Global-scale altitude effect on leaf wax n-alkane δD values in terrestrial higher plants

Numerous field studies have shown that leaf wax n-alkane δD values (δD_n-alkane) can be used as a proxy for paleoelevation reconstruction. However, the lack of systematic global analysis of δD_n-alkane values with respect to altitude limits the reliability of δD_n-alkane values for paleoaltimetry at the global scale. In this study, we analyzed the variation of δD_n-alkane values with altitude in terrestrial higher plants based upon our compiled global δD_n-alkane database. The general decrease in δD_n-alkane values with altitude corresponds to the variation in precipitation δD (δD_prec) with altitude, suggesting that the δD_n-alkane values effectively reflect δD_prec values. When eliminating the effect of latitude at the global scale, the global δD_n-alkane-altitude lapse rate for all species was −1.01±0.10‰ (100 m)⁻¹, while these lapse rates were −1.03±0.13‰ and −0.47±0.13‰ (100 m)⁻¹ for dicots and monocots, respectively. Our study reveals that it is reliable to use δD_n-alkane values to gain information about paleoelevation at the global scale, and the global δD_n-alkane-altitude lapse rates provide an alternative to reconstruct paleoelevation at some δD_n-alkane-uninvestigated areas.