The Environmental Impact Of Hunting For Antlers
Trophy hunting is often touted as an “environmentally-friendly practice” by hunters and “wildlife managers,” as few animals are killed and they are often chosen very selectively (e.g., only those with the most impressive characteristics, like large horns or manes, are hunted).
Supporters of trophy hunting as an environmentally friendly practice argue that very few animals are killed, and that they are often mature males. The rate of animals being killed is managed to prevent over-hunting, and the dead males will be replaced quickly, given the mating and social structure of many hunted species. However, by killing animals with desirable characteristics, hunters are affecting which traits are passed on. For example, killing off large male lions can result in smaller male lions breeding, which — theoretically — reduces the overall size of lions over time.
This study argues that trophy hunters and other selective harvesters may be removing individuals that are best adapted to their ecosystem, and by doing so, they are lowering the species’ long-term survivability.
The authors of this study used a simulation to test their theory. They used variables like animal population size, rate and direction of environmental change, rate and selectivity of hunting, selectivity of mate selection, and extinction probability. The hypothesis was that, if environmental change is random over time, selective hunting should have no major effect on extinction probability; if the environment changes in one direction over time, however, selective hunting would greatly increase the risk of extinction.
The logic behind their hypothesis is straightforward: selective hunting reduces the ability of a species to adapt to a gradually changing environment. The traits that are coveted by hunters may also be those which signal greater survivability. If the fittest animals are killed off, then the next generation is less fit. And if the fittest of that generation is killed off, their descendants will be even less fit. The end result is a species that goes extinct because it isn’t fit enough to adapt to their environment.
There are two possible problems with the authors’ simulation, which they recognize. First, they don’t account for the rate of inbreeding within a species. It’s possible that selective hunting actually reduces the rate of inbreeding, because the remaining mating groups technically have more genetic variety. In species with high rates of inbreeding, selective hunting may actually increase survivability by increasing the diversity of the gene pool.
Secondly, the researchers note that males and females in some species may have different desirable traits, and that females who mate with the most desirable males may have undesirable female offspring. Therefore, mating with undesirable males may produce more desirable females. The researchers believe that this is unlikely, as field studies have found that desirability for both males and females are generally similar. However, more research is needed to reach a conclusion on either of these points.
Overall, the study shows that the number of animals killed by hunters isn’t necessarily a sufficient indicator of the sustainability of trophy hunting, and a small number doesn’t necessarily indicate better results. In this case, the researchers argue that trophy hunting can be a powerful force for environmental preservation, but only if it is properly regulated, and that these regulations must not only address the number of animals killed, but also the age and fitness of the individuals being hunted.
For animal advocates, the results reveal just how chaotic “wildlife management” through hunting can be. While it is true that the natural world is never as clear-cut as simulations may portray it — and the authors acknowledge this — this study can be used as a reference point for further field research. It shows, first and foremost, that we still have a lot to learn about the ripple effects of hunting. In the meantime, the most ethical approach may be a precautionary one.