Effects of land‐use changes on ecosystem services: decrease in ant predation in human‐dominated landscapes in central Brazil

Abstract

AbstractAnthropogenic disturbances often affect the abundance and diversity of ants (Hymenoptera: Formicidae) but relatively few studies have explored the implications of such changes on the ecosystem services mediated by these insects. Here, we evaluated how the transformation of Cerrado savanna habitats into crop plantations affects the abundance, diversity, and the predatory activity of ants. A survey of the ant faunas foraging above‐ and belowground was performed in six crop and six non‐crop (i.e., native vegetation) sites. Above‐ and belowground rates of ant predation were estimated at these same sites using mealworms, Tenebrio molitor L. (Coleoptera: Tenebrionidae), as baits, simulating crop herbivores. Belowground predation rates were significantly greater in the non‐crop sites, despite the lack of difference in overall abundance and species richness of ants foraging belowground between the crop vs. non‐crop sites. In contrast, we did not detect any significant difference in aboveground predation rates between crop vs. non‐crop sites even though there were significantly more species of ants foraging aboveground in the non‐crop sites. Army ants (subfamily Dorylinae) were the main predatory species belowground, and their abundance was significantly greater in non‐crop sites. In contrast, the main predators aboveground were omnivore ants of the genera Pheidole and Solenopsis, which had similar abundances in the crop and non‐crop sites. Overall, our results indicate that transformation of native Cerrado habitats into crop plantations reduces the abundance of some important predatory species, notably those that forage belowground, and this may negatively affect the potential for ants to provide pest control services in agroecosystems.