新疆荒漠草地亮柔伪步甲虫害与草地变化关系研究——以昌吉州南山草场为例

The relationship between attack by Prosodes dilaticollis and desert grassland changes in Xinjiang:A case study of southern mountain grassland in Changji

探索亮柔伪步甲虫害发生与草地退化的耦合关系,定量分析虫害发生对草地植被的影响,为草原部门科学有效地防治虫害提供理论依据。本研究基于环境一号遥感影像、土地覆盖产品数据、气象数据分别反演草地植被覆盖度、土地利用状态、气候要素等环境变量,结合野外调查数据,使用线性趋势分析、叠加分析、土地利用状态转移矩阵、相关分析、方差分析等方法,分析亮柔伪步甲发生水平与草地植被覆盖度、气候等环境因素相互作用关系,总结亮柔伪步甲虫害的发生机制。结果表明:亮柔伪步甲虫口密度与归一化植被指数(NDVI)呈显著负相关性,NDVI随虫害发生程度的加重呈降低趋势:level 3(重度发生)<level 2(中度发生)<level 0(对照)<level 1(轻度发生);亮柔伪步甲虫口密度与年际间的植被覆盖变化无相关性,且各危害水平之间也无显著性差异。河床、河漫滩、农牧交错区等裸露地表是亮柔伪步甲虫害的高爆发区,而草地内部的发生水平较低。虫口密度高的实测点与草地退化区域并无空间关系。荒漠草地生态系统脆弱且敏感,植被覆盖度低,草地破碎。草地退化是气候干旱、过度放牧等因素综合作用的结果,并非直接由亮柔伪步甲虫害造成。

This research explored the coupling relationship between the occurrence of the pest Prosodes dilaticollis and grassland degradation. The impact of the pest on grassland vegetation was quantitatively analyzed,so as to provide a theoretical basis for government officials managing grasslands to scientifically and effectively manage the pests. The study used multi-temporal remote images obtained from the HJ-1 satellite system(HJ-1 satellite system is an earth observation system of China specially used for environmental and disaster monitoring. It is composed of two optical satellites and one radar satellite. It has a variety of optical,infrared and hyperspectral detection means,and has the ability of wide-range,all-weather,all-time and dynamic environmental and disaster monitoring),land cover product and meteorological data to infer grassland vegetation coverage and climatic drivers. Based on field survey data using overlay analysis,correlation analysis,one-way ANOVA and linear trend analysis were used to quantitatively analyze the interaction between grassland status,climatic factors and P. dilaticollis occurrence,to investigate factors and mechanisms involved in pest outbreaks. The results showed that:there was a significant negative correlation between the insect density and NDVI(normalized differential vegetation index). The NDVI decreased with the aggravation of pest,and was assigned four damage categories:level 3(severe)<level 2(moderate)<level 0(control)<level 1(mild). There was no correlation between the population density of P.dilaticollis and the interannual vegetation coverage variation and there was no significant difference among the damage categories. Bare land such as riverbeds,river flood beaches,and farming-pastoral zone are highly prone to outbreaks of P. dilaticollis,but the insect density is low in grasslands. Sites with a high measured density of P.dilaticollis have no spatial correlation with the degraded areas of grassland. Desert grassland ecosystems are fragile and sensitive. Grassland degradation is the result of the interaction of aridity and overgrazing,and is not directly caused by P. dilaticollis.