24 
Charles K. Biernbaum 
numbers in this same borrow pit. Juveniles of F. uhleri were collected in 
September and November. Fallicambarus uhleri occurs in lentic and 
lotic habitats along the coastal plain from Maryland to South Carolina 
(Hobbs 1974). 
Horton H. Hobbs, Jr., stated (pers. comm.) that other crayfishes 
are found near the refuge and may occur, perhaps rarely, in the refuge. 
These include Cambarus ( Depressicambarus ) latimanus (Le Conte), 
Cambarus ( Depressicambarus ) reflexus Hobbs, Cambarus ( Puncti - 
cambarus ) acuminatus Faxon, and Procambarus ( Ortmannicus ) enplo- 
sternum Hobbs. It is also possible that Procambarus ( Ortmannicus ) 
ancylus Hobbs and Cambarus {La cuni cambarus) diogenes diogenes 
Girard may be encountered. 
SUMMARY 
Diversity of crustaceans within the Santee National Wildlife Refuge 
is quite high, especially for the cladocerans. The high diversity of 
cladocerans is due in part to the variety of aquatic habitats available, 
from open lake to ditches and swamps, but probably is chiefly due to 
the great amount of vegetation occurring in most of the impoundments, 
in ditches, and along the margin of the lake. As suggested by Lemly and 
Dimmick (1982) in a study of zooplankton in the littoral zone of some 
North Carolina lakes, a large quantity of aquatic macrophytes provides 
great habitat heterogeneity, resulting in increased species diversity in 
vegetated areas (Brooks 1959). Of the 25 cladoceran species collected at 
the refuge, at least 17 are known to be directly associated with vegetation 
(Brooks 1959). 
Crustaceans of the refuge go through significant seasonal fluctua- 
tions in abundance and dominance. Such seasonal changes are correlated 
with temperature changes as well as with such seasonal variations as the 
amount of water in shallow aquatic habitats and the late-summer 
deterioration of certain habitats owing to prolific growth of vegetation 
and subsequent decomposition. 
In winter the crustacean fauna of the refuge is dominated by the 
cladocerans Simocephalus serrulatus, Eurycercus vernalis, and, to a 
lesser extent, Ilyocryptus spinifer; the isopods Caecidotea forbesi and 
Lirceus lineatus; the amphipods Hyalella azteca and Crangonyx r. 
richmondensis ; mature Palaemonetes paludosus; and the crayfish 
Procambarus blandingii. Early spring is characterized by reductions in 
numbers of cladocerans, Lirceus lineatus , and Crangonyx r. rich- 
mondensis, with an increase in numbers of Hyalella azteca. In late 
spring the refuge has very high water levels, resulting in expanded 
habitats for swamp- and ditch-dwelling Caecidotea forbesi and Pro- 
cambarus blandingii. By June there are large numbers of juvenile 
