Two major factors determine the seedling crop, type, and abundance of 

 plant fragments on washovers each year: winter conditions that distribute 

 propagules and climatic conditions in the late spring and summer months. The 

 February 1978 storm swept massive areas of Nauset Spit-Eastham and North Beach 

 clean of storm debris, leaving few obstacles to trap seeds and fragments. 

 Following the storm, spring tides on the bay side deposited large amounts of 

 drift material progressively lower on the edges of washovers. Large numbers 

 of drift seeds settled out to the lower parts of these drift lines. Wind- 

 distributed sand buried the debris. 



The weather was particularly wet and cool in spring 1978. In April, May, 

 and June, 279 millimeters of precipitation fell at the Chatham Weather Sta- 

 tion, located 12 miles south of Nauset Spit-Eastham. Temperatures averaged 6° 

 Celsius in April, 11° Celsius in May, and 17° Celsius in June 1978 (Fig. 80). 

 Eleven 6pecies of flowering plants germinated on washovers in 1978 (Table 29). 

 Most new plants were located in large clumps of debris or in well-organized 

 drift lines. The first seedlings noted on Nauset Spit-Eastham were of Cakile 

 edentula (5 April 1978). The last day with freezing temperatures was 10 

 April. Seeds did not germinate between 3 July and early September 1978, after 

 which all new seedlings did not survive brief fall droughts. 



Living plant material torn from the dunes is, in many cases, able to 

 regenerate. All four major dune species on Nauset Spit-Eastham, Ammophila 

 brsviligulata, Solidcgo eempe-rvirene, Lathyrus japoniaue, and Artemisia 

 stsllern-ana, can reproduce vegetatively froai pianL fragments. The February 

 1978 storm destroyed large sections of dune line, uprooting vast quantities of 

 organic material. In 1978 seven species of flowering plants regenerated from 

 fragments (Table 29) . 



30- 



20 



Z, 10 



-10 



-20 



©mean temperature per month 



temperature rantjs 

 Otoiol precipitation 



200 



50 



100 o 



50 



-0 



Jon Feb. Mar Apr fc!oy June July Aug Sept Oct. Nov Dec 



(MONTH) 



Figure 80. Monthly temperature and aoisture values on Cape Cod, 1978. 



127 



