Density and abundance estimation of unmarked ungulates using camera traps in the Mudumu National Park, Namibia
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Date
2024
Journal Title
Journal ISSN
Volume Title
Publisher
European Journal of Wildlife Research
Abstract
Density and abundance estimates are critical to effective wildlife management and are essential for monitoring population
trends and setting effective quotas for harvesting. Management of roan (Hippotragus equinus) and sable (H. niger) antelopes
in Mudumu National Park (MNP), Namibia, is challenging because they are elusive, naturally unmarked, and believed to
occur at low densities. The species are threatened by habitat fragmentation, human population growth, and illegal hunting,
and reliable density and abundance estimates have not been quantified, hampering management and conservation plans. Our
objective was to estimate roan and sable densities and abundances using the time in front of the camera model (TIFC) and the
Poisson-binomial N-mixture model (PB), respectively. We also evaluated the effects of environmental and ecological variables
on roan and sable abundance. We used data from two camera trap surveys conducted between March and September 2021
in the MNP. Results showed that the TIFC model provided low-density estimates of 1.62 (95% CI 1.61–1.64) roans/km2
and
2.46 (95% CI 2.42–2.50) sables/km2
, consistent with trends reported in Africa where these species occur at low densities.
In addition, the total abundance of roans and sables in the MNP from the PB model were 57 and 242, respectively. Higher
roan abundance occurred in sites with higher grass cover. This study provides the first accurate camera trap-derived density
and abundance estimates for roan and sable in the MNP, which will be critical for developing comprehensive conservation
programs and strategies that are likely to reduce the risk of extinction for both species
Description
Keywords
Effective detection distance, Field-of-view, Kavango Zambezi Transfrontier Conservation Area, Population ecology, Site covariates, Namibia, University of Namibia