近30年关天经济区植被净初级生产力对土地利用变化的动态响应

Response of vegetation net primary productivity to LUCC in Guanzhong-Tianshui Economic Zone in recent 30 years

利用1980-2010年4期Landsat遥感影像,获取相应年份的土地利用图,并提取NDVI,在此基础上利用CASA模型计算关天经济区植被NPP,计算分析土地利用变化对NPP的影响。结果表明:1)林地NPP均值最大(383.38gC·m-2·a-1),其次是草地、耕地,建设用地NPP最低(271.66gC·m-2·a-1)。2)关天经济区近30年NPP呈现先降低后增加再小幅降低的趋势,1980年的植被NPP为2.3×107gC·m-2·a-1,2000年为1.7×107gC·m-2·a-1,2005年为3.2×107gC·m-2·a-1,2010年2.2×107gC·m-2·a-1。3)关天经济区植被NPP在空间上分布不均衡。秦岭山区以及宝鸡与天水交界处的山区植被NPP高,秦岭山区植被NPP高达631.15gC·m-2·a-1,而低值区(53.85gC·m-2·a-1)位于经济发达的关中平原。4)土地利用变化区域,土地利用类型变化对区域植被NPP的影响显著,耕地转变为建设用地使NPP降低,关中平原与天水地区人口居住区与开垦区植被NPP明显下降,土地开发利用导致了植被NPP的降低。所以,关天经济区在维持经济发展的同时,要控制建设用地的无序增长,维持好区域的植被覆盖,保障区域生态平衡。

Vegetation net primary productivity （NPP） is the main factor of ecosystem carbon source, carbon pool and for regulating ecological process, it represents the regional ecological quality, and is an important index to estimate the earth＇s support ability and evaluate sustainable development of terrestrial ecosystems. LUCC affects vegetation NPP. We obtained LUCC map and extracted Normalized Difference Vegetation Index （NDVI） by using 4 years Landsat remote sensing data which was around September during 1980 -2010. Based on the above, vegetation NPP was extracted by means of CASA model. At last, we analyzed the impact of LUCC on NPP. Results showed that： （1） The maximum of mean NPP was forest land （383.4gC ·m^-2·a^-1）, followed by grassland, farmland, and NPP of construction land was the lowest （271.66 gC·m^-2·a^-1 ）. （2） NPP of GTEZ decreased firstly and then increased again, lastly decreased slightly in the past 30 years. NPP was 2.3 ×10^7gC ·m^-2·a^-1 in 1980, 1.7 ×10^7gC ·m^-2·a^-1 in 2000, 3.2×10^7gC ·m^-2·a^-1in 2005, and 2.2×10^7gC·m^-2·a^-1 in 2010. （3） The area with high NPP was located in the mountainous area of the Qinling Mountains and the juncture zone of Baoji and Tianshui, and that in Qinling Mountains reached up to 625.37gC ·m^-2·a^-1, and the area with low NPP was in the developed Guanzhong Plain. （4） LUCC had the great influence on regional vegetation NPP in land use change area. NPP of residential and reclaimable area significantly decreased in Guanzhong Plain and Tianshui, and the minimum value of NPP reached 47.78gC·m^-2·a^-1. Land development and utilization led to the reduction of NPP. GTEZ should control the disorderly growth of the construction land, and maintain vegetation cover to protect the regional ecological balance while maintaining economic development.