State University, Baton Rouge, LA 70803; pers. comm.) notes that floating marshes in Lake Boeuf 

 have remained stable ecosystems for more than 46 years. Similarly, Hogg and Wein (1988) state 

 that Canadian "floating Typha spp. mats develop to become very resilient systems and it appears 

 doubtful that mat buoyancy and the current trend toward bog-like conditions will be disrupted, 

 either by natural or anthropogenic perturbations at the mat surface." Conversely, several 

 researchers reported that floating marshes may be ephemeral. Williamson et al. (1984) determined 

 that as "floating wax myrtle stands increase in size, they develop tilt and add instability to an 

 already tenuous system because the weight of the tree forces the surface roots under water causing 

 the shrubs to slowly die." The question is, do these areas surrounding the dead Myrica cerifera 

 stump convert to open water or fill in with herbaceous floating vegetation? Huffman and Leonard 

 (unpubl.) reported that sinking floating mats are actually a successional phase to swamp forests 

 with cypress. This is probably not the case in a subsiding environment such as coastal Louisiana. 



Management of these floating marshes, whether they are ephemeral or not, must take into 

 account the long-term productivity and health of the environment. Within coastal wetlands, new 

 mineral sediment and nutrient input lead to healthier vegetation and firmer substrate (Gosselink 

 and Gosselink 1985; Kadlec 1987; Kadlec and Bevis 1987). Therefore, we suggest that resuspended 

 and diverted sediment and nutrient sources be diverted into these floating areas to possibly convert 

 them into stable marshes and to enhance their productivity. 



MANAGEMENT OF JEAN LAFITTE NATIONAL PARK 



In developing a management plan for the park, there should be three primary objectives: 

 retardation of lakeside erosion, improved hydrology, and enhancement of sediment input to the 

 area. If these three objectives are accomplished, there will be a number of beneficial effects, 

 including enhanced vegetation health and productivity, more rapid soil formation, and stronger 

 connections among different wetland habitats. 



Insofar as possible, improvement of hydrology of the area should reestablish overland flow which 

 follows the east to west elevational gradient from the bottomland hardwoods to the cypress swamp, 

 fresh marsh, intermediate marsh, and finally into the open water bodies. To facilitate overland flow 

 through the park subbasins, canal spoil banks should be breached, lowered, or eliminated in some 

 cases. The extreme fluctuation and dominance of the water flows into and out of Pipeline and 

 Kenta canals should be moderated. The flow in natural channels (Bayous Boeuf, Des Families, and 

 Coquille) should be encouraged where possible. The degree and speed of water level fluctuations 

 within both the wetlands and the canals should be adjusted to what would occur naturally. 



Sediment input to the park should be increased by encouraging input and trapping of 

 resuspended sediments from Lakes Salvador and Cataouatche and local canals (Millaudon and the 

 Intercoastal Waterway). Resuspended sediments and nutrients from local canals and lakes would 

 serve to partially offset the process of subsidence. But the only sediment diversion option which 

 could truly overcome the subsidence problem occurring in the central Barataria Basin would be 

 diversion of sediment-laden water from the Mississippi River. The implementation of the Davis 

 Pond diversion will thus be beneficial to the park. 



Managed Succession 



The pattern of vegetation adjustment to gradually increasing salinity suggests that an important 

 conceptual tool for the management of some Louisiana coastal wetlands may be the idea of 

 managed succession. The objective of a number of management plans is to maintain fresh and 

 intermediate marshes in areas which are converting to brackish marshes or open water. This is 



269 



