Instead, eland moved seasonally between the reserve and the ranches. It is plausible that short, nutritious forbs which eland selects in the wet season (Watson and Owen-Smith 2000; Augustine et al. 2010) occurred at higher densities in the livestock-dominated areas in the ranches in the wet season. By contrast, giraffe are almost exclusively browsers favouring trees and shrubs and feeding almost entirely on forage at least 1 m off the ground (Owen-Smith and Cooper 1987). The ranches support 11–12% woody cover and the reserve 4% as measured by Reid et al. (2003). Milciclib ic50 This higher abundance of trees and shrubs on the ranches may be partially
the result of rocky topography in parts of the ranches, but may also RGFP966 clinical trial be because combined livestock and wildlife grazing removes more grass fuel on the ranches than in the reserve, thus discouraging extensive fires that suppress tree and shrub establishment (Scholes and Archer 1997). As a result, giraffe were more abundant in the ranches with more trees and shrubs in the wet season. Comparisons of age ratios and female proportions between landscapes We predicted that the lower number of predators, lower predation risk, and Vactosertib price shorter grass (Ogutu et al. 2005), and better predator visibility (Kanga et al. 2011), will lead to a higher proportion of the pregnant females bearing and raising their young on the ranches than in the reserve. As expected, newborn warthog and juvenile topi were significantly more abundant in
the ranches, suggesting
a preference for shorter grass areas where predation risk is lower. Contrary to our expectation, however, the proportions of newborn topi and zebra were higher in the reserve, suggesting a push from pastoralists or a pull by something for in the reserve, such as tall and dense grass cover for young to hide. The ratio of females to males varied significantly from parity for impala and topi, for which a female biased sex ratio is common (Sinclair et al. 2000). Our results suggest that female impala and topi were more abundant in the reserve, consistent with our speculation that competition with livestock and disturbance by humans and dogs in the ranches forces more females accompanied by their young into the reserve. Female giraffe and hartebeest were evenly distributed between the reserve and ranches, suggesting little influence of land use on the distribution of females relative to males. Implications for pastoralism, wildlife management and conservation Dispersal areas for wildlife in pastoral systems and their adjoining protected areas in African savannas represent wet season refuges for many wild herbivores that range seasonally beyond the protected area boundaries (Ogutu et al. 2008; Augustine et al. 2010). Our study shows that these areas can, and indeed do, support a high diversity of wildlife, especially in the wet season when resources are widely available due to maintenance of grasslands by livestock in short, nutritious growth stage.