青藏高原植被动态与环境因子相互关系的研究现状与展望

青藏高原是中国乃至全球对气候变化最敏感的地区之一,是全球平均海拔最高的地理单元,对周边地区起到重要的生态安全屏障作用。近年来,当地植被受到气候变化和人类活动的双重压力。本文基于文献检索分析青藏高原的植被生理、生态特征对气候变化和人为干扰的响应,并利用荟萃分析定量综述植被覆盖度变化对土壤理化性质的影响。在此基础上分析青藏高原植被与环境因子相互关系的研究尺度与方法。结果表明:(1)气温、降水、辐射等自然因素和放牧、农耕、筑路等人为活动均对青藏高原植被的碳交换、水分利用效率、元素含量与分布格局、物候、多样性等指标产生显著影响,植被的变化也同时影响着土壤的水热交换、水文过程和理化性质等;(2)在植被退化过程中,由高覆盖度向中覆盖度转变时对土壤理化性质产生的不利影响强于由中覆盖度转为低覆盖度时,高覆盖度地区的植被保护需要引起更多关注;(3)现有研究更多关注单一要素、单一尺度,未来应关注多要素间的相互耦合,通过合作与共享获取数据,开展多尺度对比和尺度效应研究,系统梳理和分析植被与环境因子的相互关系可为制定科学合理的生态修复策略提供科学依据。

The relationships between vegetation dynamics and environmental factors on the Qinghai-Tibet Plateau: A review of research progress and prospect

The Qinghai-Tibet plateau is one of the regions most sensitive to climate change both in China and in the world at large. In recent years, local vegetation has been under the dual pressure from climate change and human activities. Its physiological and ecological characteristics, in response to climate change and human interference, were analyzed in this paper based on literature research, and the impact of change in vegetation coverage on soil physical and chemical properties were quantitatively summerized based on meta-analysis. On this basis, this paper reviewed the research scales and methods in studying the relationship between vegetation and environmental factors on the Qinghai-Tibet plateau and summerized the results as the follows: 1) Natural factors such as temperature, precipitation and radiation, and human activities such as grazing, farming and road construction, significantly affected the carbon exchange, water use efficiency, elemental content and distribution pattern, phenological period and diversity of vegetation. The change of vegetation also affected the water heat exchange, hydrological process and physical and chemical properties of soil. 2) In the process of vegetation degradation, the changes in vegetation coverage from high to medium had a stronger negative effect on the physical and chemical properties of soil than changes from medium to low; therefore, more attention should be paid to vegetation protection in the high coverage area. 3) Previous researches mainly focused on the impact of a single factor and a single scale. In future, more attention should be paid to multi-factor coupling by considering the intra- and out-of-domain effects on the ecosystem. Besides, multi-scale comparison and scale-effect research should be conducted to explore the ecological restoration strategies and climate change coping mechanisms at different scales based on data compiled through cooperation and data sharing. To implement further research, it is also necessary to integrate multi-source, multi-point, long-term series monitoring data to establish an observational network covering the whole Qinghai-Tibet plateau. In addition, data sharing should be strengthened to save research resources while reducing damage caused by unnecessary repeated sampling to the fragile plateau ecosystem. The systematic review of the relationships between vegetation and environmental factors could be applied to the planning, design and monitoring of ecological protection and restoration projects, so as to develop the ecological protection and restoration technology and management system suitable for the Qinghai-Tibet plateau region, and also provide support for policy-making in this region.