My research focuses on understanding the causes and consequences of biodiversity change on ecosystem functions and services, with a particular emphasis on freshwater biodiversity, fisheries and human nutrition. I use theoretical, experimental and observational approaches, and their combination, to answer questions about how humans are changing biodiversity and, in turn, how these changes affect the services we rely on. Scroll below for more detail!
Ecosystem vulnerability to biodiversity loss Species differ in their responses to anthropogenic drivers and in their contributions to different ecosystem functions and services. However, predicting how ecosystem functions respond to biodiversity loss is a challenge because human-driven extinction is not random and the response of functions depends on the ability of remaining species to functionally compensate for biodiversity loss. Traits mediate both processes and my research investigates whether community-level trait information (e.g., covaraition, distribution) can be used to infer and quantify the vulnerability of ecosystems to biodiversity loss. Representative publications: Heilpern, S.A., B. Weeks, and S. Naeem. 2018. Predicting ecosystem vulnerability to biodiversity loss from community composition. Ecology 99(5): 1099-1107. Heilpern, S.A., K. Anujan, S. Naeem, and A. Osuri. 2020. Positive correlations in species functional contributions drive the response of ecosystem multifunctionality to biodiversity loss. Proc. R. Soc. B 287: 20192501. |
Fish biodiversity, human nutrition and the dietary transition
Biodiversity underlies many ecosystem services that are critical to human well-being, and no other service illustrates the link between ecosystem and human health as well as food does. Across Earth's river systems, people consume a wide variety of fish, relying on this biodiversity for protein and other macro- and micro-nutrients, such as iron, zinc and omega-3 fatty acids. However, fish biodiversity is threatened by deforestation, overexploitation and dam development. The Westernization of diets is also shifting people away from wild fisheries to other animal species, such as aquaculture and chicken. I am exploring how these different factors are affecting human nutrition in the world's most diverse river systems, such as the Amazon. Representative publications Heilpern, S.A., S.A. Sethi, R.B. Barthem, V. da Silva Batista, C.R.C. Doria, F. Duponchelle, A. Garcia Vazquez, M. Goulding, V. Isaac, S. Naeem, and A.S. Flecker. In Review. Biodiversity underpins the resiliency of fisheries to indiscriminate exploitation in Earth’s largest tropical river basin. Heilpern, S.A., K. Fiorella, C. Cañas, A.S. Flecker, L. Moya, S. Naeem, S.A. Sethi, M. Uriarte, and R. DeFries. In Review. Substituting wild fisheries with aquaculture and chicken undermines human nutrition. Heilpern, S.A., R. DeFries, A.S. Flecker, S. Sethi, M. Uriarte, and S. Naeem. In Review. Freshwater biodiversity maintains human nutrition. |
Process catalyzers, strong interactors and large woody debris in Amazonian rivers
While traveling by boat down the large river at the heart of Manu National Park, one of the world’s most biodiverse protected areas, it was hard to not notice the massive piles of stranded trees scattered throughout the riverbed. In a variety of ecosystems, large structures such as coral beds and whale falls tend to play important roles in an ecosystem’s ecology and I wondered whether these large woodpiles could do the same in Amazonian rivers. In addition to potentially catalyzing processes, such as increased productivity and altering food web dynamics, palizadas, as they are locally known, are favored locations for fishing. By attracting small and medium sized fish, which depress organic matter accumulation (an important resource for aquatic consumers) and macroinvertebrate production, palizadas affect trophic dynamics and ecosystem processes fundamental to the structure of Amazonian rivers. This work was conducted as part of my first attempt at a PhD, which resulted in a Master's at the University of Chicago, under the supervision of Tim Wootton. Representative publications: Heilpern, S.A., and J.T. Wootton. 2018. Cross-ecosystem exchange of process catalyzers in Amazonian Floodplain river systems: understanding the role of large woody debris using experiments, observations and path analysis. Ecosphere 9: e02030. |
Balancing hydropower and ecosystem services
I am part of a large collaboration to examine the effects of dams on rivers and the ecosystem services they provide in the Andes Amazon region. Lead by Elizabeth Anderson (Florida International University), we have created the most comprehensive database of existing, in development and proposed dams in the region, mapped them and examined their cumulative effect on river connectivity. Additionally, working with colleagues at Cornell University (Alex Flecker et al.), we are examining the effect of dam development on a variety of ecosystem services such as fisheries production, sediment transport and navigation.
Representative publications:
Anderson, E., C. Jenkins, S.A. Heilpern, J. Maldonado-Ocampo, F. Carvajal-Vallejos, A. Encalada, J. Rivadeneira, M. Hidalgo, C. Cañas, H. Ortega, N. Salcedo, M. Maldonado, P.A. Tedesco. 2018. Fragmentation of Andes-to-Amazon connectivity by hydropower dams and associated consequences for natural and human systems. Science Advances 4 (1): eaao1642.
I am part of a large collaboration to examine the effects of dams on rivers and the ecosystem services they provide in the Andes Amazon region. Lead by Elizabeth Anderson (Florida International University), we have created the most comprehensive database of existing, in development and proposed dams in the region, mapped them and examined their cumulative effect on river connectivity. Additionally, working with colleagues at Cornell University (Alex Flecker et al.), we are examining the effect of dam development on a variety of ecosystem services such as fisheries production, sediment transport and navigation.
Representative publications:
Anderson, E., C. Jenkins, S.A. Heilpern, J. Maldonado-Ocampo, F. Carvajal-Vallejos, A. Encalada, J. Rivadeneira, M. Hidalgo, C. Cañas, H. Ortega, N. Salcedo, M. Maldonado, P.A. Tedesco. 2018. Fragmentation of Andes-to-Amazon connectivity by hydropower dams and associated consequences for natural and human systems. Science Advances 4 (1): eaao1642.