No abstract

We studied diet selection and density of forest buffalo in the Campo Ma'an National Park of southern Cameroon. The buffalo's diet in this rainforest comprised 43% grass, including 15% Leptochloa caerulecens. Other species eaten were non-graminoid monocots (21.3%), mainly Commelinaceae (18.2%), including Palisota spp. and dicotyledons (32.7%), mainly leaves (26.5%). This diet revealed that buffalo collect their food on road verges, logging tracks and along large rivers. This agrees well with the distribution of buffalo tracks in the study area. Mean buffalo density in the forest was only 0.01 buffalo km )2 , whereas the density on the road together with its direct surroundings was 0.4 buffalo per km of road. We estimated the total number of buffalo in the 650 km 2 southern part of National Park Campo-Ma'an of only twenty individuals. We suggest that the buffalo's ancestral niche was not a primeval type of rainforest, as suggested by Kingdon, but an interface between savanna and rainforest. The Campo-Ma'an buffalo most likely depend to a very large extent on anthropogenic vegetation types. Maintaining some grass cover by annual clear-cutting along roads and on logging tracks might be necessary for the survival of the buffalo population within the National Park. RésuméNous avons étudié la sélection alimentaire et la densité des buffles de forêt du Parc National de Campo Ma'an, dans le sud du Cameroun. Le régime alimentaire du buffle dans cette forêt pluviale se composait à 43% d'herbes, y compris 15% de Leptochloa caerulescens. Les autres espèces con-sommées étaient des monocotylées non graminoïdes (21,3%), principalement des Commelinaceae (18,2%), y compris Palisota spp., et des dicotylédones (32,7%), surtout des feuilles (26,5%). Ce régime révèle que le buffle récolte sa nourriture sur le bord des routes et des pistes d'exploitation du bois et le long des grandes rivières. Ceci correspond bien à la distribution des traces de buffles dans la zone étudiée. La densité moyenne des buffles dans la forêt était seulement de 0,01 ⁄ km 2 , alors que la densité moyenne sur la route et dans le voisinage immédiat était de 0,4 ⁄ km de route. Nous estimons que le nombre total de buffles dans les 650 km 2 de la partie sud du Parc National de Campo Ma'an ne dépasse pas 20 individus. Nous suggérons que la niche ancestrale du buffle n'était pas un type primitif de forêt pluviale, comme le laisse penser Kingdon, mais une interface entre savane et forêt pluviale. Le buffle de Campo Ma'an dépend très vraisemblablement en grande partie de types de végétation anthropogènes. Il pourrait être nécessaire de maintenir un couvert herbeux en dégageant chaque année le long des routes et des pistes forestières pour la survie de la population de buffles dans le parc national.

The composition of the plant species eaten by kudu (<em>Tragelaphus strepsiceros</em>) determines the diet quality, which impacts on kudu condition and mortality levels. The yearround diet composition of kudus in the Limpopo Province, a mopane (<em>Colophospermum mopane</em>) dominated area, was determined by faecal analysis. The most important dietary plant species were <em>Colophospermum mopane, Grewia bicolor, Terminalia prunioides, Tinnea rhodesiana, Boscia albitrunca</em> and <em>Combretum apiculatum</em>, with <em>C. mopane</em> comprising on average 39.2 % of diet per month. Small amounts of herbs, grasses and seeds made up the remaining part of the diet. The contribution of <em>C. mopane</em> in the diet was negatively correlated with precipitation. <em>Colophospermum mopane</em> was consumed, irrespective of its high condensed tannin load (5.2–9.8 % DW) for the majority of the months. No seasonally significant differences were detected for modelled kudu diet crude protein, tannin or phenol concentrations. <em>Colophospermum mopane</em> showed significant seasonal differences with lowest values of protein, tannin and phenols in the late wet season. Surprisingly, crude protein concentrations were positively correlated with high levels of tannins and phenols for <em>C. mopane</em>. The diet of kudus comprised of significantly more species during the wet season compared to the dry season. Diet diversification, instead of protein maximization, seems a potential tool to satisfy protein requirements while reducing potential toxic effects associated with a high intake of secondary compounds. A significant positive correlation was therefore detected between the tannin concentration of <em>C. mopane</em> leaves and the number of plant species in the diet

Multiple factors determine diet selection of herbivores. However, in many diet studies selection of single nutrients is studied or optimization models are developed using only one currency. In this paper, we use linear programming to explain diet selection by African elephant based on plant availability and nutrient and deterrent content over time. Our results indicate that elephant at our study area maximized intake of phosphorus throughout the year, possibly in response to the deficiency of this nutrient in the region. After adjusting the model to incorporate the effects of this deficiency, elephant were found to maximize nitrogen intake during the wet season and energy during the dry season. We reason that the increased energy requirements during the dry season can be explained by seasonal changes in water availability and forage abundance. As forage abundance decrease into the dry season, elephant struggle to satisfy their large absolute food requirements. Adding to this restriction is the simultaneous decrease in plant and surface water availability, which force the elephant to seek out scarce surface water sources at high energy costs. During the wet season when food becomes more abundant and energy requirements are satisfied easier, elephant aim to maximize nitrogen intake for growth and reproduction. Our study contributes to the emerging theory on understanding foraging for multiple resources.

The winter diets of roe deer culled from Kielder Forest, in north-east England, where the incidence of liver carcinomas in roe deer is high, and Galloway Forest, in south-west Scotland, where the incidence of liver carcinomas is low, were compared by microhistological analysis of faeces. Both areas are planted with spruce forests but the diets of the deer from Kielder Forest were less varied and contained more spruce and heather than the diets of the deer from Galloway Forest.