Effect of plant life form on relationship between δD values of leaf wax n-alkanes and altitude along Mount Taibai, China

Abstract

We present δD wax values from different forms of plants and soils, and δD sw values from soil water along the northern slope of Mount Taibai, China. The results show a highly negative linear correlation of the δD wax values for soils with altitude ( R 2 0.74) and we observed the same correlation for δD sw values of soil water with altitude ( R 2 0.68). The δD wax of living plants behaves like the soil, but does not exhibit a significant linear correlation with altitude ( R 2 0.11). The δD wax values of woody plants and grasses also show a similar trend with respect to altitude with significant and no linear correlation, respectively ( R 2 0.50 for woody plants and 0.17 for grass), which suggest that the “altitude effect” can not be well documented for the δD wax values of living plants, which may be due to differences in plant type and/or evapotranspiration controlled by the plant microclimate. The ε wax-sw values of woody plants, grasses and soil show minor fluctuations with altitude. However, the ε wax-sw and δD wax values of woody plants are roughly 51‰ and 50‰ more positive, respectively, than those of grasses, suggesting that an “altitude effect” could be documented in the δD wax of woody plants and grasses, with each responding independently to changes in precipitation along the altitude transect. Additionally, the ε wax-sw values of soil are relatively constant with altitude, suggesting that the altitudinal change in the proportions between woody plant and grass input to soils will likely change the relationship between the δD wax values of soil n-alkanes and altitude.