10.5061/DRYAD.PG4F4QRKN
Braczkowski, Aleksander
0000-0002-0099-7803
Griffith University
Density estimates of African lions in Queen Elizabeth National Park
Dryad
dataset
2020
National Geographic Society
https://ror.org/04bqh5m06
WW-106ER-17
Siemiatkowski Foundation*
University of Queensland
https://ror.org/00rqy9422
Siemiatkowski Foundation
2020-06-15T00:00:00Z
2020-06-15T00:00:00Z
en
4214671 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
African lions are declining across much of their range, yet robust
measures of population densities remain rare. The Queen Elizabeth
Conservation Area (QECA; 2400 km2) in East Africa’s Albertine Rift has
potential to support a significant lion population. However, QECA lions
are threatened, and information on the status of lions in the region is
lacking. Here, we use a spatially explicit search encounter approach to
estimate key population parameters of lions in the QECA. We then compare
home range sizes estimated from our models to those from a radio-collaring
study implemented a decade earlier. We recorded 8243.5 km of search effort
over 93 days, detecting 30 individual lions (16 female and 14 male) on 165
occasions at a rate of 2 lion detections/100 km2. Lion density in the QECA
was 2.70 adult lions/100 km2(SD=0.47), while mean abundance was 71
individuals (SD=11.05). Worryingly, the movement parameter for male lions
was 3.27 km and 2.22 km for females, suggesting >400%, and
>100% increases in home range size, respectively, compared to a
decade earlier. Sex ratio of lions in the QECA was lower (1 male: 0.75
females), when compared to a previously published review (mean=1:2.33).
The large movements and skewed sex ratios we report on in this paper are
likely a result of human driven prey depletion. Our results suggest lions
in the QECA are in a precarious state and the lion densities are
significantly lower than what they could be. As lions are under pressure
throughout much of Africa, our study presents the utility of a census
technique that could be used elsewhere as an early warning of lion
declines.
The following document provides the user with the R code to generate
African lion densities and other state variables for the QECA (and
accompanying raw outputs from R) using the csv input files in
Supplementary Information 1. We initially ran models at 11000 iterations
(with a burn in of 1000) and achieved convergence for the Global (most
parameterized), Xand Y models. The full (ie. Model with most support but
where theta was 1), Sextheta, Sex and Theta models were run for 39000
iterations with a burn in of 1000 to achieve convergence. *This code is
tested and correct as of 12 August 2019. If you experience any problems
replicating these results, or have queries about the code, please contact
the lead author on alexander.braczkowski@gmail.com.
Please use the accompanying manual (with R code) and RAW csv files to
generate the results we produce in our paper.