DODD: ECOLOGY OF SANDHILLS POPULATION OF GASTROPHRYNE CAROLINENSIS


Table 3. Relationship between the number of adult Gastrophryne carolinensis captured and daily rainfall
during the month of June 1986-1990.


 Rainfall Number % of Monthly
Year Date (in mm) Captured Capture Rain

1986 18-22 147 156 75.4 85.5
1987 15-18 2 96
 22-26 42 60 68.7 75.9
 1988 6-10 29 79
 28 2 27 78.5 100
 1989 5-14 51 139
 20-23 108 89
 26-28 67 53 86.1 96.1
 1990 7-12 108 45
 25-27 136 31 74.5 98.4



those years (1987), the pond dried in June. A cumulative high monthly rainfall
total also was not associated with movement to or away from the pond (Fig. 1).
The sole exception was associated with a September 1988 tropical depression that
drenched north-central Florida. Individual frogs probably went back and forth
between the pond basin and upland retreat sites, depending on weather conditions,
throughout the breeding season.
 Most of the eastern narrow-mouthed toads that were captured at the
beginning of the activity season in May or June were unmarked (Figs. 4, 5).
However, the relative proportion of unmarked to marked animals neither remained
constant nor decreased, except in 1990. Instead, a second influx of unmarked
animals appeared in August and September. The proportion of unmarked to
marked animals changed from one year to the next as the activity season
progressed, but the within-year patterns were similar between the sexes (Figs. 4,
5).


 Population Structure


 The overall sex ratio of unmarked adult (> 23 mm SUL) eastern narrow-
mouthed toads was one female for every 1.30 males. A male bias in the sex ratio
was present in all years except for 1990 (Table 4). The sex ratio of unmarked
animals differed significantly from 1:1 in 1986 (y2=9.95, df=l, p =