气候和土地利用变化对上海市农田生态系统净初级生产力的影响

以上海市主要植被类型农田为研究对象,利用大气-植被相互作用模型(AVIM2)模拟的近50年上海市农田净初级生产力(NPP)以及1987、1997和2004年上海市的TM遥感影像数据,分别计算了气候变化和土地利用变化对上海市农田生态系统NPP总量变化的影响.研究结果表明,如果只考虑气候变化,1961～2006年上海农田年平均NPP值增加了64.37g·m-2(以C计),平均每年增长1.43g·m-2.年平均温度和降水量均与NPP显著正相关.另一方面,上海农田面积占总面积的比例由1987年的76%递减到2004年的43%.在土地利用变化和气候变化双重因素的驱动下,自20世纪80年代以来,上海农田NPP总量减少了42%;相对于气候变化影响,土地利用变化对农田NPP总量影响较大,其中,20世纪80年代到90年代,土地利用变化对NPP总量变化的贡献率占78%;20世纪90年代到21世纪初土地利用变化的贡献率达92%.

Impacts of land use and climate change on agricultural productivity in Shanghai

The impacts of land use and climate change on the agricultural productivity of Shanghai were studied by using simulated cropland net primary productivity (NPP) data from 1961 to 2006. The data were based on the Atmosphere| Vegetation Interaction Model (AVIM2), and Landsat TM satellite images from 1987, 1997 and 2004. The results indicated that the annual agricultural NPP, driven by climate change, increased 64.37 g·m-2·a-1 with a growth rate of 1.43 g·m-2·a-1 during 1961~2006. Both annual mean temperature and precipitation had significant positive correlations with cropland NPP. For cropland area, its proportion of the total area of Shanghai decreased from 76% in 1987 to 43% in 2004. Considering both land use and climate change factors, the total NPP of the early 21st century decreased by 42% compared with that of the 1980s. However, the land use change had greater impact than climate change on total cropland NPP in Shanghai. From the 1980s to the 1990s, the decrease of land use contributed 78% to the change of total NPP, and it increased to 92% from the 1990s in the early period of 21st century.