Lion (Panthera Leo Melanochaita) Diet in Relation to Prey Preference and Density in Meru National Park, Kenya
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Lion (Panthera leo melanochaita) diet in relation to prey preference and density in Meru National Park, Kenya MSc Research Project Report 2019 – 2020 Mateo Bal MSc Biodiversity, Conservation and Restoration Evolutionary Ecology Group Department of Biology Institute of Environmental Sciences Antwerp University Leiden University Research supervisors: Prof. Dr. Ir. Hans H. de Iongh (Leiden University, Leo Foundation) MSc Luka L. Narisha (Kenya Wildlife Service) Lion (Panthera leo melanochaita) diet in relation to prey preference and density in Meru National Park, Kenya Mateo Bal s0185753 This research project was developed within a collaborative framework between the University of Antwerp, the Institute of Environmental Sciences of Leiden University, Kenya Wildlife Service, the Leo Foundation and the Born Free Foundation. Submitted to obtain the master’s degree in biology - specialisation Biodiversity, Conservation and Restoration. 2 ABSTRACT The African lion (Panthera leo) plays a key role in savannah ecosystems by directly and indirectly regulating trophic structure. Their foraging behavior has frequently been described as opportunistic, but often reveals a distinct preference for certain prey species that are energetically more profitable. This research project focussed on the population structure and diet of lions in Kenya’s Meru National Park. Data were collected from February until April 2019 and contribute to the PhD research of MSc Luka Narisha. A total of 28 lions were identified during fieldwork, indicating a lion density of 2.2 adult lions per 100 km2. Transect counts of potential prey species in the park revealed that Kirk’s dik-dik (Madoqua kirkii) had the highest relative abundance of all prey species (50.89%), while African buffalo (Syncerus caffer) contributed the most to the total prey biomass (33.94%). Based on carcass counts and microscopic prey hair analysis from lion scats, African buffalo and plains zebra were found to be the principal prey species of the lions in Meru National Park. Few hairs of livestock were found in the lion scats, which indicates a low level of livestock raiding. Prey preference analysis using Jacobs’ Index showed that lions had a high prey preference for African buffalo and plains zebra, but Grevy’s zebra appeared to be the most preferred prey species. Lions did not seem to have a significant preference or avoidance for selected prey body mass ranges. Overall, results from this study indicate that Meru National Park hosts a healthy lion population in a relatively undisturbed ecosystem, but further research is needed to eliminate remaining uncertainties and monitor the prey and lion populations in view of climate change. 3 SUMMARY The global lion (Panthera leo) population is declining rapidly. Loss of habitat and prey, and the resulting conflicts between humans and lions, are increasingly threatening the very survival of the species. This study, which contributes to the PhD research of Luka Narisha, aims to better understand the ecology of the lion population in Meru National Park (Kenya) in order to support local management and conservation efforts. Meru National Park is situated in central Kenya and is largely unfenced, allowing wildlife to move freely between the protected area and the surrounding community lands. Over the course of 3 months, lions were actively tracked to understand their population dynamics and structure, and prey populations were monitored to map prey availability inside the park. By recording carcasses and analysing prey hair found in lion scats, it was possible to assess what prey species the lions generally consumed, and how this might be related to conflicts between lions and humans in neighbouring communities. Overall, African buffalo and plains zebra made up the largest portion of the lions’ diet, and only a few remains of livestock were found in their diet. This indicates that the lion population in the park is relatively healthy, since it predominantly predates on large, wild prey species. Ample prey was available inside Meru National Park, and it seems unlikely that the lions would resort to livestock raiding due to a shortage of wild prey. However, with large numbers of livestock congregating just outside the park, and climate change potentially disturbing water and prey availability, the risk of conflict between lions and local people may increase in the future. Continuous research and monitoring of the lion population and their prey is therefore critical in establishing mitigation measures and preventing losses on both sides of the conflict. 4 TABLE OF CONTENTS ABSTRACT ............................................................................................................................. 3 SUMMARY .............................................................................................................................. 4 INTRODUCTION ................................................................................................................... 6 General background ............................................................................................................................ 6 Lion taxonomy and conservation status in Africa and Kenya ............................................................ 7 Social structure of the African lion ..................................................................................................... 8 Diet and prey preference ..................................................................................................................... 9 Research hypothesis .......................................................................................................................... 11 RESEARCH OBJECTIVES ................................................................................................. 12 METHODS ............................................................................................................................. 13 Site description .................................................................................................................................. 13 Lion population size and structure .................................................................................................... 15 Prey population characteristics .......................................................................................................... 15 Lion diet ............................................................................................................................................ 20 Prey preference .................................................................................................................................. 21 Data analysis and statistics ................................................................................................................ 22 RESULTS ............................................................................................................................... 23 Lion population size and structure .................................................................................................... 23 Prey population characteristics .......................................................................................................... 25 Lion diet ............................................................................................................................................ 30 Prey preference .................................................................................................................................. 31 DISCUSSION ......................................................................................................................... 34 Lion population size and structure .................................................................................................... 34 Prey population characteristics .......................................................................................................... 36 Lion diet ............................................................................................................................................ 39 Prey preference .................................................................................................................................. 41 CONCLUSION ...................................................................................................................... 43 ACKNOWLEDGMENTS ..................................................................................................... 43 REFERENCES ...................................................................................................................... 44 APPENDIX ............................................................................................................................ 52 5 INTRODUCTION GeNeral backgrouNd Large carnivores play an important ecological role in regulating and maintaining ecosystem dynamics and integrity (Ripple et al., 2014). Through so-called trophic cascades, the direct predation pressure they exert on prey populations trickles down across other trophic levels and may directly and indirectly affect other herbivores, sympatric carnivores and vegetation structures (Ripple et al., 2014; Atkins et al., 2019). The impact of large carnivores on other predators is not only manifested by altering prey availability, their mere presence leads to avoidance behaviour and intraguild competition, especially when there is dietary overlap (Ripple et al., 2014; Vogel et al., 2019). Furthermore, in addition to reducing grazing-