AME 83:237-250 (2019)  -  DOI: https://doi.org/10.3354/ame01916

ABSTRACT: The diversity of leaf-associated microbial communities is predicted to show a unimodal pattern over time, with peak taxonomic diversity occurring during mid-decomposition. Predation may modify successional trajectories, with the nature of modifications depending on the stage of community development. We compared temporal changes of early-stage and established bacterial and fungal communities associated with senesced American beech (Fagus grandifolia) leaves with and without predation by Aedes triseriatus mosquito larvae. Bacterial and fungal communities had different successional patterns. Established bacterial communities were more diverse compared to those in the early stages of succession, while fungal diversity was similar in both developmental stages. Fungal diversity generally remained constant while bacterial diversity showed a non-linear, unimodal pattern over time. Community composition differed significantly between early-stage and established communities for both bacteria and fungi; compositional shifts over time were more marked in early-stage communities for both groups. Predatory effects depended on the stage of community development and community type. In early-stage communities, predation increased bacterial richness; however, richness in established communities decreased with predation. The contrasting successional trajectories of bacterial and fungal communities suggest differential successional drivers and responses to predation for microorganisms inhabiting a shared substrate.

KEY WORDS: Microbial succession · Leaf-associated microbes · Detritivory · Aedes triseriatus · Tree holes