江西省兴国县植被覆盖度及其空间格局变化

  目的  分析植被覆盖度及其空间格局的变化特征，为生态环境建设和土地利用等提供参考依据。  方法  以江西省兴国县为研究区，利用6期Landsat TM/OLI遥感数据，基于归一化植被指数的像素二分模型和景观生态学原理，分析了1988?2019年不同时期的植被覆盖度及其空间格局演变特征。  结果  ①1988?2019年兴国县植被覆盖度增加，年际植被覆盖度均值由1988年的63.89%增至2019年的79.16%；31 a间植被覆盖度增长区占总面积的72.18%，主要表现为林地、农地面积的增加，减少区占总面积的11.30%，主要表现为建设用地面积的增加；各级植被覆盖度主要呈现为朝更高级覆盖度进化演变的特征。②植被覆盖度呈中部与南部较小，东、西、北部较大的分布特征，其大小总体上与海拔高低较为吻合；31 a间植被覆盖度极度增加区主要集中在南部的龙口镇、杰村乡、社富乡等，极度减少区主要在中部的潋江镇和长岗乡。③1988?2019年植被覆盖度呈破碎化、异质性、多样性降低、空间分布不均匀的变化趋势，而聚集度呈增大趋势。不同盖度等级下的空间格局表现为极低、低、中、中高植被覆盖斑块异质性减小，斑块形状趋于简单化；高、极高植被覆盖占优势地位，其形状趋于不规则，极高植被覆盖主要以较为集中的连片形式分布。  结论  兴国县植被覆盖及其空间格局总体上向良性方向发展，有利于区域的可持续发展。土地利用类型、海拔、人类活动等因素对植被空间格局有着重要影响。图5表2参35

Vegetation coverage and its spatial pattern changes in Xingguo County,Jiangxi Province

  Objective  With an analysis of the change characteristics of vegetation coverage and its spatial patterns, this study is aimed to provide reference for ecological environment construction and land use.  Method  Taking Xingguo County in Jiangxi Province as the study area, with the six phases of Landsat TM/OLI remote sensing data employed, under the guidance of the pixel dichotomy model of normalized difference vegetation index and the principle of landscape ecology, an investigation has been conducted of the characteristics of vegetation coverage and spatial pattern evolution in different periods from 1988 to 2019.  Result  (1) The annual vegetation coverage of Xingguo County has witness an increase from 63.89% in 1988 to 79.16% in 2019 with the growth area accounting for 72.18% of the total area (mainly due to the the increase of woodland and agricultural land) whereas the decline area accounting for 11.30% (mainly due to the increase of construction land) and the vegetation coverage at all levels was mainly featured with the evolution towards a higher-level coverage. (2) The vegetation coverage was featured with a smaller distribution in the center and south of the county and a larger distribution in the east, west and north of the county, which was generally consistent with the altitude and over the 31 years, the areas with a significant increase in vegetation coverage were mainly towns in the southern area including Longkou Township, Jiecun Township and Shefu Township while the areas with a significant decline were mainly towns in the center such as Lianjiang Township and Changgang Township. (3) From 1988 to 2019, the vegetation coverage witnessed a changing trend featured with fragmentation, heterogeneity, decreased diversity, uneven spatial distribution as well as enhanced aggregation and in terms of the spatial pattern under different coverage levels, the heterogeneity of patches covered by extremely low, low, medium and high vegetation decreased, and the shape of patches is featured as increasingly simpler; at the same time, the high and extremely high vegetation coverage was dominant, with its shape becoming irregular whereas the extremely high vegetation coverage was mainly distributed in a concentrated contiguous form.  Conclusion  The vegetation coverage and its spatial pattern of Xingguo County generally develop in a benign direction, which is conducive to the sustainable development of the region. Also, land use types, altitude, human activities and other factors have an important impact on the vegetation spatial pattern. [Ch, 5 fig. 2 tab. 35 ref.]