Large and undisturbed forests are better at harbouring biodiversity than fragmented landscapes, according to an international team of ecologists.
Professor Raphael Didham, from The University of Western Australia's School of Biological Sciences, was co-author of the paper led by the University of Michigan, which was published in Nature.
"Ecologists agree that habitat loss and the fragmentation of forests reduce biodiversity at a local scale within remaining tracts," Professor Didham said.
"But controversially some people have argued that fragmenting forests into many small tracts could increase opportunities for different kinds of species to live in each separate patch, thus 'rescuing' biodiversity in the wider landscape."
Researchers examined 4,006 species of vertebrates, invertebrates and plants, sampled at 37 sites around the world to provide a standardised global comparison of biodiversity differences between continuous and fragmented landscapes.
The study found that on average, fragmented landscapes had 13.6 per cent fewer species at the local patch scale, as well as 12.1 per cent fewer species at the wider landscape scale.
"Our results showed that fragmentation into many small patches, which harboured distinct species, did not rescue biodiversity at the landscape scale," Professor Didham said.
"Across all taxonomic groups, we found fewer species in fragmented landscapes than you would find in a continuous landscape with large undisturbed forests."
The findings also suggested that the species primarily lost were rarer, specialist species that are not good at surviving in the fragmented areas.
"The loss of specialist species can affect how ecosystems function, such as effective pollination, and even the ability of fragmented landscapes to store carbon," Professor Didham said.
The findings can help inform protection and restoration of forest landscapes to support biodiversity.
"There are not a lot of large intact forests remaining around the world," Professor Didham said.
"We need to focus on planting new forests and restoring habitat to protect biodiversity while we still can."
