Effects of deer grazing on soil C and N dynamics in Miscanthus sinensis grassland and Quercus serrata forest in Ashiu research forest, Japan

ABSTRACT

To elucidate the grazing-induced changes in soil nutrient cycling, we compared vegetation and soil C and N dynamics, including inorganic N content and total C and N contents, among four plots: Quercus serrata plots inside and outside of a deer exclusion fence and Miscanthus sinensis plots inside and outside of the fence. A linear model with stepwise procedures was used to assess the effects of vegetation type, deer grazing, and soil layer. In the fenced M. sinensis plot, soil C and N contents were higher than in the other plots in autumn. This is likely because the mass of litter from regenerating herbaceous plants was about three times larger than that from Q. serrata. Regardless of the presence of Q. serrata canopy, soil contents were significantly higher outside the fence than inside during the observation periods, whereas the net nitrification rate showed the opposite trend in the summer. The result indicates that N uptake by herbaceous plants is effective in retaining in the fenced plots. In our study site, the regenerating herbaceous plants, especially M. sinensis, would play a greater key role in C sequestration and retention in the surface soil than do the canopy tree Q. serrata.

KEYWORDS:

• Deer exclusion fence
• Japanese sika deer (Cervus nippon)
• Miscanthus sinensis grassland
• Quercus serrata forest
• Soil C and N dynamics

Acknowledgments

We thank Masae Ishihara, Ayumi Imanishi, Ryunosuke Tateno, Naoko Tokuchi, and Atsushi Takayanagi for valuable discussion, and the staff of the Ashiu Forest Research Station for their assistance in the field survey. This study was financially supported by the research project “the connectivity of hills, humans and oceans on the local society based on ecosystem services in the forested watershed environment” at FSERC, and JSPS KAKENHI [Grant Numbers 22780145 and 25292088].

Disclosure statement

No potential conflict of interest was reported by the authors.

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Funding

This work was supported by the JSPS Kakenhi [Grant Number 25292088] and JSPS Kakenhi [Grant Number 22780145].