New Research on Biodiversity and Nature

A round-up of recent work published in scientific journals

Trophy hunting perceptions. Sacred deer dilemma. Africa-wide deforestation drivers. Self-sustaining condors. Forestation side effects. Tuna mercury. And more…

What shapes public perceptions of trophy hunting: Trophy hunting is a contentious topic, especially in the case of tourists visiting Africa to hunt wildlife. This study investigated perceptions of trophy hunting among urban residents of South Africa, the United States and the United Kingdom by presenting them with hypothetical hunt situations with variable characteristics. Views about the acceptability of trophy hunting changed depending on which species was hunted, whether local people or wildlife got the meat, and whether hunting revenues went to conservation, economic development or hunting enterprises. Views also varied among people according to factors including their location and level of education. Overall, they were more likely to accept trophy hunting if it brought benefits to local people. The findings show that public attitudes are more nuanced than the polarized views of pro- and anti-trophy-hunting lobby groups. Read the full paper in Proceedings of the Royal Society B: Biological Sciences.

Sacred deer and a conservation dilemma in Japan: Sika deer have been revered and protected as sacred animals for over a thousand years in an open sanctuary in the Japanese city of Nara. But as the deer population has grown, the animals have been damaging crops on farmland beyond their sanctuary. This study examined the genetics of deer inside and outside of the sanctuary, and found that the former are a genetically distinct population — the true sacred deer. The latter group have mixed ancestry, deriving from sacred deer that left the sanctuary and ‘normal’ deer. The authors say urgent decisions are required about whether to exterminate the deer beyond the sanctuary or risk losing the genetic identity of the sacred deer. Read the press release or the full paper in Conservation Science and Practice.

What drives deforestation in Africa: This study provides the first high resolution, Africa-wide mapping of land use following deforestation. It identifies the main human activities that drove deforestation across the continent between 2001 and 2020. In general, small-scale crop farming was the main driver, accounting for 64 percent of the total. Regional patterns included an ‘arc of commodity crops’— such as cacao, oil palm and rubber — driving loss of humid forest in western and central Africa; large-scale croplands replacing forest in Nigeria and Zambia; and a growing role for cashew production in the loss of dry forests in western and south-eastern Africa. The authors say that by assessing forest loss and its causes, their work can inform action to achieve zero-deforestation supply chains for commodities and reduce carbon emissions from forests under the UN-led REDD+ initiative. Read the press release or the full paper in Scientific Reports.

Ending conservation-dependency of California condors: The California condor is an iconic bird species. It is famous for having its extinction in the wild reversed, but is still utterly dependent on conservation for its ongoing survival. The wild population needs to be supplemented with captive releases because so many of the birds are being poisoned by lead ammunition in carcasses on which they feed. This study looked at how to ensure the wild population can survive on its own. It concluded that releasing captive-bred birds would boost population growth more than replacing failed eggs in wild nests with captive-laid ones. And it found that even small, but lasting, reductions in condor mortality due to lead poisoning would eventually contribute to population growth more than annual releases of captive-bred birds. The authors say captive-breeding is key to increasing the wild population and that reducing lead-related deaths would allow the population to become self-sustaining. Read the full paper in Biological Conservation.

Side effects of forestation offset carbon gains by up to a third: Increasing forest cover is a key way of reducing the amount of carbon in the atmosphere to mitigate climate change. But, as this study shows, forestation comes with side effects that can offset the amount of carbon stored by up to 30 percent. For example, replacing grassland with forest reduces the reflectivity of the land surface (as trees are darker). Expanding forest areas will also affect atmospheric concentrations of methane, ozone and tiny particles called aerosols in ways that offset the amount of carbon new areas of forest pull from the atmosphere and store. The authors say these effects are more pronounced at higher latitudes than in the tropics. They say that tree planting is still important for addressing climate change but that reducing use of fossil fuels is also essential. Read the press release or the full paper in Science.

Mercury levels in tuna: stable since the 1970s. When mercury enters water it forms toxic methylmercury, which can enter marine organisms and increase in concentration higher up food chains — the main way that people are exposed to it is by eating ocean fish such as tuna. According to this study, methylmercury levels in tropical tuna have barely changed since 1971, despite global efforts that have greatly reduced emissions of mercury from mining, coal-burning and other human activities. The authors think this may be because ‘legacy’ mercury, emitted many years before action to reduce emissions, is moving from deeper to shallower ocean waters where tuna feed. They say their work shows that more aggressive cuts in mercury pollution are needed, as it could take decades before oceanic concentrations decline measurably. Read the press release or find the full paper in Environmental Science & Technology Letters.

See also, new papers on:

• Increasing wildfires in the Brazilian Amazon

• Rewilding for climate action

• How farmers in ten European nations perceive and value biodiversity

• Seabird recovery after world’s biggest multi-predator eradication

• Climate change could force bowhead whales into the path of ships

• How well more than 6,000 bird species tolerate human pressures

In case you missed it…

Earlier this week, I published Nature Beat #17 — full of news, resources, jobs, great stories, and more.

Nature Beat #17

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