Drivers of ecological niche breadth in partially mycoheterotrophic orchids and implications for future distributions

Many orchid species are dependent on mycorrhizal fungi as well as pollinators for reproduction and seed germination. Adaptation to different mycorrhizal species and habitat conditions may contribute to speciation in orchids through reproductive isolation; however, the role of mycorrhizal communities in promoting divergence in orchid taxa is not yet clearly defined. This research investigates whether adaptation to different mycorrhizal species and habitats contributes to reproductive isolation in the orchid genus Epipactis. The effects of different mycorrhizal assemblages on Epipactis phylogenies will be explored in relation to the genomic and morphological variation among Epipactis species. Reciprocal seed germination experiments will be performed to assess whether orchid seedling establishment is affected by mycorrhizal divergence or habitat adaptation. Species distribution models will be used to explore geographic isolation of Epipactis species, and temporal isolation will be investigated by monitoring pollinator visits and flowering phenology.