Factors regulating the Luangwa (Zambia) common hippopotamus (hippopotamus amphibius) population within the carrying capacity band
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Date
2011
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Publisher
University of Dar es Salaam
Abstract
This study assessed factors regulating the Luangwa (Zambia) hippo (Hippopotamus amphibius) population within the Carrying Capacity Band as these were unknown. Objectives of the study were to; establish whether the hippo population had reached and remained within the Carrying Capacity Band in the last 32 years, determine herbage biomass producedand its influence on hippo density distribution, assess whether mortality determined population size and density, and establish influence of non food resources (geomorphologic features) and levels of protection on hippo density distribution along the 165 km stretch of the Luangwa River, eastern Zambia.Total river bank counts were made and GPS locations of hippo schools recorded. Measurements from culled hippo carcasses were taken to determine sex and age classes. Kidney fat index (KFI) was used to determine body condition. Herbaceous growth was clipped and weighed to assess biomass. River geomorphologic features were taken by flying over the area in a light aircraft. Carrying capacity (K) was found to be 6,000 individuals at a density of 35/km. Hippo population oscillated within Carrying Capacity Band of 2,000 individuals in eight irregular cycles. At K, recruitment declined; calves and juveniles being 15 % of the population and KFI was low at 40% by October. Herbaceous biomass was high at 7, 850 kg /ha in 2008 and mortality did not disrupt population density. It was concluded that food was the main factor regulating hippo population size and density while geomorphologic features influenced the pattern of hippo population density distribution. Further research is required to establish primary production between ‘lean’ and ‘fat’ years and for monitoring range trend condition.
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Keywords
Hippopotanus, Luangwa, Zambia
Citation
Chomba, C. (2011) Factors regulating the Luangwa (Zambia) common hippopotamus (hippopotamus amphibius) population within the carrying capacity band. PhD dissertation, University of Dar es Salaam. Available at http://41.86.178.3/internetserver3.1.2/detail.aspx