DODD: ECOLOGY OF SANDHILLS POPULATION OF GASTROPHRYNE CAROLINENSIS 31


possible to determine whether the invertebrate killed the toad or the predator
scavenged a carcass.


 DISCUSSION
 Life-history of Gastrophryne carolinensis


 Population Size.-There are no comparable studies on the eastern narrow-
mouthed toad in Florida with which to compare the results of this study. At least
900 adult G. carolinensis visited the pond basin (unmarked animals with
allowances for a few animals presumed to trespass the fence; Dodd 1991) in each
of two of the five years that the fence was checked. The number of animals visiting
the pond in 1987 is inexplicably low in relation to 1986, 1988, and 1989. This
could be due to a natural population fluctuation, but it makes the interpretation of
the 1990 collection data difficult. The most parsimonious explanation for the low
pond visitation in 1990 is that the effects of the long-term drought were becoming
apparent. Alternatively, the low numbers in 1990 could represent a natural
fluctuation. The numbers of breeding adults and juveniles that complete
metamorphosis of pond-breeding amphibians are known to fluctuate widely (Shoop
1974; Gibbons and Bennett 1974; Semlitsch 1987; Pechmann et al. 1989;
Raymond and Hardy 1990; Pechmann et al. 1991).

 Recaptures.-Relatively few G. carolinensis were recaptured. Most
 recaptured individuals were captured in the same season as originally marked,
 presumably as the toads crossed back and forth between the core of the pond basin
 and refugia in the surrounding uplands. Other studies on Gastrophryne also report
 low recapture rates (Anderson 1954; Fitch 1956; Franz et al. 1989). Freiburg
 (1951) recaptured 33.5% of marked G. olivacea in his 1-year study but only
 12.7% more than once. Fitch (1956) marked 1215 G. olivacea between 1949 and
 1954, but only 13 "yielded series of records, well spaced, in two or more different
 years." Of 69 tattooed G. carolinensis trapped in April and May in Louisiana, only
 five were recaptured (Anderson 1954).
 Gastrophryne carolinensis may regenerate clipped toes rapidly, become trap-
 shy or otherwise learn to avoid recapture, move to breeding ponds only once or
 twice within a 5-year period thus minimizing the chances of recapture, or have
 very high mortality rates. Rates of toe regrowth are unknown, but little evidence of
 regrowth was apparent in this study or in studies of G. olivacea (Freiburg 1951).
 Unpublished data on movements based on cobalt tagging suggest that G.
 carolinensis may be sedentary and trap-shy (Franz et al. 1989). G. carolinensis
 also easily crawl vertically upwards (Wright 1932) and cross drift fences (Dodd
 1991). Alternative forms of marking and long-term studies are needed to evaluate
 capture efficiency and individual recognition.