中国热带-亚热带地区晚第四纪植被与气候变化

LATE QUATERNARY VEGETATIONAL AND CLIMATIC CHANGES IN THE TROPICAL AND SUBTROPICAL AREAS OF CHINA

根据华南地区第四纪孢粉分析资料 ,中国热带低海拔丘陵地区冰期气候的植被表现为山地雨林垂直植被带的下降 ,而西部山区的山地雨林被常绿 -落叶阔叶混交林和松林所替代。在亚热带地区则以铁杉属、山毛榉属、桦属、冷杉属及其它落叶阔叶组分的增加为特点。除了末次盛冰期 ( 2 0 - 1 8ka B.P.)沿海平原的植被为稀树草地 ,气候环境凉干。在此之前的多次冰期 -间冰期旋回华南地区主要表现为冷 /热的气候变化 ,而湿度的变化较小 ,西部高原的一些地区冰期的降雨量甚至可能超过间冰期。根据该区冰期 -间冰期垂直植被带的变化估算 ,华南热带 -南亚热带冰期的年均温约下降 4- 6°C。晚冰期以来 ,个别剖面发现仙女木事件。全新世气候最温暖期多在 850 0 - 380 0 a B.P.之间 ,季雨性常绿阔叶林广泛发育 ,海滩红树林面积超过现在。380 0 a B.P.之后 ,在山区发现有较明显的降温事件 ,但在沿海地区气候变化较弱。全新世气温的波动范围在海拔 1 0 0 0 m以上山地可能达到 3°C,而在低地平原地区的波动幅度仅为 1 - 2°C。

Based on a number of palynological data, the Quaternary glacial vegetation in the tropical area of China was characterized by the lowering of mountain rainforest belt, while in the southwestern uplands, it showed the replacement by mixed forest with particularly Pinus and Alnus . The expansion of grassland and drier climate took place specifically in the LGM in the areas of coastal plains, whereas the climate during the earlier multiple glacial interglacial cycles were characterized by turns of cool and warm with relatively stable precipitation. In the western highlands of southern Yunnan, the rainfall should be higher in the glacial than in the interglacial. According to the lowering forest boundary as low as 600-1 000 m, indicating the temperature was estimated 4-6°C lower in the glacial episode assuming a 0.6°C/100 m of lapse rate. The younger Dryas event was found in a few high resolution pollen diagram. The feature of Holocene vegetation was close to that of presence. The warmest interval in the Holocene was between 8 500-3 800 a B.P., when seasonal evergreen broad leaved forest in the uplands and tropical mangroves in the coastline widely developed. Since 3 800 a B.P., the falls of temperature was recorded in the mountainous regions, while it was moderate in the lowland plains.