A balanced diet as a goal for grazing: the food of the Manyara buffalo

Abstract

SUMMARY The diet of African buffalo Syncerus coffer (Sparrman) was studied in Lake Manyara National Park, northern Tanzania, in conjunction with production, consumption and protein concentration of the major food plants. Production and relative growth rates of leaves of Cynodon dactylon (L.) Pers., Cynodon plectostachyus (K. Schum.) Pilg. and Sporobolus spicatus (Vahl) Kunth were generally highest during the short rains, lower during the long rains and negligible during the long dry season. The grass Chloris gayana Kunth showed its peak in production and consumption in the dry season. The concentration of crude protein in the green leaves reflected this pattern of growth and was highest during periods of vigorous growth. Green leaves always had a higher crude protein concentration than green stalk, and green parts than dead parts. Cyperus laevigatus L. did not show marked seasonality in its production pattern or in the crude protein concentration in its green parts. The diet, as determined through faecal analyses, reflected grass species high in protein, except during the dry season when the buffalo concentrated on the sedge, which had a low protein concentration but which offered a dense sward enabling them to collect sufficient food. The concentration of crude protein in the diet was determined through faecal nitrogen determination. The quality of the diet showed a clear seasonality, at the end of the dry season approaching the minimum requirements for maintenance. The crude protein concentration showed that the buffalo consumed a combination of species and species parts, so that they ingested a balanced diet with regard to their requirements for protein and energy. Résumé On a étudié le régime alimentaire du buffle africain Syncerus coffer au Pre National du Lac Manyara, en Tanzanie du Nord, en rapport avec la production, la consommation et la concentration en protéines des principales plantes alimentaires. La production et le taux de croissance relatif des feuilles de Cynodon dactylon, C. plectostachyus et Sporobolus spicatus sont généralement les plus élevés durant la petite saison des pluies, plus faibles durant la grande saison des pluies et négligeables durant la grande saison sèche. La production et la consommation de la graminée Chloris gayana sont maximales durant la saison sèche. La concentration de protéines brutes dans les feuilles vertes reflète ce mode de croissance et est la plus élevée durant les périodes de croissance vigoureuse. Les feuilles vertes ont toujours une concentration de protéines brutes plus élevée que la tige, et les parties vertes plus élevée que les parties mortes. On n'a pas relevé de saisonnalité marquée dans le mode de production ou la concentration en protéines brutes dans les parties vertes de Cyprus laevigatus. Le régime alimentaire, établi par analyses fécales, reflète la présence d'espèces de graminées riches en protéines, sauf durant la saison séche lorsque le buffle se concentre sur les laîches; celles‐ci ont une concentration faible en protéines mais constituent une p...

Fire history and management as determinant of patch selection by foraging herbivores in western Serengeti, Tanzania

“…Consequently, forage quantity (Spalinger and Hobbs 1992;Ginnett and Demment 1995;Hassan et al 2007) may influence selection between burnt and non-burnt patches. Fire can also enhance the quality of the phytomass available to herbivores through higher concentration of nitrogen, particularly in live leaf (Prins and Beekman 1989;Cook et al 1994), and higher ratio of new growth to residual low-quality material from earlier season (Everson 1999). Fire-induced spatial habitat heterogeneity can influence the density and movements of wildlife in the landscape, causing individual herbivore species to exploit patches differently (Weins 1976).…”

Optimal Foraging for Multiple Resources in Several Food Species

“…There is, however, a large range of alternative food species ( fig. 2, region V) for which none of the resources is limiting in both food species (Belovsky 1978;Prins and Beekman 1989;Voeten and Prins 1999;Raubenheimer and Simpson 2004;Simpson et al 2004;Ludwig et al 2007). Here the ratio between the resources to ; and IIc, which changes to for one part of the region and for the rest.…”

“…The concentrations of these (macro)nutrients differ between and within the different types of food (Voeten and Prins 1999;Simpson et al 2004;Klaassen and Nolet 2008;Prins and van Langevelde 2008). Although linear programming studies do take minimal requirements of several nutrients into account (Westoby 1974;Pulliam 1975;Belovsky 1978;Prins and Beekman 1989;Nolet et al 1995;Voeten and Prins 1999), the optimal acquisition of multiple resources has rarely been considered quantitatively thus far (but see Simpson et al 2004).…”

“…During these short foraging bouts, herbivores need to acquire enough of all resources to have the time to engage in nonforaging activities, such as vigilance and searching for mates. In food species, the ratio between the concentrations of resources will, in most cases, be different from the ratio of the turnover rates of these resources in the herbivore (Prins and Beekman 1989;Anderson et al 2004;Prins and van Langevelde 2008). An herbivore thus faces the twofold problem of having to choose between different food species in order to balance the intake of several resources to its requirements and of having to maximize the rate at which this optimal food mix is consumed.…”

“…Most extensions to OFT have involved the constraints animals face while trying to either maximize the intake rate of a resource or minimize the time needed to acquire a specific amount of this resource (Pulliam 1974(Pulliam , 1975Westoby 1974;Belovsky 1978;Owen-Smith and Novellie 1983;Stephens and Krebs 1986;Illius and Gordon 1991;Owen-Smith 1993;Wilmshurst et al 2000;Bergman et al 2001;Fryxell et al 2004). However, animals need to acquire more than one type of resource during foraging; many (macro)nutrients (e.g., proteins or nitrogen and phosphorus) are consumed and needed (Westoby 1974(Westoby , 1978Belovsky 1978;Prins and Beekman 1989;Prins 1996;Forbes 1999;Raubenheimer and Simpson 2004;Simpson et al 2004;Anderson et al 2005;Prins and van Langevelde 2008). The concentrations of these (macro)nutrients differ between and within the different types of food (Voeten and Prins 1999;Simpson et al 2004;Klaassen and Nolet 2008;Prins and van Langevelde 2008).…”