Movement analysis for monitoring predation by large carnivores : lions in Kruger National Park

Methods used to estimate the prey consumption by large carnivores include direct continuous observation, stomach content analysis, carcass observations and scat analysis. Continual observations are widely considered the best approach to estimate large carnivore diets, with lions (Panthera leo) being no exception. Continual observation allows the recording of all prey encounters and biases inherent in the other approaches are minimised. However, continuous observations are not always feasible, and in situations where animals cannot be observed at all times, diets are often estimated from observed carcasses. This often leads to an over-estimation of large kills in the estimated diet. Alternative methods that are free of the constraints placed on continuous observations are needed to provide data of a similar quality to that obtained using these continuous observation bouts. I employed a cluster follow up technique to locate lion kills from remotely accessed Global Positioning System (GPS) data from lions in the Kruger National Park (KNP). I develop Generalized Linear Models (GLMs) that increase the probability of locating kills at GPS cluster events. By increasing the predictive ability of detecting kills I show that this technique can be used to locate kills in a more efficient manner than random searching of GPS clusters, with further advantages in that multiple groups of lions can be monitored simultaneously. By incorporating this technique into an adaptive research framework, the diet of lions (and that of other large carnivores) can be estimated. In addition, I show that the spatial association between lions at kill sites, while feeding on carcasses, provides a further increase in the predictive ability of kill site models. Lionesses were found to be considerably closer together at the start of clusters associated with kills in comparison to clusters where no kill was found. This pattern remained consistent for both small and large kills. This proximity approach could therefore be incorporated into the GLMs that are developed to predict kill sites of large social carnivores. To further reduce the bias (where small kills are often missed) inherent in carcass observations, I combined scats and carcasses collected from known times, locations and lion groups to construct a temporal kill record for each group of lions. By combining scats and carcasses I estimate that at least 50% of the small prey items, namely impala (Aepyceros melampus) and warthog (Phacochoerus africanus) were missed when GPS clusters were investigated for carcasses. Ultimately, I show that a combination of GPS cluster investigations based on models developed using GPS movement data in combination with lion proximity data, augmented with scats collected at GPS clusters, could provide estimates of large carnivore diets that begin to approach estimated diets obtained through continuous monitoring. The resulting diet, estimated from the GPS cluster approach in combination with scat collection, indicated that the dominant prey item in the region was zebra (Equus quagga) followed by wildebeest (Connochaetes taurinus), impala and buffalo (Syncerus caffer). Selection indices for the eight dominant prey items were calculated using prey availability measures obtained from the aerial census data and ground counts of groups. It has been suggested that group level selection is a better approach to calculating predator-prey interactions, and that stability in predator-prey systems is improved if group metrics of prey are used as apposed to individual measures of availability. I show that there is a considerable shift in selection indices, as well as in the order that prey is selected, when using different measures of prey availability. In selection studies, more effort needs to be paid to the assessment and definition of prey availability to ensure results accurately reflect selection patterns in the field, especially when data are used for the development of management practices. Combining buffalo predation data collected from GPS cluster investigations with buffalo mortality data collected over five years prior to the commencement of the GPS cluster investigations, allowed an investigation into patterns of lion predation on buffalo between 2000 and 2007. Buffalo of both sexes were more vulnerable to predation in habitats that gave lions an ambush advantage (i.e. increased grass height and tree density). Despite this similarity in landscape risk, different processes lead to similar fates in dangerous habitats for buffalo of both sexes. Predation pressure by lions on buffalo increased following periods of reduced rainfall; with more buffalo predated on following drier six month periods. Predation on males constituted a significant proportion of all predation and was focused predominantly into the late dry season. The resulting method of locating kills by using GPS clusters and correcting carcass data with scats collected along the movement path represents a robust technique to estimate large carnivore diets. In the concluding chapter I present avenues where future research can build on the current thesis and present a framework that can be employed when attempting to estimate large carnivore diets.Thesis (PhD)--University of Pretoria, 2010.Zoology and Entomologyunrestricte

Lion hunting behaviour and vegetation structure in an African savanna

Emerging evidence suggests that male lions are not dependent on female’s hunting skills but are in fact successful hunters. But difficulty locating kills and objectively characterizing landscapes has complicated the comparison of male and female lion hunting strategies. We used airborne Light Detection and Ranging (LiDAR) measurements of vegetation structure in Kruger National Park, combined with global positioning system (GPS) telemetry data on lion, Panthera leo, kills to quantify lines-of-sight where lion kills occurred compared with areas where lions rested, while controlling for time of day. We found significant differences in use of vegetation structure by male and female lions during hunts. While male lions killed in landscapes with much shorter linesof- sight (16.2 m) than those in which they rested, there were no significant differences for female lions. These results were consistent across sizes of prey species. The influence of vegetation structure in shaping predatoreprey interactions is often hypothe-sized, but quantitative evidence has been scarce. Although our sample sizes were limited, our results provide a mechanism, ambush hunting versus social hunting in the open, to explain why hunting success of male lions might equal that of females. This study serves as a case study for more complete studies with larger samples sizes and illustrates how LiDAR and GPS telemetry can be used to provide new insight into lion hunting behaviour.Support from the James S. McDonnell Foundation and a United States National Science Foundation Ecology of Infectious Disease Grant DEB-0090323 to Wayne Getz at the University of California,Berkeley, and a National Research Foundation.. This study was supported by the Andrew Mellon Foundation. The Carnegie Airborne Observatory is made possible by the Gordon and Betty Moore Foundation, the Grantham Foundation for the Protection of the Environment, Avatar Alliance Foundation, W.M. Keck Foundation,the Margaret A. Cargill Foundation, Mary Anne Nyburg Baker and G. Leonard Baker, Jr and William R. Hearst, III.http://www.elsevier.com/locate/anbehavhb201

