Surprisingly, Scirpus deltarum or any other Scirpus species is not found in any abundance in the 

 Atchafalaya Delta. It may be that the fine sediment composition favors the colonization of 

 Sagittaria latifolia in the Atchafalaya Delta. The sediments are much coarser in the Mississippi 

 River Delta. 



This study has shown the abundance of Scirpus deltarum on the splays at the River Delta 2 and 

 3 years after mudflat emergence, which is of considerable importance to wildlife. During the first 

 two winters, the majority of the 80,000 plus geese that overwintered in the delta fed on this sedge, 

 particularly at the Brant Pass splay. During the plant growing season (May-October), the 

 aboveground stems of Scirpus deltarum are a major food of nutria and muskrat. Many of the seeds 

 from the other sedges and grasses are important in the diets of the overwintering ducks. Salix 

 nigra is the only significant plant with aboveground living tissue during the winter. As a result, its 

 presence sustains the local deer population and provides food to the nutria and muskrat during 

 winter. 



CONCLUSIONS 



1. Within the Mississippi River Delta more than 60,000 m 2 of new land development was 

 monitored at three sites on two splays located within a huge, shallow, freshwater pond. This 

 represents only a small fraction of total land buildup on these splays and within the delta 

 itself. 



2. The average rate of sedimentation at the three sites for 3 years was 0.0189 cm/d or 6.9 

 cm/yr. The month-by-month rate fluctuates considerably depending upon the river's 

 sediment load and volume of flow. 



3. Qualitatively, the three sites supported a diverse flora typical of freshwater alluvial deposits 

 within southeastern Louisiana. Sixty-two plant species from 21 families have been identified. 



4. Quantitatively, the three sites supported a much less diverse flora. Salix nigra, Scirpus 

 deltarum, and Colocasia esculenta are quite common in their own microhabitats, and often 

 comprise more than 80% of a community's plant biomass. 



5. Successionally, Salix nigra on the highest land and Scirpus deltarum on the lower land 

 dominate most of the mudflats' surface area 2-3 years after initial colonization. First- and 

 second-year colonizers include an assemblage of herbs, particularly grasses and sedges. 



ACKNOWLEDGMENTS 



I thank personnel of the Fish and Wildlife Service for allowing me free access and water 

 transportation to the study sites. I thank Dr. Steven Darwin for his patient taxonomic labors. 

 To the many biology students at Loyola University who were laboratory and field assistants, I 

 extend special thanks. This research was supported by the Louisiana Sea Grant College Program, 

 a part of the National Sea Grant College Program maintained by the National Oceanic and 

 Atmospheric Administration, U.S. Department of Commerce. 



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