Stable Isotope Analysis of Water Uptake Sources of Secondary Forests in the Central Yunnan Karst Plateau

Abstract:

Ecosystems in the central of Yunnan karst plateau are very fragile due to thin soil layer and intensive infiltration capacity of rock fracture, which result in a very limited amount of water storage for plant uptake. Water retention in the soil zone and shallow fractured rock zone (subcutaneous) is a key factor for plant growth. Distinction of water sources taken by karst plants is a challenging task for botanists and hydrologists but is needed for ecosystem management. In this study, stable isotope analysis was used to investigate water sources for Quercus variabilis secondary forests at Shilin Geopark in Bajiang vally, central Yunnan of China. Proportions of water sources for plant uptake were determined by the δD and δ¹⁸O values of plant stem water, and water taken from soil layers and the subcutaneous zone. The analysis reveals that water was mainly taken from the soil layers and to less degree the subcutaneous zone as well. In dry seasons with scarce precipitation, plants in the secondary forest were prone to take more water from subcutaneous zone and upper layer of soil. Different species had different water use strategies, Quercus variabilis and Pistacia weinmannifolia took a larger proportional water from the upper layer of soil and subcutaneous water, suggesting its deeper roots and wider range of shallower roots. However, Neolitsea homilantha extracted more percentage of water from the upper soil water because of its shallower roots.

• Periodical: Advanced Materials Research (Volumes 955-959)
• Pages: 3795-3798
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.955-959.3795
• Online since: June 2014
• Authors: Tao Fan, Yan Hua Wang, Lian Jun Guo, Jie Li
• Keywords: Quercus variabilis Secondary Forests, Stable Isotopes, Subcutaneous Water, Water Uptake Source

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