Resource partitioning among African savanna herbivores in North Cameroon: the importance of diet composition, food quality and body mass

Iongh, Hans H. de; Jong, C.B. de; Goethem, J.; Klop, Erik; Brunsting, A.M.H.; Loth, P.; Prins, Herbert H. T.

doi:10.1017/s0266467411000307

Cited by 29 publications

(26 citation statements)

References 43 publications

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“…In fact, a few other cases have been reported of large dietary overlap within size-structured grazer communities, and in these, also, a few common grasses were distinctly more nutritious than the vegetation as a whole (de Iongh et al 2011). In most cases, however, the overlap was restricted to a particular season (Wegge et al 2006), whereas in our study, there was little evidence of resource partitioning in any of the three observation periods.…”

Section: Sharing a Low-nutrient Habitatcontrasting

confidence: 47%

“…A few zebra were introduced at the same time as wildebeest but, unlike wildebeest, did not establish a sustained population (Treydte et al 2005). Instead, the Saadani herbivore community resembles those of other wet tallgrass savannas as far away as West Africa (East 1984;de Iongh et al 2011) that are also numerically dominated by species of the tribe Reduncini (Bohor reedbuck and waterbuck).…”

Section: Herbivoresmentioning

confidence: 99%

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Convergent grazing responses of different‐sized ungulates to low forage quality in a wet savanna

Stähli

Edwards²,

Venterink

et al. 2015

Austral Ecology

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We studied how grazing intensity by small and mid-sized ungulate grazers varied with nutritional quality and grass species composition in wet oligotrophic tallgrass savanna of coastal northern Tanzania. Average grazing intensity was low (3-15% by cover), and most grass species were scarcely used by herbivores. Only two grasses, Panicum infestum and Digitaria milanjiana, had nitrogen and phosphorus concentrations that were consistently above the minimum levels (e.g. nitrogen concentrations <7 mg g −1 ) required by the three commonest grazers, Bohor reedbuck, waterbuck and wildebeest. The best predictors of grazing intensity were cover of P. infestum (the most abundant grass, with a mean cover of 15%) and canopy height of ungrazed vegetation. Models did not contain separate predictors for nutritional quality, presumably because quality varied mainly at the grass species level and therefore was fully represented by the variable 'cover of P. infestum'. Given that the three grazers differed greatly in body size and muzzle width (parameters known to influence nutrient requirements and the ability of grazers to feed selectively at the smallest spatial scale), we expected there to be strong resource partitioning that would be detectable in terms of grazing strategies and feeding sites. However, apart from minor differences in canopy height, greenness and diameter of grazed patches (albeit consistent with our expectations), feeding stations of the three grazers were similar and strongly dominated by P. infestum. We conclude that the low quality of herbage in wet oligotrophic savannas restricts foraging choices, which produces a characteristic yet impoverished grazing community that exhibits only limited resource partitioning.

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Section: Sharing a Low-nutrient Habitatcontrasting

confidence: 47%

Section: Herbivoresmentioning

confidence: 99%

Convergent grazing responses of different‐sized ungulates to low forage quality in a wet savanna

Stähli

Edwards²,

Venterink

et al. 2015

Austral Ecology

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“…Both of these groups encompass enormous taxonomic, phylogenetic, and trait diversity, yet few studies have evaluated resource partitioning at the plant-species level (20,24). Interspecific differences in dietary species richness and composition have been proposed to structure LMH assemblages (10,18), but theoretical and empirical evaluation of this hypothesis is underdeveloped relative to mechanisms operating at both coarser (e.g., grazer-browser continuum) and finer (e.g., sward partitioning) taxonomic levels (13,23,(25)(26)(27).…”

mentioning

confidence: 99%

“…used one of two methods: direct observation of foraging animals (e.g., 20,28) or microhistology, in which plant parts from feces are visually identified (e.g., 24,29,30). These methods have wellknown limitations (31).…”

mentioning

confidence: 99%

DNA metabarcoding illuminates dietary niche partitioning by African large herbivores

