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Community level variation in plant leaf traits along an elevation gradient in the semi-arid mountains of Northwest China

Yang Jun-long, Li Xiao-wei

Polish Journal of Ecology

2022

vol. 70, nr 4

142--158

An elevation gradient affects temperature, precipitation, soil properties, and other environmental factors important for plant growth, resulting in differential responses of plant functional traits within and between species. Here, three transect lines were established along an elevation gradient of 1500 to 2900 m that spanned four vegetation types: desert grassland, low mountain shrub zone, subalpine coniferous forest, and subalpine shrub zone in a semiarid mountain ecosystem (western part of the Helan Mountains, Northwest China). Nine functional plant traits — leaf nitrogen (LN), leaf carbon (LC), leaf thickness (LT), specific leaf area (SLA), leaf phosphorus, leaf dry matter content, and the leaf carbon/leaf nitrogen (C/N), leaf carbon/leaf phosphorus (C/P), leaf nitrogen/leaf phosphorus (N/P) — were quantified to investigate (1) how the community-weighted means (CWM) and unweighted means (CM) vary; (2) how inter- and intraspecific functional traits vary; and (3) how the climate, topography and soil properties affect plant functional traits at the community level. We found that with rising elevation, SLA and LT increased and then decreased, while C/P and N/P showed opposite trend for both CWM and CM. Additionally, the higher LN and lower C/N were found in subalpine shrub zone. The leaf functional traits between CWM and CM showed no significant difference but a close relationship between them. Generally, all the leaf traits were explained better by interspecific variation than by intraspecific variation, except for N/P. The covariance analysis indicated that LP and LC showed negative covariance effects, whereas all other leaf traits showed positive covariance effects. The contribution to plant leaf traits from altitude was slightly higher than vapor pressure and soil organic carbon. Our major finding emphasize that plant communities in the western Helan Mountains were assembled along elevation primarily via interspecific variation.

Elevation Distribution of Fine Root Biomass and Soil Organic Carbon Storage of Mature Chinese Fir (Cunninghamia lanceolata) Plantations in East China

Wang Qin, Teng Zhen, Wang Jingjing, Xie Xinyun, Xu Xiaoniu

Polish Journal of Ecology

2020

Vol. 68, nr 1

84--93

Fine roots play an important role in productivity and dynamics of carbon and nutrient in forest ecosystems. The objective of this study is to reveal the elevational distribution patterns of fine-root (≤ 2 mm in diameter) biomass and its carbon and nitrogen stoichiometry, and the relationship between fine-root biomass and soil organic carbon storage in mature Chinese fir (Cunninghamia lanceolata) plantations (40-45 year old) in Mt. Dabie, eastern China. A field survey was conducted at five different sites along an elevation gradient from 360 m to 1200 m a.s.l. At each site, the sampling stands had similar density (from 1039 to 1238 stems ha–1) with three replicates. The fine-root biomass was ranged from 264.3 to 331.9 g m–2, with marginal significant correlation to elevation (P = 0.052). However, fine-root necromass was significantly decreased with elevation (P = 0.010). The C:N ratios ranged from 52.9 to 56.4 for living fine-roots and from 47.3 to 51.2 for dead ones, and showed an increasing trend over elevation gradient. Soil organic carbon (SOC) storages in the surface 50-cm soil layer ranged from 59.7 to 97.9 Mg ha–1 and significantly increased with elevation (P < 0.001). Positive correlations were observed between fine-root biomass and SOC density across this elevation gradient. These results indicate that fine-root turnover might be an important regulation of SOC in the Chinese fir plantation.