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湿地植被不同演替阶段生态化学计量学研究取得系列进展
发表日期: 2018-04-17 作者: 谢永宏等 文章来源:《科学报告》
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生态化学计量学结合了生态学和化学计量学的基本原理,是研究生物系统能量平衡和多重化学元素平衡的科学。该理论自提出以来在物种共生、营养级动态、生物养分限制及生态系统养分循环等方面得到了广泛应用。对不同演替阶段植被化学计量特征的研究是揭示演替规律内在形成机制的一个重要内容,但当前在湿地生态系统中,有关湿地植被演替与化学计量特征关系的研究仍相对较少。

为此,中国科学院亚热带农业生态研究所洞庭湖湿地站科研人员在研究员谢永宏指导下,以洞庭湖湿地为研究对象,通过野外大范围调查、固定样地监测及室内分析测定等手段,系统研究洞庭湖不同演替阶段湿地植被、土壤生态化学计量特征,并系统阐明不同海拔高程下湿地植被生态化学计量特征的变化及季节动态。具体研究结论如下:

1)三种典型湿地植物群落中(藜蒿、短尖薹草和荻),短尖薹草群落土壤有机碳含量和总氮含量明显高于藜蒿和荻两种群落,土壤总磷含量以藜蒿群落最高,荻群落最低。土壤碳氮比含量最高值和最低值分别出现在荻群落和藜蒿群落,碳磷比和氮磷比最大值和最小值分别出现在短尖薹草群落和藜蒿群落。

2)不同演替阶段三种典型湿地植被(虉草、短尖薹草和荻)群落特征及土壤理化性质存在明显差异。植被总氮顺序为短尖薹草>虉草>荻,总磷为荻>虉草>短尖薹草。氮磷比以虉草群落最高,而其他两个物种无明显差异。相关分析表明,植被生态化学计量特征与土壤理化性质,尤其是土壤含水量及土壤总氮含量存在明显相关性。

3)短尖薹草叶片总碳含量与C:NC:PN:P比值随着海拔高程增加而增加,而总氮、总磷含量则随海拔高程增加而减少。随着时间变化,叶片总氮和总磷含量呈先减少随后逐渐增加的趋势。而 C:NC:P则呈现先增加后减少的趋势。CCA分析和相关性分析表明,淹水时间以及土壤含水量变化是决定湿地植物生长及生态化学计量特征变化的关键因子。

上述研究成果分别发表在Ecological IndicatorNordic Journal of BotnayPhysics and Chemistry of the EarthScientific Reports上。该研究得到国家科技支撑计划课题、国家自然科学基金、中科院重点部署项目及中科院青年创新促进会等项目支持。(来源:中科院亚热带农业生态研究所)

 

Foliar stoichiometry of carbon, nitrogen, and phosphorus in wetland sedge Carex brevicuspis along a small-scale elevation gradient

 

Abstract  The concentrations and ratios of plant carbon (C), nitrogen (N), and phosphorus (P) are powerful indicators of various ecological processes. The effect of elevation on the ecological stoichiometric characteristics of plants is presently unclear. Here, we examined the C:N:P ratios of the wetland sedge, Carex brevicuspis, along a small-scale elevation gradient and their relationships with the physicochemical characteristics of soil and inundation time of the Dongting Lake wetlands, China. The soil water content and inundation time decreased, whereas the soil bulk density increased with increasing elevation. The height, density, coverage, and aboveground biomass of plants and the organic matter content and total N and P concentrations of the soil increased initially, and then decreased with increasing elevation. The total foliar C concentration and the foliar C:N, C:P, and N:P ratios increased, whereas the total foliar N and P concentrations decreased with increasing elevation. The canonical correspondence analysis (CCA) indicated that the soil water content and inundation time were the primary factors affecting the ecological stoichiometric characteristics of C. brevicuspis. The total foliar C concentration and the C:N, C:P, and N:P ratios decreased, but the total foliar N and P concentrations increased with increasing soil water content and inundation time. Our findings highlight the effects of elevation on plant growth and stoichiometric characteristics, which are applicable to the conservation and management of the wetlands dominated with C. brevicuspis.

