The effect of turf cutting on plant and arbuscular mycorrhizal spore recolonisation: Implications for heathland restoration

In two natural heathland vegetations, we analysed the effect of turf cutting on spore numbers of arbuscular mycorrhizal fungi (AMF). Next to this, we performed a controlled factorial experiment to examine the role of AMF for germination and establishment of Arnica montana in both turf cut and non-turf cut situations. AMF spore numbers decreased with soil depth, and, along with the topsoil, almost all AMF spores were removed with the removal of the acidified and/or eutrophied organic layer. Recolonisation of AMF spore numbers after turf cutting was slow: spore numbers of approximately 60-95 spores g(-1) dry soil were found two and a half years after turf cutting, corresponding with 55-70% of AMF spore numbers found in natural field populations of A. montana. Since AMF colonisation increased establishment and biomass, and decreased mortality of A. montana, it was suggested that lack of AMF after turf removal might complicate the establishment of this herbaceous species. Removal of organic material as a management measure should therefore carefully be applied, taking in consideration the low recolonisation rates of AMF as this can markedly effect the success of restoration.