Diets of East African Bovidae Based on Stable Isotope Analysis (original) (raw)
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Diets of Southern African Bovidae: Stable Isotope Evidence
Journal …, 2003
Although bovids have been studied for decades, debate still exists about their diets. To address this problem, we examined bovid dietary ecology through analysis of stable carbon isotopes. We analyzed tooth enamel, bone collagen, and hair from 312 individual bovids, representing 27 species from southern Africa. Although dietary information from the literature is usually supported by this technique, our results and the literature are sometimes highly divergent. For instance, our results indicate that Taurotragus oryx and Raphicerus campestris eat less grass than is widely believed. Furthermore, contrary to most theoretical expectations, our data indicate no relationship between body size and percentage of monocots consumed by southern African Bovidae. Although many researchers have abandoned the idea that bovid soft-tissue anatomy is strongly indicative of diet, we demonstrate a strong relationship between the percentage of grass in a bovid's diet and several hard-tissue craniodental indices.
South African Journal of Wildlife Research, 2013
Bovid diets have been studied for decades, but debate still exists about the diets of many species, in part because of geographical or habitat-related dietary variations. In this study we used stable carbon isotope analyses of faeces to explore the seasonal dietary preferences of 11 bovid species from a West African savanna, the Pendjari Biosphere Reserve (PBR), along the browser/grazer (or C3/C4) continuum.We compare our carbon isotope values with those for eastern and southern African bovids, as well as with dietary predictions based on continent-wide averages derived from field studies. Oribi and reedbuck, expected to be grazers were found to be predominantly C3-feeders (browsers) in the PBR. Bushbuck, common duiker and red-flanked duiker consumed more C4 grass than reported in previous studies. When comparing wet and dry season diets, kob, roan and oribi showed the least variation in C3 and C4 plant consumed proportions, while red-flanked duiker, bushbuck, reedbuck and waterbuck showed the most marked shifts. This study shows that animals in the better studied eastern and southern African savannas do not exhibit the full range of possible dietary adaptations. Inclusion of data from a wider geographical area to include less well-studied regions will inform our overall picture of bovid dietary ecology.
Diets of savanna ungulates from stable carbon isotope composition of faeces
Journal of …, 2007
Hypotheses to explain diversity among African ungulates focus largely on niche separation along a browser/grazer continuum. However, a number of studies advocate that the browser/grazer distinction insufficiently describes the full extent of dietary variation that occurs within and between taxa. Disparate classification schemes exist because of a lack of uniform and reliable data for many taxa, and failure to incorporate spatio-temporal variations into broader assessments of diet.
Proceedings of the National Academy of Sciences, 2011
Stable isotope and molecular data suggest that C 4 grasses first appeared globally in the Oligocene. In East Africa, stable isotope data from pedogenic carbonate and fossil tooth enamel suggest a first appearance between 15-10 Ma and subsequent expansion during the Plio-Pleistocene. The fossil enamel record has the potential to provide detailed information about the rates of dietary adaptation to this new resource among different herbivore lineages. We present carbon isotope data from 452 fossil teeth that record differential rates of diet change from C 3 to mixed C 3 /C 4 or C 4 diets among East African herbivore families at seven different time periods during the Late Miocene to the Pliocene (9.9-3.2 Ma). Significant amounts of C 4 grasses were present in equid diets beginning at 9.9 Ma and in rhinocerotid diets by 9.6 Ma, although there is no isotopic evidence for expansive C 4 grasslands in this part of the Late Miocene. Bovids and hippopotamids followed suit with individuals that had C 4 -dominated (>65%) diets by 7.4 Ma. Suids adopted C 4 -dominated diets between 6.5 and 4.2 Ma. Gomphotheriids and elephantids had mostly C 3 -dominated diets through 9.3 Ma, but became dedicated C 4 grazers by 6.5 Ma. Deinotheriids and giraffids maintained a predominantly C 3 diet throughout the record. The sequence of differential diet change among herbivore lineages provides ecological insight into a key period of hominid evolution and valuable information for future studies that focus on morphological changes associated with diet change.
Proceedings. Biological sciences / The Royal Society, 2012
We examine the relationship between mesowear variables and carbon and nitrogen isotopes in 16 species of African antelope (Mammalia: Bovidae). We show significant differences in carbon and nitrogen isotope values between individuals exhibiting sharp versus round cusps, and high versus low occlusal relief. We show significant correlations between mesowear variables and both carbon and nitrogen isotopes. We find significant correlations between mesowear score and nitrogen, but not carbon isotopes. Finally, we find no significant correlations between hypsodonty index and either isotope examined. Our results provide strong support for the use of mesowear variables in palaeodietary reconstructions of antelopes. Our results further suggest that for the antelopes examined here, mesowear signals are a direct result of diet, while hyposodonty may be the result of phylogenetic legacy.
Assessing diet in savanna herbivores using stable carbon isotope ratios of faeces
Koedoe, 2005
Abstract In African savannas, browse-based resources (@ 3 plants) are isotopically distinct from grasses (@ 4 plants). The carbon isotopic composition of the basic plant diet is recorded in animal tissues. Mammal faeces are a readily accessible, non-invasive, sample material for temporally resolved dietary reconstructions. Faeces, however, include both undigested plant matter and waste, hence accuracy of dietary calculations could potentially be compromised by shifts in plant isotopic values related to seasonal or spatial differences ...
Journal of Zoological Systematics and Evolutionary Research, 2014
Understanding the evolutionary history of the herbivore niche within African bovids has traditionally relied on examining anatomical adaptations to diet, particularly those related to digestive strategy. More recently, mesowear and stable isotope analyses have been used to great effect to reconstruct dietary preferences. We use these dietary proxies to construct a morphology-free dietary ecospace and examine the topology of the phylogenetic relationships of African bovids mapped onto this ecospace. The reconstructed dietary ecospace provides evidence for four distinct dietary classes: species with C3-or C4-dominated diets that produce low or high occlusal relief, likely related to diets high or low in abrasives, respectively. We detected no evidence for a discrete mixed feeder category; the species often categorized as such represent the end members of groups of species with either C3-or C4-dominated diets. Our analysis reveals high variability within the C4 grazing ecospace, and phylogenetic evidence indicates at least two pathways to grazing, likely related to the abrasive qualities of ingested food, which may be determined by the moisture content or the height of consumed grasses. These different pathways probably contribute to the high diversity of African grazers, both today and in the fossil record. C3 browsers (nonfrugivores) also display a high degree of variation, but there are no species associated with highly abrasive diets and there is evidence for only a single evolutionary pathway. We find evidence for only one evolutionary route towards frugivory, which includes species with diets that produce both high and low occlusal reliefs. The cause of abrasive wear in frugivores may be related to grit and/or the hard parts of fruits, but this requires further examination.
The use of mesowear to infer diets of extinct species is fast becoming widespread in palaeoecological studies. Nevertheless, traditional mesowear analyses suffer from a specimen number limitation, in that a minimum number of specimens identified to the species level is necessary to make accurate dietary predictions. This is problematic in many fossil African antelope (Mammalia: Bovidae) assemblages, where isolated teeth cannot always be assigned to species. Hereweexplore the possibility of using simple dental metrics to predict diets on the basis of individual teeth as well as gnathic rows using linear discriminant function analyses.We find that browsers are accurately classified at both the individual and species levels, across all models and tooth positions. Mixed feeders and grazers are classified accurately only sometimes, and this is probably a reflection of the more limited sample size of larger bodied species in our study. Body size was a highly significant predictor of the i...