2013. Habitat selection by large herbivores in a southern African savanna: the relative roles of bottom-up and top-down forces. Ecosphere 4(11):139. http://dx.Abstract. Animals must often balance food availability and predation risk when selecting habitat. Here, we examined habitat preferences of large mammalian herbivores in a long-term fire experiment in the Kruger National Park, South Africa to assess the role of bottom-up (e.g., forage quantity/quality) and topdown (e.g., predation risk) processes in driving herbivore distributions. We focused on experimental plots (;10 ha on average) that have been burned in the winter (August) since 1954 at 1-and 3-yr intervals, or left unburned (n ¼ 3 per burn type). Herbivore distributions (during both day and night) and plant community structure were surveyed on each plot during the growing seasons (. Overall, we sighted 4,187 individuals representing twelve species of mammalian herbivores. Impala (Aepyceros melampus), zebra (Equus quagga), and wildebeest (Connochaetes taurinus) comprised 37%, 28%, and 18% of all individuals observed, respectively. Several species such as African buffalo (Syncerus caffer), wildebeest, and giraffe (Giraffa camelopardalis) exhibited a significant trade-off between food acquisition and minimizing predation risk by foraging in areas with lower density of woody vegetation. We also observed significant day vs. night dynamics in herbivore habitat selection. For example, zebra utilized annual or triennial burns during the day depending on which years the plots were burned, but they avoided triennial burns with dense woody vegetation in favor of more open annual burns at night when predators such as lions (Panthera leo) are more active. Similarly, the smaller, mixed-feeding impala appeared to use riskier habitats with more diverse forage options during the day (triennial burns and unburned plots) but used less risky habitats at night (annual and triennial burns). Diurnal vs. nocturnal patterns are often overlooked in studies of habitat selection but are necessary for understanding the factors that shape distribution. The variation we observed in herbivore distribution patterns during this three-year period indicates that different species exhibit different trade-offs with respect to food and predation risk. Factors such as body size, nutritional requirements, prey escape tactics, and recent fire history likely mediated these interspecific differences.

Many African protected areas (PAs) are not functioning effectively. We reviewed the performance of Zambia’s PA network and provide insights into how their effectiveness might be improved. Zambia’s PAs are under-performing in ecological, economic and social terms. Reasons include: a) rapidly expanding human populations, poverty and open-access systems in Game Management Areas (GMAs) resulting in widespread bushmeat poaching and habitat encroachment; b) underfunding of the Zambia Wildlife Authority (ZAWA) resulting in inadequate law enforcement; c) reliance of ZAWA on extracting revenues from GMAs to cover operational costs which has prevented proper devolution of user-rights over wildlife to communities; d) on-going marginalization of communities from legal benefits from wildlife; e) under-development of the photo-tourism industry with the effect that earnings are limited to a fraction of the PA network; f) unfavourable terms and corruption which discourage good practice and adequate investment by hunting operators in GMAs; g) blurred responsibilities regarding anti-poaching in GMAs resulting in under-investment by all stakeholders. The combined effect of these challenges has been a major reduction in wildlife densities in most PAs and the loss of habitat in GMAs. Wildlife fares better in areas with investment from the private and/or NGO sector and where human settlement is absent. There is a need for: elevated government funding for ZAWA; greater international donor investment in protected area management; a shift in the role of ZAWA such that they focus primarily on national parks while facilitating the development of wildlife-based land uses by other stakeholders elsewhere; and new models for the functioning of GMAs based on joint-ventures between communities and the private and/or NGO sector. Such joint-ventures should provide defined communities with ownership of land, user-rights over wildlife and aim to attract long-term private/donor investment. These recommendations are relevant for many of the under-funded PAs occurring in other African countries.

Broad-scale models describing predator prey preferences serve as useful departure points for understanding predator-prey interactions at finer scales. Previous analyses used a subjective approach to identify prey weight preferences of the five large African carnivores, hence their accuracy is questionable. This study uses a segmented model of prey weight versus prey preference to objectively quantify the prey weight preferences of the five large African carnivores. Based on simulations of known predator prey preference, for prey species sample sizes above 32 the segmented model approach detects up to four known changes in prey weight preference (represented by model break-points) with high rates of detection (75% to 100% of simulations, depending on number of break-points) and accuracy (within 1.3±4.0 to 2.7±4.4 of known break-point). When applied to the five large African carnivores, using carnivore diet information from across Africa, the model detected weight ranges of prey that are preferred, killed relative to their abundance, and avoided by each carnivore. Prey in the weight ranges preferred and killed relative to their abundance are together termed “accessible prey”. Accessible prey weight ranges were found to be 14–135 kg for cheetah Acinonyx jubatus, 1–45 kg for leopard Panthera pardus, 32–632 kg for lion Panthera leo, 15–1600 kg for spotted hyaena Crocuta crocuta and 10–289 kg for wild dog Lycaon pictus. An assessment of carnivore diets throughout Africa found these accessible prey weight ranges include 88±2% (cheetah), 82±3% (leopard), 81±2% (lion), 97±2% (spotted hyaena) and 96±2% (wild dog) of kills. These descriptions of prey weight preferences therefore contribute to our understanding of the diet spectrum of the five large African carnivores. Where datasets meet the minimum sample size requirements, the segmented model approach provides a means of determining, and comparing, the prey weight range preferences of any carnivore species.

Under conditions of political instability and economic decline illegal bushmeat hunting has emerged as a serious conservation threat in Zimbabwe. Following settlement of game ranches by subsistence farming communities, wildlife populations have been eradicated over large areas. In several areas still being managed as game ranches illegal hunting is causing further declines of wildlife populations (including threatened species such as the wild dog Lycaon pictus and black rhinoceros Diceros bicornis), threatening the viability of wildlife-based land uses. From August 2001 to July 2009 in Savé Valley Conservancy 10,520 illegal hunting incidents were recorded, 84,396 wire snares removed, 4,148 hunters caught, 2,126 hunting dogs eliminated and at least 6,454 wild animals killed. Estimated future financial losses from illegal hunting in the Conservancy exceed USD 1.1 million year -1 . Illegal hunters' earnings account for 0.31-0.52% of the financial losses that they impose and the bushmeat trade is an inefficient use of wildlife resources. Illegal hunting peaks during the late dry season and is more frequent close to the boundary, near areas resettled during land reform and close to water. Illegal hunting with dogs peaks during moonlight periods. Our study highlights several management and land-use planning steps required to maximize the efficacy of anti-poaching and to reduce the likelihood of high impacts of illegal hunting. Anti-poaching efforts should be aligned with the regular temporal and spatial patterns of illegal hunting. Leases for hunting and tourism concessions should ensure minimum adequate investment by operators in anti-poaching. Reserve designers should minimize the surface area to volume ratio of parks. Fences should not be constructed using wire that can be made into snares. Land reform involving game ranches should integrate communities in wildlife-based land uses and ensure spatial separation between land for wildlife and human settlement. Means are required to create stakeholdings for communities in wildlife and disincentives for illegal hunting.