Open AccessCorrelations between net primary productivity and foliar carbon isotope ratio across a Tibetan ecosystem transect
Author(s) -
Luo Tianxiang,
Zhang Lin,
Zhu Huazhong,
Daly Christopher,
Li Mingcai,
Luo Ji
Publication year - 2009
Publication title -
ecography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.973
H-Index - 128
eISSN - 1600-0587
pISSN - 0906-7590
DOI - 10.1111/j.1600-0587.2008.05735.x
Subject(s) - primary production , transect , environmental science , productivity , ecosystem , vegetation (pathology) , photosynthesis , precipitation , climate change , carbon cycle , ecology , terrestrial ecosystem , nitrogen , atmospheric sciences , biology , chemistry , botany , geography , economics , macroeconomics , medicine , organic chemistry , pathology , meteorology , geology
Warming climate could affect leaf‐level carbon isotope composition (δ 13 C) through variations in photosynthetic gas exchange. However, it is still unclear to what extent variations in foliar δ 13 C can be used to detect changes in net primary productivity (NPP) because leaf physiology is only one of many determinants of stand productivity. We aim to examine how well site‐mean foliar δ 13 C and stand NPP co‐vary across large resource gradients using data obtained from the Tibetan Alpine Vegetation Transects (1900–4900 m, TAVT). The TAVT data indicated a robust negative correlation between foliar δ 13 C and NPP across ecosystems (NPP=−2.7224δ 13 C‐67.738, r 2 =0.60, p<0.001). The mean foliar δ 13 C decreased with increasing annual precipitation and its covariation with mean temperature and soil organic carbon and nitrogen contents. The results were further confirmed by global literature data. Pooled δ 13 C data from global literature and this study explained 60% of variations in annual NPP both from TAVT‐measures and MODIS‐estimates across 67 sites. Our results appear to support a conceptual model relating foliar δ 13 C and nitrogen concentration (N mass ) to NPP, suggesting that: 1) there is a general (negative) relationship between δ 13 C and NPP across different water availability conditions; 2) in water‐limited conditions, water availability has greater effects on NPP than N mass ; 3) when water is not limiting, NPP increases with increasing N mass .