Structural and functional spatial heterogeneity of arbuscular mycorrhizal fungi.

摘要

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.