One of the world's largest growing threats to endangered animals and plants is coming from a very small source: fungus. The discovery was made by researchers in the United Kingdom and the United States. Presented in the journal Nature, the study was funded in part by the BIODIVERSA2 (Cooperation and shared strategies for biodiversity research programmes in Europe) project, which received EUR 2 million in funding under the Environment Theme of the EU’s Seventh Framework Programme (FP7). The results suggest that in 70% of instances where an infectious disease caused the extinction of a type of animal or plant, the culprit was a nascent species of fungus.
Fungi are microorganisms and are different from plants, animals and bacteria. Their small size, however, belies the huge impact they make on the world's flora and fauna. It is estimated that each year fungal infections are responsible for destroying more than 125 million tonnes of staple crops, which include rice, wheat, maize, potatoes and soybeans. These diseases that emerge include rice blast, soybean rust, stem rust in wheat, corn smut in maize and late blight in potatoes.
As staple crops, they are a large source of calories needed by people to survive; preventing their destruction could go a long way to feeding populations who do not, at present, get enough to eat. In fact, the researchers believe that more than 600 million people around the globe could be fed each year if the spread of fungal diseases in the world's five most important crops was stopped.
The research group was led by the University of Oxford and Imperial College London in the United Kingdom. Commenting on the results, lead author Dr Matthew Fisher from the School of Public Health at Imperial College London said: 'The alarming increase in plant and animal deaths caused by new types of fungal disease shows that we are rapidly heading towards a world where the "rotters" are the winners. We need strive to prevent the emergence of new diseases as we currently lack the means to successfully treat outbreaks of infection in the wild.'
And if destroying food sources was not enough, another finding that raised alarm bells was the externality impact that fungal diseases have on the planet. Trees are an important part of the ecosystem and play a role in soaking up carbon dioxide (CO2). However up to 7%, or 230-580 megatonnes, of atmospheric CO2 are not being absorbed by trees because they have either been killed or are infected by fungi. This impact has caused scientists to believe that fungi may be behind an increase of the greenhouse effect.
Wildlife is not immune from fungal diseases either, according to the researchers. Over 500 species of amphibian species, as well as many endangered species of bees, sea turtles and corals have found themselves under threat as well. Studies suggest that white nose syndrome fungus in the United States has led to a decline in bat populations, and this in turn has led to an increase in the insect crop-pests because the bats are no longer around to keep their numbers down. The cost to agriculture is estimated at more than USD 3.7 billion per year.
Co-author Sarah Gurr, a professor of Molecular Plant Pathology at the University of Oxford, said: 'Crop losses due to fungal attack challenge food security and threaten biodiversity, yet we are woefully inadequate at controlling their emergence and proliferation. We must have better funding channelled into the fight against fungal disease.'
In a worst-case scenario, fungal infection could damage of up to 900 million tonnes of food if disease epidemics were to hit all the top five food crops in the same year, and would leave over 4.2 billion people starving, the researchers said.
As a result of these findings, scientists are calling for solutions to this threat to prevent the proliferation of existing and emerging fungal infections in plants and animals. By tackling this problem now they hope to prevent further loss of biodiversity and food shortages in the future.