Abstract: Changes of vegetation coverage and response to climate change and human activities were studied in the northern Hexi Corridor. The relations of NDVI (1982-2005 NASS/GIMISS) with climate change and livestock number were analyzed in Minqin, Jiuquan and Yumen counties of northern Hexi Corridor from 1982 to 2005. Results indicated that the annual variations of NDVI showed an increase tendency in Minqin (P<0.01) and Jiuquan (P<0.05) as annual trends of temperature in each county increased (P<0.01). However, uncertain tendencies were found in the variations of annual precipitation and rain use efficiency (RUE). The coefficient of variation (CV) of NDVI and temperature were small, whereas the CV of precipitation, livestock number and RUE were large. The ranking of NDVI, temperature, precipitation and livestock number were Minqin>Jiuquan>Yumen. RUE were ordered as of Jiuquan>Minqin=Yumen. NDVI was positively correlated with precipitation and temperature in Minqin (P<0.05), however, NDVI was not correlated with temperature, precipitation and livestock number in Jiuquan. NDVI was negatively correlated with livestock number in Yumen (P<0.05). Based on above analyses, precipitation was more important to NDVI than temperature in Minqin. Both climate and livestock were important contributors to NAVI in Jiuquan and livestock was a restrictive factor to NDVI in Yumen.

Key words: Northern Hexi corridor, NDVI, Precipitation, Temperature, Livestock number

摘要： 利用1982-2005年的NASA/GIMMS半月合成植被指数(NDVI)数据,结合气候与家畜数量资料,分析河西走廊北部风沙源区东部民勤、中部酒泉和西部玉门的NDVI、气温、降水和家畜数量年变化及其关系,以探讨河西走廊北部风沙源区植被覆盖变化对气候变化和人类活动的响应。结果表明:民勤和酒泉的NDVI年变化呈增加趋势(P<0.01和P<0.05);民勤、酒泉和玉门的气温年变化均呈增加趋势(P<0.01);降水与降水利用效率(RUE)年变化则相反(P>0.05)。NDVI和气温的年变异系数(CV)小,降水和家畜数量及RUE的CV大。3地的NDVI、气温、降水及家畜数量为民勤>酒泉>玉门,RUE为酒泉>民勤=玉门。民勤的NDVI与降水和气温成正相关(P<0.05),酒泉的NDVI与降水、气温及家畜数量均无显著相关性,玉门的NDVI与家畜数量成负相关(P<0.05)。分析认为,降水对民勤NDVI的贡献大于气温,气候和载畜量都是影响酒泉植被的重要因素,家畜数量是玉门NDVI变化的限制因子。

关键词: 河西走廊北部, NDVI, 温度, 降水, 家畜数量