September 7, 2016, by Tim Radford
Bearded pigs in the forests of Borneo. Image: Oliver Wearn/Imperial College London
Scientists find evidence that selective logging of forests could be providing a diversity haven for some species of mammals.
LONDON, 7 September, 2016 – Even in degraded forests, wild animals can survive. Selectively-logged forests in Borneo can still be home for the clouded leopard and the civet, the orangutan and the bearded pig.
And for small mammals such as squirrels and rodents, population densities could be even higher in no-longer-pristine woodland, according to new research.
Scientists from the UK report in Ecological Applications journal that they used trap-and-release techniques and motion-sensing cameras over a three-year span to build up 20,000 records of species sightings in old growth forest, logged forest, and oil palm plantations.
Selectively logged forest – in which the most valuable trees are taken – is considered degraded, and is sometimes cleared to make way for plantations.
But the data delivered a surprising finding: larger mammals seemed just as at home in the partially-cleared sites, and the diversity of smaller mammals seemed to be even higher than in the untouched rainforest. Mammal diversity in plantations, however, was impoverished.
Oliver Wearn, a conservation biologist at Imperial College London and the Zoological Society of London, and colleagues think that the selective logging may have created habitat diversity and opened up opportunities for some mammal species.
“Where old growth forests remain, these are still the best habitats for mammals and other native species”
“The logging process creates a greater variation in habitat types in a smaller area, from untouched areas on steep slopes to completely denuded areas of open grassland. Old growth forests would probably have the same diversity if we looked at them on a much larger scale,” he said.
The study adds another level of detail to the understanding of threat to biodiversity as the tropical rainforests come under increasing pressure.
There is evidence that forest loss threatens biodiversity. There is also evidence that without biodiversity, forests are in any case threatened: a habitat’s health is managed by the creatures that make their home in it.
Healthy rainforests soak up carbon dioxide and help contain global warming; cleared or degraded forests are likely to make climate change more catastrophic. Another recent study from Imperial College warned that even if forest destruction stops, the loss and potential extinction of species continues.
The latest study shows that ecosystems can be resilient. It does not however mean that mammal populations would continue to be safe in logged forests.
“What we can say from this is that protecting those large areas of forest that have already been logged would help conserve mammal species better than preserving fragmented pockets of forests inside oil palm landscapes,” Dr Wearn said.
“Where old growth forests remain, however, these are still the best habitats for mammals and other native species, and should be the absolute top priority for conservation.” – Climate News Network
Tim Radford, a founding editor of Climate News Network, worked for The Guardian for 32 years, for most of that time as science editor. He has been covering climate change since 1988.