Effects of land use change on dry heathland soil moisture in a changing climate

Conversion of natural and semi-natural systems to agricultural use is one of the largest conservationchallenges of our time. As the worlds population continue to grow at unprecedented rates,multinational organizations like the United Nations and its subsidiary the Food and AgricultureOrganization call for higher crop production and the expansion of existing agriculture to ensure futurefood security, especially in the face of changing climate. However, these efforts will most likely endangernumerous landscapes of historical and cultural value, including those found in northwest Europe. Howthese possible changes in land use may alter the functions of these ecosystems and the associatedservices they provide are questions that need to be answered before any policy decisions can be made. Using a state-of-the-art ecotron facility, we compared soil moisture profiles between an intact dryheathland system and heathland soils that had been cleared for cereal agriculture, both of which weresubjected to climate conditions projected for the year 2070, in line with the IPCC RCP8.5. Aftercontinuously monitoring moisture changes in the top 1.5 meters of soil for three years, we found thatthere are significant differences between the two modes of land use. Soils used for cereal crops weresignificantly drier (up to >60%) in the upper 10-20cm than intact heathland soils, and significantly wetter(up to >500%) at the lowest soil levels (140cm). This redistribution of moisture within the soil columnunder different land use schemes can have serious implications for overall ecosystem functioning,particularly with regard to potentially mitigating heathland soils ability to store and capture carbon andexacerbating detrimental soil-climate feedbacks under agricultural use.