Altitudinal Variation in Mountain Gorilla (Gorilla beringei beringei) Plant Food Nutritional Chemistry

Virunga mountain gorillas (Gorilla beringei beringei) live at an ecological extreme compared to other great apes. Ranging at altitudes of ~2,330 to greater than 4,000 meters, they encounter variable vegetation zones characterized by differences in habitat and food availability, which may affect their feeding behavior and the nutritional composition of favored foods. To better understand the dietary nutritional chemistry of a subpopulation of mountain gorillas, fifteen food parts from nine different plant species in Volcanoes National Park (VNP), Rwanda were analyzed for mineral content (ash), crude protein (CP), fiber, crude fat, and gross energy (GE). Three foods present throughout the mountain gorillas’ range (Galium, Rubus, and Peucedanum spp.) were collected at every 100-meter altitude increase up the slope of Mt. Visoke (range: 2860 – 3660 meters) to assess altitudinal variation in nutritional chemistry. Foods contain 6 to 31% CP, 22 to 55% neutral detergent fiber (NDF), 13 to 43% acid detergent fiber (ADF), 0 to 3% fat, and 4 to 26% ash content on a dry matter basis. Results reveal strong and opposite altitudinal relationships for GE (rs = 0.625, p < 0.05) and ash content (rs = -0.507, p < 0.05). For Peucedanum stems, the increase in GE with altitude is greater than what would be expected from the increase in organic matter due to the decrease in ash content, suggesting that there is a macronutrient composition change with altitude. A principal components analysis suggests that nutritional variation is primarily driven by significant differences in both GE (Z = 3.696, p < 0.05) and CP (Z = 3.127, p < 0.05) between leaves and stems, and a negative relationship between gross energy and mineral content (rs = -0.681, p < 0.05). Given that some mountain gorillas have been shown to prioritize consuming non-protein energy, these results suggest that the subpopulation of Virunga mountain gorillas in this study may target relatively energy-rich foods at higher altitudes.

Author

• Vakiener, Meagan

Language

• en

Keyword

• gorilla
• macronutrients
• nutrition
• Gorilla beringei
• diet

Date created

• 2022

Type of Work

• Master's Thesis

License

• All rights reserved

Rights statement

• In Copyright

GW Unit

• Hominid Paleobiology

Degree

• M.S.

Advisor

• McFarlin, Shannon C.

Committee Member(s)

• Power, Michael L.

Persistent URL

•  https://scholarspace.library.gwu.edu/etd/jw827c65r