Climate change is very complex, and, consequentially, models predicting it need to take into account many different aspects, from wind patterns to plant and algal growth. One of the expected consequences of the changing climate is that some regions will be drier, while others will be subjected to higher rates of precipitation, which, up in the north, means more snow.

Snow doesn't have to be bad. In fact, the insulating effect of snow helps plants grow bigger. But, a new study found that it also encourages the rapid growth of killer fungal strains, killing the plants. Such an outbreak of fungus can extensively damage certain plant species. This might open up new niches for other plants,but it could also alter the food-web in the area, affecting insects, voles, lemmings and so on. This shows that more research into long-term vegetation and fungal life cycles could have its merits for the understanding of the potential impacts of climate change.

The researchers constructed snow fences, allowing them to manipulate the amount of snow. In the first years of the experiment, the expected insulation effect helped the plants grow, but at year six, a tipping point was reached. The fungus Arwidssonia empetri spread rapidly and killed the plants of the species Empetrum hermaphroditum. Under heavier and prolonged snow conditions, the fungus killed the majority of the plant shoots. The demise of the plants changed the area from a natural carbon sink to a net carbon source, which is bad news in climate change terms.

This unexpected finding illustrates that many unforeseen consequences of climate change can have a large influence on the vegetation and the food webs in a region. It also shows that modeling climate chance is a huge challenge.

Reference

Olofsson, J.; Ericson, L.; Torp, M.; Stark, S. and Baxter, R. (2011). Carbon Balance of Arctic Tundra Under Increased Snow Cover Mediated by a Plant Pathogen. Nature Climate Change. doi:10.1038/nclimate1142.