London: An international study initiated by a late Indian-origin scientist have found that primary forests – those least disturbed old-growth forests – sustain the highest levels of biodiversity and are vital to many tropical species.
Rampant rates of logging and agricultural expansion have transformed the world’s tropical forests, leaving little remaining primary forests unaltered by humans.
The value of these rapidly expanding degraded and converted forest landscapes is hotly debated, and was the subject of the study started by the late Professor Navjot Sodhi, a renowned conservation ecologist at National University of Singapore, who devoted his career to studying the biodiversity crisis in Southeast Asia and around the planet.
“Some scientists have recently argued that degraded tropical forests support high levels of biodiversity,” said Luke Gibson, the lead author from the NUS, who was mentored by Professor Sodhi.
“Our study demonstrates that this is rarely the case,” he stated.
Drawing on information from 138 scientific studies spanning 28 tropical countries, Gibson and his colleagues from Singapore, Australia, Switzerland, the UK and the USA compared biodiversity in primary forests to that in regenerating forests and forests degraded by logging and converted to agriculture.
Overall, biodiversity values were substantially lower in disturbed forests.
“There’s no substitute for primary forests. All major forms of disturbance invariably reduce biodiversity in tropical forests,” said Gibson.
With the global population projected to surpass 9 billion by 2050, tropical forests will face increasing threats posed by human-driven land-use changes.
“Human populations are exploding and very few areas remain untouched by the expanding horizon of human impacts,” said Gibson.
“It is therefore essential to limit the reach of humans and to preserve the world’s remaining old-growth rainforests while they still exist. The future of tropical biodiversity depends on it,” he concluded.
The study has been published in Nature.