FEMS Microbiology Ecology, 96, 2020, faa041 doi: 10.1093/femsec/faa041 Advance Access Publication Date: 16 March 2020 Research Article RESEARCH ARTICLE From pine to pasture: land use history has long-term impacts on soil bacterial community composition and functional potential Syrie M. Hermans 1, * ,† , Matthew Taylor 2 , Gwen Grelet 3 , Fiona Curran- Cournane 4 , Hannah L. Buckley 5 , Kim M. Handley 1 and Gavin Lear 1,‡ 1 School of Biological Sciences, University of Auckland, 3A Symonds Street, Auckland, New Zealand, 2 Waikato Regional Council, 401 Grey Street, Hamilton 3216, New Zealand, 3 Manaaki Whenua – Landcare Research, 54 Gerald Street, Lincoln, New Zealand, 4 Ministry for the Environment – Manat ¯ uM¯ o Te Taiao, 45 Queen Street, Auckland 1010, New Zealand and 5 School of Science, Auckland University of Technology, 46 Wakefeld St, Auckland, 1010, New Zealand ∗ Corresponding author: School of Biological Sciences, University of Auckland, 3A Symonds Street, Auckland 1010, New Zealand. E-mail: mher626@aucklanduni.ac.nz One sentence summary: Soil bacterial community composition and functional potential at converted sites remain distinct from those at reference sites from both historic and current land uses. Editor: Ian Anderson † Syrie M. Hermans, http://orcid.org/0000-0002-6957-0795 ‡ Gavin Lear, http://orcid.org/0000-0001-5083-4773 ABSTRACT Bacterial communities are crucial to soil ecosystems and are known to be sensitive to environmental changes. However, our understanding of how present-day soil bacterial communities remain impacted by historic land uses is limited; implications for their functional potential are especially understudied. Through 16S rRNA gene amplicon and shotgun metagenomic sequencing, we characterized the structure and functional potential of soil bacterial communities after land use conversion. Sites converted from pine plantations to dairy pasture were sampled fve- and eight-years post conversion. The bacterial community composition and functional potential at these sites were compared to long-term dairy pastures and pine forest reference sites. Bacterial community composition and functional potential at the converted sites differed signifcantly from those at reference sites (P = 0.001). On average, they were more similar to those in the long-term dairy sites and showed gradual convergence (P = 0.001). Differences in composition and functional potential were most strongly related to nutrients such as nitrogen, Olsen P and the carbon to nitrogen ratio. Genes related to the cycling of nitrogen, especially denitrifcation, were underrepresented in converted sites compared to long-term pasture soils. Together, our study highlights the long-lasting impacts land use conversion can have on microbial communities, and the implications for future soil health and functioning. Keywords: bacterial communities; metagenomics; land use; pine forest; dairy; pasture; functional diversity nitrogen cycle Received: 22 November 2019; Accepted: 9 March 2020 C  FEMS 2020. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com 1 Downloaded from https://academic.oup.com/femsec/article/96/4/fiaa041/5807072 by guest on 14 July 2022