in circulation patterns, wind fetch, and tidal prism. 



There has been little planning for bird use of man-made islands. How- 

 ever, a recent nationwide examination of bird use of dredged material islands 



39 



