A two-decade study of biodiversity loss

Lake islands in northern Sweden. Credit: David Wardle.

When an ecosystem experiences a loss of biodiversity, such as a fall in the number of plant species, the species that remain have been shown to collectively produce less biomass than before.

Hoping to understand the contribution of soil fertility and biomass production to ecosystems’ ability to withstand biodiversity loss, Prof David Wardle from NTU’s Asian School of the Environment and Assoc Prof Paul Kardol from the Swedish University of Agricultural Sciences ran an experiment—one that has lasted over two decades and is still ongoing.

The experiment, which is taking place across 30 lake islands in the boreal forest zone of northern Sweden, simulates biodiversity loss by removing species in various combinations on experimental plots on each island.

The research team found that the effects on biomass productivity differ greatly across ecosystems experiencing a loss of biodiversity. Although the remaining species partly compensated for the ones that were lost, the extent of compensation was found to be highest in ecosystems where soil fertility and biomass production were lowest.

“The results are contrary to previous beliefs that all ecosystems respond to biodiversity loss in similar ways,” says Prof Wardle. “They show that we need to look at all factors, such as soil, geology, climate and organisms, to draw conclusions on how species and biodiversity loss might influence any particular ecosystem, including agricultural and forest production systems.”

The findings are described in “Long-term effects of species loss on community properties across contrasting ecosystems”, published in Nature (2018), DOI: 10.1038/s41586-018-0138-7. Prof David Wardle recently received the Eminent Ecologist award from Journal of Ecology for his contributions to research on terrestrial ecosystems.

This article appeared first in NTU’s research & innovation magazine Pushing Frontiers (issue #14, December 2018)