A new study finds that in the state of Pará alone, selective logging, road-building, fires and other disturbances have reduced biodiversity as much as clearing 92,000–139,000 km2of pristine forest.
For more than a decade, Brazil has been aggressively fighting deforestation in the Amazon, including through a legal mandate in the Forest Code that landowners in the region maintain as much as 80% of their forest cover. Yet selective logging and road-building are still permitted. Forest fires are also common, mostly started by burns on nearby agricultural fields.
As forest degradation due to human activities has become more visible, scientists have begun to try to gauge the impact. A new study published in the journal Nature for the first time quantifies the collective impacts of all these disturbances on forests in the Brazilian state of Pará, comparing them with losses from deforestation.
The international study team, which included researchers from 18 institutions, assessed the occurrence of 1,538 plant, 460 bird and 156 dung beetle species throughout Pará – an area the size of South Africa that has been a focal point of Amazon protection efforts. They found that even in landscapes that have the highest level of protection under Brazil´s Forest Code, disturbed forests had lost 46–61% of their conservation value.
“We provide compelling evidence that rainforest conservation initiatives must address forest disturbance as well as deforestation,” said Jos Barlow, lead author of the study and a professor of conservation science at Lancaster University in the UK. “Without urgent action, the expansion of logging operations and the spread of wildfires fuelled by human-induced climate change mean that tropical forests are likely to become increasingly degraded, conserving only a fraction of the breathtaking diversity they once harboured.”