Does thinning-induced gap size result in altered soil microbial community in pine plantation in eastern Tibetan Plateau?

Bing Yang,Xueyong Pang,Weikai Bao,Guanglong Tian,Bin Hu

doi:10.1002/ece3.2714

Bing Yang, Xueyong Pang + Show 3 more

Open Access

https://doi.org/10.1002/ece3.2714

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Abstract

Although the effects of gap formation resulting from thinning on microclimate, plant generation and understory plant community have been well documented, the impact of thinning on soil microbial community and related ecological functions of forests particularly in subalpine coniferous region is largely unknown. Here, the effects of thinning on soil microbial abundance and community structure using phospholipid fatty acid (PLFA) in pine plantations were investigated 6 years after thinning. The experimental treatments consisted of two distinct‐sized gaps (30 m2 or 80 m2 in size) resulting from thinning, with closed canopy (free of thinning) as control. Soil temperature as well as the biomass of actinomycete and unspecific bacteria was sensitive to gap formation, but all these variables were only responsive to medium gap. Nonmetric multidimensional scaling confirmed that soil microbial community was responsive to gap size. In addition, gap size exerted contrasting effect on bacteria‐feeding nematode and fungi‐feeding nematodes. In conclusion, thinning‐induced gap size would affect soil microbial community through changing soil temperature or the abundance of fungi‐feeding nematodes.

Highlights

The low and midaltitude forests of eastern Tibetan Plateau have experienced vegetation shift from native broad-leaved forests dominated by Quercus liao-tungensis to monoculture plantations of Chinese pine and spruce, which were characterized by high density, litter herbaceous cover, less herbaceous diversity and a thick litter layer (Li et al, 2009; Pang, Bao, Zhu, & Cheng, 2013; Wu, Liu, Fu, Liu, & Hu, 2006)
Two specific questions were addressed: (1) What is the impact of gap size on soil microbial biomass and (2) Whether and how does thinning-induced gap size change soil microbial community composition?
To avoid the problem resulting from unreliably represented phospholipid fatty acid (PLFA) and associated uncertain classification at developing the analysis, PLFAs that only appeared in less than 25% of the samples were omitted before analysis, because their values are near the detection limit and are unreliable

Summary

| INTRODUCTION

The low and midaltitude forests of eastern Tibetan Plateau have experienced vegetation shift from native broad-leaved forests dominated by Quercus liao-tungensis to monoculture plantations of Chinese pine and spruce, which were characterized by high density, litter herbaceous cover, less herbaceous diversity and a thick litter layer (Li et al, 2009; Pang, Bao, Zhu, & Cheng, 2013; Wu, Liu, Fu, Liu, & Hu, 2006). Soil microorganisms are essential components in forest ecosystems (Burton, Chen, Xu, & Ghadiri, 2010) playing a crucial role in biogeochemical cycling and ecosystem functioning (Falkowski, Fenchel, & Delong, 2008; Singh, Bardgett, Smith, & Reay, 2010) They are sensitive to change in environmental factors (Bach, Grytnes, Halvorsen, & Ohlson, 2010; Busse, Beattie, Powers, Sanchez, & Tiarks, 2006; Han et al, 2007; McIntosh, Macdonald, & Quideau, 2013; Mitchell et al, 2010; Zak, Holmes, White, Peacock, & Tilman, 2003; Zogg et al, 1997). Two specific questions were addressed: (1) What is the impact of gap size on soil microbial biomass and (2) Whether and how does thinning-induced gap size change soil microbial community composition?

| MATERIALS AND METHODS

Findings

| DISCUSSION