辽河三角洲地区植被的地上净初级生产力格局及其制约因子

植被地上净初级生产力是监测和评价生态系统功能的重要指标之一,也是农业区划和生态资源分区管理的重要依据。通过实地调查,研究了辽河三角洲地区的植被地上净初级生产力的空间分布格局及其制约因子。2008年9月末,在辽河三角洲地区设立79个调查点,调查了植被地上净初级生产力、土壤和水文特征。借助ArcGIS软件制作了植被地上净初级生产力的分层设色等值线图,并利用简单相关分析和无条件主成分分析方法探讨了植被地上净初级生产力与环境因子的关系。结果发现：辽河三角洲地区的植被地上净初级生产力具有内部较低,外围较高的半环形分布格局。在三角洲内部,植被地上净初级生产力一般1 500 g.m-2.a-1左右;外围一般3 000 g.m-2.a-1以上。这种分布格局不仅与植被类型分布有一定的相关性,而且还与海拔高度、土壤含水量、土壤容重和土壤总磷等自然环境因子有明显的相关性。多种证据表明土壤含水量是决定辽河三角洲地区植被地上净初级生产力格局的最直接、最重要的自然环境因子。

The spatial pattern and the constraint factors of the above ground net primary productivity in the Liaohe River Delta

The above ground net primary productivity of vegetation is an important index to inspect and evaluate the functions of eco-system,and it is also the important base for agricultural division and subarea management.This paper explored the spatial pattern of the above ground net primary productivity and its constraint factors by a field survey in the Liaohe River Delta.The field survey was carried out at the end of September in 2008.Seventy nine sites were sampled to investigate the above ground net primary productivity and the characteristics of both soil and hydrology.A hierarchical color isoline map was made by GIS（Geographical Information System） software,and the simple correlation analysis and the categorical principal component analysis were also employed to explore the relationship between the above ground net primary productivity and the environmental factors.The results showed there was a semi-annular spatial pattern of the above ground net primary production surrounding the interior of the Liaohe River Delta.The above ground net primary production was lower in the interior,but higher in the peripheral land.The above ground net primary production was about 1500 g·m-2·a-1 in the interior,while it was often higher than 3000 g·m-2·a-1 in the peripheral land of the Liaohe River Delta.This spatial pattern was related not only to vegetation types but also to altitude,soil moisture,soil bulk density and total soil phosphorus.Many evidences showed that soil moisture was the most important environmental factor directly controlling the spatial pattern of the above ground net primary production in the Liaohe River Delta.