Land use change has long-term effects on the structure of soil microbial communities, but the specific community assembly processes underlying these effects have not been identified. To investigate effects of historical land use on microbial community assembly, we sampled soils from several currently forested watersheds representing different historical land management regimes (e.g., undisturbed reference, logged, converted to agriculture). We characterized bacterial and fungal communities using amplicon sequencing and used a null model approach to quantify the relative importance of selection, dispersal, and drift processes on bacterial and fungal community assembly. We found that bacterial communities were structured by both selection and neutral (i.e., dispersal and drift) processes, while fungal communities were structured primarily by neutral processes. For both bacterial and fungal communities, selection was more important in historically disturbed soils compared with adjacent undisturbed sites, while dispersal processes were more important in undisturbed soils. Variation partitioning identified the drivers of selection to be changes in vegetation communities and soil properties (i.e., soil N availability) that occur following forest disturbance. Overall, this study casts new light on the effects of historical land use on soil microbial communities by identifying specific environmental factors that drive changes in community assembly.
Despite the abundance of studies demonstrating the effects of drought on soil microbial communities, the role of land use legacies in mediating these drought effects is unclear. To assess historical land use influences on microbial drought responses, we conducted a drought‐rewetting experiment in soils from two adjacent and currently forested watersheds with distinct land use histories: an undisturbed ‘reference’ site and a ‘disturbed’ site that was clear‐cut and converted to agriculture ~60 years prior. We incubated intact soil cores at either constant moisture or under a drought‐rewet treatment and characterized bacterial and fungal communities using amplicon sequencing throughout the experiment. Bacterial alpha diversity decreased following drought‐rewetting while fungal diversity increased. Bacterial beta diversity also changed markedly following drought‐rewetting, especially in historically disturbed soils, while fungal beta diversity exhibited little response. Additionally, bacterial beta diversity in disturbed soils recovered less from drought‐rewetting compared with reference soils. Disturbed soil communities also exhibited notable reductions in nitrifying taxa, increases in putative r‐selected bacteria, and reductions in network connectivity following drought‐rewetting. Overall, our study reveals historical land use to be important in mediating responses of soil bacterial communities to drought, which will influence the ecosystem‐scale trajectories of these environments under ongoing and future climate change.
more » « less- NSF-PAR ID:
- 10366520
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Environmental Microbiology
- Volume:
- 23
- Issue:
- 11
- ISSN:
- 1462-2912
- Page Range / eLocation ID:
- p. 6405-6419
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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