Declining biodiversity will hit stored carbon stocks given an ecosystem’s ability to keep carbon out of the air is linked to its biological diversity, a paper published last week has found.

Writing in Nature Communications, lead author Sarah R. Weiskopf of the University of Massachusetts said that “hundreds of experimental studies have consistently found that within a place, more diverse assemblages, and in particular more diverse plant assemblages, have higher standing biomass production and carbon sequestrations”.

“More diverse assemblages are more likely to contain the most productive species, which can increase overall functioning.”

Biodiversity declines from climate and land use change could lead to loss of carbon storage of anywhere between 7.44 billion tonnes of carbon and up to 103.14 bln under a global sustainability scenario, and 10.87-145.95 bln tonnes under a fossil fuelled development scenario, creating a self-reinforcing feedback loop of biodiversity loss driving climate impacts, which in turn destroy more biodiversity, according to the study.

“Conversely, biodiversity conservation and restoration can help achieve climate change mitigation goals,” the study said.

Biodiversity loss can be “on par with elevated carbon dioxide or effects of drought”.

One problem with wider implementation is that nature-based solutions work focuses more on the actual amount of trees across an area than the biodiversity within it, leading to poorer outcomes.

The fundamental issue, the multiple authors assert, is that “many carbon sequestration models fail to account for the role biodiversity plays in carbon storage”.

“Models projecting changes in biodiversity, ecosystem functioning, and ecosystem services typically operate independently and do not account for interactions or feedback,” the paper said.

“Not accounting for biodiversity may lead to inaccurate projections of ecosystem function and ecosystem services. Incorporating biodiversity-ecosystem function relationships could improve model accuracy, especially over long timescales as biodiversity effects become stronger over time.”

There are many ways to go about this, it said.

“One approach that can be applied at the global scale is to connect biodiversity to ecosystem function and ecosystem service models using empirical, observational, or experimental biodiversity-ecosystem function data.”

Loss of plant diversity could be assessed to see how it will affect carbon storage is one useful way to demonstrate the ease of this biodiversity and carbon approach, according to the authors.

Their modelling found that “plant species loss, and therefore proportional biomass loss driven by plant species loss were especially high in the tropics. Southern Australia, eastern Europe, and some regions of South America also had high losses”..

The Amazon will suffer especially, but southern Australia, which is typically more temperate and not tropical, will also face high levels of loss.

Jurisdictions are already factoring biodiversity into their carbon plans, such as Australia’s carbon-plus-biodiversity pilot scheme launched last year, and government-run programmes in some European countries like France, which account for biodiversity gains in carbon projects.

Last week the federal government announced the first methodology for the Nature Repair Market methodology to be released in January.

By Helen Clark – helen@carbon-pulse.com