The intersection between biodiversity conservation, agroecology and ecosystem services
Two major ecological research areas investigate 1) how changes in environmental features at different spatial scales influence the maintenance of biodiversity and 2) the role of biodiversity in ecosystem processes. The field of agroecology, in particular, has been instrumental in advancing our understanding of the mechanisms behind biodiversity loss and conversely, the conditions under which biodiversity conservation can be promoted in agricultural landscapes. Agroecological studies have also advanced our knowledge about the implications of biodiversity loss for species interactions including ecosystem services like pest-predation and pollination. In this talk, I will investigate the following questions: 1) How have studies in agroecosystems contributed to our knowledge of local and landscape drivers of biodiversity? 2) What has agroecology contributed to what we know about relationships between biodiversity and ecosystem services, with a focus on pest-predation and pollination? And 3) How can agroecosystems contribute to biodiversity conservation? I will use case studies from coffee agroecosystems, tropical pastures, urban gardens, and temperate cropping systems to explore these questions.
Hundreds of studies and syntheses from agroecosystem research indicate that biodiversity generally declines with intensification of agricultural management (decreases in crop and non-crop diversity, increases in agrochemical use) and simplification of landscape complexity (diversity of habitat types, proximity to non-crop habitats, presence of non-crop habitat features) although the specific features of farms and landscapes that influence biodiversity depend on agricultural system and taxon examined. Changes to agricultural habitats and surrounding landscapes alter taxonomic richness, but also strongly affect species composition, evenness, and functional richness of species that provide important ecosystem services. Most of our understanding of multi-predator effects and the relationships between biodiversity and predation services come from agroecology studies. Thus changes in local management characteristics of farms, as well as the surrounding landscapes affect predation and pollination services by altering the biodiversity of interacting species, and the resource base on which these species depend. Although increases in biodiversity augment ecosystem services, mechanisms and results may differ depending on the service providers and systems examined. Agroecosystem management strongly affects dispersal of organisms across the agricultural matrix. Thus diverse agroecosystems, embedded in diverse landscapes support biodiversity, higher levels of ecosystem services, and have advanced our understanding of basic ecology.