2000～2015年鄱阳湖区植被净初级生产力变化及驱动因素分析

Variation of Net Primary Productivity of Vegetation in Poyang Lake Area from 2000 to 2015 and Its Influence Factors

利用多源遥感数据,采用改进CASA（Carnegie-Ames-Stanford-Approach）模型,研究了2000~2015年期间鄱阳湖区植被净初级生产力（net primary production,NPP）的时空变化状况,并分析了其驱动因素。研究结果表明,（1）除林地外,研究区年内各类型植被的平均16 d植被净初级生产力呈单峰型分布,最高峰值出现在4月中旬至5月初,芦苇（Phragmites australis）-南荻（Triarrhena lutarioriparia）群落和薹草（Carex spp.）群落在9~10月还出现了次高峰值,空间上,植被净初级生产力由湖心向湖缘方向增加;（2）研究时段内,研究区年植被净初级生产力变化范围为360.09~735.94 g/m2碳,呈逐年增加趋势,这主要是由秋季植被净初级生产力增加所致;（3）研究区年植被净初级生产力的时空分布和变化主要由鄱阳湖水情主导,气候因素的影响则被相对弱化或掩盖。近年来,鄱阳湖水位下降和枯水期延长导致的植物生长时间延长是湖区植被净初级生产力增大的主要原因。

The complicated water regime of Poyang Lake has great impacts on the succession and growth of the plant in the wetlands. Hence, it is of great significance to quantitatively study the productivity of the vegetation in the Poyang Lake area and its response to the change of water regime. Based on the multi-source remote sensing data and Carnegie-Ames-Stanford-Approach（CASA） model, the spatial-temporal pattern and driving factors of net primary productivity（NPP） of vegetation in the Poyang Lake area during 2010-2015 were estimated and analyzed. The results showed that except the woodland, the annual variation of NPP of different types of vegetation performed a single peak pattern with maximum value occurred in April and May,and NPP increased from the centre of the lake to the margin; during the study period, average annual NPP of vegetation in the Poyang Lake area varied from 360.09-735.94 g/m2 carbon, showing an increasing trend,which was attributed to the increase of NPP of vegetation in autumn; the spatial-temporal pattern of NPP of vegetation is mainly affected by water regime, and the influence of meteorological factors was relatively weakened or masked. In recent years, the prolonged plant growth time caused by the decline of water level and prolonged dry season in the Poyang Lake area was the main reason for the increase of NPP of vegetation in the lake area.