Hunting and poaching are not just bad news for wildlife, but also the climate according to a new study undertaken by New York-based Wildlife Conservation Society (WCS).
Findings from 20 years of research suggests that the removal of large living animals is leading to a greater concentrations of greenhouse gases being released into the atmosphere due to a loss of carbon absorbing forest. Animals are good guardians of these critical forests, helping to maintain their normal functions through their dietary choices and daily habits. As these animals disappear, so do the trees that best capture CO2.
Forests capture CO2 from the atmosphere via photosynthesis and store it in their biomass, they are responsible for absorbing 30 per cent of CO2 emissions emitted every year.
The issue with a reduction in species is that bio-diverse forests become susceptible to climate change. Whether that be a change in temperature or rain patterns, these effects are more pronounced where there are fewer species left to regulate the forest. As some species die off, the ecosystem as a whole is more likely to fail.
Elizabeth (Liz) Bennett, Vice President for Species Conservation at WCS was one of the lead researchers on the project. Liz received her Ph.D. from Cambridge University, UK, for research on the ecology of primates in Malaysia. Her services to conservation have been recognised by the Golden Ark Award by Prince Bernhard of the Netherlands, an MBE by Her Majesty Queen Elizabeth II, and the Merdeka Award for Outstanding Contribution to the People of Malaysia.
The Ethicalist talks to Liz to explain the findings.
TE: How did you first determine a link between poaching and climate change?
EB: Some 20 years ago, my colleague John Robinson and I wrote syntheses on the scale and impacts of hunting in tropical forests. One such impact is a loss of species vital to maintaining forest function and diversity. The link with climate change was more recent. It seemed intuitive that there should be a link, but it was not until 2016 that papers started to be published providing models and data to support the reality of such a link.
The first of these was from Carlos Peres and his colleagues positing that hunting of large primates and tapirs in Amazonia would significantly affect the amount of carbon stored in the forest. Since then, a suite of other peer-reviewed papers have come out, supporting that link for tropical forests in different parts of the world, including by Fabio Berzaghi on the significant impacts that loss of forest elephants in Africa has on the forests’ ability to capture and store carbon. This is especially critical given the massive losses of forest elephants in recent years due to hunting for the illegal ivory trade.
TE: How exactly does the disappearance of species effect forests?
EB: Many of the large mammals and birds sought by hunters are fruit-eaters with large gapes that disperse large seeds – seeds characteristic of tree species with high carbon content. Loss of large fruit-eaters such as primates, hornbills and toucans, over time, shifts the species composition of forests so that small-seeded or wind-dispersed tree species become more prevalent – species with a lower wood density and carbon content. Hunters also target species whose activities directly affect forest structure. In Central Africa, elephant browsing reduces the density of tree stems in the forest, resulting in the emergence of fewer, larger trees, and hence greater carbon stock.
TE: The killing of which species have the most impact on the climate?
EB: In tropical forests, they are large fruit-eating birds and mammals such as primates and large frugivorous birds which disperse large seeds, as well as species such as elephants which affect forest structure. Tropical forests across the world have largely fallen silent due to loss of those species to hunting, the so-called “empty forest syndrome”. This significantly reduces the amount of carbon captured by and stored in the forest, and thereby our overall ability to mitigate climate change.
TE: How have other members of the scientific community reacted to your findings?
For ecologists who have studied hunting, this comes as no surprise. For those who focus on trees and carbon, it is a little too soon to assess. They are a key target audience for the paper, with the intent that conservation of intact wildlife communities should become part of the policies, actions and markets around forests and carbon, so hopefully others will start to pick up on the findings, especially in the build-up to the UNFCCC CoP28.
TE: What action needs to be taken to mitigate the effects on both the climate and wildlife?
Since the loss of intact forests has detrimental impacts on both the climate and on wildlife, addressing it involves protection of all remaining intact forests across the tropics, including their full complement of fauna managed effectively to prevent unsustainable hunting. This would both conserve the forests with their wildlife with their multiple ecological benefits, and increase carbon sequestration and storage, hence helping to mitigate climate change. In addition, if carbon markets can recognise the critical role of wildlife in attaining the full carbon values of forests, they could provide a critical, new and sustainable source of funding for forest conservation and management, including management of hunting.
TE: Are you looking at other so-far unidentified links between human activity and climate?
Recognising the multiple and vast links between human activity and climate overall, our focus is primarily on the role that loss of wildlife around the world has on the natural world’s ability to mitigate climate change. There is clear evidence that the loss of large marine mammals such as whales has major negative impacts on the carbon value of oceans. I am also intrigued about the potential role of top predators in influencing the carbon values of forests and seas. They are well known to influence the whole structure and composition of their ecological communities, so what impact does the loss of tigers, lions and sharks have on the carbon values of those communities?
TE: Will you be attending Cop28?
WCS will have a strong delegation there, building on our organisation’s strengths in nature-based solutions to climate change, especially the protection of forests.