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Estimating carnivoran diets using a combination of carcass observations and scats from GPS clusters

Authors

  • C. J. Tambling,

    Corresponding author
    1. Centre for African Conservation Ecology, Department of Zoology, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa
    • Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
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  • S. D. Laurence,

    1. Enviro-Insight, Murrayfield, Pretoria, South Africa
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  • S. E. Bellan,

    1. Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, USA
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  • E. Z. Cameron,

    1. Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
    2. School of Zoology, University of Tasmania, Hobart, Tasmania, Australia
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  • J. T. du Toit,

    1. Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
    2. Department of Wildland Resources, Utah State University, Logan, UT, USA
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  • W. M. Getz

    1. Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
    2. Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, USA
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Correspondence

Craig J. Tambling, Centre for African Conservation Ecology, Department of Zoology, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa.

Email: cjtambling@gmail.com

Abstract

Scat analysis is one of the most frequently used methods to assess carnivoran diets, and global positioning system (GPS) cluster methods are increasingly being used to locate feeding sites for large carnivorans. However, both methods have inherent biases that limit their use. GPS methods to locate kill sites are biased towards large carcasses, while scat analysis overestimates the biomass consumed from smaller prey. We combined carcass observations and scats collected along known movement routes, assessed using GPS data from four African lion Panthera leo prides in the Kruger National Park, South Africa, to determine how a combination of these two datasets change diet estimates. As expected, using carcasses alone underestimated the number of feeding events on small species, primarily impala Aepycerosmelampus and warthog Phacochoerus africanus, in our case, by more than 50%, and thus significantly underestimated the biomass consumed per pride per day in comparison with when the diet was assessed using carcass observations alone. We show that an approach that supplements carcass observations with scats that enables the identification of potentially missed feeding events increases the estimates of food intake rates for large carnivorans, with possible ramifications for predator–prey interaction studies dealing with biomass intake rate.

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