Differential Effects of Hunting on Pre-Dispersal Seed Predation and Primary and Secondary Seed Removal of Two Neotropical Tree Species

• Published in: Biotropica Vol. 39; no. 3; pp. 328 - 339
• Main Authors: Beckman, Noelle G, Muller-Landau, Helene C
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Malden, USA Blackwell Publishing Inc 01.05.2007; Blackwell Publishing; Blackwell
• Subjects: Animal, plant and microbial ecology; Applied ecology; Arecaceae; Biological and medical sciences; Boraginaceae; conservation; Conservation, protection and management of environment and wildlife; Cordia; Cordia bicolor; defaunation; Forest ecology; Fruit production; Fruits; Fundamental and applied biological sciences. Psychology; General aspects; Hunting; life history traits; Mammals; natural resource management; Oenocarpus mapora; Panama; Plants; seed dispersal; Seed predation; seed size; Seedlings; Special Section: Pervasive Consequences of Hunting for Tropical Forests; Trees; Tropical forests; Panama; Central America; America; defaunation; Hunting; Seeds; Cordia bicolor; Tropical zone; Conservation; life history traits; Granivorous; Life history trait; Boraginaceae; Dispersion; Oenocarpus mapora; seed dispersal; Dicotyledones; Panama; Angiospermae; seed size; Tree; Spermatophyta; Neotropical Region
• ISSN: 0006-3606; 1744-7429
• DOI: 10.1111/j.1744-7429.2007.00273.x

Many of the mammals undergoing drastic declines in tropical forests worldwide are important seed dispersers and seed predators, and thus changes in mammal communities due to hunting will affect plant recruitment. It has been hypothesized that larger-seeded species will suffer greater reductions in seed removal and thus greater increases in predispersal seed predation than smaller-seeded species. We compared primary and secondary seed removal and predispersal seed predation of two tree species between hunted and nonhunted sites in Central Panama. Seeds of Oenocarpus mapora (Arecaceae) are 16-times greater in size than those of Cordia bicolor (Boraginaceae). We quantified primary seed removal and predispersal seed predation using seed traps, and we assessed secondary seed removal using seed removal plots. Primary removal of C. bicolor was 43 percent lower in the hunted sites, while primary removal of O. mapora was not significantly different. Secondary removal of unprotected O. mapora seeds on the ground was 59 percent lower in hunted sites, while secondary removal of C. bicolor was not significantly different. Predispersal seed predation of O. mapora by mammals was significantly lower in hunted sites, while predispersal seed predation by insects was not significantly different in either species. In combination with other studies, our results suggest that seed size is not a reliable predictor of the impacts of hunting. Mammal defaunation differentially affects stages and modes of seed dispersal and seed predation of different plant species, suggesting that these influences are complex and related to multiple plant traits.