Herbaceous Forage and Selection Patterns by Ungulates across Varying Herbivore Assemblages in a South African Savanna

Abstract

Herbivores generally have strong structural and compositional effects on vegetation, which in turn determines the plant forage species available. We investigated how selected large mammalian herbivore assemblages use and alter herbaceous vegetation structure and composition in a southern African savanna in and adjacent to the Kruger National Park, South Africa. We compared mixed and mono-specific herbivore assemblages of varying density and investigated similarities in vegetation patterns under wildlife and livestock herbivory. Grass species composition differed significantly, standing biomass and grass height were almost twice as high at sites of low density compared to high density mixed wildlife species. Selection of various grass species by herbivores was positively correlated with greenness, nutrient content and palatability. Nutrient-rich Urochloa mosambicensis Hack. and Panicum maximum Jacq. grasses were preferred forage species, which significantly differed in abundance across sites of varying grazing pressure. Green grasses growing beneath trees were grazed more frequently than dry grasses growing in the open. Our results indicate that grazing herbivores appear to base their grass species preferences on nutrient content cues and that a characteristic grass species abundance and herb layer structure can be matched with mammalian herbivory types.

Environments and trypanosomiasis risks for early herders in the later Holocene of the Lake Victoria basin, Kenya

“…Controlled grazing by cattle, sheep, and goats can stimulate new grass growth where grazing herbivores thrive (64,65). Overgrazing, however, makes environments more bushy and reduces grass height (66). Burning promotes new grass and may have maintained grasslands if herders were regularly burning savanna for livestock, as is a common practice in modern eastern Africa (67)(68)(69).…”

Browsing intensity of herbaceous forbs across a semi-arid savanna catenal sequence

“…herbivore productivity) rather than conservation in southern Africa (Tainton, 1999). For this reason, savanna management models exclusively used grass species, particularly due to their significant contribution to total standing biomass and their important role in forage for both ruminant and non-ruminant savanna grazers (Treydte et al, 2013). Herbaceous dicotyledonous species, non-graminoid monocots and geophytes (collectively termed 'forbs' hereafter) have been ignored or merely lumped into a 'non-grassy, Increaser II' category in management models (Scott-Shaw and Morris, 2014), although they constitute the largest component of herbaceous species richness in grasslands (Pokorny et al, 2004;Bond and Parr, 2010;Koerner et al, 2014;Scott-Shaw and Morris, 2014), temperate deciduous forests (Axmanová et al, 2012) and savanna ecosystems (Shackleton, 2000;Uys, 2006;Jacobs and Naiman, 2008;Pavlovic et al, 2011;Van Coller et al, 2013).…”

Analysis of the Spatial Relationship between Cattle and Wild Ungulates across Different Land-Use Systems in a Tropical Savanna Landscape

“…Based on feeding habits, wild herbivores were grouped as grazers, browser, and mixed feeders. Grazers comprise herbivores that consume herbaceous plants including grass, grass-like plants, and forbs; browsers predominantly consume leaves, twigs or reproductive parts of shrubs, woody vines, and tree while mixed feeders graze or browse depending on habitat and/or season [38,39]. Based on the body size, the wild herbivores were classified as megaherbivores or medium-sized ones.…”