| Summary: | [Aim]: Lichens are often regarded as paradigms of mutualistic relationships. However, it is still poorly known how lichen-forming fungi and their photosynthetic partners in-teract at a community scale. We explored the structure of fungus-alga networks of in-teractions in lichen communities along a latitudinal transect in continental Antarctica. We expect these interactions to be highly specialized and, consequently, networks with low nestedness degree and high modularity.Location: Transantarctic Mountains from 76° S to 85° S (continental Antarctica). [Time Period]: Present. [Major Taxa Studied]: Seventy-seven species of lichen-forming fungi and their photobionts. [Methods]: DNA barcoding of photobionts using nrITS data was conducted in 756 li-chen specimens from five regions along the Transantarctic Mountains. We built in-teraction networks for each of the five studied regions and a metaweb for the whole area. We explored the specialization of both partners using the number of partners a species interacts with and the specialization parameter d'. Network architecture parameters such as nestedness, modularity and network specialization parameter H2' were studied in all networks and contrasted through null models. Finally, we meas-ured interaction turnover along the latitudinal transect. [Results]: We recovered a total of 842 interactions. Differences in specialization be-tween partners were not statistically significant. Fungus-alga interaction networks showed high specialization and modularity, as well as low connectance and nested-ness. Despite the large turnover in interactions occurring among regions, network parameters were not correlated with latitude. [Main Conclusions]: The interaction networks established between fungi and algae in saxicolous lichen communities in continental Antarctica showed invariant properties along the latitudinal transect. Rewiring is an important driver of interaction turno-ver along the transect studied. Future work should answer whether the patterns ob-served in our ...
|
|---|