The giant world of fungi

Context : A study published in Science produced the first global map of underground arbuscular mycorrhizal (AM) fungi networks. 

Prelims : 

• AM fungi have supported plant life for millions of years. The study analysed data from more than 16,000 soil cores using machine learning.
• Topsoils worldwide contain an estimated 110 quadrillion km of fungal hyphae.
• The AM fungal network stores around 300 million tonnes of carbon.
• This carbon mass is estimated to be four to six times the weight of the entire human population.
• AM fungi form symbiotic relationships with about 70% of plant species. They exchange soil nutrients for carbon obtained from plants.
• AM networks sequester an estimated 4 billion tonnes of CO₂-equivalent annually. This equals roughly 11% of all human-related carbon emissions.
• Grasslands in South Sudan, the Tibetan Plateau and India’s Banni grasslands contain around 40% of the world’s AM fungal networks.
• Croplands have about 50% lower fungal density than wild ecosystems. Grasslands are being converted to farms four times faster than forests.
• The Society for the Protection of Underground Networks (SPUN) described these fungal systems as a form of “living infrastructure.”

Mains: 

1. Ecological Importance

• AM fungi play a vital role in sustaining plant life through nutrient exchange.
• They support ecosystem functioning through symbiotic relationships with plants.

2. Carbon Sequestration

• AM fungal networks act as major carbon sinks.
• They sequester significant amounts of CO₂ equivalent annually.

3. Threats to Fungal Networks

• Conversion of grasslands into agricultural land threatens fungal biodiversity.
• Croplands support lower fungal densities than natural ecosystems.

4. Conservation Significance

• The study identifies global hotspots of AM fungal diversity.
• It argues that fungi should move from the margins of environmental policy to the centre of climate action.