Jm. Hero et al., DIRECT AND INDIRECT EFFECTS OF PREDATION ON TADPOLE COMMUNITY STRUCTURE IN THE AMAZON RAIN-FOREST, Australian journal of ecology, 23(5), 1998, pp. 474-482
The relationship between the distribution of predators (fish, odonates
and water beetles) and prey assemblages (amphibian larvae) was invest
igated in the tropical rainforest of central Amazonas, Brasil. The anu
ran community uses a variety of waterbodies for reproduction, ranging
from streams and streamside ponds to isolated forest ponds. Predators
in this system include fish in streams and streamside ponds, and inver
tebrates (primarily odonate naiads and beetles) in forest ponds. Tadpo
le species richness and assemblage structure were related to fish dens
ity and species richness. No relationships between tadpole assemblages
and abiotic pond characteristics were detected. The presence of fish
explained much of the variation in both species composition and specie
s richness within and among ponds. Some species of tadpole were consis
tently found to coexist with high densities of fish. Path analyses sug
gest that while fish have a strong direct effect on tadpole associatio
ns and species richness, they also have an indirect effect through inv
ertebrate predators (odonate larvae and coleopteran beetles). Prey sur
vival-strategies such as palatability and behaviour may explain how ta
dpole species composition is affected by predators at the community le
vel. These findings suggest that the observed patterns of habitat use
by larval anurans may be structured in response to the distribution of
key predators (fish) in this system.