气候和景观多样性对青藏高原草地植物多样性与生物量的影响

青藏高原是亚洲的重要生态安全屏障区和高海拔牧区，生物多样性资源丰富、生态环境脆弱，对气候变化和人类活动响应敏感。本研究在青藏高原跨经纬度带开展草地植物群落调查和采样，测度物种多样性、功能多样性和地上生物量，计算采样地月均气温和月均降水气候因子的多年均值、多年变化速率和变异系数，同时计算了景观多样性指数，分析在不同环境梯度下草地植物多样性、生产力及其关系的变化。研究结果表明：（1）青藏高原西藏南部和纳木错附近的暖干化趋势明显，西藏纳木错附近沼泽草甸降水波动变异性较大、青海东南部高寒草原气温波动变异性较大，祁连山林草过渡带山地草甸景观多样性在采样点中最高；（2）群落植物株高和单株平均叶盖度对气候因子和景观多样性的响应相一致，但前者从统计结果来看更加敏感，气候因子变异性与株高和叶盖度均呈负相关、景观多样性高的地点其株高和叶盖度更大；（3）气候因子变异性高的地点功能多样性以及群落加权平均株高和叶盖度都更小，即气候环境的不稳定将降低多样性水平，气候因子变化速率越大群落功能多样性水平更高，反映草地植物群落在加速变化环境中通过多样化物种功能性状构成以趋于稳定化的适应过程；（4）景观多样性与物种多样性和生物量呈正相关，反映草地景观多样性对物种多样性及生物量积累有促进作用；（5）大多数植物多样性指标均与群落生物量成正比，验证了草地多样性对生产力的积极作用。本研究结论为揭示青藏高原不同气候和景观背景下草地植物多样性格局变化及其影响因素提供科学依据，为制定应对气候变化的青藏高原草地植物多样性保护策略提供实证参考。

The Qinghai-Tibet Plateau has been an important ecological security barrier area and high-altitude pastoral area in Asia. It is rich in biodiversity resources and fragile ecological environment, and is sensitive to climate change and human activities. This study conducted plant community surveys and sampling across different latitudes and altitudes on the Qinghai-Tibet Plateau. The measurements included species diversity, functional diversity, and above ground biomass. Additionally, calculations were performed to determine the multi-year mean values, multi-year change rates, and variation coefficients of monthly mean temperature and precipitation, along with the landscape diversity index to reflect the ecosystem's type diversity in the sampling area. The analysis aimed to reveal the relationship between plant diversity and the productivity of grassland under large-scale environmental gradients. Findings based on the assessment of environmental changes and functional traits indicate the following: (1) The trend of warming and drying is obvious in southern Tibet and near Namtso. The variability of precipitation in the marsh meadow near Namtso Lake and the grassland temperature variability in the alpine grassland of the Qinghai southeastern were high. The mountainous meadow of forest-grassland ecotone in the Qilian Mountains showed the highest diversity among the sampling sites. (2) The plant height and average leaf coverage per plant demonstrated consistent response to climatic factors and landscape diversity, with the former being more sensitive. Climate factor variations exhibited a negative correlation with plant height and leaf coverage, while locations with high landscape diversity displayed higher plant height and leaf coverage. (3) Sites with high variability of climate factors had lower functional diversity, weighted average plant height, and leaf coverage in the community. This implies that an unstable climate environment reduces the level of community diversity. Higher change rates of climate factors were associated with increased levels of functional diversity, reflecting the adaptive process of grassland plant communities in stabilizing themselves through diversified species functional traits under accelerated environmental change. (4) Landscape diversity exhibited a positive correlation with species diversity and grassland biomass, indicating that the diversity of the grassland landscape diversity promotes species diversity and biomass accumulation. (5) Most plant diversity indexes demonstrated a direct proportionality with grassland biomass, confirming the positive effect of grassland diversity on productivity. Our study contributes in understanding the formation and influencing factors of biodiversity patterns in alpine steppe under different gradient climate and landscape environments on the Qinghai-Tibet Plateau. Moreover, it provides a theoretical basis and valuable references for studying diversity protection under environmental change and informing decision-making processes.