ians and reptiles and the factors that influence them.
We lack sufficient data on growth, maturation, fecun-
dity, and survivorship to develop a life table (sched-
ule of age-specific survivorship and fecundity) for
any species in the area. In this section, I outline a
potential demographic consequence of living in a
cloud forest and discuss patterns of abundance, natu-
ral sources of mortality, and possible causes of the
declines.
Studies of anoline lizards suggest that slow rates
of growth and maturation may be associated with
cool, montane environments. Cloud Forest Anoles,
which are active at low body temperatures and feed
at relatively low rates (see Sec. 5.6.2), grow and ma-
ture slowly. A hatchling female (body length of 20
mm) requires 9 months to reach sexual maturity (at
42 mm; Fitch 1973). Gray Lichen Anoles, which inhabit
warmer environments and feed more frequently, grow
and mature more than twice as quickly. A hatchling
female (18 mm) matures in 4 months (at 39 mm). If
cloud-forest species commonly grow and mature
slowly, their populations may naturally be slow to
rebound following declines.
5.4.1. Patterns of Abundance
Amphibians. Ecological studies documented pre-
decline abundances of Golden Toads, Meadow Tree-
frogs, Fleischmann's and Emerald Glass Frogs, and
Harlequin Frogs (Jacobson 1985, Pounds and Crump
1987, 1994, Crump and Pounds 1989, Crump and
Townsend 1990, Hayes 1991, Jacobson and Vanden-
berg 1991, Crump et al. 1992). Hayes (1991) used
mark-recapture data to estimate densities of Fleisch-
mann's Glass Frogs. He found that 294 males held
territories along a 120-m segment of the Rio Guacimal
in June 1980, and suggested that inclusion of females,
juveniles, and transient males might at times have
doubled his estimate. Populations of all these species
crashed in 1987 (Crump et al. 1992, Pounds and
Crump 1994, Pounds et al. 1997). In April-May 1987,
more than 1500 Golden Toads gathered at Brillante,
the principal known breeding site of the species. In
1988 and again in 1989, however, only a single male
appeared there. Harlequin Frogs in the Monteverde
area likewise declined by about 99% between March
1987 and May 1988. Despite intensive searches, nei-
ther species has been found in the 1990s.
To test for evidence of recovery among the surviv-
ing species, my co-workers and I monitored popu-
lations of the Meadow Treefrog, Fleischmann's and
Emerald Glass Frogs, the Common Dink Frog, and the
Red-eyed Stream Frog during 1990-94 (Pounds et al.
1997). We included the Common Dink Frog, despite
the lack of baseline data, because it had been among
the most common and widespread species in the area
before the 1987 crash. We included the Red-eyed
Stream Frog to study recolonization; from field notes,
we identified six previously occupied sites, one of
which was inhabited in 1990. The species for which
baseline data exist remained far less abundant than
they were before the 1987 crash and showed no in-
crease during 1990—94. We documented an increase
only for the Common Dink Frog—a result that agrees
with our impression that several congeners of this
species (rain frogs, Eleutherodactylus) increased in
abundance. We observed two events of recolonization
by the Red-eyed Stream Frog, but recovery in this
species was limited. Its numbers remained low, and
one local extinction took place. Three sites were
never recolonized, even though occupied sites oc-
curred within 1 km. Data collected during 1995-98
likewise suggest that anuran populations are not re-
covering (J. A. Pounds, M. P. L. Fogden, and J. H.
Campbell, unpubl. data). The species monitored dur-
ing 1990-94, including the Common Dink Frog,
underwent synchronous downturns in 1998.Reptiles. Estimates of relative abundance based on
sightings recorded in relation to a time line provide
evidence of population declines in anoline lizards. In
1983-84, the encounter rate for the Cloud Forest
Anole at a site on the upper Pacific slope (1540 m),
where it was the most common species (Pounds 1988),
averaged 3.01 individuals per hour of daytime search.
After the mid-1980s, the population declined and dis-
appeared along with that of the Montane Anole, pre-
viously the second most common species at this site
(Fig. 5.5). Both species showed a strong downward
trend in abundance for 1983—95 (lizards found per
hour, vs. year, Kendall's T < -.91, P < .003; Fig. 5.7).
Neither was observed in 1996-98. In contrast to these
high-elevation forms, the wider ranging Gray Lichen
Anole, which reaches its greatest abundance at
warmer, drier sites farther down the Pacific slope,
showed no trend at the 1540 m site (t = -.07, P > .70).
This species, previously the third most common anole
at the site, is now the most common. Because the
Cloud Forest Anole and the Montane Anole still oc-
cur at cooler, wetter sites farther upslope, it would be
valuable to study the demography of these species at
different points along the climatic gradient (see Sees.
5.4.3, 5.5.5, 5.6.1).
A similar decline has affected diurnal frog-eating
snakes. In 1986-87 in the Penas Blancas valley (Zone
6), the average search time required to find a snake
was 8.8 hr, based on pooled data for nine species: the
Ebony Keelback, Fire-bellied Snake, Pink-bellied Lit-
ter Snake, Green Frog-eater, Banded Green Racer,
Glossy Litter Snake, Ridge-nosed Snake, Cloud For-158 Amphibians and Reptiles