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<p>Under ongoing climate change, changes in net primary productivity (NPP), a key indicator of vegetation growth and ecosystem functioning, are crucial for understanding regional carbon sequestration, forage supply, and ecosystem stability in alpine grasslands on the Tibetan Plateau (TP). However, it is unclear how the NPP of alpine grasslands (including alpine meadow and steppe) on the TP responds to regional climate change. Based on this, we explored the spatial and temporal variations of alpine grassland NPP and its response to changes in temperature, precipitation, solar radiation, vapor pressure deficit, and wind speed over the past forty-one years by using remotely sensed data, the improved Carnegie-Ames-Stanford Approach (CASA) model, higher-order partial correlation analysis, and the Constraint Lines approach. The results showed that: (1) from 1982 to 2022, the NPP of alpine grasslands on the TP showed a slow growth trend, and its spatial distribution pattern showed a prominent characteristic of “low in the northwest and high in the southeast”. The NPP of the alpine meadow is higher, while that of the alpine steppe is relatively lower. (2) The correlation between the NPP of alpine grasslands on the TP and temperature and precipitation is closer than that with solar radiation, vapor pressure deficit, and wind speed. Temperature and precipitation explained 28% and 30% of the variation in NPP of grasslands, and the dominant climatic factors for alpine steppe and alpine meadow were temperature and precipitation, respectively. (3) NPP responses to climatic factors exhibited clear threshold effects, and the optimal climatic conditions differed between alpine meadow and alpine steppe. In particular, alpine meadow reached peak NPP under wetter and warmer conditions than alpine steppe. Alpine steppe NPP began to decline when precipitation exceeded 407.24&#xa0;mm, temperature exceeded -0.19&#xa0;°C, and solar radiation exceeded 5254.79&#xa0;MJ·m<sup>−2</sup>, whereas alpine meadow NPP began to decrease when precipitation exceeded 697.44&#xa0;mm, temperature exceeded 2.99&#xa0;°C, and solar radiation exceeded 4853.29&#xa0;MJ·m<sup>−2</sup>.</p>

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Response of alpine grassland NPP to climate change on earth’s third pole

  • 期刊论文

  • 发表日期：

    2026年5月4日

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  • Genghan Zheng,
  • Minxia Liu,
  • Yingying Zhang,
  • Jianyang Shi

摘要

Under ongoing climate change, changes in net primary productivity (NPP), a key indicator of vegetation growth and ecosystem functioning, are crucial for understanding regional carbon sequestration, forage supply, and ecosystem stability in alpine grasslands on the Tibetan Plateau (TP). However, it is unclear how the NPP of alpine grasslands (including alpine meadow and steppe) on the TP responds to regional climate change. Based on this, we explored the spatial and temporal variations of alpine grassland NPP and its response to changes in temperature, precipitation, solar radiation, vapor pressure deficit, and wind speed over the past forty-one years by using remotely sensed data, the improved Carnegie-Ames-Stanford Approach (CASA) model, higher-order partial correlation analysis, and the Constraint Lines approach. The results showed that: (1) from 1982 to 2022, the NPP of alpine grasslands on the TP showed a slow growth trend, and its spatial distribution pattern showed a prominent characteristic of “low in the northwest and high in the southeast”. The NPP of the alpine meadow is higher, while that of the alpine steppe is relatively lower. (2) The correlation between the NPP of alpine grasslands on the TP and temperature and precipitation is closer than that with solar radiation, vapor pressure deficit, and wind speed. Temperature and precipitation explained 28% and 30% of the variation in NPP of grasslands, and the dominant climatic factors for alpine steppe and alpine meadow were temperature and precipitation, respectively. (3) NPP responses to climatic factors exhibited clear threshold effects, and the optimal climatic conditions differed between alpine meadow and alpine steppe. In particular, alpine meadow reached peak NPP under wetter and warmer conditions than alpine steppe. Alpine steppe NPP began to decline when precipitation exceeded 407.24 mm, temperature exceeded -0.19 °C, and solar radiation exceeded 5254.79 MJ·m−2, whereas alpine meadow NPP began to decrease when precipitation exceeded 697.44 mm, temperature exceeded 2.99 °C, and solar radiation exceeded 4853.29 MJ·m−2.