Chin J Plan Ecolo ›› 2010, Vol. 34 ›› Issue (1): 17-22.DOI: 10.3773/j.issn.1005-264x.2010.01.004

• Special feature: Ecological Stoichiometry • Previous Articles     Next Articles

Canopy leaf N and P stoichiometry in grassland communities of Qinghai-Tibetan Plateau, China

YANG Kuo1,2;HUANG Jian-Hui1*; DONG Dan1,2; MA Wen-Hong3,4;HE Jin-Sheng4   

  1. 1State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; 2Graduate Univer-sity of Chinese Academy of Sciences, Beijing 100049, China; 3College of Life Sciences, Inner Mongolia University, Hohhot 010021, China; and 4Department of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
  • Online:2010-01-01 Published:2010-01-01
  • Contact: HUANG Jian-Hui

Abstract: Aims Leaf N and P stoichiometry has been widely studied at the species level in both aquatic and terrestrial ecosystems, however, it lacks research at the community level. Since the ecological stoichiometric characteristics could play important roles in connecting different levels of ecological studies and former studies mainly focused on the individual level, in this study, we try to figure out the pattern of foliar N and P at the community level of grassland ecosystems in Qinghai-Tibetan Plateau. Additionally, we also try to find out the relationships between community level leaf N, P and site climate factors. Methods Leaf samples were collected from 47 research sites in Qinghai-Tibetan Plateau at the end of the grow-ing season yearly from 2006 to 2008. We measured the leaf N concentrations by using an elemental analyzer and the leaf P concentration based on a molybdate/stannous chloride method. Climate data of annual mean tempera-ture and annual mean precipitation (65 national standard stations) between 2006 and 2008 were used to interpolate into gridded data with a resolution of 1 km × 1 km through the tchebycheffian spline function. Important findings Leaf N, P concentrations and N:P ratios at the community level over the southern part of Qinghai-Tibetan Plateau were 23.2 mg·g–1, 1.7 mg·g–1and 13.5, respectively. Significant inter-annual differences were presented in leaf N, P concentrations and N:P ratios. Mean annual temperature was strongly correlated with leaf N, P and N:P ratios. Besides, the correlations between climate factors and leaf N, P, N:P ratios were generally consistent with the previous results found at the global scale. Our results suggest that the high variation in leaf P concentration and its strong correlation with environmental factors reveal that, to some extent, stoichiometric traits at the community level are adaptive to local environmental conditions.