祁连山区植被净初级生产力的空间变化特征分析

The Spatial Variation of Vegetation Net Primary Productivity in Qilian Mountains

基于MODIS数据分析了2000~2010年祁连山区植被净初级生产力(Net Primary Productivity,NPP)的空间变化特征。结果显示:祁连山区植被NPP并不高,多年平均植被NPP仅为121.95gC/(m2·a),自东向西植被NPP逐渐减少。不同植被类型其NPP具有明显差异,大体上为:常绿阔叶林】平原草地】常绿针叶林】典型草地】农田】高寒草甸草地】荒漠草地】落叶针叶林。祁连山区植被NPP变化在区域间也存在差异。植被NPP呈增长趋势的地区主要分布在青海年南山、拉脊山、达坂山和青海湖及其西侧,约占47.30%;乌鞘岭东部及以东的地区(约占1.97%)植被NPP呈减少趋势。降水是祁连山区植被NPP变化的主要因素,气温对植被NPP的影响并不明显,不合理的人类活动可能是造成部分区域植被NPP减少的重要原因。

This study analyzed the spatial distribution of vegetation NPP in Qilian Mountains from 2000to2010 based on MODIS NPP.The study showed that the vegetation NPP had a decreasing trend from east to west in Qilian Mountains due to effects from precipitation.Average vegetation NPP values of Qilian Mountains were only 121.95 g C/(m2·a).NPP values of different vegetation types could be sorted in a descending trend:evergreen broadleaved forests,plain grasslands,evergreen coniferous forests,meadows,farmlands,alpine and sub-alpine grasslands,desert grasslands,deciduous coniferous forests.Overall,the average NPP of Qilian Mountains had been increasing during the past 11 years.The NPP of most of the area(about 47.30%)in Qilian Mountains showed an increasing trend,while less than 2%area showed a decreasing trend.Precipitation is a major factor of vegetation NPP change in Qilian Mountains.The effects of temperature on the NPP is not obvious,and irrational human activities may be the important reasons of Vegetation NPP reduction in part of Qilian Mountains.