Effects of Rhododendron removal on soil bacterial and fungal communities in southern Appalachian forests

Ernest D. Osburn, Chelcy F. Miniat, Katherine J. Elliott, J. E. Barrett

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Rhododendron maximum, a native ericaceous evergreen shrub, is expanding in forests of the southern Appalachian region following eastern hemlock (Tsuga canadensis) mortality due to hemlock woolly adelgid (Adelges tsugae) infestations. The goal of our study was to examine soil microbial community responses to experimental R. maximum removal treatments. The experiment was implemented as a 2 × 2 factorial design, including two R. maximum canopy removal levels (cut vs. not cut) combined with two forest floor removal levels (burned vs. not burned). These treatments were designed as potential management strategies to facilitate hardwood tree establishment in forests that have experienced T. canadensis declines. We sampled soils after removals and characterized bacterial and fungal communities using amplicon sequencing. Shrub removal did not affect bacterial or fungal α diversity but did affect both bacterial and fungal community composition. Relative abundances of bacterial phyla and fungal classes exhibited no differences among R. maximum removal treatments. However, specific bacterial and fungal taxa that were responsive to R. maximum removal (i.e., differentially abundant sequences) did exhibit clear patterns at high taxonomic levels. Specifically, taxa that responded negatively to R. maximum removal were found primarily in two bacterial phyla (Proteobacteria and Bacteroidetes) and one fungal class (Archaeorhizomycetes) while positive responders were clustered in several other bacterial phyla (e.g., Actinobacteria, Planctomycetes, Cyanobacteria). Fungal functional guilds also responded to R. maximum removal, including negative responses of ericoid mycorrhizae and positive responses of arbuscular mycorrhizae and wood saprotrophs. Effects of R. maximum removal on soil microbial communities were minor overall, but clear effects on some key functional groups were evident (i.e., mycorrhizal fungi), suggesting that microbial responses to R. maximum removal may influence recovery of forests in the southern Appalachian region.

Original languageEnglish
Article number119398
JournalForest Ecology and Management
Volume496
DOIs
StatePublished - Sep 15 2021

Bibliographical note

Publisher Copyright:
© 2021 Elsevier B.V.

Funding

This project was supported by the Coweeta LTER, funded by National Science Foundation grant DEB-1637522. We thank the Coweeta Hydrologic Laboratory, Southern Research Station, USDA Forest Service for support and the USDA Forest Service Nantahala Ranger District staff, Nantahala National Forest, for executing the treatments. We also thank Bobbie Niederlehner for help with soil chemistry analyses. The use of trade or firm names in this publication is for reader information and does not imply endorsement by the U.S. Department of Agriculture of any product or service. This project was supported by the Coweeta LTER, funded by National Science Foundation grant DEB-1637522. We thank the Coweeta Hydrologic Laboratory, Southern Research Station, USDA Forest Service for support and the USDA Forest Service Nantahala Ranger District staff, Nantahala National Forest, for executing the treatments. We also thank Bobbie Niederlehner for help with soil chemistry analyses. The use of trade or firm names in this publication is for reader information and does not imply endorsement by the U.S. Department of Agriculture of any product or service.

FundersFunder number
National Science Foundation Arctic Social Science ProgramDEB-1637522
U.S. Department of Agriculture
U.S. Dept. of Agriculture Forest Service

    Keywords

    • 16S
    • Diversity
    • ITS
    • Microbial community
    • Mycorrhizal fungi
    • Sequencing

    ASJC Scopus subject areas

    • Forestry
    • Nature and Landscape Conservation
    • Management, Monitoring, Policy and Law

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