• 标题：Increasing leaf δ13C values of woody plants in response to water stress induced by tunnel excavation in a karst trough valley: Implication for improving water-use efficiency
• 关键词：Carbon stable isotope,Tunnel excavation,Soil water,Karst trough valley,Southwest China
• 作者：Min Cao, Chao Wu, Jiuchan Liu, Yongjun Jiang

全文下载

Plant species growing in karst shallow-soil areas always experience water defificit especially in seasonally dry. Moreover, such water stress is aggravated by tunnel excavation in karst areas. However, the effffects of tunnel excavation on karst ecosystems remain largely unknown. This study aimed at investigating whether there were variations in soil water contents and shifts of water use strategies of plants between rainy and dry seasons in a karst trough valley affffected by tunnel excavation, and comparing their difffferences with those in a tunnel-free karst trough valley in Southwest China. Monthly soil water contents at two soil layers of the upper 0–20 cm and the lower 20–40 cm were measured from January 2017 to December 2018. Foliage of woody plants were sampled in the dry season of December 2017 and March 2018, and in the rainy season of June and September 2018, respectively, and leaf δ13C values were analyzed. The soil water contents at both valleys showed signifificant seasonal variations, and the soil water contents of two soil layers in the tunneling affffected valley were signifificantly lower than that of the tunnel-free valley at both seasons. Plant water use strategy changed from proflfligate water-use pattern in the rainy season to conservative water-use pattern in the dry season. Moreover, increased leaf δ13C values at both seasons in the tunneling affffected valley suggests that the water stress resulted from the tunnel excavation has signifificantly impacted the physiological process of plants in karst areas. These results highlight that improving water use effiffifficiency (WUE) is a common water use strategy to overcome water limitation for native plants in karst areas during unfavorable drought conditions.