Monteverde : Ecology and Conservation of a Tropical Cloud Forest

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Figure 12.10. Density of stems as a function of the
species identity of the shade tree left in the pasture for
all species combined and for the Lauraceae. Kruskal-
Wallis ANOVA showed significant differences in both
cases (H = 9.54, p = .02 and H = 20.9, p < .001, respec-
tively). Significant differences among means are signified
by lowercase letters.

THE IMPACT OF THE MONTEVERDE LECHBRIA ON
THEQUEBRADAGUACIMAL
Douglas E Gill

airy farming and cheese-making have been
economically important activities in Monte-
verde since its founding in the 1950s. Sequen-
tial pulses of acidic and caustic soda washes and whey
from the cheese-making were discharged into the
stream every day for 30 years. Beginning in 1983, the
washes and whey were mixed in a holding tank and
dripped continuously into the stream. What impact
has the discharge from the lecheria (dairy plant) had
on the Quebrada Guacimal?
The rocks below the bridge have always been coated
with slime, but mats of choking filamentous algae were
never seen downstream. An unpleasant pungence usu-
ally hung in the air below the bridge. A succession of
Organization for Tropical Studies (OTS) field problems
compared the stream insect fauna in sections of the
stream above and below the discharge at the lecheria.


Below the outfall, there was a sharp reduction in di-
versity and an enormous increase in the number of
larval chironomids (sludge midges). Groups of high
oxygen-demanding insects, including mayflies, stone-
flies, and caddisflies, declined in sections of the stream
that received the discharge (Table 12.4).
These results did not fit standard patterns of eutro-
phication, which were derived from the study of tem-
perate lakes. The absence of mats of green or blue-
green algae downstream indicated that the discharge
was not enriching the primary producers with phos-
phate or nitrate. Chemical analyses of the stream
water and the contents of the holding tank confirmed
that pattern. The slime, elevated carbon dioxide lev-
els, and elevated respiration in downstream waters
(Table 12.5) compared to upstream indicated that lac+
bacteria, most likely Lactophilus spp., responded

446 Conservation Biology

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