新疆北部地区典型湿地孢粉组合与古环境研究

发布时间：2019-01-11 12:32

【摘要】：随着环境的日益恶化,我们所面临的问题不再只是温室效应和臭氧层漏洞。水资源的不合理利用和湿地的大幅度减少,使得新疆北部全新世以来环境演变问题变得更加复杂。定量地研究环境变化规律,可以更好地解释全球气候变化规律,为解决当今生态问题乃至预测未来气候变化提供理论依据。本文拟以在新疆北部艾比湖和喀纳斯两个有小叶桦生长的湿地所取的地层剖面为主体,结合P14PC年龄进行多指标分析,旨在研究古气候变化和植被演变的关系。在艾比湖地区沿博尔塔拉河流域采集49个表土孢粉样品;喀纳斯地区沿东西两侧山坡采集65个表土,进行不同海拔高度间花粉谱差异性研究;然后结合新疆北部214个表土孢粉数据运用加权平均最小二乘法(WAPLS)模型重建3000a BP的古环境、古气候演变历史。结果显示,艾比湖地区的表土孢粉谱划分为6个孢粉带,分别对应该区的现代高山草甸带、亚高山草甸草原带、森林灌丛带、灌丛草原带、荒漠草原带和荒漠植被带。其中带VI又被分为单纯的荒漠植被亚带和对应于当地生长的隐域植被小叶桦的荒漠植被亚带。喀纳斯地区采自东坡和西坡的表土孢粉划分为3个带,分别对应现代的山地温带半荒漠草原带、山地寒温带草原带和山地针叶林带。艾比湖和喀纳斯的剖面孢粉以及其他综合指标的分析得出,两个研究区的气候总体状况均表现为相对冷湿和暖干的变化模式,1300a BP以前都表现出冷湿的环境,嗣后逐渐转为暖干,但在喀纳斯地区380a BP时却出现了稍微冷湿的波动。艾比湖地区过去2000多年以来植被大多是以荒漠草原或草原植被为主,360cal.a BP以来,桦属植物大量生长在湿地上,180cal.a BP之后,该植物急速减少,旱生植物含量增加,湿地严重退缩。喀纳斯地区3000多年以来始终以森林植被景观为主,随着时间的变化仅有建群树种的改变。因此,通过对两个有小叶桦生长的典型湿地区植被和环境演变数据对比,有助于把握历史时期以来全球变化对区域和局域植被的影响。湿地作为地球之肾,对气候变化的缓冲能力较强,对其加以系统地研究,将有助于新疆的生态文明建设。
[Abstract]:As the environment deteriorates, the problems we face are no longer just Greenhouse Effect and ozone holes. The unreasonable utilization of water resources and the decrease of wetlands make the environmental evolution of northern Xinjiang more complicated since Holocene. The quantitative study on the law of environmental change can better explain the law of global climate change and provide a theoretical basis for solving the ecological problems and predicting the future climate change. In this paper, the stratigraphic profiles of two wetlands with small Betula platyphylla growing in Ebinus Lake and Kanas in northern Xinjiang are taken as the main body, combined with P14PC age to carry out multiple index analysis, in order to study the relationship between paleoclimate change and vegetation evolution. Forty-nine surface soil pollen samples were collected along the Boltara River basin in Ebinur Lake area, 65 topsoil samples were collected along the hillsides of east and west sides in Kanas area to study the differences of pollen spectrum between different elevations. Then the paleoenvironment and paleoclimate evolution history of 3000a BP were reconstructed by using weighted mean least square (WAPLS) model based on 214 surface soil pollen data in northern Xinjiang. The results showed that the surface soil sporopollen spectrum of Ebinur Lake area was divided into 6 sporopollen zones, corresponding to the modern alpine meadow belt, subalpine meadow grassland belt, forest thicket belt, shrub grassland belt, desert steppe zone and desert vegetation belt respectively. Among them, VI is divided into simple desert vegetation subzone and desert vegetation subzone corresponding to local growth of small Betula platyphylla. The sporopollen collected from the east slope and the west slope of Kanas area can be divided into three zones, corresponding to the modern mountainous temperate semi-desert steppe zone, mountain cold temperate grassland belt and mountain coniferous forest belt. The analysis of sporopollen and other comprehensive indexes in the sections of Ebinus Lake and Kanas shows that the overall climate conditions of the two study areas are both relatively cold and wet and warm and dry, and before 1 300 a BP, they all showed cold and wet environments. Then it gradually turned to warm and dry, but slightly cold and wet fluctuated at 380 years BP in Kanas area. In the past 2000 years, most of the vegetation in Ebinur Lake area is desert steppe or steppe vegetation. Since 360cal.a BP, Betula plants have grown in large numbers on wetlands. After 180cal.a BP, the plants decreased rapidly and the content of xerophytes increased. The wetlands flinched. Forest vegetation landscape has been dominant in Kanas area for more than 3000 years. Therefore, the comparison of vegetation and environmental evolution data between two typical wet areas with Betula platyphylla is helpful to understand the influence of global change on regional and local vegetation in historical period. Wetland, as the kidney of the earth, has a strong buffer capacity to climate change. It will be helpful to the construction of ecological civilization in Xinjiang to study it systematically.
【学位授予单位】：石家庄经济学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：Q914

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