Scale-dependent niche axes of arbuscular mycorrhizal fungi.

Arbuscular mycorrhizal fungi (AMF) are mutualistic with most species of plants and are known to influence plant community diversity and composition. To better understand natural plant communities and the ecological processes they control it is important to understand what determines the distribution and diversity of AMF. We tested three putative niche axes: plant species composition, disturbance history, and soil chemistry against AMF species composition to determine which axis correlated most strongly with a changing AMF community. Due to a scale dependency we were not able to absolutely rank their importance, but we did find that each correlated significantly with AMF community change at our site. Among soil properties, pH and NO(3) were found to be especially good predictors of AMF community change. In a similar analysis of the plant community we found that time since disturbance had by far the largest impact on community composition.