摘要
木兰溪流域作为福建省重要的水源涵养地,也是生态环境敏感脆弱的区域,对该流域的植被覆盖进行检测和分析具有重要意义。基于空间分辨率为1 km的2000—2020年NDVI年时序数据,采用Theil-Sen Median趋势分析法和Mann-Kendall检验,并叠加土地利用数据和海拔高度数据,分析了木兰溪流域不同土地利用类型和不同高程的植被覆盖变化趋势。结果表明:(1)从时间变化上看,2000—2020年植被覆盖区域NDVI年均值波动不大,整个研究时段内的平均值为0.69;(2)从空间分布上看,研究区NDVI呈现“西高东低”的特征;(3)从变化趋势上看,研究区2000—2020年地表植被覆盖改善面积大于退化面积,明显改善区域主要分布在仙游县和城厢区,其中仙游县植被覆盖明显改善所占比例最高,为52%。明显退化区域主要分布在涵江区和荔城区,其中涵江区植被覆盖明显退化,所占比例最高,为93%;(4)在不同土地利用类型中,林地、草地和未利用土地的植被覆盖明显改善所占比例最高,耕地、建设用地和水域的植被覆盖明显退化所占比例最高;(5)在不同高程带下,随着高程的增加,植被覆盖明显改善逐渐增加,植被覆盖明显退化、轻微退化逐渐减少;在特高高程带上,植被覆盖甚至未发生退化。
As an important water source conservation area in Fujian Province,the Mulan River Basin is also a sensitive and fragile ecological environment.Therefore,it is of great significance to detect and analyze the vegetation coverage in this area.Based on NDVI long-term time-series data with a spatial resolution of 1km from 2000 to 2020,Theil Sen Median trend analysis method and Mann Kendall test were used,and land use data and altitude data were overlaid to analyze the vegetation cover change trends of different land use types and elevations in the Mulan River Basin.The results showed that:(1)From a temporal perspective,the average annual NDVI value of vegetation coverage areas from 2000 to 2020 did not fluctuate significantly,with an average value of 0.69 throughout the entire study period;(2)From a spatial distribution perspective,the NDVI in the study area exhibited high in the west and low in the east;(3)From the trend of change,the area of improved surface vegetation coverage in the study area from 2000 to 2020 was greater than the area of degraded vegetation coverage.The significantly improved areas were mainly distributed in Xianyou County and Chengxiang District,with Xianyou County having the highest proportion of significantly improved NDVI,at 52%;The obvious degradation areas were mainly distributed in Hanjiang District and Licheng District,among which Hanjiang District had the highest proportion of NDVI obvious degradation,at 93%.(4)Among different land use types,forest land,grassland,and unused land had the highest proportion of significantly improved NDVI while cultivated land,construction land,and water bodies had the highest proportion of significantly degraded NDVI.(5)Under different elevation zones,as the elevation increased,NDVI showed significant improvement and gradual increase while obvious degradation and slight degradation in NDVI gradually decreased.In the ultra-high elevation zone,NDVI even did not undergo degradation.
作者
徐延芳
Xu Yanfang(Environmental Supervision Group of Xianyou County,Putian City,Putian 351200,China)
出处
《江苏林业科技》
2024年第5期29-34,共6页
Journal of Jiangsu Forestry Science & Technology
