Above and below ground impacts of terrestrial mammals and birds in a tropical forest
Author
Dunham, Amy E
Date
2008Abstract
Understanding the impact of losing trophic diversity has global significance for managing ecosystems as well as important
theoretical implications for community and ecosystem ecology. In several tropical forest ecosystems, habitat
fragmentation has resulted in declines and local extinctions of mammalian and avian terrestrial insectivores. To assess
the ability of a tropical rainforest community in Ivory Coast to resist perturbation from such loss of trophic diversity, I
traced feedbacks in above and below ground communities and measured changes in nutrient levels and herbivory rates in
response to an experimental exclosure of avian and mammalian terrestrial insectivores. I present evidence that loss of this
functional group may result in increased tree seedling herbivory and altered nutrient regimes through changes in the
abundance and guild structure of invertebrates. Exclusion of top predators of the forest floor resulted in increased seedling
herbivory rates and macro-invertebrate ( 5 mm) densities with strongest effects on herbivorous taxa, spiders and
earthworms. Densities of microbivores including Collembola, Acarina and Sciaridae showed the opposite trend as did
levels of inorganic phosphorus in the soil. Results were evaluated using path analysis which supported the presence of a
top down trophic cascade in the detrital web which ultimately affected turnover of phosphorus, a limiting nutrient in
tropical soils. Results illustrate the potential importance of vertebrate predators in both above and belowground food
webs despite the biotic diversity and structural heterogeneity of the rainforest floor.
Description
journal article
Citation
Keyword
diversity; tropical rainforest
Type
Journal article