Diversity patterns of soil macro-Coleoptera in Mexican shaded and unshaded coffee agroecosystems: an indication of habitat perturbation

Abstract

The soil Coleoptera community was sampled with pitfall traps in shaded and unshaded coffee agroecosystems in Veracruz, Mexico. The insect collection resulted in a total of 31 species which belong to nine families. The most frequent families collected in this study (in terms of species and number of organisms) were Scarabaeidae and Carabidae. Species diversity was measured using the Hill's family of diversity numbers. The Coleoptera community was more diverse in shaded than in unshaded coffee. Also, the collected organisms were more evenly distributed between species in shaded coffee. The diversity of the scarab beetles was shown to be strongly affected by the degree of forest perturbation. The richness and evenness of scarab beetles was correlated with the diversity of shade trees present in coffee agro-ecosystems; scarab richness drops from 19 species collected in virgin tropical rain-forests, to five species in polyspecific shade (more than ten species of shade trees) and six species in monogeneric shade (three species of shade trees) coffee agro-ecosystems, and to three scarab species in unshaded coffee. Evenness in scarab beetles follows a similar pattern: a single species tends to gradually become dominant as more shade trees are removed from the agro-ecosystem. It is suggested that some shade trees should be preserved within the agro-ecosystem during the intensification of coffee production in Mexico.