Forest conversion influences soil organic carbon (SOC) decomposition through cascading effects on forest structure, soil properties, and soil microbial communities. However, interactive effects of these drivers and the key pathways that mediate forest SOC decomposition remain relatively unexplored. In this study, we compared relative importance of variables describing forest structure, soil properties, and soil microbial community on affecting SOC decomposition response to the conversion of a broadleaved Korean pine mixed forest into three other forests in the Changbai Mountains of China. We quantified SOC decomposition rate of these four forest types by measuring incubation soil respiration (SR). We then employed univariate regressions to quantify effect size of individual factor on SOC decomposition rate. A structural equation model (SEM) was developed to analyze pathways, relative importance, and interactive effects of these factors on SR. Our results showed strong marginal effects of dissolved organic carbon (DOC) content, fungal Phospholipid fatty acids (PLFAs) to bacterial PLFAs ratio (F/B), broadleaved to conifer ratio (B/C), and total PLFAs content (TPC) on SR. Measured SOC decomposition rate was most closely related to F/B, which was in turn influenced primarily by soil C/N ratio and fraction of non-oxidized carbon (NOC%). Our study identified “Aboveground forest composition → SOC chemistry → Soil microbial composition → SOC decomposition” as the key pathway by which forest conversion affected SOC decomposition. This research work highlights the critical role of soil microbial community composition in altering SOC decomposition response to forest conversion.
|Number of pages||10|
|State||Published - Mar 1 2017|
Bibliographical noteFunding Information:
The authors are thankful to Dr. Qingkui Wang and Dr. Heikki Setaelae for their valuable suggestions to a preliminary version of this paper. This paper was supported by China's National Natural Science Foundation (41301200 and 31270511).
© 2016, The Ecological Society of Japan.
- Forest conversion
- SOC chemistry
- SOC decomposition
- Soil microbial composition
- Structural equation modeling
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics