c. Rate of Recovery. A special study was carried out to determine the 
rate of recovery of a particular spot on the beach following nourishment. On 
19 March 1978, a fixed study transect was established in the center of the 
beach segment nourished on that day. This transect was located 1070 meters 
west of the eastern park boundary. 
No living organisms were found in any of the tidal zones on the day of 
nourishment; however, this situation was expected since the entire intertidal 
macrofauna had just been buried by about 2 meters of sediment and the effective 
intertidal zone had been transposed 75 meters seaward of its former position. 
Colonizers would have had insufficient time to become established. 
The first recruits to the area arrived between 15 and 30 days after estab- 
lishment of the study transect. On 16 April Scolelepts squamata were found at 
the high tide drift line and seven juvenile #. talpotda were found in the 
swash zone. On 14 May only one juvenile Emerita was found; therefore, species 
diversity was 0.00. No organisms were found 29 May; thus species diversity 
was undefined. 
Nourishment activities stopped on 12 June and by 15 June 260 juvenile £. 
talpotda were taken from the swash and surf zones. This number represents an 
average density of 2,080 individuals per square meter. Species diversity, 
however, remained 0.00. All these individuals were postmegalops larvae or 
young juveniles. The fact that they appeared so quickly and in such great 
numbers immediately after the cessation of the nourishment activities indicates 
that the increased turbidity (suspended solids load) in the water probably 
acted as an effective block to larval recruitment. 
The first report of an organism other than £. talpotda occurred on 29 July 
1978, nearly 2 months after the nourishment stopped. On that day 9 juveniles 
and 1 adult £. talpoida; 2 H. canadensis; 15 Donax vartabilis; 6 Donax parvula; 
and 1 S. squamata were found. This brought the species diversity up to 0.56 
which was actually higher than the average Shannon-Weaver Species Diversity at 
the Emerald Isle comparison beach. Fort Macon usually had higher diversity 
estimates before nourishment due to a greater number of species than were pres- 
ent at Emerald Isle. The unmnourished comparison beach at Emerald Isle still 
far surpassed the nourished beach in terms of organism density. 
The special transect study was useful because it indicated that the effects 
of beach nourishment are not limited to the beach. Pelagic larvae were pre- 
vented from colonizing the beach. Inhibition of pelagic larval recruitment 
may have resulted from the high turbidity of nearshore water associated with 
beach nourishment. However, some Z. talpoida juveniles were able to overcome 
this stress and occupied the beach although in lesser density than nearby 
unnourished beaches. Larval recruitment of Donax spp. occurred during nour- 
ishment, but because Donax spp. larvae were not as fit as the #. talpotda 
larvae, the appearance of this clam on the beach was prevented until a few 
young adults could colonize. The first clams found on the nourished beach 
were larger than normal young of the year and were recruited by means of 
littoral drift from the adult population of a neighboring beach. If nourish- 
ment continues beyond a period of larval recruitment, the only mechanism that 
the beach has for regaining these species before the next year's larval 
recruitment is via chance diffusion and littoral drift. 
37 
