Abstract/Summary

Many forest ecosystems are experiencing increased drought stress due to changing patterns of aridity, due to both climate change and human land-use activities. Mycorrhizal fungi are known to provide their hosts with increased drought resistance in many circumstances, either through improved resource acquisition, direct uptake of water, or translocation of water obtained by their hosts. The ability of many mycorrhizal fungi to form mycelial networks, in which an individual mycelium connects to the roots of multiple host plants, provides a mechanism for the redistribution of water into upper soil layers experiencing low soil water potential. Here we review the roles of mycorrhizal fungi and mycorrhizal networks in water uptake and hydraulic redistribution, and consider how these may interact with host plants to moderate forest responses to increasing drought pressure. Lastly we present knowledge gaps and suggest several areas which would benefit from further research.