“Trophy hunting of dominant male lions does not cause population-level infanticide from which lion populations cannot recover.”

In species such as lions, excessive trophy hunting could theoretically cause male replacements (and associated infanticide 4, 5) to become sufficiently common to prevent cubs reaching adulthood. … Although our simulations confirm that infanticide increases the risk of population extinction, trophy hunting could be sustained simply by hunting males above a minimum age threshold, and this strategy maximizes both the quantity and the quality of the long-term kill.

In species such as lions, excessive trophy hunting could theoretically cause male replacements (and associated infanticide 4, 5) to become sufficiently common to prevent cubs reaching adulthood. … Although our simulations confirm that infanticide increases the risk of population extinction, trophy hunting could be sustained simply by hunting males above a minimum age threshold, and this strategy maximizes both the quantity and the quality of the long-term kill.

Trophy hunting of lions has been shown to be sustainable under strict conditions15, although several intensive feld studies have also shown that unsustainably managed trophy hunting of lion populations can precipitate population declines16–18. … Indeed, sexually-selected infanticide, which occurs frequently following a pride takeover, amplifes mortality18.

Trophy hunting of lions has been shown to be sustainable under strict conditions 15, although several intensive field studies have also shown that unsustainably managed trophy hunting of lion populations can precipitate population declines16,17, 18. Indeed, sexually-selected infanticide, which occurs frequently following a pride takeover, amplifies mortality 18.

In the case of lions, the harvest of younger males (<5years) has a particularly significant impact due to the removal of individuals before they have raised a litter of cubs to independence and the associated risk of infanticide following the removal of pride males (Whitman et al., 2004).

Indeed, hunting may cause social perturbation in territorial species and amplify mortality through sexually selected infanticide (Swenson et al., 1997). … Indiscriminate harvest of males has been shown to hamper recruitment and cause population declines both theoretically (Caro et al., 2009) and in practice, with areas most heavily hunted showing the most significant population declines (Packer et al., 2011, Packer et al., 2009).

Indeed, sexually-selected infanticide, which occurs frequently following a pride takeover, amplifies mortality18. … That study proposed that trophy hunting is sustainable if only male lions aged a minimum of 6 years old are hunted. … This discrepancy was most severe in the ≥ 6 year and ≥ 7 year age groups where ‘estimated’ age scenarios resulted in population extirpation.

On the other hand, hunting of lions can disrupt social organization and cause superadditive effects on cub survival, and policies regulating hunting for lions and other large carnivores often fail to avoid negative population growth [15, 18]. … Studies continue to demonstrate strong population impacts on lions from trophy hunting, ranging from male depletion, skewed sex ratios, elevated levels of infanticide, and population decline [12,15,20–28], but isolating the effects of trophy hunting from other sources of mortality, particularly in lion populations traversing gradients of protection has been difficult [13].

Female population size was sensitive to the harvesting of young males (≥3 years), whereas hunting represented a relatively trivial threat to population viability when the harvest was restricted to mature males (≥6 years).

During male take-over infanticide is a regular phenomenon, and small cubs are most at risk from incoming males (Pusey and Packer, 1994, Whitman et al., 2004). … One example detected in the Hwange population previously was an increased risk of infanticide (Loveridge et al., 2007). … Conversely, with increasing male density following a trophy hunting moratorium, male replacement may decrease as incoming males settle in discrete territories. If male tenure is long enough to allow reproduction and dispersal of cubs, approximately 18–24months (Pusey and Packer, 1987), perturbation effects may recede. If so, we hypothesize that infanticide will decrease, and home range sizes and ranging behaviour will be affected.

Lion trophy hunting specifically targets adult males and sport hunters are extremely efficient in locating their quarry. This has large impacts because the males that replace the hunted individuals in the pride kill any cubs they have not fathered [25] . … However, by 2009 parts of the Msolwa sector supported some of the highest lion densities in SGR [45] . It is thought that the over-harvesting of the late 1990s had led to a scarcity of lions to hunt, which made it difficult to attract clients to the blocks and allowed lion populations to recover by 2009.

Trophy hunting can maintain lion range under a wildlife-based land use and generate substantial economic revenue, which often support the country’s wider conservation efforts. It can generate positive conservation and development impacts when well managed, but can also have negative impacts on individual lion populations, especially where harvest rates are high.

These results suggested that the lion population was not significantly affected by hunting in the WAP. We concluded that a quota of 1 lion/1000km2 would be sustainable for the WAP. Based on our results, an import embargo on lion trophies from the WAP would not be justified.

An intense demography study of the South Luangwa lion population showed that it was characterised by a severe depletion of adult males, low recruitment of cubs and an ageing adult female population (Rosenblatt et al., 2014). The research pointed towards hunting and high

We observed a significant decline in male immigration, which resulted in lowered levels of male replacement in the study population, reduced infanticide, and greater cub survival. … Reduced infanticide might well have compensated for harvests of nomadic males during the years included in this study, but as human-wildlife conflicts intensify with the rapidly growing population in Africa, compensatory mechanisms may become overwhelmed.

Best practice rests on the enforcement of a minimum age rule for hunting of males, which allows them to breed before they are killed.

By removing males from the population, hunters destabilized the spatial organization of the population for at least two years after a male had been killed. … This period of two years might be specific to brown bears, due to their denning period and could be different in other harvested species with SSI, such as lions (Panthera leo) 20 or cougars (Puma concolor) 24.

Previous simulation modelling found that large felid species could theoretically be hunted sustainably by restricting harvests to older individuals that have likely reproduced.

Predictions from matrix population models constructed within a Bayesian framework confirmed that the observed population structure was likely due to high rates of adult male loss and that instituting age limits on male harvests with quota reductions would reduce male depletion, improve tourism by providing older and more abundant males, and slightly increase population size.

However, where poorly managed, trophy hunting can have negative ecological impacts including altered age/sex structures, social disruption, deleterious genetic effects, and in extreme cases, population declines.

Lion harvests declined by 50% across Tanzania between 1996 and 2008, and hunting areas with the highest initial harvests suffered the steepest declines.

One of the consequences of replacement of the ter ritorial male or coalition by a new male or coalition was infanticide by the incoming male or males. … In all five cases infanticide occurred during the period subsequent to territorial males being removed by sport hunters.

Here we simulate the population consequences of lion trophy hunting using a spatially explicit, individual-based, stochastic model parameterized with 40 years of demographic data from northern Tanzania. Although our simulations confirm that infanticide increases the risk of population extinction, trophy hunting could be sustained simply by hunting males above a minimum age threshold, and this strategy maximizes both the quantity and the quality of the long-term kill.

Any sexually reproducing population will suffer from excessive removal of breeding-aged males simply due to a lack of mating partners for the females (Fig. 4a), but the lions’ social system and associated infanticide greatly increases the population risks from over-harvesting (Fig. 4b). … The most important lesson from these simulations is that there is no risk of over-harvesting a lion population when hunting is restricted to males that are at least 6 yrs of age – regardless of the quota.