Stable water isotopes in soil–plant systems reveals ecohydrological dynamics in a typical flood wetland in the subtropical monsoon region, China
Water transformation within soil–plant systems is one of the critical aspects that reflects the ecohydrological dynamics. However, it remains limited to understand soil water movement and plant water uptake in wetland ecosystems under changing moisture conditions. Here, we analyzed stable isotopic v...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-09-01
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| Series: | Ecological Indicators |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S1470160X25009537 |
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| Summary: | Water transformation within soil–plant systems is one of the critical aspects that reflects the ecohydrological dynamics. However, it remains limited to understand soil water movement and plant water uptake in wetland ecosystems under changing moisture conditions. Here, we analyzed stable isotopic variations of precipitation, soil water and plant water in a typical flood wetland in Poyang Lake from December 2020 to May 2021. A progressive enrichment of the δ2H and δ18O values existed from soil water to plant stem and leaf water. The importance of considering the precipitation isotopic time-scale was emphasized when interpreting seasonal soil water isotopes in the flood wetlands. The temporal isotopic fluctuations in shallow soil water (0∼40 cm) were more pronounced, and frequent abrupt isotopic enrichment of subsurface layers was attributed to the ubiquitous preferential flow. The vertical isotopic distributions of deep soil water (40∼150 cm) exhibited two distinct patterns: stable isotopes remained relatively constant, and showed a gradual depletion trend with increasing depths, which were related to the infiltration depth of precipitation in the form of translatory flow. There were significant monthly variations in water uptake from shallow soil layers by dominant plants based on the MixSIAR model, with the highest and lowest values of ∼94 % (December) and ∼47 % (May), respectively. A definite shift in water use strategies from multi-source combinations towards increased dependence on precipitation was revealed from the dry to wet conditions. These findings enhance our understanding of ecohydrological processes in Poyang Lake wetland, and provide a scientific basis for improving water resources management aiming at sustainable development of regional ecosystem service functions. |
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| ISSN: | 1470-160X |