Adding Fungi to Soil may Introduce Invasive Species, Threatening Ecosystems

By Miranda Hart

Invasive, alien species are bad for ecosystems. They reduce bidoversity and disrupt food chains, including our own.

History is full of examples of intentional and unintentional introductions of invasive species. The introduction of cane toads to Northern Australia in the 1930s to fight cane beetles led to decline of many native predators. The fungus that causes chestnut blight snuck into North America via infected nursery stock; four billion trees died in 40 years.

It's easy enough to see the devastation by invasive species of plants, just look your window: spotted knapweed, Eurasian milfoil and giant hogweed have completely changed communities across North America .

Soil ecosystems

What about creatures in the soil? Have they been affected by invasive species? Which species have gone extinct? Which ones are proliferating? It is important to think about soil as an invisible ecosystem, because many agricultural practices include the deliberate addition of microbes to the soil, biofertilizers.

Biofertilizers are microbes that are grown specifically for application to soil. There are many microbes that are used as biofertilizers, including bacteria and fungi, and the most common application is to improve crop nutrient status. These products are considered by some to be a more sustainable alternative to synthetic fertilizers.

The use of mycorrhizal fungi—fungi that grow on plant roots—as biofertilizers is becoming more common. Applying them as a kind of fertilizer makes sense because these fungi grow in plant roots and help plants get more nutrients from the soil.