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Valeix M.,French National Center for Scientific Research | Valeix M.,CIRAD - Agricultural Research for Development | Fritz H.,French National Center for Scientific Research | Sabatier R.,CIRAD - Agricultural Research for Development | And 3 more authors.
Biological Conservation | Year: 2011

African elephants can affect the quality of the habitat of other species by breaking or uprooting trees and shrubs in savannas. Their effect on vegetation has been widely studied but less is known about the effects of such vegetation changes on other animals. We studied how changes in the vegetation caused by elephants influence the selection of microhabitats by five African herbivore species (giraffe, kudu, steenbok, impala, and zebra) in Hwange National Park, Zimbabwe. There was no clear significant effect of overall elephant-induced vegetation changes on microhabitat selection except for the small species (steenbok and impala) that used vegetation modified by elephants preferentially. This is consistent with a medium-term browsing facilitation hypothesis. More subtle possible effects were detected for larger browsers (giraffe and kudu). They selected areas with broken and uprooted plants and avoided coppiced areas. All of the browsers selected sites characterized by plants uprooted and broken by elephants, which were associated with a higher visibility, and ultimately a better probability of detecting an approaching predator, suggesting that perceived predation risk plays an important role in microhabitat selection. These results illustrate how elephants can initiate indirect effects that influence microhabitat selection by other herbivores. Understanding the indirect effects of elephants through changes in food availability and predation risk thus needs further investigation. The results of this study do not provide support for the hypothesis that elephant-induced changes in the structure of habitats have caused the declines in the populations of the other herbivores in the study area. © 2010 Elsevier Ltd.

Groom R.J.,University of Johannesburg | Groom R.J.,Conservation Fund | Funston P.J.,Tshwane University of Technology | Mandisodza R.,Zimbabwe Parks and Wildlife Management Authority
ORYX | Year: 2014

The African lion Panthera leo is an iconic species but it has faced dramatic range reductions and possibly as few as 30,000 individuals remain in the wild. In the absence of detailed ground-based surveys, lion populations may be estimated using regression models based on prey biomass availability but these often overestimate lion densities as a result of a variety of compounding factors. Anthropogenic factors can be key drivers of lion population dynamics and in areas with high human impact lion numbers may be significantly lower than those predicted by prey biomass models. This was investigated in two protected areas in Zimbabwe, where lion population densities were found to be significantly lower than would have been predicted by prey-availability models. High hunting quotas either within or around the protected areas are the most likely cause of the low lion numbers, with quotas in some areas being as high as seven lions per 1,000 km2 in some years. Other factors, including persecution, poisoning and problem animal control, as well as disease and competition with spotted hyaenas Crocuta crocuta, are also discussed. Copyright © Fauna & Flora International 2014.

Crosmary W.-G.,University Claude Bernard Lyon 1 | Crosmary W.-G.,Laval University | Crosmary W.-G.,CIRAD - Agricultural Research for Development | Valeix M.,University Claude Bernard Lyon 1 | And 3 more authors.
Animal Behaviour | Year: 2012

Prey make several behavioural adjustments to minimize the risk of predation by their natural predators. When hunted, however, they may have to adjust their behaviour further or differently to cope with this additional mortality risk. Here, we investigated whether African large ungulates would adjust their behaviour in response to hunting risk (i.e. risk of being shot by human hunters). We predicted that they would shift their use of surface water, a key and scarce resource in African savannas, from day hours to night hours to reduce the risk of encountering human hunters. In Hwange National Park, Zimbabwe, we monitored waterholes to record the temporal drinking niche of three nonhunted ungulates (i.e. impala, Aepyceros melampus, greater kudu, Tragelaphus strepsiceros, sable antelope, Hippotragus niger). We also monitored waterholes in hunting areas in the vicinity of Hwange National Park. In Hwange National Park, the three species avoided waterholes at night, when the risk of natural predation was higher. Conversely, in the hunting areas, all three species visited waterholes more often at night. Impala and greater kudu, however, were less prone to switch towards night-time use of waterholes in hunting areas compared to sable antelope, although all three species were exposed to similar hunting risk. Our results suggest that hunting may force African ungulates to shift their visits at waterholes from day hours towards night hours, but that the magnitude of this shift may be constrained by the predation risk imposed by large nocturnal carnivores. We conclude that species preyed upon by natural predators adjust their antipredator behaviour in response to the additional risk of predation imposed by hunting. © 2011 The Association for the Study of Animal Behaviour.

Davidson Z.,University of Oxford | Valeix M.,University of Oxford | Loveridge A.J.,University of Oxford | Madzikanda H.,Zimbabwe Parks and Wildlife Management Authority | Macdonald D.W.,University of Oxford
Biological Conservation | Year: 2011

Hunting of individuals from a population can affect its demography and socio-spatial parameters. This study provided opportunities to assess such effects, and may help to improve the conservation of populations threatened by conflict and over-use. We treated the periods before and after a moratorium on the trophy hunting of lions around Hwange National Park, Zimbabwe, as a quasi-experimental opportunity to examine changes in lion socio-spatial behaviour during and after perturbation. Changes in ranging behaviour coincided with the release from heavy mortality from hunting outside the Park and were likely to be due to changes in the perturbation regime, rather than factors such as prey abundance, which did not change over the study period. Lion home range sizes decreased in both sexes after the moratorium. Overlap between groups decreased in males but increased in females. Variation in home range size reduced both annually and seasonally for both sexes. Home range centres became more closely distributed. Lions increased the use of denser vegetation cover classes (>30%) and decreased the use of open cover classes (10-30%). Lions increased the use of areas within 2-5. km of water, and decreased their use of the >20. km class. Perturbation therefore appeared to influence the socio-spatial behavior of the lion population. Managers considering the use of moratoria as a conservation tool must anticipate changes in the behavior and distribution of the target species. © 2010 Elsevier Ltd.

Valeix M.,University of Oxford | Valeix M.,University Claude Bernard Lyon 1 | Chamaille-Jammes S.,CNRS Center of Evolutionary and Functional Ecology | Loveridge A.J.,University of Oxford | And 4 more authors.
American Naturalist | Year: 2011

We test two hypotheses that could account for patch departure by large mammalian carnivores. One hypothesis is the unsuccessful-hunt hypothesis, where carnivores leave an area after an unsuccessful hunt but continue hunting in the same area after a successful hunt. The second hypothesis is the patch-disturbance hypothesis, where carnivores depart the area after a successful hunt because of behavioral responses of prey to predator presence. We used global positioning system collars to monitor the movements of African lions (Panthera leo) and identified their kill sites to distinguish between these two hypotheses. Lions moved to a different area (≥5 km away) after 87% of the kills, which supports the patchdisturbance hypothesis for patch-departure behavior of large mammalian carnivores. © 2011 by The University of Chicago.

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