(b) Comparison 2 . All quadrats sampled at site 3 throat in 1977 

 (3-T-77) were compared with the same quadrats sampled in 1978 to determine the 

 effect of overwash on a dune that had been eroded in some areas and buried by 

 washover deposits in other areas (Tables 11 and 16). Site 3-T-77 was a well- 

 developed, stable dune area (Fig. 33). A high foredune had cut off most of 

 the area fLoro windblown sand. Many dead Ammovhila breviligulata (I.V. ■ 

 97.3), once more abundant, had in recent years been replaced by Artemicia 

 steller-Lana (I.V. = 161.7) as the most important plant species. The landward 

 edge of the dune was populated with a dense stand of Ammophila breviligulata. 

 A total of 214 sampled quadrats were eroded during the 1978 storm; 152 quad- 

 rats were buried by between 1 and 98 centimeters of sand. The mean elevation 

 for the site was raised 15 centimeters, and a6 at site 1 throat, the elevation 

 ranges were severely truncated from a range of 2.10 to 0.69 meter. Mean net 

 depth of sand burial was 0.30 meter (±0.24 teeter). 



Table 16. Summary of data collected from 351 quadrat samples 4t site 3 

 throat, August 1978. 



Species 



Anmopkila breviligulata 

 Artemisia etelleriana 

 Cakile edentula 

 Lathy rus javor.iaus 

 Solidaao semvervirens 



Bare sand 

 Drift 



Fr 



jquency 

 Relative 





Cover 



Density 



I.V. 2 



Pet 



Pet 



Relative 



Total 



Relative 





57.0 



48.1 



3.3 



47.1 



384 



38.6 



133.8 



10.8 



21.2 



1.7 



24.7 



490 



49.3 



95.2 



1.7 



3.4 



0.2 



2.1 



1 



0.1 



5.5 



8.6 



16.8 



1.0 



13.5 



90 



9.1 



39.3 



5.4 



10.6 



0.9 



12.7 



30 



3.1 



26.3 



100.0 





92.1 











8.0 





0.8 











Diversity » 0.6824; Richness ■ 5. 

 2 '.V.'s are importance v. .lues calculated from cover, frequency, and density 



of the planes. 

 Vegetative cover was reduced from 28 percent in 1977 to 7 percent in 1978. 

 Specie* tithness was reduced from 11 species in 1977 to 5 species in 1978. 

 Species diversity, however, remained similar between 1977 (0.6075) and 1978 

 (0.6824). firrmophila breviligulata, Artemisia stelleriana, Solidago 

 xcmoervirens, ar.d Latkyrus japonieus, all of which contributed to the high 

 upeci3S diversity in 1977, wer° either able to recover from overwash burial or 

 were found In drift piles. Although species diversity and the magnitude of 

 the I.V. for each of the major species did not vary greatly between 1977 and 

 1978, Kruskal-Wallis tests run for each of these species showed that, in all 

 casus, cover and density data were significantly lower in 1978 th&n in 1977 

 (? < 0.01). Carcx silicea was eroded by overwash in 1978. Agropyron pungens, 

 Spartina patens, * rtemicl-t caudata, and Rhus radicans (poison ivy) did not 

 recover from overw«sh burial, at site 3, but were formerly present in only a 

 few quadrats, [ 



The washover throat of site 3 was tot bordered by high dunes, as was the i. 



case at site I. Surges moving through site 3 throat were not restricted to a ■[ 



channel but were spread laterally. Site 3 throat eroded less than site 1 [ 

 throat due to the lack of flow constriction and prestorta vegetative cover. 



Drift piles at site 3 had a richer flora than at site 1 throat because fine «« 



f 



f 



i 



78 I 



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