Ecological and financial impacts of illegal bushmeat trade in Zimbabwe

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 Save´ 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.TRAFFIC Southern and East Africa, the European Union, Wilderness Trust, Chicago Board of Trade and the supporters of the African Wildlife Conservation Fund.http://journals.cambridge.orgab201

Brown hyena habitat selection varies among sites in a semi-arid region of southern Africa

In the last 50 years, the human impact on ecosystems has been greater than during any other time period in human history (Millennium Ecosystem Assessment 2003). Large carnivores face anthropogenic threats worldwide, specifically persecution, habitat degradation, and habitat fragmentation (Everatt et al. 2014; Groom et al. 2014; Ripple et al. 2014; Wolfe et al. 2015). Because large carnivores often occupy high trophic levels, their presence influences species at lower levels through trophic cascades (Ripple et al. 2014). Natural experiments, taking advantage of large carnivore management, have shown that large predators provide fundamental ecosystem and economic services that help maintain healthy and diverse ecosystems (Ripple et al. 2014). Additionally, carnivores play an important role in other ecosystem processes, for example, scavenging carnivores may provide regulatory services, such as waste removal, nutrient cycling, and disease regulation. Such services add stability to ecosystems and ensure energy flow through multiple trophic levels (DeVault et al. 2003; Wilson and Wolkovich 2011)

Underperformance of African protected area networks and the case for new conservation models : insights from Zambia

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.The Wildlife Producers Association of Zambia. CJT was funded with a Claude Leon Fellowship.http://www.plosone.orgam201

Underperformance of African protected area networks and the case for new conservation models : insights from Zambia

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.The Wildlife Producers Association of Zambia. CJT was funded with a Claude Leon Fellowship.http://www.plosone.orgam201

Environmental controls on African herbivore responses to landscapes of fear

Herbivores balance forage acquisition with the need to avoid predation, often leading to tradeoffs between forgoing resources to avoid areas of high predation risk, or tolerating increased risk in exchange for improved forage. The outcome of these decisions is likely to change with varying resource levels, with herbivores altering their response to predation risk across heterogeneous landscapes. Such contrasting responses will alter the strength of non-consumptive predation effects, but are poorly understood in multiple-predator/multiple-prey systems. We combined fine-scaled spatial information on two predator and 11 herbivore species with remotely-sensed measurements of forage quantity and vegetation structure to assess variation in herbivore response to predation risk with changing environmental context, herbivore body size, herbivore foraging strategy (browsers versus grazers), predator type (ambush versus coursing hunters) and group size across a South African savanna landscape. Medium-sized herbivore species were more likely to adjust their response to risk with a changing resource landscape: warthog, nyala and wildebeest tolerated increased long-term predator encounter risk in exchange for abundant (warthog and nyala) or preferred (wildebeest) forage, and nyala selected areas with higher visibility only in landscapes where food was abundant. Impala were more likely to be observed in areas of high visibility where wild dog risk was high. In addition, although buffalo did not avoid areas of high lion encounter risk, large buffalo groups were more frequently observed in open areas where lion encounter risk was high, whereas small groups did not alter their space use across varying levels of risk. Our findings suggest that risk effects are not uniform across landscapes for medium-sized herbivores and large buffalo groups, instead varying with environmental context and leading to a dynamic landscape of fear. However, responses among these and other prey species were variable and not consistent, highlighting the complexities inherent to multi-predator/multi-prey systems.Data availability statement: Data available from the Dryad Digital Repository: (Davies et al. 2020).http://www.oikosjournal.orghj2022Mammal Research InstituteZoology and Entomolog

Decision rules for determining terrestrial movement and the consequences for filtering high-resolution global positioning system tracks: a case study using the African lion ( Panthera leo )

The combined use of global positioning system (GPS) technology and motion sensors within the discipline of movement ecology has increased over recent years. This is particularly the case for instrumented wildlife, with many studies now opting to record parameters at high (infra-second) sampling frequencies. However, the detail with which GPS loggers can elucidate fine-scale movement depends on the precision and accuracy of fixes, with accuracy being affected by signal reception. We hypothesized that animal behaviour was the main factor affecting fix inaccuracy, with inherent GPS positional noise (jitter) being most apparent during GPS fixes for non-moving locations, thereby producing disproportionate error during rest periods. A movement-verified filtering (MVF) protocol was constructed to compare GPS-derived speed data with dynamic body acceleration, to provide a computationally quick method for identifying genuine travelling movement. This method was tested on 11 free-ranging lions (Panthera leo) fitted with collar-mounted GPS units and tri-axial motion sensors recording at 1 and 40 Hz, respectively. The findings support the hypothesis and show that distance moved estimates were, on average, overestimated by greater than 80% prior to GPS screening. We present the conceptual and mathematical protocols for screening fix inaccuracy within high-resolution GPS datasets and demonstrate the importance that MVF has for avoiding inaccurate and biased estimates of movement