气候变化与人类活动对青藏高原湿地的影响研究进展

Advances in impact of climate change and human activities on wetlands on the Tibetan Plateau

青藏高原是中国湿地分布最多的区域,其独特的高寒湿地对区域生态环境安全有着不可或缺的作用。梳理了青藏高原湿地变化的时空特征,基于此,重点分析了气候变化与人类活动对不同类型湿地的影响和作用机制。研究发现:(1)主导不同类型湿地变化的气候因素有差异,影响存在区域异质性。湖泊湿地主要受降水量影响,湖泊湿地在北部扩张、南部缩小的趋势与降水量的空间差异存在较强的一致性;沼泽湿地主要受气温影响,气温升高导致水分蒸发、植被群落演替,沼泽湿地向草地转化,江河源区和若尔盖高原等主要分布区域呈现退化趋势;河流湿地主要受气温影响,气温升高加速河源冰川消融、同时也增大河流蒸散发量,共同作用下河流湿地呈现北部减少、南部增加的趋势。(2)过度放牧、泥炭开采、水利建设等是影响湿地变化的主要人类活动。若尔盖高原同时存在过度放牧、泥炭开采和沟渠建设多重人类活动影响,当地沼泽湿地退化明显;柴达木盆地的人工湿地由于盐业开采迅速扩张。(3)当前研究存在数据可对比性不足、大区域尺度和野外定点持续监测数据缺乏等问题,导致对气候变化与人类活动影响机制研究不够深入。未来应加强高寒湿地定期监测与风险评估,完善高寒湿地生态系统与环境变化和人类活动间的相互作用机制研究,关注高寒湿地生态过程,为筑牢国家生态安全屏障提供重要科学支撑。

The Tibetan Plateau covers the largest distribution of wetlands in China,and its unique alpine wetlands are indispensable for regional ecological security.This paper summarized the spatiotemporal variation characteristics of wetlands on the Tibetan Plateau,focusing on the impact mechanism of climate change and human activities on different wetland types.The main findings are presented as follows:(1)the climate factors dominated the wetland changes vary with wetland types and regions.Specifically,lacustrine wetlands expand in the north but shrink in the south,which corresponds with the spatial pattern of precipitation,indicating that the lacustrine wetlands variation is mainly driven by precipitation.Palustrine wetlands are mainly affected by temperature.The increase in temperature leads to water evaporation,vegetation community succession,palustrine wetlands conversion to grassland,and degradation of main distribution areas such as the Yangtze,Yellow River source regions and the Zoige Plateau.Furthermore,riverine wetlands are mainly affected by temperature.The increased temperature accelerates the glacier melting of river sources and increases the evapotranspiration of rivers,jointly causing the decrease of riverine wetlands in the north while increasing in the south.(2)Overgrazing,peat mining and water conservancy construction are the main human activities affecting wetland changes.Under the joint influence of overgrazing,peat mining and ditch construction,the palustrine wetlands degrade sharply on the Zoige Plateau.Meanwhile,the constructed wetlands in the Qaidam Basin are rapidly expanding due to salt mining.(3)Less comparability of wetland data,lack of continuous monitoring data at large regional scale and field fixed-points lead to insufficient in-depth research on the impact mechanism of climate change and human activities on alpine wetlands.In the future,it is urgent to strengthen the regular monitoring and risk assessment of alpine wetlands,improve the research on the interaction mechanism between alpine wetland ecosystems,the environmental change and human activities,and pay attention to the ecological process of alpine wetlands,to provide important scientific support for building nationally ecological security barrier.