Table 31. Count of seedlings and regenerating axes for drift-line vegetation 

 at site I fan, 1979. 



5 June 22 Ju^e b July 19 July I Aug. 24 Aug. 5 Sept. 20 Se^ 



Agropuro*x punqenG 

 iisnophila b^evil igutata 



frenarux peploiden 

 i^tt»Ttiaia etpllertann 



Atriplex patula 

 ?*kile edentula 

 ^ennpn.iium alhidum 

 "nnvolvuluc eeprum 

 v upho^hia polucjoni folisi 

 '.tthun4F japoriLCUft 



254 

 1,630 



323 

 2,129 



7,298 MO, 000 



"iki i 



"taona 





"l J fraimt/2 virci 



Mrr. 



-rf*r<\ 



\n l-i7t 





-■pi ;-< 



mo fipmppr* 



Hw 



"r-i'fi 



'm .litem. 



IflOfn 



~d<wi 



'm pntenp 





*■««<■ 



'. "riritimi 





"nknm 







»inf>ii 



„•., 'him 



■//•?, 



S » secJlInRi. 



F - regenerating from fragnents. 



calculate Che percentage of new, recovering fragments. Forty percent of the 

 Ammophila bveviligulata axes in these drift lines were newly established in 

 1979 from fragments. Site 1 fan had 161 Ammophila bveviligulata axes in 

 April 1979, most of which were previously regenerating fragments. The number 

 increased steadily during the summer to 2,129 in late August. 



Seedlings of Ammophita bveviligulata were also found in site 1 during both 

 1978 and 1979. Reports vary in the literature concerning the importance of 

 seedlings to Airmjphila bveviligulata colonization and population dynamics. 

 Seedlings have been reported to be rare in the fixed dune comsaunity and 

 unimportant in the colonization of new areas \,Laing, 1958). Other reports 

 have suggested that there are seed years when large numbers of seedlings 

 survive and genetic diversity increases (Tansley, 1968; Kuiskes, 1977, 1979). 



In 1978, 18 seedlings were located in site 1 on 5 June. New seedlings 

 appeared until 10 July. Throughout July and Augusts seedling counts were made 

 weekly (Table 32). Most seedlings died during late July and August, presum- 

 ably from drought. Van der Valk (1974) reported that the main cause of seed- 

 ling mortality was sand deflation. Although the site was unprotected from 

 southwest and northwest winds, there was no major wind erosion during the 

 summer. 



131 



