庙岛群岛北五岛生态系统净初级生产力与景观格局时空分布异质性研究

利用ArcGIS10.2、ENVI5.1、SPSS26等软件，本文基于经典CASA模型估算了2005年、2010年、2017年庙岛群岛北五岛的净初级生产力(Net Primary Productivity, NPP)，从季节、岛屿、景观类型、地形梯度等多种角度分析了NPP的时空分布异质性；进而分析了2005年、2010年、2017年北五岛的景观格局时空分布异质性；探讨了NPP与景观格局时空变化之间的关系及其原因。结果表明:庙岛群岛北五岛平均全年NPP总量为7 520.54 t/a(以碳计)，平均密度为406.07 g/(m2·a) (以碳计)；NPP分布呈明显的时空分异性；各景观类型平均面积由大到小依次为:针叶林、阔叶林、建设用地、草地、耕地；其NPP平均密度由大到小依次为:阔叶林、针叶林、耕地、草地、建设用地；各景观NPP平均密度随坡度和高差的增大先上升后出现平缓下降态势；坡向对林地NPP影响较大，半阴坡林地NPP平均密度最大；不同地形梯度的NPP年平均密度随时间推移总体呈下降态势；NPP高值出现在山林区域，低值主要在建设用地区域；由于自然地理条件、植物自身生长条件和人类活动强度等原因，NPP时空异质性分布受季节差异、景观格局时空异质性和地形因子影响显著。

Spatial and temporal heterogeneity of net primary productivity and landscape patterns on five northern islands of Miaodao Archipelago

In this paper, the net primary productivity (NPP) of the northern islands of Miaodao Archipelago in 2005, 2010 and 2017 was estimated by using ArcGIS10.2, ENVI5.1, SPSS26 and other software based on the classic CASA model, and analyzed the spatial-temporal heterogeneity of NPP from the perspectives of season, individual of island, landscape type, terrain gradient, and then analyzed the spatial-temporal heterogeneity of the landscape pattern of the five northern islands in 2005, 2010 and 2017. The relationships between them and the reasons were discussed. The results showed that: the total NPP for the five northern islands of Miaodao Archipelago was 7 520.54 t/a in terms of carbon; the mean density of NPP was 406.07 g/(m²·a) in terms of carbon; the distribution of NPP showed a significant spatial-temporal heterogeneity; the order of the average area of each landscape type from largest to smallest was coniferous forest, broad-leaved forest, construction land, grassland, arable land; the mean density of NPP from largest to smallest was broad-leaved forest, coniferous forest, arable land, grassland, construction land; the mean density of NPP of each landscape increased first with the increase of slope and height difference, and then decreased slowly; the aspect had a great influence on the NPP of forest, and the mean density of NPP of half shady slope is the largest; the annual mean density of NPP of different terrain gradients decreased with the time; the high value of NPP appeared in the mountainous area, and the low value of NPP is mainly in the flat area; due to the natural geographical conditions and the plant growth strip, the distribution of NPP was influenced by season, geographical location and landscape type.