2000—2018年西辽河流域植被覆盖度时空变化特征及影响因素研究

ANALYSIS ON THE CHARACTERISTICS OF SPATIAL- TEMPORAL CHANGES AND INFLUENCING FACTORS OF VEGETATION COVERAGE IN THE XILIAO RIVER BASIN FROM 2000 TO 2018

关键词:  植被覆盖度  气候因子  地形  农村居民点  土地利用变化

Key words:  vegetation coverage  climate factors  topography  rural residential  land use change

摘要:

目的 研究“退耕还林”“退牧还草”及“镰刀弯”等生态政策实施以来西辽河流域植被覆盖时空变化趋势及驱动因素，探究各类驱动因子对区域植被覆盖的影响，为区域生态建设和环境保护提供参考。方法 文章采用像元二分模型，估算西辽河流域植被覆盖度，归纳了植被覆盖变化的驱动因素，利用一元线性回归和Pearson相关系数等方法，定性定量分析2000—2018年西辽河流域植被覆盖时空变化趋势及其与气候、地形、农村居民点分布和土地利用变化等驱动因子的响应关系。结果 19年来，西辽河流域植被覆盖度呈波动增加趋势。分区看，农区植被覆盖度最高，其次是半农半牧区，牧区植被覆盖度最低。全区植被覆盖空间变化趋势较为稳定，96.63%面积植被覆盖无明显变化，2.07%面积植被覆盖极显著改善，1.30%面积植被覆盖显著改善，基本无退化区域。结论 （1）植被覆盖度与降水、气温因子正向相关，降水对植被覆盖度的影响高于气温。（2）高程、坡度和农村居民点密度均与植被覆盖度正向相关，其中农区人类农业种植活动正向促进作用要大于生产建设活动的负向抑制作用。（3）林地和作物种植面积长势的增加促进了全区植被覆盖的改善。“退耕还林”和“镰刀弯”生态实施促进了全区植被覆盖的改善，但“退牧还草”生态工程效益有待提高。应注重区域植被覆盖变化监测与预警，充分发挥生态政策的积极导向作用，优化生态工程实施结构，提高生态脆弱区抵御风险能力。

Abstract:

Studying the spatial-temporal change trend and factors of vegetation cover in Xiliao River Basin since the implementation of ecological policies such as "returning cropland to forestland ", "return grazing land to grassland" and "sickle bend". We explores the impact of various driving factors on regional vegetation cover, in order to provide reference for regional ecological construction and environmental protection. In this paper, the pixel binary model was used to estimate the vegetation coverage of Xiliao River Basin. We summarized the driving factors of the change of vegetation cover. Some methods such as unary linear regression and Pearson correlation coefficient were used to analyze the spatial-temporal change trend of vegetation cover in Xiliao River Basin from 2000 to 2018 and its responding relationship with the driving factors, such as the climate,topography, rural residential distribution and the changing of land use, etc.The results were listed as follows. Over the past 19 years, the vegetation coverage of the Xiliao River Basin had been fluctuating, and the overall trend was increasing. In terms of zoning, the vegetation coverage in agricultural zones was the highest, followed by semi agricultural and semi pastoral zones, and the vegetation coverage in pastoral zones was the lowest. The spatial change trend of vegetation cover in the whole region was relatively stable, 96.63% of the area had no obvious change, 2.07% of the area had been significantly improved, 1.30% of the area had been obviously improved, and there was no degraded area basically. The conclusion are listed as follows.(1) Vegetation coverage is positively correlated with the factors of precipitation and air temperature, and the impact of precipitation on vegetation coverage is higher than that of air temperature. (2) Elevation, slope and rural residential density are positively correlated with vegetation coverage, in which the positive promotion of human agricultural planting activities in agricultural areas is greater than the negative inhibition of production and construction activities. (3) The increasing growth of forestland and crop planting area has promoted the improvement of vegetation cover in the whole region, and the ecological implementation of "returning cropland to forestland" and "sickle bend" has promoted the improvement of vegetation cover in the whole region. However, the benefits of the ecological project of "return grazing land to grassland" need to be improved. We should pay attention to the monitoring the change of regional vegetation cover, give full play to the positive guiding role of ecological policies, optimize the implementation structure of ecological projects, in order to improve the risk resistance ability of ecologically fragile areas.