新疆地区全新世植被演替与气候环境演变

Holocene vegetation succession and climate-environment change in Xinjiang Region

综述了近20年来新疆地区全新世高分辨率的孢粉记录,通过时间序列和空间格局的对比,初步认识了新疆地区全新世气候环境的变化特征与荒漠植被格局的演变规律.早全新世气候温暖干旱,北疆地区出现荒漠植被,南疆地区发育荒漠草原和荒漠植被,但荒漠植被在不同区域出现和持续的时间有差异.中全新世气候环境逐渐改善,北疆地区植被由荒漠类型向荒漠草原和草原转变,南疆地区仍以荒漠、荒漠草原为主.晚全新世气候环境趋向干旱化方向发展,北疆地区以荒漠草原和草甸草原占优势,但是旱生成分明显增加,南疆地区覆盖荒漠植被.新疆不同区域全新世植被演替具有一定的可比性,也存在差异性,而研究地点的地理位置、地形地貌、海拔、天山山脉的阻挡和西风环流的演化等因素可能是导致这种差异的原因.

Xinjiang Uygur Autonomous Region is located in the internal add area of Eurasia which is highly sensitive to global climate change. A large number of publications related to Holocene environmental change in dry area of Xinjiang are available based on different time scales. This paper reviews the Holocene high-resolution pollen records in Xinjiang during the last two decades. By means of temporal and spatial comparison, we recognize the evolution of climate-environment and desert vegetation in the Holocene in Xinjiang. During the early Holocene, desert vegetation occurred in northern Xinjiang and desert-steppe and desert vegetation covered in southern Xinjiang, reflecting a warm and dry climate condition. However, occurrence and duration times of desert vegetation were different in each region. In the middle Holocene, the climate and environment developed toward a better condition. The vegetation shifted to desert-steppe and steppe in northern Xinjiang, while desert and desert-steppe still dominated in southern Xinjiang. In the late Holocene the climate and environment became more and more add. The desert-steppe and meadow-steppe dominated in northern Xinjiang with an increasing of dry-tolerant elements. Sothern Xinjiang was covered by desert vegetation. Holocene vegetation succession in each region of Xinjiang is comparable and also has difference due to the geographical position, topography and altitude of the study site, obstruction of the Tianshan Mountains, and evolution of the westerly circulation.