Informing aerial total counts with demographic models: population growth of Serengeti elephants not explained purely by demography

Morrison, T. A., Estes, A. B., Mduma, S. A.R., Maliti, H. T., Frederick, H., Kija, H., Mwita, M., Sinclair, A.R.E. and Kohi, E. M. (2018) Informing aerial total counts with demographic models: population growth of Serengeti elephants not explained purely by demography. Conservation Letters, 11(3), e12413. (doi:10.1111/conl.12413)

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Abstract

Conservation management is strongly shaped by the interpretation of population trends. In the Serengeti ecosystem, Tanzania, aerial total counts indicate a striking increase in elephant abundance compared to all previous censuses. We developed a simple age-structured population model to guide interpretation of this reported increase, focusing on three possible causes: (1) in situ population growth, (2) immigration from Kenya, and (3) differences in counting methodologies over time. No single cause, nor the combination of two causes, adequately explained the observed population growth. Under the assumptions of maximum in situ growth and detection bias of 12.7% in previous censuses, conservative estimates of immigration from Kenya were between 250 and 1,450 individuals. Our results highlight the value of considering demography when drawing conclusions about the causes of population trends. The issues we illustrate apply to other species that have undergone dramatic changes in abundance, as well as many elephant populations.

Item Type:Articles (Letter)
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Morrison, Dr Thomas
Authors: Morrison, T. A., Estes, A. B., Mduma, S. A.R., Maliti, H. T., Frederick, H., Kija, H., Mwita, M., Sinclair, A.R.E., and Kohi, E. M.
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
Journal Name:Conservation Letters
Publisher:Wiley
ISSN:1755-263X
ISSN (Online):1755-263X
Published Online:26 September 2017
Copyright Holders:Copyright © 2017 The Authors
First Published:First published in Conservation Letters 11(3): e12413
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
681691AfricanBioServicesDaniel HaydonEuropean Commission (EC)641918RI BIODIVERSITY ANIMAL HEALTH & COMPMED