Human health and environmental sustainability in pathogenic landscapes : feedbacks and solutions

Feedbacks between human health, well-being, and environmental sustainability are increasingly well recognized, but evidence on actionable solutions to leverage these feedbacks and improve their outcomes is limited. And yet, the recently adopted United Nations Sustainable Development Goals compel decision makers to achieve health for all people while reducing poverty and conserving nature. This dissertation attempts to fill this urgent research gap and empirically assess feedbacks between human health and the environment from two perspectives: (i) environmental drivers of disease in changing landscapes, and (ii) consequences of human health and well-being on environmental change and conservation outcomes. But first, using synthesis science, we describe the environmental components of the world's most burdensome human parasitic and infectious diseases, then assess a specific type of ecosystem service -- natural enemies of human infections -- as a sustainable tool to reduce some communicable diseases. Then, we assess feedbacks between human health and environmental sustainability through two data-rich case studies. First, in the Senegal River Basin, a region hyperendemic for schistosomiasis disease, we assess ecological associations and spatial scales of human disease risk. In this region, schistosomiasis disease, which is transmitted to humans by freshwater snail hosts, can be caused by two species of schistosome parasites (and their two unique snail hosts). The World Health Organization currently recommends that snail control be implemented in endemic areas to curb transmission. However, snail control methods rarely take into consideration the unique transmission dynamics of co-endemic species, which could interfere with control outcomes for one or both species. So here we ask a critical question: what is the spatial scale and ecological correlates of schistosomiasis risk, considering two distinct schistosome species in a co-endemic landscape? We find specific, yet divergent, ecological correlates and spatial scales of risk for each species. Ultimately, these findings can be used to design ecological levers for health (like snail control) that best reflect the unique transmission ecology the targeted species. Second, in rural Borneo, we assess the impact of a 10-year, on-the-ground intervention aiming to improve human health care access in order to curb illegal logging in protected forests, and ask: Is healthcare an effective lever for conservation? Using earth observation, household surveys, and clinic data records, we find that the intervention provided health care access for more than 28,000 patients and averted > 27km2 forest loss (~70% reduction compared to controls), thus improving human health and well-being, and simultaneously preserving globally important forest carbon. In conclusion, this dissertation shows that, by recognizing and embracing complex mechanisms driving health-environment feedbacks, we can identify effective ecological levers for human health, and health levers for conservation

Keywords: Biology.
Advisor: De Leo Giulio A.
Mordecai Erin
Palumbi Stephen R.