Functional responses of forest soil biota to climate change and biochar: ecosystem carbon budget, soil condition and management implications

The society must strive to understand how climate change will affect biodiversity and important processes in our ecosystems. This kind of understanding is necessary for mitigation of and adaptation to climate change in an efficient way. The project ForBioFunCtioN investigates how climate change influences species richness and functions of fungi, bacteria, soil fauna and ground vegetation in boreal spruce forests. The functions we look at are connected to critical ecosystem processes such as the carbon and nitrogen cycles. With the help of a climate manipulation experiment in forests, we will assess how carbon emissions from soil and dead wood are affected by climate change. We will evaluate how these changes are expected to affect the forest ecosystem carbon budget: how much carbon does the forest store, and how much does it release to the atmosphere. We will also study the effects of fertiliser application, together with a new climate change mitigation tool, biochar in forest soil. The effects of biochar application on soil biota, soil properties and soil processes will be studied both in current climate and in conditions corresponding to future climate. The effect of biochar application will be compared with the effects of fertiliser application, as biochar is expected to improve soil nutrient status so that the need for forest fertilisation may become reduced. We will consequently predict future forest carbon budgets that include both the future carbon fluxes and biochar. We will also evaluate which soil properties that are suitable as indicators of soil condition. Our project may reveal important trends that can be difficult to overturn after the changes have taken place, such as loss of soil carbon into the atmosphere in a warming climate. If we notice such trends early, we can design targeted and efficient actions to safeguard the species or soil properties that are the most important ones for ecosystem processes such as the carbon cycle.

Understanding the effects of climate change on biodiversity and processes in our ecosystems is a first necessary step for optimal societal mitigation and adaptation to climate change. The project ForBioFunCtioN will investigate how climate change, biochar and fertiliser application influence natural communities of fungi, bacteria, soil fauna and ground vegetation in boreal spruce forests in terms of species richness, functional diversity and functions that are connected to critical ecosystem processes such as the carbon and nitrogen cycles. With the help of a climate manipulation experiment in forests, we will quantify the climate-induced changes in greenhouse gas emissions from soil and dead wood, and establish the relevance of these changes for the forest ecosystem carbon budget, utilising eddy-covariate measurements from ICOS Norway. We will predict future forest carbon budgets that include both the future carbon fluxes and a novel climate-change mitigation too, biochar in forest soils. The effects of biochar application on soil biota, soil properties and soil processes will be studied both in current climate and in conditions corresponding to future climate. The effect of biochar application will be compared with the effects of fertiliser application, as biochar is expected to improve soil nutrient status so that the need for forest fertilisation becomes reduced. Based on our results and literature review, we will evaluate which soil properties are suitable as indicators of soil condition. Our project may reveal trends of global importance that can be difficult to overturn after the changes have taken place, such as loss of soil carbon to the atmosphere in warming climate. Early detection enables targeted and efficient actions to safeguard the species or properties with the greatest impact on ecosystem processes. We will produce knowledge necessary for the design of evidence-based conservation and management schemes as well as policy development.