[Latitudinal trends in foliar δ13C and δ15N of Quercus variabilis and their influencing factors.] / æ “çš®æ Žå¶ç‰‡Î´13C和δ15Nçš„çº¬å‘è¶‹åŠ¿åŠå ¶å½±å“å› å­.

ABSTRACT

We aimed to reveal the latitudinal trends in foliar δ13C and δ15N of Quercus variabilis, a widely distributed species in East Asia, associated with two ontogenetic stages (juvenile and mature trees) along a North-South transect (26°-40° N). The results showed that mature trees had higher foliar δ13C and δ15N values than juveniles. Foliar δ13C and δ15N values of trees with both ontogenetic stages were nonlinearly increased and decreased with latitude, respectively. No interaction between ontogenetic stage and latitude for the changes of foliar δ15N and δ13C indicated that both ontogenetic stages across the transect consistently responded to latitudinal environmental variations. Results from the random forest models indicated that foliar δ15N of Q. variabilis was mainly affected by soil nutrient contents, e.g., soil organic matter, phosphorus, nitrogen, whereas dominated factors for foliar δ13C were related to moisture, such as relative humidity, precipitation of growing season.