Grazing animals key to long-term soil carbon stability: Study

Removal of grazing by herbivores may lead to an increase in the level of soil carbon

According to a 16-year-long study carried out by researchers at the Centre for Ecological Sciences (CES) and the Divecha Centre for Climate Change (DCCC), Indian Institute of Science (IISc), large mammalian herbivores like the yak and ibex play a crucial role in stabilising the pool of soil carbon in grazing ecosystems such as the Spiti region in the Himalayas.

Because grazing ecosystems make up about 40 per cent of the Earths land surface, protecting the herbivores that keep the soil carbon stable should remain a key priority for mitigating climate change.

Many previous studies have focused on measuring carbon and nitrogen levels at long time intervals, assuming that the accumulation or loss of carbon is a slow process, explains Dilip GT Naidu, PhD student at DCCC and first author of the study. But the inter-annual fluctuations paint a very different picture.

These fluctuations can be consequential for climate as they are linked to how large mammalian herbivores influence soil.

Since soil contains more carbon than all plants and the atmosphere combined, it is important to ensure its persistence. When plants and animals die, dead organic matter remains in the soil for a long duration before microbes break it down and release carbon into the atmosphere as carbon dioxide. 

Credit : Sumanta Bagchi 
Associate Professor  
Centre for Ecological Sciences (CES) 
Indian Institute of Science (IISc)