利用NDVI产草量模型浅探新疆叶城县天然草地退化状况

Study on Degradation of Natural Grassland in Yecheng County by NDVI Model

本文以新疆喀什地区叶城县天然草地为研究区域,基于2009年、2014年和2019年3年8月的MODIS遥感影像产品提取研究区NDVI,以同期研究区内不同草地类鲜草产量为天然草地退化分级指标,利用NDVI与各草地类鲜草产量进行相关性分析,反演天然草地退化程度,浅探2009年以来叶城县天然草地退化的时空分布变化和现状。结果表明:2014年叶城县天然草地重度退化比例相比2009年下降16.71%,中度退化比例下降了4.14%,轻度退化比例下降了0.69%,未退化比例上升了21.53%。2019年重度退化比例相比2014年减少1.44%,中度退化比例增加了1.27%,轻度退化比例增加了0.34%,未退化比例减少了0.16%。结论:叶城县天然草地普遍退化情况得到初步遏制,低海拔区荒漠草地类退化程度整体相对较轻,但形势依然严峻,当前南部中高海拔山区的温性草原类草地、高寒草原类草地、高寒草甸类草地的退化情况仍然严重。

In this study,taking the natural grassland in Yecheng county of Kashgar prefecture of Xinjiang as the research area,the NDVI of the study area was extracted based on the MODIS remote sensing image products in 2009,2014 and 2019.Then the fresh grass yield of different grassland types in the same period was used as the degradation classification index of natural grassland,the correlation between NDVI and fresh grass yield of each grassland type was analyzed to reversely deduce the degradation degree,and the temporal and spatial distribution changes and current situation of natural grassland degradation in Yecheng county since 2009 was analyzed.The results showed that,firstly,the proportions of severe,moderate and mild degradation of natural grassland in Yecheng county in 2014 compared to 2009 decreased by 16.71%,4.14%and 0.69%,respectively,and that of non degradation increased by 21.53%.Secondly,the proportion of severe degradation in 2019 compared to 2014 decreased by 1.44%,the proportions of moderate and mild degradation increased by 1.27%and 0.34%,respectively,and that of non degradation decreased by 0.16%.In conclusion,the general degradation of natural grassland in Yecheng county had been initially curbed.The overall degradation degree of desert grassland in low altitude area was relatively light,but the situation was still severe considering that the serious degradation of temperate grassland,alpine grassland and alpine meadow grassland in the middle and high altitude mountainous areas in the South.