庙岛群岛南部岛群无居民海岛植被净初级生产力评估

无居民海岛具有显著的战略地位和重要的生态价值，植被净初级生产力(NPP)评估对维护无居民海岛生态系统稳定性和活力具有重要意义.以庙岛群岛南部岛群中螳螂岛等5个无居民海岛为研究对象，通过遥感手段，对海岛NPP总量和密度及其空间分布特征进行分析.结果显示：1) 全年NPP总量为134.22 tC·a－1，平均密度为274.13 gC·m－2·a－1，并表现出明显的季节差异，各岛NPP平均密度由大到小依次为牛砣子岛、羊砣子岛、螳螂岛、南砣子岛和挡浪岛；2) 不同地表覆盖类型NPP平均密度由大到小依次为阔叶林、针叶林、草地、建设用地和裸地，各岛NPP平均密度与裸地面积占比呈明显的负相关，区域NPP密度与海拔、坡度、坡向和归一化植被指数呈显著正相关；3) 黑松和刺槐是北方无居民海岛人工林的理想树种，持续的人工林种植是提升无居民海岛NPP的重要途径.

Evaluation of vegetation net primary productivity on uninhabited islands in southern Miaodao Archipelago in China

There are important strategic functions and ecological values in uninhabited islands， and the evaluation on vegetation net primary productivity (NPP) is of great significances for maintaining the stability and vitality island ecosystem. Five uninhabited islands in southern Miaodao Archipelago， typical islands in North China， were used as the study area. The NPP and spatial distribution of these islands were analyzed based on the method of Remote Sensing. The results indicated that the total amount of NPP of the study area reached 134.22 tC·a－1， with the mean density of 274.13 gC·m－2·a－1， and the NPP differed greatly in different seasons； the mean densities of NPP of the five islands showed the descending order as Niutuozi Island， Yangtuozi Island， Tanglang Island， Nantuozi Island and Danglang Island. The land cover types included broad-leaf forest， coniferous forest， grassland， construction land and bare land in the descending order of the mean density of NPP， and the mean densities of NPP on different islands were negatively associated with the proportion of bare land； the mean densities of NPP in the study area were positively associated with altitude， slope， aspect and normalized difference vegetation index (NDVI). Pinus thunbergii and Robinia pseudoacacia are ideal tree species for island plantation in North China， and continuous plantation is one of important measures to improve the NPP of uninhabited islands.