Department of Environmental Studies
Permanent URI for this collectionhttp://localhost:4000/handle/20.500.12092/1935
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Item Fine-scale variation in soil and topography influences herbaceous vegetation and the distribution of large mammalian herbivores(John Wiley & Sons Ltd., 2023-09) Ang'ila, Robert O.; Kimuyu, Duncan M.; Wambugu, Geoffrey M.; Kenfack, David; Musili, Paul M.; Kartzinel, Tyler R.Current understanding of the distribution of vegetation and large mammalian herbivores (LMH) is based on a combination of biogeographic studies and highly controlled field experiments, but a more complete understanding of these patterns requires study of their natural co-occurrence patterns at intermediate spatial scales. The study was conducted in the 120-ha Mpala Forest Global Earth Observatory (ForestGEO) plot, Kenya. We examined differences in herbaceous plant communities and habitat use by LMH among three topographic habitats with distinct soil types, namely steep slopes, valley and plateau. Each pair of habitats differed in plant and animal com-position. The steep slopes and plateau respectively had ≥1-fold higher percentage herbaceous cover than the valley, whereas the steep slopes and valley had >1.5-foldgreater grass species richness and diversity than the plateau. The activity of LMH was≥1.7-fold higher in the valley than the steep slopes and plateau, reflecting a positive relationship between LMH activity index and richness and diversity of grass species. Results indicate that fine-scale variation in topography and soil are associated with both the distribution of herbaceous vegetation and LMH, suggesting a need to ac-count for local habitat characteristics when examining the distributions of plants, animals, and plant-herbivore interactions in natural systems.Item Spatial scales influence long-term response of herbivores to prescribed burning in a savanna ecosystem(CSIRO PUBLISHING, 2017-01) Kimuyu, Duncan M.; Sensenig, Ryan L.; Chira, Robert M.; Githaiga, John M.; Young, Truman P.Both wild and prescribed fire in savanna ecosystems influence habitat use by herbivores by creating or maintaining spatial and temporal heterogeneity in forage quality and vegetation cover. Yet little is known about how spatial scales influence long-term persistence of fire effects. We examined changes over a 6-year period in herbivore preference for experimentally burned patches that varied in spatial extent and grain. Avoidance for the burns by elephants andpreferencefortheburnsbyimpalaandGrant’sgazelledecreasedsignificantly.Fortherestofthespecies(zebra,eland, oryx, hartebeest, warthog and hare), there were no significant changes in preference for the burns. Changes in preference for the burned areas depended on the spatial extent and grain of the burn, with intermediate-size (9-ha) burns and large (8-ha) patchy burns being more preferred 6–7 years after fire. Grain, but not the spatial extent of the burned area, influenced changes in grass height. Fire resulted in a delayed reduced tree density irrespective of the spatial scale of the burn. Results of this study indicate that, depending on the scale of fire prescription, the impacts of fire on herbivores may last longer than previous studies suggest