Underground biodiversity: closing the knowledge gap in soil mycobiomes in the understudied gulf coast prairie dune ecoregion through research and outreach

The gulf coast prairie dune ecosystems of the barrier islands along the northern US Gulf Coast represent an important yet under-studied ecoregion in fungal biodiversity. These islands face increasing anthropogenic threats with important consequences to the coastal communities, including loss of biodiversity and the first line of defense against hurricanes. While the responses of dune vegetations to environmental change have been well-characterized, basic knowledge on underground fungal biodiversity, especially of mycorrhizal fungi, in these nutrient-poor environments remain limited. Even more limited is public awareness of fungi and their importance for the management of dune ecosystems. Here, we aim to increase knowledge on both fronts: fundamental fungal research and public awareness in local communities for conservation, addressing it in two ways. First, we characterized soil mycobiomes - focusing on arbuscular mycorrhiza fungi (AMF) and ectomycorrhiza (EcM) - along four barrier islands in South Texas, spanning salinity gradient and land-use history. We used high-throughput amplicon sequencing of the internal transcribed spacer (ITS) and 18S rRNA small subunit (SSU) genetic regions to assess abiotic factors influencing community diversity and composition. Our results showed overall low fungal diversity though distinct fungal communities across the region, which were influenced more by spatial distance rather than other factors. Comparison between EcM and AMF revealed contrasting patterns: AMF communities exhibited spatial structuring with distinct AMF genera while EcM communities are more influenced by salinity levels rather than spatial distance. These findings reflect the ecological roles of mycorrhizal groups, as AMF act as generalists supporting herbaceous dune flora while the EcM association to woody species may have limited their capability to establish in coastal dunes. Second, we conducted basic fungal educational training and participation of local students - from fungal culture and mycorrhizal quantification to fieldwork.  This outreach resulted in hands-on fungal activities by 4th graders, participation and training of local high school students in fieldwork, and research experience for undergraduate students. Taken together, our project highlights the importance of accounting for fungal diversity in these typically nutrient-poor soils of barrier islands, which will aid in successful future management and conservation of these natural resources.