Tropical Ecology and Conservation [Monteverde Institute]

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Publication Date

March 2003

Abstract

High rates of habitat alteration increase the effects of fragmentation and creation of pasture. Degraded habitat can negatively affect predator abundance and hence predation. In this study, variation in predation rates between closed forest, open forest, and pasture were assessed for a matrix of degraded tropical premontane moist forest in Costa Rica. In order to compare predation rates in the different habitat types, non-toxic clay caterpillars were made, placed on understory leaves, and then rates of predation in each habitat type were determined. This study focused on three types of predators, insects, birds, and rodents, with insects as the most predominant predators. Overall percentages of predation were 15.6% ± 9.7 in closed forest, 19.1% ± 11.0 in open forest, and 19.0% ± 8.5% in pasture. No significant difference was found in the predation rates between the habitat types (F = 0.255, P = 0.7781). These results, are contrary to other research indicating that fragments and agricultural lands experience higher predation than continuous forest, and may have been caused by effects of the dry season on insect abundance. Índices altos de alteración de hábitat suben los consecuencias de fragmentación y apacentaración que afectan negativamente la abundancia de los depredores. Porque la abundancia de los depredores influencian los índices de depredación, estes índices son expectados a bajarse con grados aumentados de heterogeneidad de hábitat. En este investigación, evalué las diferencias entre índices de depredación en bosque cerrado, bosque abierto, y pastizal. Para comparar índices de depredación, hice orugas de plasticina sin tóxico, las puse sobre las hojas, y determiné los índices de depredación de cada tipo de hábitat. Los depredores fueron insectos, aves, y roedores. Insectos fueron el más común. Los índices de depredación fueron 15.6% ± 9.7 en bosque cerrado, 19.1% ± 11.0 en bosque abierto, y 19.0% ± 8.5% en pastizal. No hubo diferencias significativas entre los habitates (F = 0.255, P = 0.7781). Estos resultados son en contra de otros investigaciones que indican que hay más depredación en fragmentos y pastizales que los bosques grandes. Es posible que estas diferencias sean causado por la estación seca.

Description

Student affiliation: Biological Aspects of Conservation, University of Wisconsin at Madison Digitized by MVI

Genre

Reports

Holding Location

Monteverde Institute MVI

Identifier

M39-00134

Effects of habitat type on predation rates

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