TY - JOUR
T1 - Ecosystem type and resource quality are more important than global change drivers in regulating early stages of litter decomposition
AU - Ochoa-Hueso, Raúl
AU - Delgado-Baquerizo, Manuel
AU - An King, Paul Tuan
AU - Benham, Merryn
AU - Arca, Valentina
AU - Power, Sally A.
PY - 2019
Y1 - 2019
N2 - Litter decomposition is fundamental for nutrient and carbon (C) cycling, playing a major role in regulating the Earth's climate system. Climate change and fertilization are expected to largely shift litter decomposition rates in terrestrial ecosystems, however, studies contextualizing the relative importance of these major global change drivers versus other key decomposition drivers such as substrate quality and ecosystem type are lacking. Herein, we used two independent field experiments in an Eastern Australian grassland (Experiment 1) and a forest (Experiment 2) to evaluate the role of (i) litter quality, (ii) nutrient addition (N, P and K in full factorial combination; Experiment 1), and (iii) a combination of N addition and irrigation (Experiment 2) in litter decomposition, substrate-induced respiration and microbial abundance. Regardless of experimental treatments, forest soils decomposed litter between 2 and 5 times faster than grassland soils. This was principally controlled by the greater ability of forest microbes to respire C-based substrates and, ultimately, by soil N availability. The experimental treatments accounted for only relatively small differences in our measured variables, ranging from 10 to 15% in the case of the irrigation-by-N-addition forest experiment to almost negligible in most of the grassland nutrient addition plots. In the latter experiment, decomposition and soil activity responses were associated with either K addition or interactions between K and other nutrients, suggesting a key role for this often-neglected soil nutrient in controlling litter decomposition. Our study provides evidence that while nutrient enrichment and/or irrigation have the potential to affect litter decomposition rates in grassland and forest ecosystems, land use change that results in loss or gain of forested area is likely to exert a much greater impact than these other two drivers.
AB - Litter decomposition is fundamental for nutrient and carbon (C) cycling, playing a major role in regulating the Earth's climate system. Climate change and fertilization are expected to largely shift litter decomposition rates in terrestrial ecosystems, however, studies contextualizing the relative importance of these major global change drivers versus other key decomposition drivers such as substrate quality and ecosystem type are lacking. Herein, we used two independent field experiments in an Eastern Australian grassland (Experiment 1) and a forest (Experiment 2) to evaluate the role of (i) litter quality, (ii) nutrient addition (N, P and K in full factorial combination; Experiment 1), and (iii) a combination of N addition and irrigation (Experiment 2) in litter decomposition, substrate-induced respiration and microbial abundance. Regardless of experimental treatments, forest soils decomposed litter between 2 and 5 times faster than grassland soils. This was principally controlled by the greater ability of forest microbes to respire C-based substrates and, ultimately, by soil N availability. The experimental treatments accounted for only relatively small differences in our measured variables, ranging from 10 to 15% in the case of the irrigation-by-N-addition forest experiment to almost negligible in most of the grassland nutrient addition plots. In the latter experiment, decomposition and soil activity responses were associated with either K addition or interactions between K and other nutrients, suggesting a key role for this often-neglected soil nutrient in controlling litter decomposition. Our study provides evidence that while nutrient enrichment and/or irrigation have the potential to affect litter decomposition rates in grassland and forest ecosystems, land use change that results in loss or gain of forested area is likely to exert a much greater impact than these other two drivers.
KW - biotic communities
KW - climatic changes
KW - eutrophication
KW - litter (trash)
UR - http://hdl.handle.net/1959.7/uws:49662
U2 - 10.1016/j.soilbio.2018.11.009
DO - 10.1016/j.soilbio.2018.11.009
M3 - Article
VL - 129
SP - 144
EP - 152
JO - Soil Biology and Biochemistry
JF - Soil Biology and Biochemistry
ER -