Contrasting response of coexisting plant’s water-use patterns to experimental precipitation manipulation in an alpine grassland community of Qinghai Lake watershed, China

PLOS ONE, Nov 2019

Understanding species-specific changes in water-use patterns under recent climate scenarios is necessary to predict accurately the responses of seasonally dry ecosystems to future climate. In this study, we conducted a precipitation manipulation experiment to investigate the changes in water-use patterns of two coexisting species (Achnatherum splendens and Allium tanguticum) to alterations in soil water content (SWC) resulting from increased and decreased rainfall treatments. The results showed that the leaf water potential (Ψ) of A. splendens and A. tanguticum responded to changes in shallow and middle SWC at both the control and treatment plots. However, A. splendens proportionally extracted water from the shallow soil layer (0–10cm) when it was available but shifted to absorbing deep soil water (30–60 cm) during drought. By contrast, the A. tanguticum did not differ significantly in uptake depth between treatment and control plots but entirely depended on water from shallow soil layers. The flexible water-use patterns of A.splendens may be a key factor facilitating its dominance and it better acclimates the recent climate change in the alpine grassland community around Qinghai Lake.

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Contrasting response of coexisting plant’s water-use patterns to experimental precipitation manipulation in an alpine grassland community of Qinghai Lake watershed, China

April Contrasting response of coexisting plant's water-use patterns to experimental precipitation manipulation in an alpine grassland community of Qinghai Lake watershed, China Huawu Wu 0 1 Jing Li 1 Xiao-Yan Li 1 3 Bin He 0 1 Jinzhao Liu 1 2 Zhiyun Jiang 1 Cicheng Zhang 1 0 Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology Chinese Academy of Sciences , Nanjing , China , 2 Nanjing Institute of Geography and Limnology Chinese Academy of Sciences , Nanjing , China , 3 Key Laboratory of Grassland Ecosystem (Gansu Agricultural University), Ministry of Education , Gansu , China , 4 Tourism School, Jiujiang College , Jiujiang , China , 5 State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University , Beijing , China 1 Editor: Ricardo Aroca, Estacion Experimental del Zaidin , SPAIN 2 State key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences , Xi'an, China , 8 School of Geography, South China Normal University , Guangzhou , China 3 School of Natural Resources, Faculty of Geographical Science, Beijing Normal University , Beijing , China Understanding species-specific changes in water-use patterns under recent climate scenarios is necessary to predict accurately the responses of seasonally dry ecosystems to future climate. In this study, we conducted a precipitation manipulation experiment to investigate the changes in water-use patterns of two coexisting species (Achnatherum splendens and Allium tanguticum) to alterations in soil water content (SWC) resulting from increased and decreased rainfall treatments. The results showed that the leaf water potential (Ψ) of A. splendens and A. tanguticum responded to changes in shallow and middle SWC at both the control and treatment plots. However, A. splendens proportionally extracted water from the shallow soil layer (0±10cm) when it was available but shifted to absorbing deep soil water (30±60 cm) during drought. By contrast, the A. tanguticum did not differ significantly in uptake depth between treatment and control plots but entirely depended on water from shallow soil layers. The flexible water-use patterns of A.splendens may be a key factor facilitating its dominance and it better acclimates the recent climate change in the alpine grassland - Data Availability Statement: All relevant data are within the paper and its Supporting Information files. community around Qinghai Lake. Introduction Water, disturbance, and edaphic factors determine the species distribution, composition, and productivity of arid and semiarid regions [1±3]. Precipitation in these regions is characterized No. NIGLAS2017GH07). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. by high temporal and spatial variability, affecting the amount of soil water available to plants [ 4 ]; thus, plants might be expected to respond rapidly to obtain water from different soil depths. However, the frequency of drought periods and the precipitation intensity is projected to increase over the coming decades in northwest regions of China, such as Qinghai, and the eastern regions of Gansu and Inner Mongolia, as a result of climate change [ 5, 6 ]. Moreover, results from regional models (e.g., RegCM4) have shown that the spring and summer seasons in these regions are subject to an increased frequency of drought [7], impacting the productivity, distribution, and species compositions of alpine grassland communities in eastern regions of the Tibetan Plateau [ 5 ]. Scenarios predict that mean precipitation is also projected to increase at middle and high latitude regions, and both increases and decreases in consecutive dry days between precipitation events are observed in these regions [ 1, 8 ]. These alterations of precipitation induce the changes of water status of terrestrial ecosystem takes great impacts on net primary productivity (NPP), species diversity, and plant community structure [9]. Previous studies indicate that long-term water addition in grasslands either increased [ 10 ] or had little consistent effect on species diversity [ 11 ], which are related with differential plants water uptake among associated species [ 12, 13 ]. Flexible water uptake patterns by plant facilitate its competitions among different plant functional types in the water-limited habitats [ 14, 15 ]. Hence, detecting the effects of altered precipitation in the water-limited ecosystems requires understanding how species will respond to drought or increases in precipitation. Although the ecological effects of spring and summer droughts on grasslands have been investigated in different rainfall manipulation experiments [ 2, 3 ], most of these field studies have focused on either C4-grass dominated prairies in arid North America [16] or C3-grasslands in Europe [ 17 ], whereas a limited number of studies have (...truncated)


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Huawu Wu, Jing Li, Xiao-Yan Li, Bin He, Jinzhao Liu, Zhiyun Jiang, Cicheng Zhang. Contrasting response of coexisting plant’s water-use patterns to experimental precipitation manipulation in an alpine grassland community of Qinghai Lake watershed, China, PLOS ONE, 2018, Volume 13, Issue 4, DOI: 10.1371/journal.pone.0194242