应用CASA模型估算浙江省植被净初级生产力

自然植被和生产力的变化是表征区域生态环境质量变化的重要指标,利用CASA (Carnegie-Ames-Stanford Approach)模型对浙江省植被净初级生产力(NPP)进行估算,分析了净初级生产力的时空分布变化及受土地利用变化影响的特点.结果表明:①2006年浙江省净初级生产力平均为625.68 g·m-2·a-1；空间上,呈现出随着海拔的增高而增大的趋势；时间上,各土地利用类型的净初级生产力均表现出一致而明显的季相变化,不同土地利用类型之间的净初级生产力高低差异明显；②全年净初级生产力总量为6 451.24万t·a-1,林地和耕地是净初级生产力总量的主要构成部分,占净初级生产力年总量的70％以上；其中,丽水市净初级生产力年总量最高,为1 336.05万t·a1,舟山市最低,为47.18万t·a-1；生态公益林的净初级生产力均值为815.28 g·m-2·a-1,固碳能力明显优于其他林地；③相比1996年,2006年浙江省净初级生产力年总量因土地利用类型的变化增加了52.96万t·a-1,净初级生产力年总量保持着相对稳定的态势.有效提升浙江省植被净初级生产力途径主要有:在平原地区构建森林网络体系,在山区积极实施阔叶林化改造工程,以及对竹林进行科学集约化经营.

Net primary productivity estimates for Zhejiang Province based on the CASA model

Changes in vegetation and net primary productivity （NPP） are important indicators representing re- gional ecological qualitative changes. To examine NPP vegetative seasonal variation, spatial patterns, and land use change that affected variation, an NPP simulation was performed for Zhejiang Province in 2006 based on the Carnegie-Ames-Stanford Approach （CASA） model with results further analyzed by Geographic Informa tion System（GIS）-based software. Results showed that （1） average annual NPP was about 625.68 g. m-2·a^-1 NPP also showed a spatial heterogeneity which lying down within the relief over the study area. NPP differed with land use type, but there seems to be a similar seasonal change which increased fast in Feb. to May＇ and peaked in July and Aug. （2） Total NPP in 2006 was about 6 451.2 ×10^4 t·a^-1 with more than 70% found mainly in forest and cropland near each city in Zhejiang Province. Total NPP of Lishui City was highest （1 336.05 ×l0^4t ·a^-1） ; whereas Zhoushan City was lowest （47.18 ×10^4 t·a^-1）. For the Ecological Service Forests, the average annual NPP was about 815.28 g. m^-2·a^-1 which was higher than the mean values of forests. （3） Compared to 1996. total NPP in 2006 increased about 52.96 ×1 0^4t·a^-1 dut to land use type change..Thus,to effectivelt enhance vegetation NPP for Zhejiang Province, a forest network system should be built in the plains areas, the project accelerating the succession of coniferous forest into broadleaf forest should be conducted in mountain areas, and an intensive management for bamboo stands should be undertaken. Ch, 2 fig. 3 tab. 19 ref.]