Climate and dispersal influence the structure of leaf fungal endophyte communities of Quercus gambelii in the eastern Great Basin, USA

Endophytic fungi form communities within living plant tissues. Their functions vary tremendously so the structures of their communities influence plant and ecosystem functions. We determined the separate effects of neutral and deterministic processes structuring communities of Quercus gambelii leaf endophytes by sampling north- and south-facing flanks of four canyons so local climate varied independently from spatial separation. We found that both deterministic (response to climate) and neutral (dispersal limitation) processes significantly influenced community structure. These findings, if applicable to other systems, may have consequences in both agricultural and natural ecosystems. Endophyte dispersal could limit agricultural production, ecosystem restoration or natural plant establishment. Thus deliberate inoculation may prove useful in some situations. Moreover, the influence of climate on fungal endophyte communities indicates that climate change may not only impact plant distributions directly, but may also do so indirectly via the effect of endophytes on plant tolerance to temperature and moisture extremes.