Date of Award


Document Type

Open Access Master's Report

Degree Name

Master of Science in Biological Sciences (MS)

Administrative Home Department

Department of Biological Sciences

Advisor 1

Casey Huckins

Committee Member 1

Amy Marcarelli

Committee Member 2

John Vucetich


A small population of Hippopotamus amphibius remains in Sierra Leone and conservation efforts may be needed to support the Hippos and their indirect benefits to fisheries and grassland production. The hippo is a known ecosystem engineer, and a potentially important contributor of nutrients to the river systems they inhabit supporting the food web and local fisheries. In this study I observed hippos in the Little Scarcies River and uplands of the Outamba-Kilimi National Park to estimate their numbers and ultimately their potential input of nutrients into the river. Hippos forage at night in grasslands neighboring rivers, removing up to 3.62 ha of annual production, but spend most of the day submerged in the river. The group of hippos observed in this study contained up to 12 individuals, estimated to be contributing approximately 44 kilograms of wet matter (feces) into the river each day, liberating approximately 8 kg of dissolved organic carbon, 1.14 kg of total nitrogen, and 0.14 kg (140 g) of total phosphate to the Little Scarcies River. Because of these valuable nutrient contributions, as well as other ecosystem services provided by their movements and interactions with other species, hippopotami should be closely monitored and protected. Park management includes a buffer zone that has been created to mitigate anthropogenic changes to hippo habitat and ensure survival of the population, and with proper enforcement could help hippo populations. The results of this study are presented in the context of the broader picture of hippo conservation in Sierra Leone.