Communities of Arbuscular Mycorrhizal Fungi in Salt Marsh Habitats: Diversity, Structure, and Ecosystem Function

The relationship between ecosystem functioning and the biodiversity of microorganisms has been a central focus of recent ecological studies, and fungi are considered to play a key role in this relationship. For example, the Mycorrhizae’s association with two-thirds of terrestrial plants makes them one of the most common forms of symbiosis on Earth. Although Arbuscular Mycorrhizal Fungi (AMF) have been shown to be important in nutrient cycling, soil stability and enhancing plant growth by increasing root mycelia, much of the information we have on them is restricted to a small sample of woodland and grassland habitats. Consequently, the mechanisms regulating the diversity and community structure of fungi remain poorly studied across many habitats. This is particularly true for salt marshes, which are key conservation priority habitats in many countries, including the UK. Using the latest sequencing technologies, this work examined the community ecology of fungi across six different salt marsh habitats over two locations in Essex and Lancashire, UK and related this to local environmental variables and sediment nutrient statuses. In addition, by linking with other datasets from the same sites, this study also examined the role of biotic factors that are likely to influence the relationship of rhizosphere fungal communities with each other. Although a range of local abiotic factors significantly influenced the composition of fungal communities within each salt marsh, at larger scales, the compositions of these fungal communities were significantly affected by the pattern of the biotic factors that also differed over seasons. Indeed, the ability of these variables to predict fungal richness and abundances differed greatly between sites, suggesting that drivers of fungal II community structure may be site-specific to some extent. Indeed, fungal richness in relation to abiotic or biotic factors explained considerably different amounts of variation in each site, and generalised poorly to other sites. Therefore, it is possible now to argue against deriving general environment-diversity relationships without empirical validation in multiple sites. Finally, functionally similar fungi ponded similarly to the environmental gradients, suggesting a possible disconnect between functional redundancy and resilience in microbial communities