城市扩张导致京津冀区域生境质量下降

城镇化发展极大地改变了区域生境分布格局和功能,从而影响区域生态安全。因此,开展生境质量的评估,对于城市生态安全保障具有重要作用。基于In VEST生境质量模型,评估了京津冀区域2005—2015年生境质量时空变化格局。研究结论如下:1)2005—2015年,京津冀生境面积减少7134.2 km~2,占2005年生境面积的3.7%。耕地、草地和水域生境面积分别减少5081.0、1695.1、421.6 km~2,占对应类型生境面积的4.7%,4.9%和7.2%。2)京津冀生境质量从0.88降至0.83,下降幅度达5.69%。其中,耕地生境质量下降最为严重,其次为水域生境质量。3)生境质量下降区域主要沿北京-保定-石家庄-邢台-邯郸等经济发展迅速的区域分布,表现为城市扩张侵占原有生境。4)京津冀高生境质量斑块破碎度增加,低生境质量斑块集聚度增加。整体上看,京津冀区域生境斑块破碎度增加。

Urban expansion led to the degradation of habitat quality in the Beijing-Tianjin-Hebei Area

The habitat diversity is widely recognized to contribute to human wellbeing by ensuring ecosystem functionality and resilience. However, over the past several years, human activities, especially urban expansion, changed the spatial pattern and ecological function of habitats, thus affecting the regional ecological security and human wellbeing. The Beijing-Tianjin-Hebei region, as one of the important cores of China''s economic development, has undergone rapid urbanization and intensive land-use change, exerting enormous external pressure on the regional habitat quality. Therefore, the assessment of habitat quality plays an important role in urban ecological security for the region. First, this study evaluated the loss of habitat area based on land use data from 2005 and 2015. Then, the research assessed the spatial-temporal changes in habitat quality based on the InVEST habitat quality model. Finally, we used landscape indexes to analyze the spatial-temporal changes in the landscape pattern of habitat patches. The main conclusions of the study are as follows: 1) From 2005 to 2015, the habitat area decreased by 7134.2 km², accounting for 3.7% of that in 2005. The area of cropland, grass, and water decreased by 5081.0 km², 1695.1 km², and 421.6 km², accounting for 4.7%, 4.9%, and 7.2% of the corresponding habitat type, respectively. 2) From 2005 to 2015, habitat quality decreased from 0.88 to 0.83. The habitat quality of cropland decreased the most, followed by water. 3) The declining habitat quality is mainly located along the Beijing-Baoding-Shijiazhuang-Xingtai-Handan axis, which experienced fast economic development and urban expansion. 4) The habitat patches with high-quality habitat tended to be more fragmented, whereas the habitat patches with low-quality habitat tended to be more concentrated. In general, the fragmentation of the habitat patches increased. Rapid urban expansion in the Beijing-Tianjin-Hebei region occupied a large number of habitats. On the one hand, it resulted in the reduction of habitat area. On the other hand, it also led to the decline of habitat quality and the fragmentation of habitat patches. These adverse effects had a negative impact on biodiversity conservation and urban ecological security. Future regional development plans should take the maintenance of habitat quality into consideration.