Kartzinel

Chen

Coverdale

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

440

536

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Niche partitioning facilitates species coexistence in a world of limited resources, thereby enriching biodiversity. For decades, biologists have sought to understand how diverse assemblages of large mammalian herbivores (LMH) partition food resources. Several complementary mechanisms have been identified, including differential consumption of grasses versus nongrasses and spatiotemporal stratification in use of different parts of the same plant. However, the extent to which LMH partition food-plant species is largely unknown because comprehensive species-level identification is prohibitively difficult with traditional methods. We used DNA metabarcoding to quantify diet breadth, composition, and overlap for seven abundant LMH species (six wild, one domestic) in semiarid African savanna. These species ranged from almost-exclusive grazers to almost-exclusive browsers: Grass consumption inferred from mean sequence relative read abundance (RRA) ranged from >99% (plains zebra) to <1% (dik-dik). Grass RRA was highly correlated with isotopic estimates of % grass consumption, indicating that RRA conveys reliable quantitative information about consumption. Dietary overlap was greatest between species that were similar in body size and proportional grass consumption. Nonetheless, diet composition differed between all species-even pairs of grazers matched in size, digestive physiology, and location-and dietary similarity was sometimes greater across grazing and browsing guilds than within them. Such taxonomically fine-grained diet partitioning suggests that coarse trophic categorizations may generate misleading conclusions about competition and coexistence in LMH assemblages, and that LMH diversity may be more tightly linked to plant diversity than is currently recognized.African savannas | body size | competition | coexistence | ungulates D ietary niche partitioning contributes to the origin and maintenance of biodiversity by alleviating competition and allowing ecologically similar consumers to coexist (1-3). Of the many faunas in which this mechanism is thought to play a major structuring role, few have inspired as much research and debate as the diverse assemblages of large mammalian herbivores (LMH) (≥5 kg) that occur in African savannas and that were globally widespread before the Pleistocene extinctions (4-7). These assemblages often comprise 10-25 species (8, 9) that forage within the same areas. How can so many apparently generalist consumer species coexist on a limited range of resource types?Attempts to address this question have yielded several key insights. One is that sympatric LMH vary in their proportional consumption of grasses versus browse (i.e., all nongrasses, including trees, shrubs, and forbs) (10). Thus, LMH can achieve dietary separation along a spectrum from pure grazers to pure browsers, and species can be categorized as predominantly grazers, browsers, or mixed feeders. In recent decades, stable-isotope analysis of C 3 (browse) versus C 4 (grass) consumption has been used to quantify this continu...

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“…Furthermore, there was a spatial overlap between hartebeest, sable and reedbuck, species which occurred in low densities (Rduch 2014). However, this considerable overlap in habitat and food can be a sign of a non-problematic coexistence due to low densities and abundant food resources (de Boer and Prins 1990;de Iongh et al 2011).…”

Section: Discussionmentioning

confidence: 99%

Diet of the puku antelope (Kobus vardonii) and dietary overlap with selected other bovids in Kasanka National Park, Zambia

Rduch

2016

Mamm Res

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Diet and dietary competition among puku (Kobus vardonii) and other grazing bovids were investigated in Kasanka National Park, Zambia, a prime area for puku. The objective was to provide new insights into the puku's feeding ecology including autecological and synecological traits. Other bovids assessed for their diets were sitatunga (Tragelaphus spekii), reedbuck (Redunca arundinum), Lichtenstein's hartebeest (Alcelaphus lichtensteinii), sable antelope (Hippotragus niger) and African buffalo (Syncerus caffer). Dung was collected during different periods in 2009 and 2010 and examined using microhistological analyses. The diets were assessed for potential differences or overlap using the Pianka Index. Puku feed mainly on monocotyledons and consumed Panicum spp., Brachiaria sp., Sporobolus spp. and Hyparrhenia/Andropogon grasses. Differences in dietary composition between sexes were observed, especially during the cool dry season, as well as differences at a temporal and spatial scale. It can be concluded that puku exhibit a flexible diet with regard to grass species. Diet breadth changed throughout the year being narrowest in the late rainy season but showed no sexual differences. The dietary overlap of puku with other grazing bovids was low. This combination contributes to the puku's extraordinary situation in Kasanka National Park.

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Resource partitioning among African savanna herbivores in North Cameroon: the importance of diet composition, food quality and body mass

Cited by 29 publications

References 43 publications

Convergent grazing responses of different‐sized ungulates to low forage quality in a wet savanna

Convergent grazing responses of different‐sized ungulates to low forage quality in a wet savanna

DNA metabarcoding illuminates dietary niche partitioning by African large herbivores

Diet of the puku antelope (Kobus vardonii) and dietary overlap with selected other bovids in Kasanka National Park, Zambia

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