Aging traits and sustainable trophy hunting of African lions

Miller

Journal of Applied Ecology

2017

Sport hunting of wildlife can play a role in conservation but can also drive population declines if not managed sustainably. Previous simulation modelling found that large felid species could theoretically be hunted sustainably by restricting harvests to older individuals that have likely reproduced. Several African countries currently use age‐based hunting for lions although the outcomes have yet to be evaluated in a wild population. Here we provide the first empirical evidence that a system of incentives sufficiently encouraged age‐based hunting and reduced offtake of a wild felid, thereby reducing the potential risk of unsustainable hunting on a threatened species. We examined long‐term hunting data and the lion population trend in Niassa National Reserve, Mozambique. To incentivise hunter compliance, a “points” system was developed, which rewards operators that harvest lions older than the 6‐year minimum trophy age recommended for sustainable hunting and penalises operators that hunt “underage” lions (<4 years). A key component of this system is the ecological application of key physical traits that predictably change with age in order to estimate (by hunters) and validate (by authorities) trophy individuals’ ages pre‐ and post‐mortem, respectively. Analysis of 138 lion hunts and 87 lion trophies from 2003 to 2015 revealed that after enforcement of age restrictions in 2006, hunters shifted harvests to suitably aged lions (>6 years), from 25% of offtakes in 2004 to 100% by 2014. Simultaneously, the number of lions and percentage of quota harvested decreased, resulting in lower lion offtakes. Following an initial decrease after enforcement of the ageing system, the percentage of hunts harvesting lions stabilised, demonstrating that hunters successfully located and aged older lions. Synthesis and applications. Evidence suggests that age restrictions combined with an incentive‐based points system regulated sport hunting and reduced pressure on the lion population. We attribute the successful implementation of this management system to: (1) committed, consistent enforcement by management authorities, (2) genuine involvement of all stakeholders from the start, (3) annual auditing by an independent third party, (4) the reliable, transparent, straightforward ageing process and (5) the simple, pragmatic points system for incentivising hunter compliance. Our study demonstrates that the use of age restrictions can increase the selectivity of sport hunting and lower trophy offtakes to reduce the possibility of unsustainable sport hunting negatively impacting species populations in the absence of reliable estimates of population size. It must be noted, however, that there was no measurable change in the lion numbers over the past decade that could be attributed to the implementation of this policy alone.

Section: Discussionmentioning

confidence: 99%

“…year from 2003 before age restrictions were enforced). As age-specific variation in appearance decreases with age (Miller et al, 2016) and…”

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Effective implementation of age restrictions increases selectivity of sport hunting of the African lion

Miller

Journal of Applied Ecology

2017

Detecting early warnings of pressure on an African lion (Panthera leo) population in the Queen Elizabeth Conservation Area, Uganda

Braczkowski

Gopalaswamy

Nsubuga

et al. 2020

Ecol Sol and Evidence

1. African lions are declining across much of their range, yet robust measures of population densities remain rare. The Queen Elizabeth Conservation Area (QECA; 2,400 km 2 ) 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.2. 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.3. We recorded 8,243.5 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 km 2 .Lion density in the QECA was 2.70 adult lions/100 km 2 (SD = 0.47), while mean abundance was 71 individuals (SD = 11.05).4. 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).

Camera trapping and spatially explicit capture–recapture for the monitoring and conservation management of lions: Insights from a globally important population in Tanzania

Strampelli

Searle

Smit

et al. 2022

Ecol Sol and Evidence

Self Cite

Accurate and precise estimates of population status are required to inform and evaluate conservation management and policy interventions. Although the lion (Panthera leo) is a charismatic species receiving increased conservation attention, robust status estimates are lacking for most populations. While for many large carnivores population density is often estimated through spatially explicit capture–recapture (SECR) applied to camera trap data, the lack of pelage patterns in lions has limited the application of this technique to the species. Here, we present one of the first applications of this methodology to lion, in Tanzania's Ruaha‐Rungwa landscape, a stronghold for the species for which no empirical estimates of status are available. We deployed four camera trap grids across habitat and land management types, and we identified individual lions through whisker spots, scars and marks, and multiple additional features. Double‐blind identification revealed low inter‐observer variation in photo identification (92% agreement), due to the use of xenon‐flash cameras and consistent framing and angles of photographs. Lion occurred at highest densities in a prey‐rich area of Ruaha National Park (6.12 ± SE 0.94 per 100 km2), and at relatively high densities (4.06 ± SE 1.03 per 100 km2) in a community‐managed area of similar riparian‐grassland habitat. Miombo woodland in both photographic and trophy hunting areas sustained intermediate lion densities (1.75 ± SE 0.62 and 2.25 ± SE 0.52 per 100 km2, respectively). These are the first spatially explicit density estimates for lion in Tanzania, including the first for a trophy hunting and a community‐managed area, and also provide some of the first insights into lion status in understudied miombo habitats. We discuss in detail the methodology employed, the potential for scaling‐up over larger areas, and its limitations. We suggest that the method can be an important tool for lion monitoring and explore the implications of our findings for lion management.