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PLANT ASSOCIATIONS 



Plum Island can be divided into five major 

 physiographic zones (described in Chapter 2) . Running from 

 east to west across the island, they include the 1) beach, 

 2) foredune, 3) interdune, 4) backdune, and 5) salt marsh. 

 In this section the dominant plant associations in each zone 

 are described. The vegetation in the backdune is very 

 diverse and has been further divided into four vegetation 

 types: scrub forest, shrub thickets, pine forest, and 

 meadow. The plants which occur in the freshwater habitats 

 created by the construction of North and South Pools and the 

 damming of Stage Island Pool are discussed in a separate 

 section. Roadsides and waste places provide a distinct 

 habitat for a number of plant species. The plants commonly 

 found in these areas will be described in the last section. 



Beach 



The beach is normally a very dynamic area, not 

 typically thought of as a habitat for vascular plants. On 

 the upper edge of the beach, above the mean high tide, a few 

 plants have become established. Four species in particular 

 tend to grow in this zone: Cakile edentula (sea-rocket), 

 Salsola kali (saltwort) , Raphanus raphanistrum (wild 

 radish) , and Ammophila breviligulata (beach grass) . 

 Occasionally, after a winter storm, portions of the salt 

 marsh are washed up on the beach and such species as 

 Spartina patens (saltmeadow hay) and Distichlis spicata 

 (spike-grass) have continued to grow, at least for a short 

 time. 



Foredune 



The extreme environmental conditions, such as intense 

 salt spray and wind, sand accumulation, low moisture content 

 and acute temperature fluctuations, serve to limit species 

 diversity on the foredune. The dominant species in this 

 community is Ammophila breviligulata (beach grass) , in some 

 areas making up 100 percent of the vegetation cover. Other 

 less predominant species which also occur in this zone 

 include Lathyrus japonicus (beach pea) , Artemisia 

 stellar iana (dusty miller) , Solidago sempervirens (seaside 

 goldenrod) , Salsola kali (saltwort) , and Euphorbia 

 polygonifolia (seaside spurge) . In general these species 

 are not as abundant as A. breviligulata , but in some areas 

 L. japonicus and Artemisia stellar iana become the dominant 

 vegetation cover. 



