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NEUHAUS, R & STELTER, TH. & KIEHL, K. (1999): Sedimentation in salt marshes affected by grazing regime, topographical patterns and regional differences. -Senckenbergiana marit., 29 (Suppl.): 113-116, 4 figs.; Frankfurt a. M.]The future perspective of salt marshes strongly depends on a positive balance between sedimenta'don and ah increased sea-level rise. Sedimentation itself is influenced indirectly by grazing as well as the position of the location in relation to the nearest sediment source and by amount and quality of the available sediment.Two salt marshes were studied (S6nke-Nissen-Koog marsh, Friedrichskoog marsh) at the mainland coast of Schleswig-Holstein (FRG). In both marshes experimental plots had been established which were grazed by sheep at high and intermediate intensity or remained ungrazed. To figure out the effect oftopography on net-sedimentation rate, we included sites close to and far from the locations ,dike" and ,creek" in all management variants. In general, a reversible soil shrinkage in summer due to desiccation could be detected.Sedimentation rates differed siguificantly between grazed and ungrazed salt marshes. The ungrazed Puccinellia-dominated marsh as well as in the Festuca-dominated marsh demonstrated highest annual netsedimentation rates of 1.8-2.1 cm and 1.2-1.7 cm, respectively, and can thus counterbalance the average sea level rise unless they show a decreasing trend in future.

The paper deals with general outlines of salt marsh and dune vegetation in the Ellenbogen and Listland area on Sylt (Schleswig-Holstein, FRG). The composition of current salt marsh vegetation is considered to be mainly the result of a long-lasting process of tidal inundation, grazing, and a permanent influence of groundwater seepage from the surrounding dunes. The lower salt marsh communities have shown constancy for 67 years, due to the effect of heavy grazing. The mid-upper salt marsh communities demonstrated a succession from a Puccinellia maritima-domihated community of the lower marsh to a Juncus gerardii-dominated community of the mid-upper salt marsh, which may be due to the transport of sand -over a short time -on the surface of the marsh. The area covered by plant communities of annuals below Mean High Water (MHW) seemed to diminish. Salt marsh soils, especially of the mid-upper marsh, indicate sandy layers resulting from sand drift of the dunes. Dry and wet successional series of the dunes in the Listland/EUenbogen area both show grassy stages shifting to dwarf shrubs as final stages. White primary dunes can only be found on the accreting shorehne of the EUenbogen, which is also grazed by sheep; vegetation cover therefore remains dominated by grasses, mosses and hchens. Three mobile dunes (as the most prominent features of this landscape) have been left unaffected by seeding and planting by local authorities. Grazing is considered to be an inadequate tool in nature conservation as long as natural processes are to prevail in the landscape as major determinants.

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