Chin J Plan Ecolo ›› 2015, Vol. 39 ›› Issue (8): 797-806.DOI: 10.17521/cjpe.2015.0076

• Orginal Article • Previous Articles     Next Articles

Effects of understory removal on soil respiration and microbial community composition structure in a Chinese fir plantation

HE Tong-Xin1,2, LI Yan-Peng1,2, ZHANG Fang-Yue1,2, WANG Qing-Kui1,3,*()   

  1. 1State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China
    2University of Chinese Academy of Sciences, Beijing 100049, China
    3Huitong Experimental Station of Forest Ecology, Chinese Academy of Sciences, Huitong, Hunan 418307, China
  • Received:2015-02-10 Accepted:2015-06-10 Online:2015-08-01 Published:2015-08-17
  • Contact: Qing-Kui WANG
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    # Co-first authors

Abstract:

Aims Soil respiration (Rs) is the largest fraction of carbon flux in forest ecosystems, but the effects of forest understory removal on Rs in Chinese fir (Cunninghamia lanceolate) plantations is poorly understood. In order to quantify the effects of forest understory removal on Rs and microbial community composition, a field experiment was conducted in a subtropical Chinese fir plantation. Methods Forest understory was removed manually in June 2012. Rs was measured monthly using a LI-COR 8100 infrared gas analyzer from July 2012 through July 2014. Soil temperature and moisture were also measured at 5 cm depth at the time of Rs measurements. Surface soil (0-10 cm) samples were collected in July 2013 and 2014, respectively, and the soil microbial community structures were determined by phospholipid fatty acids (PLFAs) analysis. Important findings Rs decreased by 32.8% over a two-year period following understory removal (UR), with a greater rate of decrease in the first year (42.9%) than in the second year (22.2%). The temperature sensitivity of Rs was affected by UR, and was 2.10 and 1.87 in the control and UR plots, respectively. UR significantly reduced the concentration of fungal PLFAs by 18.3%, but did not affect the concentration of bacterial PLFAs, resulting in an increase in the fungal:bacterial ratio; it significantly increased the concentration of gram-positive bacterial PLFAs by 24.5%, and the ratio of gram-positive to gram-negative bacterial PLFAs after one year of treatment, but decreased the concentration of gram-positive bacterial PLFAs by 9.4% and the ratio of gram-positive to gram-negative bacterial PLFAs after two years of treatment. The results suggested that Rs and microbial community composition were both affected by UR in Chinese fir plantation, and the effects were dependent of the duration following the UR treatment.

Key words: CO2 efflux, Cunninghamia lanceolata plantation, phospholipid fatty acid, temperature sensitivity, understory removal