Las interacciones ecológicas y estructura de una comunidad altoandina de colibríes y flores en la Cordillera Oriental de Colombia

Ecological interactions and structure of a high Andean community of hummingbirds and flowers in the Eastern Andes of Colombia

Abstract

In this two-year study of hummingbird-flower interactions, I focused on the relations between the distribution of hummingbird populations in space and time and patterns of flower selection by the birds, and the impact of these factors upon the pollination of plants in two high Andean ecosystems: high Andean forest and subpáramo. I identified resource preferences by recording floral visits and pollen loads. The community was composed of 18 hummingbird species which interacted with at least 58 plant species. The of the plant community was classified according to plant characteristics (floral morphology and nectar production), as well as the number and morphological characteristics of the hummingbirds that served as pollen vectors. These characteristics are associated directly with the establishment of interactions at different levels of intensity with hummingbird species or groups of species, as the most frequent pollinators. The structure in the two communities showed evidence of a strong influence of these interspecific interactions in the ecological configuration of nonrandom patterns in such communities. A strong influence of competition and coevolution was evident in the organization of this hummingbird-flower community. The coexistence mechanisms of the species involve: divergences in spatial distribution, floral characteristics, morphological relations, and spatiotemporal distribution of the abundances of the birds. Notable convergences were established with other hummingbird-flower communities of high mountain ecosystems of the northern Andes and the mountains of Central America.