Evaluation of the elephant immunocontraception program at Hluhluwe-iMfolozi Park, South Africa
type: CreativeWork
description: Managing African savannah elephant (Loxodonta africana) overpopulation in enclosed reserves is currently a major issue in southern Africa due to the potential negative impact of high elephant density on biodiversity. Immunocontraception of elephants has been proven to be an effective method of population control on small reserves with populations of less than 250 individuals, but there is uncertainty regarding its application in larger populations. South Africa's Hluhluwe-iMfolozi Park (HiP), with over 700 elephants, started a porcine zona pellucida (pZP) immunocontraception program in 2014 with the aim of reducing the population growth rate from 7.7% (2014-2016) to between 2 and 3%, but the program has not yet been formally assessed. In this study, I aimed to (1) evaluate the effectiveness of the 8-year program at the park, by measuring its effect on the population growth rate, and (2) explore potential factors affecting contraception efficacy. The proportion of infants within breeding herds was used to estimate growth rate. The proportion was determined using on-the- ground observations of breeding herds collected during six weeks of fieldwork in October and November 2022 and compared to previous years. The infant proportion in breeding herds and population growth rate were estimated as 0.156 and 7.16% respectively, only slightly less than the 2016 values of 0.167 and 7.7%. A critical assessment suggests that the key reasons for reduced contraception efficacy are consistency of individuals being contracepted and population coverage of breeding-age females. Approximately 75% of all reproductive-age females in the park are associated with collared herds (GPS collars are used to help locate herds for darting), but herd size variation due to fission-fusion social dynamics limited the role of collars in improving efficacy. An average 14% of reproductive-age females were missed each year due to failure to locate some collared herds. Despite high annual coverage of femal…
abstract: Managing African savannah elephant (Loxodonta africana) overpopulation in enclosed reserves is currently a major issue in southern Africa due to the potential negative impact of high elephant density on biodiversity. Immunocontraception of elephants has been proven to be an effective method of population control on small reserves with populations of less than 250 individuals, but there is uncertainty regarding its application in larger populations. South Africa's Hluhluwe-iMfolozi Park (HiP), with over 700 elephants, started a porcine zona pellucida (pZP) immunocontraception program in 2014 with the aim of reducing the population growth rate from 7.7% (2014-2016) to between 2 and 3%, but the program has not yet been formally assessed. In this study, I aimed to (1) evaluate the effectiveness of the 8-year program at the park, by measuring its effect on the population growth rate, and (2) explore potential factors affecting contraception efficacy. The proportion of infants within breeding herds was used to estimate growth rate. The proportion was determined using on-the- ground observations of breeding herds collected during six weeks of fieldwork in October and November 2022 and compared to previous years. The infant proportion in breeding herds and population growth rate were estimated as 0.156 and 7.16% respectively, only slightly less than the 2016 values of 0.167 and 7.7%. A critical assessment suggests that the key reasons for reduced contraception efficacy are consistency of individuals being contracepted and population coverage of breeding-age females. Approximately 75% of all reproductive-age females in the park are associated with collared herds (GPS collars are used to help locate herds for darting), but herd size variation due to fission-fusion social dynamics limited the role of collars in improving efficacy. An average 14% of reproductive-age females were missed each year due to failure to locate some collared herds. Despite high annual coverage of femal…
author: Fagan, Emma
keywords: Biological Sciences
date published: 2023
date modified: 2026-07-24T01:33:39Z
provider: University of Cape Town
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Department of Biological Sciences

PropertyValue
property ID: Handle
value: http://hdl.handle.net/11427/39425