Environmentally mediated coffee pest densities in relation to agroforestry management, using hierarchical partitioning analyses

Understanding pest density patterns in the field is important to account for distinct environmental variables potentially influencing populations across different habitat types. Here, we assessed the relative importance of single environmental abiotic and biotic variables on densities of three major coffee pests, i.e., spider mites, leaf miners and berry borers, in simple, complex and abandoned agroforests of coastal Ecuador, using hierarchical partitioning methods. Most of the variation in spider mite and leaf miner densities was accounted for by the abiotic variables temperature and relative humidity, while agroforestry type, relative humidity and tree diversity were more important in explaining densities of berry borers. Furthermore, densities of spider mites and berry borers, but not leaf miners, were affected by agroforestry type, with lower densities in structurally complex agroforests. In conclusion, very different environmental variables influence coffee pest population density. Understanding such species density-environmental relationships provide insights on how to predict and manage populations in the field. (C) 2007 Elsevier B.V. All rights reserved.