地震灾区植被净初级生产力恢复效应评价

地震等重大灾害的发生,对区域植被及生态环境造成了巨大破坏,植被净初级生产力(net primary productivity,NPP)能够反映绿色植物的生长状况,进行地震灾区植被NPP恢复效应评价,对掌握震后植被恢复情况和变化趋势具有指导意义。以"5·12"汶川大地震的极重灾区为研究区,选择地震前后3个时期的TM及MODIS卫星遥感数据,结合气象资料等其他数据,利用改进的CASA模型估算了灾区前后三年植被NPP。结果表明,灾后2009年植被NPP总量为9.827亿gC/a,相比灾前2007年减少了31.99%,2011年恢复期相比2009年增长了28.55%,但仍比2007年低12.57%,震后两年,灾区植被净初级生产力有所恢复,但未达到震前水平;从植被NPP空间分布来看,离地震中心越近的地方,植被NPP受到的削减程度越大,其恢复能力越差;经验证分析,评价结果具有较高的可信度,可为相关部门制定灾区生态重建和生态恢复计划与实施提供科学依据。

Assessment of Restoration of Vegetation Net Primary Productivity in Earthquake Disaster Area

The occurrence of major disasters such as earthquake has caused great damage to the vegetation and ecological environment.The net primary productivity (NPP) of vegetation can reflect the growth status of green plants,and evaluation on the effect of vegetation restoration on primary productivity in earthquake stricken areas is helpful to understand the situation and trend of vegetation restoration after earthquake.Based on the multi-phase remote sensing data (e.g.MODIS and TM),and combination of the meteorological information and other data as auxiliary data,by means of RS and GIS,we improved the CASA model and used it to estimate NPP of three years before and after the disaster area.Results show that the total vegetation NPP was 982.7 million gC/a after the disaster in 2009,decreased by 31.99 percent compared to the previous disaster in 2007,increased by 28.55％ due to recovery in 2011 compared to 2009,but still 12.57％ lower than in 2007,two years after the quake,vegetation net primary productivity of the disaster area recovered somewhat,but not reached the level before the earthquake;according to the spatial distribution of vegetation NPP,the closer to the center of the earthquake is,the greater the degree of vegetation NPP reduction is,the worse the recovery ability is.The comparison results show that the improved model has high reliability,which can provide scientific basis for the relevant departments to develop the ecological restoration and ecological restoration plan and implementation.