Greipsson, S.; Stover, K.; Whitney, S., and McElroy, T., 2024. Arbuscular mycorrhizal fungi and soil fungi associated with Uniola paniculata L. (sea oats) on restored and natural sand dunes on the Georgia Coast, U.S.A. Journal of Coastal Research, 40(5), 875–886. Charlotte (North Carolina), ISSN 0749-0208.

Coastal sand dunes are fragile ecosystems that serve as natural defenses to protect barrier islands and the adjacent mainland during severe storms. A high frequency of disturbances may result in dune erosion. Several strategies have been used for coastal restoration; however, previous practices often lack the connection between plants and below-ground microbial communities. Symbiotic arbuscular mycorrhizal fungi (AMF) are beneficial in supplying a range of limiting nutrients to the host plant while improving dune stability. This study assessed the diversity of the indigenous AMF and soil fungal communities associated with Uniola paniculata L. (sea oats) on natural dunes and restored dunes at Jekyll and Tybee Islands on U.S. Georgia's coast. The phosphorus (P) concentrations of dune sand were also analyzed. At each site, samples were collected from 10 dune ridges that were randomly selected along a 100-m transect where sea oats were growing. The genomic DNA was extracted from 60 sand and sea oats root samples. A total of 13 amplicon sequence variants of AMF were identified; seven were classifiable to the species level. The most abundant genera of AMF were Glomus; the most abundant species were unclassified Glomus spp., followed by Glomus custos and G. deserticola. Using the Sorensen-Dice coefficient, the study showed that AMF assemblages of the natural dunes of both sites shared a high similarity (0.73). However, AMF assemblages of the Jekyll Island natural site had no (0) similarity to Jekyll Island restored site 1. The greatest number of classes of soil fungi were found at Jekyll Island's restored site 1 (18 classes); conversely, the lowest number was found at Jekyll Island's natural site (nine classes). Natural dunes contained significantly greater levels of P in the sand compared with restored dunes. These findings demonstrate the need to manage sand material and AMF assemblages during coastal dune restoration.