Wildlife space use in a Ugandan wetland

What is it about?

From 2015-2017, the Mayanja River area of central Uganda experienced drastically different water levels, including flood conditions and a severe drought leading to a wildfire within the wetland. Because of the divergent river conditions experienced and the presence of domestic cattle, this ecosystem was an ideal location, duration, and ungulate assemblage on which to test hypotheses about cattle and native ungulate species space use in and around wetlands under varying hydrologic conditions. To assess space use of native and domestic ungulates in various habitats and hydrologic conditions, we used a camera trap array in central Uganda over three years. Species included in our study include: Sitatunga Waterbuck Hippopotamus Bushbuck Bush Pig Warthog And Cattle. For each species, we assessed the difference in the proportion of days with camera-trap detections during three water-level conditions (low in 2017, normal in 2015, and high in 2016). Sitatunga was the only species regularly using wetlands; their use of remote wetlands remained consistent regardless of water-level conditions, and their use of forest habitats decreased during the study. In the forest, warthogs showed no change in use, while proportion of days with detections increased over time for all other ungulates.

Featured Image

Photo by Jonathan Gensicke on Unsplash

Photo by Jonathan Gensicke on Unsplash

Why is it important?

Wetlands cover only 6% of the world’s land surface, yet they and associated floodplains are among the most-altered landscapes worldwide. Climate change is changing the timing and volume of water in wetlands and riverine systems. Wetlands and riverine floodplains also support high biological diversity. In Africa, the high diversity of large ungulates carries over into wetlands. To offset potential competition, species differ in preferred habitats, food items, or time of activity on daily or seasonal scales. While generalized preferences suggest mechanisms for coexistence, it remains unknown how habitat preferences change under varying conditions within the floodplain, such as flood or drought. In central Uganda, wetlands are affected by changes in land use such as agricultural livestock production. The presence of domestic cattle, a novel competitor, could affect space use by native ungulates. Changes in space use can affect ungulate community composition, leading to changes in species interactions; ungulate species that do not specifically rely on wetlands or floodplains may use them intermittently for resources, especially if preferred forage is unavailable. Our results indicate that ungulate community space use appears to be independent of hydrologic condition, and that risk for competitive exclusion between native and domestic ungulates is currently tempered by dietary and habitat use differences. Adaptations to dynamic hydrology appears to buffer consequences for ungulate communities; more serious are habitat losses to agriculture and development.