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Warming and nitrogen addition alter flowering phenology and plant community composition in a desert steppe
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  • Lu Bai,
  • Guodong Han,
  • Thomas Crowther,
  • Constantin Zohner,
  • Kailiang Yu,
  • Zhuwen Xu,
  • Zhongwu Wang,
  • Qian Wu,
  • Yi Zhu,
  • Jinglei Tang,
  • Haiyan Ren
Lu Bai
Inner Mongolia Agricultural University
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Guodong Han
Inner Mongolia Agricultural University
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Thomas Crowther
ETH Zurich
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Constantin Zohner
ETH Zurich Department of Environmental Systems Science
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Kailiang Yu
Princeton University
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Zhongwu Wang
Inner Mongolia Agricultural University
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Jinglei Tang
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Haiyan Ren
Inner Mongolia Agricultural University

Corresponding Author:[email protected]

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Abstract

The strong control of temperature on the timing of plant phenology is expected to cause substantial shifts in flowering times under climate change. Yet, the sensitivity of flowering phenology in dryland regions to climate change, and the potential implications for community composition, remain largely unexplored. Here, we investigate the effects of climate warming and nitrogen addition on flowering phenology of four C3 plants and two C4 plants and explore cascading effects on shifts in C3 vs C4 plant dominance in a 17-year field experiment in a desert steppe. Across the last 10 years of the experiment (2013–2022), we found that warming had a greater effect on phenological shifts in C3 than in C4 plants. Warming significantly advanced the flowering time of C3 plants by 4.3 ± 0.1 days and of C4 plants by 2.8 ± 0.1 days. Warming also reduced the duration of flowering by 1.8 ± 0.1 days and decreased the dominance of C3 plants compared to C4 plants (P<0.05). Nitrogen addition extended the duration of flowering of C4 plants by 3.4 ± 0.2 days and increased their relative dominance, while having no effect on C3 plants. Structural equation models highlighted that these phenological responses were influenced by soil temperature and soil water availability. Our results show the divergent phenological responses between C3 and C4 plants under global changes, predicting shifts in dominance between these plant types in temperate dryland ecosystems.