Patterns of Herbivory in Belizean Mangrove Swamps

Abstract

We quantified herbivory on leaves of two mangrove species, Rhizophora mangle and Avicennia germinans, at eight sites in Belize. Amounts and types of damage were compared among three mainland sites and five mangrove cays off the coast. Several environmental and autecological factors that potentially influence herbivory were examined, including canopy cover, tree age, leaf age, tidal height, and nutrient enrichment. Herbivores damaged 4.3 percent to 25.3 percent of Rhizophora leaf area and 7.7 percent to 36.1 percent of Avicennia leaf area, figures comparable to other mangal throughout the world. On average, Avicennia was less frequently damaged than Rhizophora at all sites but one. Herbivory at a bird rookery was not significantly higher than elsewhere, indicating that nutrient enrichment of leaves did not stimulate herbivory at this site. Significant but inconsistent differences in damage were detected between the cays and mainland sites. Significant differences, dependent on tidal height, were found between seedlings and trees. Rhizophora seedlings growing under a canopy of adult conspecifics suffered twice as much damage as seedlings growing in areas where the adult canopy was removed. Damage types occurring on each species were consistent across all sites, but the two species did not share the same herbivores.