| Arbuscular mycorrhizal fungi (AMF) are plant root symbionts that are known to play important functional roles in plant communities, but small-scale spatial variation in AMF structure and function is poorly understood. In a calcareous fen plant community, I conducted a field study to examine spatial patterns of AMF abundance and diversity using a DNA-based community fingerprinting approach. Both abundance and diversity were spatially heterogeneous within a 2m x 2m plot where the depth to water table showed significant spatial structure. AMF abundance, but not molecular diversity, showed statistically significant spatial structure. When I manipulated the presence and absence of AMF and depth to water table in fen mesocosms, the community-level and individual plant species effects of AMF were mediated by water table, with many negative responses of plants to AMF. These data provide evidence for small-scale structural and functional spatial heterogeneity of AMF within calcareous fens. |
