40South 

 — -j ! — j- .vest 



OSouin 40 Sojin 



Figure 32. Vegetation map of site 2, August 1977. 



(A) Site 3 Throat . At site 3 a small breach t.15 meters) in the dune 

 line had been opened during the 10 May 1977 northeaster, killing the Ammophila 

 bveviligulata that was flooded by saltwater. Overwash surges penetrated into 

 the dune line depositing a small amount of sand in low-lying areas. The vege- 

 tation of site 3 throat consisted primarily of stable dune community species 

 dominated by Artemisia stelleriana with a dense stand of Ammophila bveviligulata 

 along the back margin of the dune between 40 to 50 meters (Fig. 33). The western 

 edge of the dune line was steeply scarped by vehicles along the high sand road. 



Vegetation data for site 3 throat appear in Table 11. Site 3 throat was 

 similar to site 1 throat, but the distribution and abundance of their com- 

 ponent species were very different. Ammophila, bveviligulata was a major 

 component (l.V. = 97.3), but Artemisia stelleriana was the dominant species 

 (I.V. = 161.7); Spartina patens var. monogyna was only a minor element 

 (l.V. = 0.5). 



(5) Site 3 Marsh . Site 3 marsh was chosen both as a control, 

 unaffected by overwash, and as a marsh likely to be overwashed in the near 

 future. Unlike site 1 fan and site 2, site 3 marsh had an even mixture of 

 high and low marsh vegetation; this undisturbed site was at the transition 

 between the two communities (Fig. 34). Spartina patens (I.V. * 133.1) was the 

 dominant species (Table 12), but Salicormia virginica (I.V. •» 80.9) and 

 Puaainellia sp. (I.V. = 45.9) were found in large numbers only at site 3 marsh 

 in areas sampled on Nauset Spit-Eastham. 



3. Community Response to Overwash . 



a. Intro duction. Plant community response to overwash burial has been 

 studied along the Outer Banks of North Carolina by several investigators. By 

 comparing biomass samples in areas affected by overwash with areas unaffected 



70 



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