Nutrient content and digestibility of forage plants in relation to plant phenology and rainfall in the Kalahari, Botswana

Skarpe, Christina; Bergström, Roger

doi:10.1016/s0140-1963(18)31226-6

Cited by 50 publications

(34 citation statements)

References 8 publications

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“…This area has distinctly seasonal growing periods, with most of the annual rainfall occurring between November and April (Skarpe & Bergstrom, 1986;Thomas & Shaw, 1991). Rainfall that occurs outside of this time has little effect on the growth of annual grasses (Skarpe & Bergstrom, 1986) because colder temperatures and rainfall of < 10 mm do not stimulate plant growth (Leistner, 1967). For this study, the wet season was thus considered to include the 6-month period November to April and the dry season included the 6-month period May to October.…”

Section: Methodsmentioning

confidence: 99%

Delayed maturity, group fission and the limits of group size in female Cape ground squirrels (Sciuridae: Xerus inauris)

Waterman

2002

Journal of Zoology

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Female Cape ground squirrels Xerus inauris live in matrilineal kin groups in which the number of reproductive positions is limited to three females. Field observations on a population in Namibia revealed that the mechanisms by which group size was limited were reproductive suppression and group ®ssion. Sub-adult females attained sexual maturity at 8 months of age when only a single adult female was present in their social group, whereas sub-adult females in groups with more than one adult female matured at 12 months of age. Social groups with more than three breeding females subsequently split into smaller groups. Several hypotheses for limiting group size were considered. There was no evidence of higher ectoparasite loads on females in larger groups, nor was survival of adult females affected by group size. Although adult females have lower body masses and higher mortality during the winter when food is more scarce, feeding competition alone does not seem to limit group size. Groups that split continued to overlap in their feeding ranges and there was no seasonal difference in juvenile survival. However, juvenile survival was affected by group size. The greatest cost of being in a larger group was lower juvenile survival. Larger groups use larger feeding ranges, and because squirrels return to their sleeping burrow when threatened, not just to the nearest refuge, slower juveniles have greater exposure to predators. Thus, although competition for food resources may be important, predation seems to be a major constraint on female group size as well as the primary selective force leading to female group formation.

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Section: Methodsmentioning

confidence: 99%

Delayed maturity, group fission and the limits of group size in female Cape ground squirrels (Sciuridae: Xerus inauris)

Waterman

2002

Journal of Zoology

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“…This is a major limitation as the response of arid and semiarid ecosystems to changes in rainfall regime is mediated by variations in the soil moisture dynamics, which, in turn, depend on the soil hydraulic properties. In contrast, a few studies have investigated the biogeochemical properties of the Kalahari sands Bird et al, 2004;Dougill et al, 1998;Feral et al, 2003;Hudak et al, 2003;Pardo et al, 2003;Skarpe and Bergstrom, 1986), although a comprehensive synthesis of the main results remains to be accomplished. This paper provides a brief review of previous studies on the sandy Kalahari soils (hereafter called the Kalahari sands) combined with previously unpublished results from recent analyses of the soil physical (mostly hydraulic) and biogeochemical properties.…”

Section: Article In Pressmentioning

confidence: 99%

Biogeochemistry of Kalahari sands

Wang

D’Odorico

Ringrose

et al. 2007

Journal of Arid Environments

113

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“…In the lab the samples were dried at 40 1C to constant weight and weighed (to 0.001 g). Data on chemical characteristics, including nitrogen (N), phosphorus (P) and in vitro dry matter digestibility (IVDMD) for Acacia mellifera, Grewia flava, Acacia hebeclada and Acacia luederizii were taken from previous studies in an adjacent area (Skarpe and Bergstro¨m, 1986). Plant species names here and elsewhere are from Coates-Palgrave (2002).…”

Section: Collection Of Datamentioning

confidence: 99%