The effect of habitat quality and forest fragments on butterfly diversity in a coffee agroecosystem mosaic

Background/Question/Methods   As empirical evidence accumulates regarding the capacity of the agroecological matrix to support biodiversity, the need for a better understanding of the types of species that are able to exploit the matrix is apparent. To assess the influence of coffee habitat quality on butterfly diversity and community composition, I compared the fruit-feeding butterfly communities in an organic traditional coffee polyculture, a shaded coffee monoculture and a forest fragment in the Soconusco region of Chiapas, Mexico. Butterflies were trapped using Van Someran Ryden bait traps. Traps, suspended 1 meter from the ground, were placed at random locations within the forest fragment, and within the two coffee farms at the edge of the forest fragment, and at 20, 70, and 150 meters from the forest edge. Butterfly species were classified into three habitat association guilds; forest, cosmopolitan and weedy.

Results/Conclusions   Butterfly diversity was significantly higher in the traditional coffee polyculture than in the shaded coffee monoculture, and the traditional polyculture had more forest species and fewer weedy species than the shaded monoculture. The forest fragment harbored the greatest diversity of butterflies, and had a very low abundance of weedy species. Butterfly diversity was stable or increased with distance from the forest in the traditional polyculture, but significantly declined with distance from the forest in the shaded monoculture. The traditional coffee polyculture retained proportionally more forest species and fewer weedy species with distance from the forest than the shaded monoculture. This study suggests that the quality of the coffee matrix and the presence of forest fragments influences the types of species that will persist in human-dominated tropical landscapes, and that the matrix matters for conservation of neo-tropical butterflies.