An almost continuous dune line, with elevations approaching 5 meters In 

 some areas, extended 2.2 kilometers along the spit in 1977. A recent study 

 of dune-building processes on Nauoec Spit-Eastham showed that 5-meter-high 

 dunes can form under optimal conditions in only 6 years (Knutson, 1980). In 

 general, community succession in coastal areas is extremely rapid, aided by 

 the nutrient input of salt spray (van der Valk, 1974; Art, 1976). The few 

 species found within an area of rapid succession suggests that environmental 

 pressures maintain plant community development at a very early stage of 

 succession. 



A 1977 map of Nauset Spit-Eastham before the 1978 storm is shown in 

 Figure 2. Three washovers were evident along the spit. The dune line was 

 approximately 150 meters wide, backed by a very wide salt marsh at the north- 

 ern end, which narrowed to the south. The dune line was steeply scarped on 

 the oceanside, and had eroded approximately 140 meters landward in the past 

 110 years (see Sec. IV). The off-road vehicle path between the high marsh and 

 dune communities had scarped the back barrier dunes preventing the landward 

 expansion of the dune line. 



2. Base-Line teta . 



a. Introduction . Three sites on Nauset Spit-Eastham in 1977 were chosen 

 that represented different stages of vegetative recovery following overwash. 

 Site I washover was created by overwash in 1972, and consisted ot a well- 

 developed Spavtina patens high marsh and the upper elevation edge of a Spar- 

 tina alterniflora law marsh. High, well-vegetated dunes bordered tne washover 

 throat. Site 2 first overwashed in September 1976, presenting thfi opportunity 

 to study the response of vegetation to burial on a very recent washover. Site 

 3 had not been affected by recent storms, but appeared to be a possible loca- 

 tion for future overwash. The dune and marsh communities could be used as a 

 control, unaffected by overwash. Fieldwork was conducted in the summer of 

 1977 with the intention of following changes in the vegetation on the three 

 washovers over a period of 2 years. 



b. Methodology . The vegetation at each site was sampled using a 0.25- 

 meter-square point-intercept board with 25 evenly spaced holes to calculate 

 cover (Fig. 26; Costing, 1956). Information concerning frequency (species 

 present), cover, and plant density was collected. A plant was considered 

 in the frequency determination if any part of the plant appeared within the 

 double-framed quadrat. Density was determined by the number of axes breaking 

 the sand surface. For fine grasses, density calculations were made using the 

 average of estimates from three researchers. Quadrats were selected within 

 the plots using a mixed, random, or systematic process (Kershaw, 1976). 



Quadrats were spaced at 2-meter intervals along transects chosen at random 

 along the base line in order to take into account the belted zones of the salt 

 marsh. The point-intercept board was placed with two fixed points located 

 along a tape measure which defined the sampling transect, so that each quadrat 

 could be relocated for future study. The elevation relative to sea level was 

 determined for each quadrat using a surveyor's level. Time was the only con- 

 straint placed on the number of transects sampled. A field map was made of 

 each plot using the 5- by 5-meter flagged elevation grid as a guideline. 



61 





