Spatiotemporal variation in vegetation coverage and its driving factors in the Guanzhong Basin, NW China

Abstract

Understanding vegetation changes caused by climate and human activities could benefit regional management. The responses of vegetation dynamics to climate change and human activities were analyzed at the pixel and regional scales in the Guanzhong Basin, Northwestern China, using Normalized Difference Vegetation Index (NDVI), land cover, and climate data for 2000–2020. Based on trend analysis and regression analysis, in this study, the temporal and spatial characteristics of the NDVI and the relationships between the vegetation and climatic factors in the Guanzhong Basin were investigated. Residual analysis trend methods were used to distinguish between human and climate–induced vegetation changes at the regional scale. The results show that the NDVI, precipitation, and temperature increased in the Guanzhong Basin during 2000–2020, with annual growth rates of 0.003 a−1, 5.210 mm/a, and 0.004 °C/a, respectively. The relative contribution rates of human activities and climate change to the vegetation changes were 66.78% and 33.22%, respectively. These results show that human activities played the dominant role in the Guanzhong Basin in 2000–2020. Extensive land use changes occurred from 2000 to 2020 in the Guanzhong Basin. The largest land use conversion type was farmland to urban and rural settlements, with 632.90 km2 of farmland converted to urban and rural settlements. During the study period, the farmland was the most important land use type, accounting for 74.86% (15,302 km2), 73.80% (15,084 km2), 73.56% (15,035 km2), 71.48% (14,611 km2), and 70.53% (14,617 km2) of the total Guanzhong Basin's area in 2000, 2005, 2010, 2015, and 2020, respectively.