As shown by the ordination (Figs. 4, 5, and 6), some plant communities 
were strongly delimited while others were similar. The distinct communities 
included the foredune community, which had been established on the 
artificially stabilized foredune and enriched by a series of plantings. 
This community, though quantitatively unique, had at least one of its 
species components represented in more than three-quarters of the other com- 
munities. Therefore, the species growing on the foredune were not 
restricted there, but represented those species able to resist the harsh en- 
vironmental conditions of this habitat. The selecting factors appeared to 
be strong winds, the accompanying salt spray, sand abrasion, and evaporative 
stress, as well as extreme temperatures (Oosting, 1945; Malloch, 1971; 
Tyndall and Levy, 1978). The most prominent species of the area were 
Spartina patens and Pantcum amarun, present in 36 and 25.5 percent of the 
sampled plots, respectively. 
The oceanside shrub and oceanside intershrub communities lay landward 
and adjacent. to the foredune community. As evident in the ordination, the 
two communities were vegetationally distinct from the foredune community as 
well as from each other. Community boundaries were sharply defined because 
transition zones were less than a few meters. Oceanside shrub and sound- 
side communities were dominated by Myrica cerifera shrubs. The two shrub- 
dominated communities (oceanside shrub and sound-side shrub) and to some 
extent the sound-side disturbed-shrub community appeared to have been 
enriched by nitrogen-fixing micro-organisms on the nodules of legumes and 
on the roots of M. cerifera, as noted for Myrtca pensylvanica by Morris, et 
al. (1974). These communities thrived in areas protected from wind and salt 
Spray by the surrounding topography, with the shrubs seldom reaching a 
height above the foredune system. The high number of species (17) found in 
the sound-side shrub community, many of which were limited in their 
tolerance to salt (e.g., Melothria pendula, Phytolaeca americana, Solanum 
americanum), attested to the sheltered nature of the community. 
The oceanside intershrub community inhabited the more exposed areas 
behind the foredune community and intermixed with the sound-side shrub 
community. Human activity and windblown sand were very high in these areas, 
and as a result vegetation was sparse and patchy. Biomass of the community 
was lower than all the other communities sampled except for the  sound-side 
disturbed-herbaceous community (Table 4). 
Inland from the three communities discussed above lay the planted 
bitter panicum-planted American beachgrass, low dune grass, and sandgrass-— 
buttonweed communities. The planted bitter panicum-planted American 
beachgrass community constituted the greatest acreage within the study area 
(18.0 hectares or 44.5 acres, Table 5). Presently dominated by Panicum 
virgatun and Erigeron canadensis var. pustllus, this community was 
previously delimited by Levy (1976) as distinct planted bitter panicum and 
planted American beachgrass communities. These two communities, as 
suggested by their names, were originally artificially established on the 
most heavily bombed part of the study area (Levy, 1976). The extensive 
acreage observed during this study tended to suggest that the planted bitter 
panicum-planted American beachgrass community represented a relatively late 
stable stage in dune succession. 
This planted bitter panicum-planted American beachgrass community was 
similar to the low dune grass community, as observed by Levy (1976), which 
30 
