TY - JOUR

T1 - Organic matter priming by invasive plants depends on dominant mycorrhizal association

AU - Kumar, Amit

AU - Phillips, Richard P.

AU - Scheibe, Andrea

AU - Klink, Saskia

AU - Pausch, Johanna

PY - 2020/1/1

Y1 - 2020/1/1

N2 - While it has long been held that invasive plants alter ecosystem processes, the magnitude and direction of these effects have rarely been quantified in situ. We measured the effects of an invasive C4 grass (Microstegium vimineum) on soil organic matter (SOM) decomposition in a deciduous forest in south-central Indiana, USA. The unique 13C signature of the C4 grass relative to the C3 trees allowed us to partition soil CO2 fluxes and estimate M. vimineum effects on decomposition. The magnitude and direction of priming effects hinged on the soil characteristics, which related to the mycorrhizal association of dominant trees. In forest plots dominated by ectomycorrhizal trees, with low nitrogen availability and most SOM in particulate (i.e., unprotected) forms, M. vimineum increased SOM decomposition by 58%. In contrast, in plots dominated by arbuscular mycorrhizal trees, characterized by high nitrogen availability and most SOM in mineral-associated (i.e., protected) forms, M. vimineum decreased decomposition by 14%. Collectively, our results demonstrate that invasive species can play a large role in altering ecosystem processes and suggest that the magnitude and direction of such effects depend on the dominant trees and edaphic characteristics of the stand.

AB - While it has long been held that invasive plants alter ecosystem processes, the magnitude and direction of these effects have rarely been quantified in situ. We measured the effects of an invasive C4 grass (Microstegium vimineum) on soil organic matter (SOM) decomposition in a deciduous forest in south-central Indiana, USA. The unique 13C signature of the C4 grass relative to the C3 trees allowed us to partition soil CO2 fluxes and estimate M. vimineum effects on decomposition. The magnitude and direction of priming effects hinged on the soil characteristics, which related to the mycorrhizal association of dominant trees. In forest plots dominated by ectomycorrhizal trees, with low nitrogen availability and most SOM in particulate (i.e., unprotected) forms, M. vimineum increased SOM decomposition by 58%. In contrast, in plots dominated by arbuscular mycorrhizal trees, characterized by high nitrogen availability and most SOM in mineral-associated (i.e., protected) forms, M. vimineum decreased decomposition by 14%. Collectively, our results demonstrate that invasive species can play a large role in altering ecosystem processes and suggest that the magnitude and direction of such effects depend on the dominant trees and edaphic characteristics of the stand.

KW - C natural abundance

KW - CO emission

KW - Flux partitioning

KW - Microbial activation

KW - Mycorrhizal-associated nutrient economy (MANE)

KW - Rhizosphere priming effects

UR - http://www.scopus.com/inward/record.url?scp=85074354236&partnerID=8YFLogxK

U2 - 10.1016/j.soilbio.2019.107645

DO - 10.1016/j.soilbio.2019.107645

M3 - Journal articles

AN - SCOPUS:85074354236

VL - 140

JO - Soil Biology and Biochemistry

JF - Soil Biology and Biochemistry

SN - 0038-0717

M1 - 107645

ER -