Importance of AM fungi and local adaptation in plant response to environmental change: Field evidence at contrasting elevations

Predicting response of plants to environmental change is a great challenge for ecologists and requires a deeper understanding of the importance of biotic interactions such as the role of arbuscular mycorrhizal (AM) associations. Using reciprocal transplantation experiments we tested the performance of two plant species (Primula atrodentata and Aster himalaicus) and AM fungal associations and their interactions in response to environmental change at sites of contrasting elevation. The results show a clear home advantage of plant performance and fungal colonization in most cases, and the consistently positive responses of plants to AM fungi in all home-away combinations. Specifically, mycorrhizal responses showed home-site advantage in P. atrodentata and the AM fungi consistently increased the fitness of A. himalaicus at the high elevation site, suggesting that the stress gradient hypothesis and adaptation hypothesis are both important theoretically in the prediction of functional responses of AM associations to environmental change in alpine ecosystems.