Huge carbon stores discovered beneath UK grasslands

 

A nationwide survey by ecologists has revealed that over 2 billion tons of carbon is stored deep under the UK’s grasslands, helping to curb climate change.

However, decades of intensive farming, involving heavy fertilizer use and excessive livestock grazing, have caused a serous decline in valuable soil carbon stocks in grasslands across the UK.

The nationwide survey was carried out by a team of scientists from the Universities of Manchester, Lancaster, Reading and Newcastle, as well as Rothamsted Research.

The team found that 60% of the UK’s total soil carbon stored in grasslands – covering a third of UK land surface – is between 30cm and 1m deep. The team estimated the total grassland soil carbon in Great Britain to be 2097 teragrams of carbon to a depth of 1m.

Though the effects of high intensity agriculture are strongest in the surface layer of soil, they also discovered that this deep carbon is sensitive to the way land has been farmed.

Dr Sue Ward, the lead author of the paper from Lancaster Environment Centre, said:

“What most surprised us was the depth at which we were still able to detect a change in soil carbon due to historic land management.

“We have long known that carbon is stored in surface soils and is sensitive to the way land is managed. But now we know that this too is true at considerable soil depths under our grasslands.

“This is of high relevance given the extent of land cover and the large stocks of carbon held in managed grasslands worldwide.”

In contrast, the soils that were richest in carbon were those that had been subjected to less intensive farming, receiving less fertilizer and with fewer grazing animals. The team found that soil carbon stocks were 10% higher at intermediate levels of management, compared to intensively managed grasslands.

Professor Richard Bardgett from The University of Manchester said:

“Our findings suggest that by managing our grasslands in a less intensive way, soil carbon storage could be important to our future global carbon targets, but will also bring benefits for biodiversity conservation.”

He added:

“These findings could impact how grasslands are managed for carbon storage and climate mitigation, as current understanding does not account for changes in soil carbon at these depths.

“Our findings suggest that by managing our grasslands in a less intensive way, soil carbon storage could be important to our future global carbon targets, but will also bring benefits for biodiversity conservation.”

The research is part of a five year research project, supported by DEFRA, aimed at managing UK grassland diversity for multiple ecosystem services, including carbon capture.

 


The paper, ‘Legacy effects of grassland management on soil 1 carbon to depth’ is available in the journal Global Change Biology.

FLS staff contribute to National Climate Change Report Card

Two Faculty scientists are helping to shape policy by submitting scientific evidence to the latest National Biodiversity Climate Change Report card. Ecologists Professor Richard Bardgett and Dr Franciska De Vries have both been asked to contribute to the report which summarises the latest scientific evidence and understanding of how climate change is affecting UK biodiversity. The card itself shows where observed changes are likely to have been caused by changes in the UK climate over recent decades, and assesses potential future impacts of climate change on biodiversity.

Dr De Vries says:

This report card is important because it shows, at a glance, how UK biodiversity is already being affected by climate change. It shows which ecosystems and groups of organisms are most vulnerable to future changes , and this information is important if we want to act on climate change and protect UK biodiversity.

It is important that we take action to protect UK biodiversity against the effects of future climate change, because many ecosystem services depend on the diversity and composition of communities present. The report card includes potential ways for adaptation to climate change. For example, it is now clear that the way we manage land influences how species populations and communities respond to climate change.

It is hoped that reports such as these will give governments a clearer picture on what actions should be taken to protect our environment.


A link to the report can be found here (pdf)