Coastal marshes are among the first ecosystems to be altered by climate change. With increasing sea level rise, assisted migration may be necessary to establish founder populations in more favorable upslope habitats. Mycorrhizal mutualisms could play a key role in determining success of these moving populations. The objectives of this study are: (1) to identify potential mycorrhizal relationships by determining whether assemblages of spores exhibit zonation mirroring that of coastal plant communities and (2) to test whether abundance and composition of mycorrhizae in roots of a dominant marsh species (Juncus roemerianus) differ with simulated assisted migration into upslope soils. Soil samples and seeds for trap plants were collected from the coenocline at Grand Bay National Estuarine Research Reserve in coastal Mississippi.
Results/Conclusions
A total of 1694 unique operational taxonomic units (OTUs) was found across the entire gradient. The soil samples had an average of 196.25 OTUs per sample while the root samples were less diverse with an average of 29.04 OTUs per sample. The DNA analysis of the soil samples show that the Glomeromycete spores exhibit little to no zonation on the seaward end of the gradient (salt and brackish marsh), but moving upslope to the fresh marsh and pine woodlands, the spore composition becomes increasingly zoned. Species richness and abundance in the soil samples increased along the elevation gradient; they were highest in the pine woodlands and lowest in the salt marsh. The salt marsh showed isolation in its species composition, sharing only two OTUs with the other three zones. The brackish marsh, fresh marsh and pine woodlands exhibited species overlap among most of the dominant OTUs. These results indicate that apart from the salt marsh, plant-mycorrhizae relationships can persist after upslope migration of coastal plant species.