 

原文链接:https://www.sciencedirect.com/science/article/pii/S1470160X17303370

 

Change in ecological stoichiometry of Carex brevicuspis in response to sampling time and elevation in Dongting Lake, China

 

Abstract  Plant nutrient stoichiometry is affected by both environmental factors and plant physiological processes. However, we know little about how elevation gradients and seasonality combine with soil physicochemical properties to influence nutrient stoichiometry. In this study, we examined these factors in the wetland plant Carex brevicuspis in Dongting Lake, China, during the nonflooding periods in March, May, and December of 2015 and February of 2016. We obtained the following results. Total foliar C concentration increased as elevation increased, especially during December 2015 and February 2016. At the lowelevation site, total foliar C concentration decreased over time, whereas it first increased and then decreased over time at higher elevations. Foliar total N and P concentrations decreased from March to May and subsequently increased over time. Their values remained much higher at the lowelevation site. The C:N and C:P ratios first increased and then decreased over time, while increasing with rising elevation. The N:P ratio was lower at the lowelevation site, especially during May 2015 and February 2016; its variation over time differed across the elevations. A canonical correspondence analysis revealed that soil organic C, total N, and soil nitrate N are important for determining C. brevicuspis stoichiometry. These results indicated that both elevation and plant life stage have a significant influence on plant stoichiometry. This study improves our understanding of seasonal dynamics of plant nutrients under different geographical conditions.

 

原文链接:https://onlinelibrary.wiley.com/doi/epdf/10.1111/njb.01821

 

Soil carbon, nitrogen, and phosphorus stoichiometry of three dominant plant communities distributed along a small-scale elevation gradient in the East Dongting Lake

 

Abstract  Soil carbon (C), nitrogen (N), and phosphorus (P) stoichiometry greatly affects plant community succession and structure. However, few studies have examined the soil stoichiometric changes in different vegetation communities of freshwater wetland ecosystems along an elevation gradient distribution. In the present study, soil nutrient concentrations (C, N, and P), soil stoichiometry (C:N, C:P, and N:P ratios), and other soil physicochemical characteristics were measured and analyzed in 62 soil samples collected from three dominant plant communities (Carex brevicuspis, Artemisia selengensis, and Miscanthus sacchariflorus) in the East Dongting Lake wetlands. The concentration ranges of soil organic carbon (SOC), total soil nitrogen (TN), and total soil phosphorus (TP) were 9.42–45.97 g/kg, 1.09–5.50 g/kg, and 0.60–1.70 g/kg, respectively. SOC and TN concentrations were the highest in soil from the C. brevicuspis community (27.48 g/kg and 2.78 g/kg, respectively) and the lowest in soil from the A. selengensis community (17.97 g/kg and 1.71 g/kg, respectively). However, the highest and lowest TP concentrations were detected in soil from the A. selengensis (1.03 g/kg) and M. sacchariflorus (0.89 g/kg) communities, respectively, and the C:N ratios were the highest and lowest in soil from the M. sacchariflorus (12.72) and A. selengensis (12.01) communities, respectively. C:P and N:P ratios were the highest in soil from the C. brevicuspis community (72.77 and 6.46, respectively) and the lowest in soil from the A. selengensis community (45.52 and 3.76, respectively). Correlation analyses confirmed that SOC concentrations were positively correlated with TN and TP, and C:N and N:P ratios were positively correlated with C:P. These data indicated that soil C, N, and P stoichiometry differed significantly among different plant communities and that these differences might be accounted for by variations in the hydrological conditions of the three communities.

 

原文链接:https://www.sciencedirect.com/science/article/pii/S1474706516302546

 

Foliar nitrogen and phosphorus stoichiometry of three wetland plants distributed along an elevation gradient in Dongting Lake, China

 

Abstract  We examined foliar nitrogen (N) and phosphorus (P) stoichiometry of 3 wetland plants (Phalaris arundinacea, Miscanthus sacchariflorus, and Carex brevicuspis) distributed along an elevation gradient in the Dongting Lake, China, and how this stoichiometry is related to soil physico-chemical characteristics, elevation, and flooding days. Plant and soil samples were collected from 3 lakeshore sites. Total N and P concentrations of plants and six physico-chemical characteristics of the soil were measured, in addition to the elevation and flooding days. P. arundinacea and M. sacchariflorus had higher total N and P concentrations than C. brevicuspis. The foliar N:P ratio decreased with increasing elevation, and only increased with increasing foliar total N concentration. Canonical correspondence analysis indicated that the foliar stoichiometry was primarily regulated by soil water content, followed by soil nutrient concentration. The foliar N and P stoichiometry of the 3 wetland plants was insignificantly correlated with soil total P concentration. However, foliar stoichiometric characteristics and soil total N concentration significantly differed among the 3 species. These results demonstrate that spatial variation of foliar stoichiometry in wetland plants exists along an elevation gradient, with this information being useful for the conservation and management of wetland plants in this lake.

 

原文链接:https://www.nature.com/articles/s41598-017-03126-9

 


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