亚高山草甸植物群落物种多样性与群落C_N_P生态化学计量的关系_陈军强.

植物生态学报 2013, 37 (11): 979–987 doi: 10.3724/SP.J.1258.2013.00101 Chinese Journal of Plant Ecology 亚高山草甸植物群落物种多样性与群落C、N、P生态化学计量的关系陈军强1张蕊1侯尧宸1马丽娜1丁路明2龙瑞军1尚占环1*1兰州大学草地农业科技学院, 兰州 730020; 2兰州大学生命科学学院, 兰州 730000摘要通过测定祁连山东部亚高山草甸256个群落样方的群落物种数和地上植物的C、N、P元素含量, 探究了该地区高产草地和低产草地植物群落物种多样性与植物群落C、N、P生态化学计量特征的关系。

结果表明: 高产样地植物群落C、N、P 含量的平均值分别为53.05%、1.99%、0.22%; 而低产样地植物群落C、N、P含量的平均值分别为52.51%、2.28%、0.19%。

高产和低产样地植物群落C、N、P元素含量均呈现显著差异。

高产样地上植物群落的物种数与N含量和N:P呈显著正相关关系, 与C:N呈显著负相关关系, 但与C、P含量和C:P无明显相关关系; 低产样地上植物群落的物种数与N、P含量呈极显著负相关关系, 与C:N和C:P呈显著正相关关系, 但与C含量和N:P无明显相关关系。

说明高产草地和低产草地植物群落物种多样性与养分元素化学计量特征显示出一定的分异性, 高产样地上植物群落的物种数主要受N含量的限制, 与N含量呈正相关关系; 低产样地上植物群落的物种数则受N、P含量共同限制, 与N、P含量呈负相关关系。

关键词生态化学计量学, 高产草地, 低产草地, 物种多样性, 亚高山草甸Relationships between species diversity and C, N and P ecological stoichiometry in plant communities of sub-alpine meadowCHEN Jun-Qiang1, ZHANG Rui1, HOU Yao-Chen1, MA Li-Na1, DING Lu-Ming2, LONG Rui-Jun1, and SHANG Zhan-Huan1*1College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China; and 2School of Life Sciences, Lanzhou University, Lanzhou 730000, ChinaAbstractAims Our objective was to investigate relationships between species diversity of pasture and C, N and P stoichiometry characteristics of plants at the community level.Methods This field survey focused on plant nutrient stoichiometry of two-level yields in alpine meadow in Eastern Qilian Mountain, China was conducted in early August 2012. Two survey sites were identified as high-yield grassland and low-yield grassland. At each survey site, two 8 m × 8 m plots were selected and divided into 64 1 m × 1 m subplots. For each subplot, the number of species was counted, and newly matured leaves were randomly selected after collecting the aboveground parts by clipping the plant at the soil surface. The collected leaves were sun-dried in the field and oven-dried at 80 °C to constant weight. All samples were finely ground and passed through a 40-mesh screen. Plant C concentration was analyzed by ash determination, plant N concentration was tested by Kjeldahl acid-digestion method and plant P concentration was analyzed by phosphorus vanadium molybdate yellow colorimetric method. Pearson’s bivariate correlation was used to test the relationship between plant C, N, and P stoichiometric traits and number of species. Two-tailed Student’s t-tests were used to compare plant stoichiometric variables.Important findings Mean values of plant C, N and P concentrations in high-yield grassland were 53.05%, 1.99%, and 0.22%, respectively, and those in low-yield grassland were 52.51%, 2.28% and 0.19%, respectively. In high-yield grassland, the number of species was significantly positively correlated with plant N concentration and N:P ratio, while significantly negatively correlated with plant C:N ratio. In low-yield grassland, the number of species was significantly negatively correlated with N and P concentrations, but significantly positively correlated with C:N and C:P. Results indicated that the species of high-yield grassland were primarily limited by N concen-tration and positively correlated with N concentration. However, the species of low-yield grassland was co-limited ——————————————————收稿日期Received: 2013-07-01 接受日期Accepted: 2013-08-27* 通讯作者Author for correspondence (E-mail: shangzhh@)980 植物生态学报Chinese Journal of Plant Ecology 2013, 37 (11): 979–987by N and P concentrations and negatively correlated with N and P concentrations, thus indicating heterogeneity in C, N and P stoichiometry characteristics between high- and low-yield grasslands.Key words ecological stoichiometry, high-yield grassland, low-yield grassland, species diversity, sub -alpine meadow植物营养元素及其化学计量学是生态学研究的重要内容。

生态化学计量学是研究生态系统能量和多重化学元素(主要是C 、N 、P)平衡, 以及元素平衡对生态耦合作用影响的科学(王振兴等, 2011; 林新坚等, 2012)。

生态化学计量学利用生态过程中的这种多种化学元素的平衡关系, 为研究C 、N 、P 等元素在生态系统过程中的交互作用提供了一种综合方法(刘万德等, 2010)。

C:N:P 计量关系与植物个体生长发育、种群增长、物种多样性、群落结构与动态和生态系统过程的联系, 对生态学研究有重要意义(Elser et al ., 1996; Zhang et al ., 2003; 高三平等, 2007; 甘露等, 2008; 阎恩荣等, 2008; 程滨等, 2010)。

随着地球生境的变化, 草地生态系统的结构、过程和功能, 以及植被的分布格局和演替进程正在发生显著的变化(任书杰等, 2007)。

国内外学者对草地植物营养元素化学计量关系进行了广泛的探讨, Reich 和Oleksyn (2004)以及Han 等(2005)、任书杰等(2007, 2012)分别在全球水平和区域尺度对陆生植物叶片N 、P 空间分布特征、变化规律及其驱动因子进行了研究。

银晓瑞等(2010)、张文彦等(2010)研究了不同放牧草地恢复演替阶段和气候因子对中国北方草地化学计量特征的影响。

宋彦涛等(2012)、牛得草等(2013)分别在小尺度上对松嫩平原草本植物叶片和阿拉善荒漠区灌木植物叶片氮磷化学计量特征进行了研究。

上述研究大多是针对不同尺度和温带草原植物群落的, 而对小尺度高山草地的生态化学计量研究还比较缺乏。