152 
J. Whitfield Gibbons and Julian R. Harrison III 
Because of its smaller land area, Capers Island would be expected to 
have fewer species of reptiles and amphibians than Kiawah (MacArthur 
and Wilson 1967). In addition, Capers has significantly more open water 
and salt marsh (~2 km; approximately twice the distance for Kiawah) 
between the island and the mainland. Greater distances from the main- 
land tend to result in lower numbers of species for oceanic islands 
(MacArthur and Wilson 1967); however, the factor of distance from the 
mainland has not yet been evaluated in assessing faunal composition of 
barrier islands. No endemic species of reptile or amphibian has been 
reported for any North American barrier island (Gibbons and Coker 
1978). 
The variety of methods used to collect reptiles and amphibians necessi- 
tates separate consideration of results obtained. The most meaningful 
approach is to compare results on the two islands by each method. 
Drift Fences 
Collections from the four drift fence and pitfall trap areas on the two 
islands revealed certain characteristics about the herpetofauna, primarily 
in regard to the occurrence of anurans (Table 3). Speculations about 
relative abundance of the species should be conservative at this time 
because of the high variability in trapping success between dates and 
locations. 
Gastrophryne carolinensis appears to be a consistent forest floor 
inhabitant on both islands and is active throughout the summer. Rana 
utricularia also ventures into the terrestrial environments on occasion, as 
seen by the sporadic captures, primarily of subadults. Scaphiopus hol- 
brooki juveniles were the most abundant anurans in the pitfall traps in 
every month sampled. The absence of S. holbrooki and Bufo terrestris 
from the Capers Island traps strongly supports our conviction that these 
species occur only on Kiawah. The absence of Hyla in the traps, although 
two species occur on both islands, is a consequence of sampling bias; 
pitfall traps are not effective in capturing tree frogs (Gibbons and Bennett 
1974). The Capers Island pitfall traps caught the only Kinosternon sub- 
rubrum confirmed from this island. 
Transects 
Three transects established as part of an interdisciplinary study which 
included the two islands were used in the herpetofaunal studies. Walking 
trips were taken along each transect, and all reptiles and amphibians seen 
or heard were noted (Table 4). No new species were recorded as a result 
of this method, but a comparison could be made of the animals between 
islands and among locations on an island. 
The lowest numbers of reptiles and amphibians on Kiawah were 
