IRFP: Investigating the ecological impacts of the hippopotamus on watershed ecology

Mccauley Douglas J, Saratoga CA

Investigators

Abstract

The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad. This award will support a twenty-four-month research fellowship by Dr. Douglas McCauley to work with Dr. John Githaiga at the University of Nairobi, Kenya and Dr. Justin Brashares at the University of California Berkeley. This project creates a new international research partnership to investigate and quantify how the common hippopotamus, Hippopotamus amphibious, links ecological processes in watersheds to those in terrestrial ecosystems. These large mammals feed nocturnally in terrestrial zones, but reside diurnally in aquatic systems thus physically, chemically, and ecologically connecting these different ecosystems. Understanding linkages across ecosystems is essential to understanding how these systems function and effectively managing their long-term health. A diverse portfolio of research methods are used in this project to visualize the terrestrial/watershed linkages that are built by H. amphibious including: stable isotopes which help track patterns of inter-system nutrient movement; exclosure experiments that provide insight into how H. amphibious foraging affects riparian plant ecology; and water chemical analyses that reveal how river biogeochemistry is altered by H. amphibious. Conclusions from these different research approaches will provide vital and novel insight into the ecology of watersheds and general patterns of ecosystem connectivity. Both the wildlife and people of sub-Saharan Africa depend upon freshwater resources for life. Understanding how freshwater ecosystems function depends on recognizing the sometimes complex ways they are linked to the ecology of surrounding terrestrial habitats. This project endeavors to describe critically important aquatic-terrestrial linkages that are created by the common hippopotamus. With populations of common hippos rapidly declining, rivers stressed by overuse, and climate change threatening to affect regional water cycles it is extremely important that we begin to understand how hippos depend upon, connect, and alter terrestrial and aquatic ecosystems. Results from this work will help us better manage this vulnerable species as well as to protect the ecosystems upon which it and the residents of sub-Saharan Africa depend. This project has created a dynamic new scientific collaboration between the IRFP fellow (Dr. D. McCauley) and Kenyan experts in aquatic ecology at the University of Nairobi (Dr. J. Githaiga) -- as well as research partners at the University of California Berkeley (Dr. J. Brashares).