Quantifying the mechanistic basis for disease-regulation ecosystem services in agricultural landscapes

Abstract

Biotic interactions between parasitic and free-living taxa are fundamental to a range of ecosystem processes, including the mediation of parasitic disease transmission between species in a community. When and where parasitic diseases directly impact humans and domestic animals, the reduction of disease transmission risk by non-parasitic species can be considered a health-related ecosystem service. Yet how environmental change affects the biotic interactions between free-living and parasitic biodiversity, and therefore influence disease transmission risk, remains poorly understood. The proposed project seeks to quantify how key drivers of global environmental change (e.g. land use change) influence the interactions between host and parasitic diversity, and therefore the provision of disease-regulation ecosystem services, using a model system composed of dung beetles and the fecal helminths of domestic mammals with which they interact. Gastrointestinal parasites (e.g. helminths) carry a tremendous global disease burden to both domestic and wild animals and represent the most common infectious agents of humans in developing countries. Preliminary evidence suggests that dung beetles species may both reduce the transmission rates of helminths with direct transmission (DT) and maintain or amplify the transmission of helminths with indirect transmission (IT) helminths. As dung beetles are highly sensitive to losses of native habitat, environmental changes that affect the diversity and density of beetles are expected to influence both positive and negative dung beetle-helminth interactions. The proposed project aims to quantify these positive and negative influences of beetle communities on helminth transmission, and estimate how disease regulation services may respond to forest cover loss. We propose to quantify (1) the mechanisms by which communities of dung beetles influence the transmission of both DT and IT helminth, and (2) how beetle communities respond to native habitat loss. This project will complement the FAPESP Thematic Project 'Interface Project: relationships among landscape structure, ecological proceses, biodiversity and ecosystem services (13/23457-6), taking advantage of the same study design and sites, and supplying data to better understand the central applied question of how native habitat availability influences the provision of ecosystem services. With these data, we can begin to address major knowledge gaps related to the transmission and regulation of economically important parasitic disease in the tropics, and the effects of habitat loss on key health-related ecosystem services. (AU)