Effects of shade-tree species and crop structure on the winter arthropod and bird communities in a jamaican shade coffee plantation

摘要

I examined the effects of two farm management vaiables, shade-tree species and crop structure, on the winter (dry season) arthropod and bird communities in a Jamaican shade coffee plantation. Birds and canopy arthropods were more abundant in areasof the plantation shaded by the tree Inga vera than by Pseudalbizia berteroana, The abundance of arthropods (potential pests) on the coffee crop, however, was unaffected by shade-tree species. Canopy arthropods, particularly psyllids (Homoptera), were especially abundant on Inga in late winter, when it was producing new leaves and nectar-rich flowers. Insectivorous and nectarivorous birds showed the strongest reponse to Inga; thus the concentration of birds in Inga may be a response to abundant food. Coffee-tree arthropod abundance was much lower than in the shade trees and was affected little by farm management variables, although arthropods tended to be more abundant in dense (unpruned) than open (recently pruned) areas of the plantation. Perhaps inresponse, leaf-gleaning insectivorous birds were more abundant in dense areas. These results underscore that although some shade coffee plantations may provide habitat for arthropod and bird communities, differences in farm management practices can significantly affect their abundances. Furthermore, this study provides evidence suggesting that bird communities in coffee respond to spatial variation in arthropod availability. I conclude that I. vera is a better shade tree than P.berteroana, but a choicein crop structures is less clear due to changing effects of prune management over time.