Abstract
Invasive plants often change a/biotic soil conditions to increase their competitiveness. We compared the microbially mediated soil nitrogen (N) cycle of invasive Mikania micrantha and two co-occurring native competitors, Persicaria chinensis and Paederia scandens.
We assessed how differences in plant tissue N content, soil nutrients, N cycling rates, microbial biomass and activity, and diversity and abundance of N-cycling microbes associated with these species impact their competitiveness.
Mikania micrantha outcompeted both native species by transferring more N to plant tissue (37.9–55.8% more than natives). We found total soil N to be at lowest, and available N highest, in M. micrantha rhizospheres, suggesting higher N cycling rates compared with both natives. Higher microbial biomass and enzyme activities in M. micrantha rhizospheres confirmed this, being positively correlated with soil N mineralization rates and available N. Mikania micrantha rhizospheres harbored highly diverse N-cycling microbes, including N-fixing, ammonia-oxidizing and denitrifying bacteria and ammonia-oxidizing archaea (AOA). Structural equation models indicated that M. micrantha obtained available N via AOA-mediated nitrification mainly. Field data mirrored our experimental findings.
Nitrogen availability is elevated under M. micrantha invasion through enrichment of microbes that participate in N cycling, in turn increasing available N for plant growth, facilitating high interspecific competition.
Original language | English |
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Pages (from-to) | 3440-3452 |
Number of pages | 13 |
Journal | New Phytologist |
Volume | 229 |
Issue number | 6 |
Early online date | 1 Dec 2020 |
DOIs | |
Publication status | Published - Mar 2021 |
Keywords
- Mikania micrantha
- biological invasions
- functional microbial diversity
- nitrification
- nitrogen cycle
- nitrogen fixation