Grazing animals key to long-term soil carbon stability: IISc study

Source: The post is based on the article “Grazing animals key to long-term soil carbon stability: IISc study” published in The Hindu on 19th October 2022.

What is the News?

A study carried out by researchers at the Center for Ecological Sciences(CES) and Divecha Centre for Climate Change (DCCC), IISc has revealed that grazing animals hold the key to long-term soil carbon stability.

How do grazing animals help in long-term soil carbon stability in the Himalayas?

Large mammalian herbivores like the Yak and Ibex play a crucial role in stabilizing the pool of soil carbon in grazing ecosystems such as the Spiti region in the Himalayas.

For instance, researchers studied the impact of grazing animals on Himalayan ecosystems in 2005 by establishing fenced plots (where animals were excluded) as well as plots in which animals like yak and ibex grazed.

From one year to the next, they found that soil carbon was found to fluctuate 30-40% more in the fenced plots where animals were absent, compared to the grazed plots where it remained more stable each year. 

A key factor underlying these fluctuations was nitrogen. Depending on the soil conditions, nitrogen can either stabilize or destabilize the carbon pool. However, grazing by herbivores changes their interactions in ways that tip the balance in favour of the former.

Hence, the researchers concluded that experimental removal of grazing by herbivores from such ecosystems was found to increase the fluctuations in the level of soil carbon, which can have unintended negative consequences for the global carbon cycle.

What is the significance of this study?

As grazing ecosystems make up about 40% of the Earth’s land surface, protecting the herbivores that keep the soil carbon stable should remain a key priority for mitigating climate change.