| Global climate change research has been a hot spot, nearly a hundred years of accurate meteorological records confirm global warming. Climate change will inevitably profound impact on human society itself, the study of past climate change, is to explore the patterns and causes of change, and then be able to predict future climate change trends, find counter-measures to adapt to these changes. From the outflow of water system impact Crater Lake, stable deposition rate, the pollen in the sediments is an ideal carrier of the study. This paper selects the lakes of climate sensitivity to bring a representative to carry out the study of lake sediment pollen characteristics and vegetation change.Through the depth of105cm, Inner Mongolia eastern Xinganmeng Aer Tianchi lake sediments short columns (1524-2010AD) of105samples of pollen assemblage study on the regional vegetation succession process, revealing the characteristics of climate change. Contrast, nearly60years with the local meteorological data and research in the background conditions of accurate climate records, the Aer the Tianchi near the vegetation variation. Achieved the following findings:1. Aer Tianchi sediments short columns identified39pollen types and including7of the arboreal shrub vegetation types8,17herbaceous types, five kinds of aquatic plant types, fern spores of two kindstypes.2. Herbaceous pollen, Artemisia is the most important component of the herb pollen.Trees, shrubs pollen Betula as the main ingredient. Dominated by herb pollen percentage content of the evolution of pollen assemblages from bottom sediments is the dominant tree, shrub pollen.3. Pollen records show that from the bottom divided into five pollen assemblage. And Recovered Aer Tianchi vegetation succession in the past500years. Pollen assemblage Ⅰ (54-105cm1524-1780AD), the vegetation is forest-steppe pollen assemblage Ⅱ (30-54cm1780-1895AD) vegetation for forest vegetation coverage increased, pollen assemblage Ⅲ (17-30cm1895-1945AD) vegetation for forest vegetation coverage reducted. pollen assemblage Ⅳ(11-17cm1945-1970AD) vegetation for forest vegetation cover increase. Pollen assemblage Ⅴ(0-11cm1970-2010AD) vegetation for forest and vegetation cover reducing.4. According to the characteristics of vegetation types evolution of the recovery of nearly500years of climate change processes.1524-1780AD, the climate has gone through a "cold and dry-cold and wet-and cold and dry volatility process:1a (1 524-1680AD) climatic characteristics of relatively cold and dry,1b (1680-1743AD) climate characterized by relatively cold and wet, Ic (1743-1780AD) the climate is characterized by relatively cold and dry;1780-1895AD, the climate is characterized by relatively warm and humid;1895-1945AD, the climate is characterized by relatively warm dry;1945-1970AD, the climate as a whole shows a relatively warm and humid;1970-2010AD the climate is relatively warm and dry, there are significant fluctuations.5. By analyzing the Aershan nearly60years of meteorological records of the study area, the average temperature experienced low-high-low-high ", respectively, in1958,1965,1988a turning point. Annual precipitation experienced a "high-low-high-low", respectively, in1961,1981,2000a turning point. The vegetation composition also changed significantly, the turning point in1970and1993than the temperature variations lag about7years. The temperature control of the relative content of the birch, and Artemisia. A change in vegetation cover is relatively complex, not only by the humidity, but also limited by topography, soil conditions.6. Vegetation zones due to climate change and migration, is mainly because with the global warming, summer wind to strengthen... |
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