The fungal ecology of seabird nesting sites in the Falkland Islands indicates a niche for mycoparasites

Soil fungal communities are complex and heterogeneous, possessing important functions in most terrestrial ecological systems. Their study has been advanced due to the development of high-throughput sequencing, which allow for complex fungal communities to be described with techniques such as metabarcoding. The Falkland Islands contain large populations of breeding seabirds; one such internationally recognised area is Saunders Island, located off the coast of the West Falkland. It contains breeding populations of gentoo penguins (Pygoscelis papua), Magellanic penguins (Spheniscus magellanicus), black-browed albatross (Thalassarche melanophris), king penguins (Aptenodytes patagonicus) and western rockhopper penguins (Eudyptes chrysocome chrysocome). The fungal communities of these sites were investigated using a fungal metabarcode approach. We found these sites contain a large spatial heterogeneity, with communities that are dominated by saprotrophic fungi. However, we noticed that the most abundant species tended to be known mycoparasites. We hypothesise the fungal communities in system undergo a 'boom-bust' cycle of varying alpha diversity which is dependent upon the breeding populations, and driven by highly competitive mycoparasitic fungi.