Overhunting of species curtails ability of forests to store carbon
Poaching the likes of elephants, gorillas, and toucans is not only disastrous for biodiversity but also impacts the ability of forests to act as a natural carbon storer, new research has found. Picture: Getty
Poaching the likes of elephants, gorillas, and toucans is not only disastrous for biodiversity but also impacts the ability of forests to act as a natural carbon storer, new research has found.
The Wildlife Conservation Society (WCS) study found that overhunting of these species, along with other large species that eat fruit and disperse large seeds, makes forests less able to store or sequester carbon.
Published in the journal PLOS Biology, the study showed that the loss of large frugivores such as primates, hornbills, and toucans leads to the composition of forests changing over time.
Wind-dispersed or small-seeded tree species with lower wood density, and therefore lower amounts of carbon, become more prevalent, said the study authors.
According to the UN, forests sequester carbon by capturing carbon dioxide from the atmosphere and transforming it into biomass through photosynthesis. Sequestered carbon is then accumulated in the form of biomass, deadwood, and litter and in forest soils.
The UN said that the forest biomass in the 27 countries of the EU, for example, contains 9.8bn tons of carbon. For context, the total carbon emissions of the same countries in 2004 was 1.4bn tons of carbon.
Carbon emitted every year by the EU's member states equals nearly one-seventh of the carbon stored in the EU27 forests, meaning the value of forest carbon storage cannot be understated in its importance, the UN says.
The WCS study said that the highly coveted species for poachers tend to be fruit eaters and therefore dispersers of seeds.
WCS vice president of species conservation and study lead author, Elizabeth Bennett, said: “Many tropical forests have been described as ‘empty’ owing to loss of animals, often as a result of unsustainable subsistence or market hunting.
"Less appreciated is the adverse impact of defaunation on the capacity of tropical forests to sequester and store carbon, which has implications for climate change.”
Co-author John Robinson said animals have a vital role in maintaining the integrity of such forests.
"Those forests with their full complement of faunal species, at healthy population densities, sequester and store more carbon than those that have lost components of their fauna.
Maintaining intact faunas is therefore a critical component of any strategy to conserve forests to address climate change.”
An adult forest elephant holds about 720kg of carbon, the WCS said. The 11,000 elephants killed in a single national park in Gabon from 2004 to 2012 would therefore have meant the loss of 7,920 tons of carbon storage, equivalent to 29,040 tons of CO2 equivalent.
CO2 equivalent is the standard unit for measuring all greenhouse gases. They include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and fluorinated gases, and are measured in a common unit for the purposes of simplicity and clarity.
One ton would be similar to driving 10,000km in a petrol car, and for every ton of emissions, some 50 trees must be grown to counteract the effects.
According to Interpol and the UN Environment Programme, wildlife crime is estimated to be worth up to $20bn (€18.3bn) a year.
A joint report from the organisations warned in 2016 that "this new area of criminality has diversified and skyrocketed to become the world’s fourth largest crime sector in a few decades, growing at two to three times the pace of the global economy".
One of the largest conservation charities in the world, the International Fund for Animal Welfare, has warned that "wildlife crime is the fifth largest transnational criminal activity, putting at risk the survival of thousands of species".
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