The role of fungi in soil carbon accumulation
Some of the endemic species in New Zealand's Tongariro National Park are being outcompeted by the imported European Calluna vulgaris plant, better known as heather. The plant is host to mycorrhizal fungi, which are known to play an important role in organic matter decomposition in soil, thus contributing to soil carbon accumulation. The EU-funded 'Does plant C regulate the decomposition of soil organic matter by ericoid mycorrhizal fungi?' (ERICARB) project investigated the role of these fungi in invasion ecology. Specifically, project aims were to characterise the response of similar native fungi to heather invasion, and to assess the impact of the invasive fungi on soil organic matter decomposition. The researchers also wanted to assess the living and non-living factors behind changes in decomposition. Project members collected root systems of native and invasive species in a broad geographical range, and used DNA analysis to identify specific fungal species. This work provided the first description of these specific fungal communities in New Zealand. ERICARB also built a system to analyse loss of soil carbon dioxide (CO2) into the atmosphere. This was used to assess whether the type of host plant or fungus affected the decomposition of carbon in soil. The researchers found that nutrient and plant carbon availability were the driving forces behind soil organic matter decomposition. In addition, they determined that heather invasion may indeed cause changes in native soil microbes and/or chemistry. The researchers expect that their data will improve models of soil carbon cycling in ecosystems such as coniferous temperate and boreal forests, and peatlants. They also hope that other scientists and conservationists can use the information to control invasive species and their symbionts.
