Parallel elevation filtering of Ericaceae root-associated fungal communities in Andean páramo ecosystems

This is a preprint and has not been peer reviewed. Data may be preliminary. Parallel elevation filtering of Ericaceae root-associated fungal communities in Andean páramo ecosystems Abstract Root-associated fungi (RAF) are central to nutrient acquisition and stress tolerance in Ericaceae, yet how RAF communities assemble across elevation gradients in tropical alpine systems remains poorly characterized, and whether geographically isolated mountain tops within a shared biogeographic system produce parallel or idiosyncratic community trajectories is untested for RAF. We used ITS2 metabarcoding to characterize RAF communities of the widespread pioneer ericaceous shrub Gaultheria myrsinoides across forest–páramo transitions (2,700–3,800 m a.s.l.) on four mountaintop “sky islands” of the Colombian Andes. Both taxonomic and phylogenetic diversity declined sharply with elevation, and RAF composition differed significantly among habitats. Despite strong geographic isolation among páramo sky islands and site-specific community baselines, the magnitude and direction of community assembly were statistically consistent across all four mountaintops in composition, diversity trajectories and lineage-specific turnover. This parallel restructuring was driven by contrasting turnover of the two dominant lineages: Helotiales increased in relative abundance toward higher elevations, driven by a subset of high-elevation specialist taxa, while Sebacinales declined. These results contrast with the prevailing view that Sebacinales dominates ericoid mycorrhizal communities across the tropical Andes. The results also suggest the idiosyncratic elevational patterns documented for plants, birds, and soil fungi at macroecological scales are scale-dependent: within a shared biogeographic system, strong and consistent environmental filtering can override geographic contingency to produce repeatable below-ground assembly across isolated mountaintops. As climate warming, altered moisture regimes and land-use pressures change páramos, the world's coldest biodiversity hotspot, these tightly filtered plant–microbe partnerships may reorganize, with consequences for vegetation persistence and ecosystem functioning. Supplementary Material - Download - 10.78 MB Information & Authors Information Version history Peer review timeline Under Review Ecology and Evolution 12 May 2026Submission Checks Completed Collection Authors Metrics & Citations Metrics Article Usage 11views 4downloads Citations Download citation Daniel Angulo Serrano, Camila Pizano, Rakel Blaalid, et al. Parallel elevation filtering of Ericaceae root-associated fungal communities in Andean páramo ecosystems. Authorea. 12 May 2026. DOI: https://doi.org/10.22541/authorea.15003248/v1 DOI: https://doi.org/10.22541/authorea.15003248/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu.