TY - JOUR
T1 - The effects of tree-mycorrhizal type on soil organic matter properties from neighborhood to watershed scales
AU - Seyfried, Georgia S.
AU - Canham, Charles D.
AU - Dalling, James W.
AU - Yang, Wendy H.
N1 - Funding Information:
This research was funded by the Clark Research Award, Ferguson Fund, and the University of Illinois Graduate College Dissertation Travel Grant to GSS. The National Science Foundation Integrative Graduate Education and Research Traineeship Program ( NSF IGERT 1069157 ) and the Illinois Distinguished Fellowship supported GSS. The Smithsonian Tropical Research Institute provided logistical support at the Fortuna Forest Reserve.
Funding Information:
We appreciate field assistance from Evidelio Garcia, Carlos Espinosa, Mark Seyfried and Helen Fisher, lab assistance from Rachel Van Allen and Helen Fisher, data analysis assistance from Adam Von Haden, and manuscript feedback from Benjamin Turner. This research was funded by the Clark Research Award, Ferguson Fund, and the University of Illinois Graduate College Dissertation Travel Grant to GSS. The National Science Foundation Integrative Graduate Education and Research Traineeship Program (NSF IGERT 1069157) and the Illinois Distinguished Fellowship supported GSS. The Smithsonian Tropical Research Institute provided logistical support at the Fortuna Forest Reserve.
Funding Information:
This research was funded by the Clark Research Award, Ferguson Fund, and the University of Illinois Graduate College Dissertation Travel Grant to GSS. The National Science Foundation Integrative Graduate Education and Research Traineeship Program (NSF IGERT 1069157) and the Illinois Distinguished Fellowship supported GSS. The Smithsonian Tropical Research Institute provided logistical support at the Fortuna Forest Reserve.
Publisher Copyright:
© 2021 Elsevier Ltd
PY - 2021/10
Y1 - 2021/10
N2 - A large portion of terrestrial carbon (C) is stored as soil organic matter (SOM) so the balance between C inputs to SOM and soil C loss through respiration has important implications for global climate change. Tree-mycorrhizal association is a promising predictor of SOM dynamics, with the effect of ectomycorrhizal (ECM) trees and associated fungi scaling with the percent basal area of ECM-associated trees in a forest stand. However, uncertainty remains in the generality of ECM effects across the different spatial scales at which soil properties are known to vary. To determine the spatial variability of ECM effects on SOM pools within a forest stand, we used likelihood modelling techniques to compare non-spatial models, which average out ECM effects at the stand scale, against spatial models, which account for the size and spatial distribution of ECM-associated trees within a stand (i.e., the tree neighborhood). To investigate how watershed-scale variability in soil fertility and pH mediate ECM effects, we quantified forest floor leaf litter and soil properties in forest stands along mycorrhizal gradients within four adjacent watersheds that varied in parent material and rainfall. We found that ECM effects on SOM pools scaled with stand-level ECM dominance rather than varying based on individual trees at the neighborhood scale. Although forest floor leaf litter and mineral C:N ratios consistently increased with ECM dominance across watersheds, ECM effects on O horizon formation and the composition of SOM at depth differed among watersheds. Specifically, watersheds with lower soil pH and fertility exhibited greater changes along mycorrhizal gradients in O horizon depth, leaf litter δ15N and in the difference between δ15N of leaf litter and mineral soil fractions. Overall, this study shows the potential for intrinsic soil properties to mediate the effects of ECM trees and associated fungi on SOM formation and persistence in the tropics.
AB - A large portion of terrestrial carbon (C) is stored as soil organic matter (SOM) so the balance between C inputs to SOM and soil C loss through respiration has important implications for global climate change. Tree-mycorrhizal association is a promising predictor of SOM dynamics, with the effect of ectomycorrhizal (ECM) trees and associated fungi scaling with the percent basal area of ECM-associated trees in a forest stand. However, uncertainty remains in the generality of ECM effects across the different spatial scales at which soil properties are known to vary. To determine the spatial variability of ECM effects on SOM pools within a forest stand, we used likelihood modelling techniques to compare non-spatial models, which average out ECM effects at the stand scale, against spatial models, which account for the size and spatial distribution of ECM-associated trees within a stand (i.e., the tree neighborhood). To investigate how watershed-scale variability in soil fertility and pH mediate ECM effects, we quantified forest floor leaf litter and soil properties in forest stands along mycorrhizal gradients within four adjacent watersheds that varied in parent material and rainfall. We found that ECM effects on SOM pools scaled with stand-level ECM dominance rather than varying based on individual trees at the neighborhood scale. Although forest floor leaf litter and mineral C:N ratios consistently increased with ECM dominance across watersheds, ECM effects on O horizon formation and the composition of SOM at depth differed among watersheds. Specifically, watersheds with lower soil pH and fertility exhibited greater changes along mycorrhizal gradients in O horizon depth, leaf litter δ15N and in the difference between δ15N of leaf litter and mineral soil fractions. Overall, this study shows the potential for intrinsic soil properties to mediate the effects of ECM trees and associated fungi on SOM formation and persistence in the tropics.
KW - Likelihood methods
KW - Mycorrhizal gradient
KW - Natural abundance nitrogen isotopes
KW - Particulate organic matter
KW - Soil carbon and nitrogen
KW - Tropical forest
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U2 - 10.1016/j.soilbio.2021.108385
DO - 10.1016/j.soilbio.2021.108385
M3 - Article
AN - SCOPUS:85112132380
SN - 0038-0717
VL - 161
JO - Soil Biology and Biochemistry
JF - Soil Biology and Biochemistry
M1 - 108385
ER -