Intermediate disturbance promotes termite functional diversity in intensively managed Vietnamese coffee agroecosystems

Abstract

The intensive agricultural practices used in coffee plantations have profound impacts on invertebrate biodiversity. We surveyed termite diversity in the central highlands of Vietnam and evaluated it relative to the in situ ecological conditions of the coffee farms. Two survey sites were established at farms that were in place for 1 month and 1, 3, 5, and 25 years at the time of sampling. In addition, two models were tested: the diversity–resource relationship and the diversity–disturbance relationship. Our results demonstrated that the loss of termite diversity due to land perturbation in newly cultivated coffee farms may be as high as 86% compared with the nearest forested site. Only two feeding groups of termite (Group II and Group III) were present in the study sites. Termite composition of young and old farms was similar, but they only shared 48% similarity and differed significantly from the composition of the 1, 3, and 5 year old coffee farms. Understory vegetation cover and moisture content were positively associated with the occurrence of Group II and III termites but negatively associated with soil bulk density. Termite species richness did not increase linearly with the increased biomass production (plant litter) that is characteristic of old coffee farms. In contrast, termite species richness and occurrence were related to the intensity of farm management. Farms subjected to an intermediate level of management intensity due to annual crop cultivation recorded the highest diversity. Our study highlights the importance of annual crop cultivation to enhance termite diversity.