关中-天水经济区人类活动对植被覆盖变化的影响

Impact of human activities on the vegetation cover change in Guanzhong-Tianshui economic zoneBAI Ziyi1, XUE Liang1*, XUE Dongqian1, ZHANG Chong2, LIU Jing3, ZENG Hanmin4

关键词:  植被覆盖  土壤湿度  人类活动

Key words:  vegetation cover  soil moisture  human activities

摘要:

为探究植被覆盖变化及人类活动对改善关中地区及西北地区的生态环境影响，利用植被覆盖和地表温度数据，结合Sen趋势与Mann-Kendall检验分析关中-天水经济区2001—2016年的植被覆盖变化趋势，并根据估算的土壤湿度因子，应用残差法评价人类活动对植被覆盖变化的影响程度及影响方向。结果表明:1)从时间变化维度来看，2001—2016年关中-天水经济区植被覆盖变化总体呈良好趋势，且整体表现为在不断波动中递增，表明关天经济区进行的生态环境建设工程正在慢慢凸显它的生态效应。2)从空间变化维度来看，关中-天水经济区植被覆盖显著增长的区域面积占35.87%，主要集中在研究区南北两侧。而显著下降的面积区域占3.21%，主要分布在城市中心，即经济发展活跃的地区，如西安市区，宝鸡市区，天水市区，铜川市区等。3)关中-天水经济区植被覆盖受自然因素影响较小，受其他因素影响大。其正相关区域占13.43%，不显著相关区域占85.26%。4)关中-天水经济区人类活动对植被覆盖变化的正作用大于负作用。其中，正作用区域主要分布在研究区北部和东南地区，其主要原因是人类活动不频繁，建设生态屏障、加强退耕还林、三北防护林保护以及水土保持等生态工程促进植被NDVI增长。负作用区域主要分布在渭河沿线、经济活动较高地区，其主要原因有:人类活动频繁、过度城市化、工业化等抑制植被生长。5)植被覆盖的增长和下降区域与人类活动对植被影响的正作用和负作用区域大致相同。这也从侧面反映了关天经济区植被覆盖情况受人类活动影响大。总之，在负作用区域，在经济建设发展的同时也要注重植被建设、以及对植被乃至生态环境的保护。

Abstract:

The aim of this study was to explore the effects of vegetation cover change and human activities on the ecological environment in Guanzhong and Northwest China. By using the vegetation and land surface temperature data, combined with Sen trend and Mann Kendall test, the vegetation cover changes in Guanzhong - Tianshui economic zone from 2001 to 2016 were analyzed. According to the estimated soil moisture factor, the residual method was used to evaluate the influence degree and influence direction of human activities on vegetation cover change. The results showed that: 1)From the perspective of time change, the vegetation cover change during 2001-2016 in Guanzhong-Tianshui economic zone showed a good trend in general, and the overall performance was increasing in the constant fluctuation. It also showed that the ecological environment construction project carried out in Guantian economic zone slowly showed its ecological effect. 2)From the perspective of spatial change dimension, the area with significant increase in vegetation cover in Guanzhong-Tianshui economic zone accounted for 35. 87%, mainly concentrated in both sides of the north and the south of the study area. And the significant decline in the area accounted for 3. 21%, mainly distributed in urban centers, which were areas with active economic development, such as Xi'an, Baoji, Tianshui, Tongchuan. 3)The vegetation cover in Guanzhong-Tianshui economic zone was less affected by natural factors and greatly influenced by other factors. And the positive correlation areas accounted for 13. 43%, while the non-significant related area accounted for 85. 26%. 4)The positive effect by human activities on the change of vegetation cover in the Guanzhong-Tianshui economic zone was greater than the negative effect. Among them, the positive area was mainly distributed in the northern and southeast areas of the study area. The main reasons were the infrequent human activities, the construction of ecological barriers, the strengthening of the conversion of farmland to forests, the protection of Sanbei shelterbelt and soil and water conservation and other ecological projects to promote the growth of NDVI. The negative action areas were mainly distributed along the Weihe River, high economic activity areas, the main reasons included frequent human activities, excessive urbanization, industrialization and other factors restraining vegetation growth. 5)The growth and decline of vegetation cover areas were about the same as those of positive and negative effects of human activities on vegetation, which illustrated from the side that the vegetation cover of the Guantian economic zone was greatly influenced by human activities. In short, attentions should also be paid on vegetation construction and the protection of vegetation and ecological environment at the same time during the economic construction and development.