| Popis: |
Urbanization is the natural trend of human social development, which leads to various changes in vegetation conditions. Analyzing the dynamics of landscape patterns and vegetation coverage in response to urban expansion is important for understanding the ecological influence of urban expansion and guiding sustainable urban development. However, existing studies on the effects of urbanization on vegetation conditions in severe cold regions are limited. Here, taking Harbin, China as an example, the study explored the evolution of the urban expansion process and adopted landscape metrics to derive landscape pattern changes from 2005 to 2020. Based on the fraction of vegetation coverage (FVC) derived from Landsat satellite observations during 2004–2020, we investigated the spatiotemporal change characteristics of FVC. By separating the direct and indirect effects of urbanization on vegetation growth, we quantified the impacts of urbanization on vegetation. The results show that the urban area increased by 70.37%, and urban expansion exhibited a compact sprawl pattern. Cropland and water were the major resources converted for urban expansion. The distribution of FVC exhibits a pattern that the urban fringe region is significantly higher than the central region. The FVC trend is decreased overall, but the changes are not significant with regional variation. Moreover, the average observed FVC decreased with increasing urban intensity. By contrast, the indirect impact is increased along the intensity gradient, with growth enhancement offsetting about 2.26%~2.71% of direct vegetation loss. The study further shows that vegetation growth responses to urbanization vary according to urbanization levels. Our findings provide detailed information and reveal the relationship between urban intensity and vegetation coverage, which could help to manage urban vegetation for planners and stakeholders. |
