中国北方干燥地城市扩展过程对生态系统服务的影响——以呼和浩特-包头-鄂尔多斯城市群地区为例

理解中国北方干燥地城市扩展过程对生态系统服务的影响对提高干燥地人类福祉和实现区域可持续发展具有重要的意义。为此,论文以正在经历快速城市化的呼和浩特-包头-鄂尔多斯（呼包鄂）地区为例,从区域、城市和旗县3个尺度上揭示了该地区1990—2013年城市扩展过程对生态系统服务的影响。首先,量化了呼包鄂地区1990年的生境质量、粮食生产、肉类生产和碳储量4种关键生态系统服务。然后,分析了1990—2013年呼包鄂地区的城市扩展过程。最后,在区域、城市和旗县3个尺度上评价了呼包鄂地区1990—2013年城市扩展过程对生态系统服务的影响。结果显示,1990—2013年,呼包鄂地区经历了快速的城市扩展过程,城市用地面积从314.22 km²增加到692.10 km²,增长了1.2倍。区域城市扩展过程导致4种生态系统服务均明显下降。其中,粮食生产服务损失最严重,损失量达1.36×10⁴ t,约占1990年全区粮食生产总量的1%。边缘型和飞地型城市扩展对生态系统服务的影响最明显。1990—2013年,边缘型城市扩展导致的粮食生产、肉类生产和碳储量损失量占区域城市扩展过程中各项服务损失总量的比例均超过60%,飞地型城市扩展造成的肉类生产服务损失量大于区域城市扩展过程中该服务损失总量的1/3。边缘型和飞地型城市扩展过程导致的耕地和草地大量减少是造成生态系统服务快速下降的主要原因。因此,建议在呼包鄂地区的城市化进程中应提高城市用地利用率,控制边缘型和飞地型城市扩展,以减少城市扩展过程对生态系统服务的影响。

Impacts of Urban Expansion on Ecosystem Services in the Drylands of Northern China: A Case Study in the Hohhot-Baotou-Ordos Urban Agglomeration Region

Understanding the impacts of urban expansion on ecosystem services (ESs) in the drylands of northern China is important for regional human well-being and sustainable develop-ment. In this paper, we assessed the impacts of urban expansion on ESs in the Hohhot-Baotou-Ordos (HBO) urban agglomeration region, a rapidly urbanizing drylands in North China, at three scales: urban agglomeration scale, city scale, and county scale. First, we quantified four key ESs in HBO region in 1990, including habitat quality (HQ), crop production (CP), meat production (MP), and carbon storage (CS). Second, we analyzed the processes and modes of urban expansion in HBO region during 1990-2013. Finally, we evaluated the influences of urban expansion on ESs at urban agglomeration, city and county scales. We found that the HBO region experienced a rapid urban expansion during 1990-2013, with urban land area increasing by 1.2 times from 314.22 km² to 692.10 km². The rapid urban expansion in HBO region resulted in obvious decreases of the four key ESs. Among these ESs, CP suffered the biggest loss with a decrease of 13 581.41 t, accounting for 0.99% of total CP in HBO region in 1990. At the same time, MP and CS decreased 70.19 t and 1.65 Tg C, accounting for 0.25% of total MP and 0.29% of total CS in HBO region in 1990, respectively. In addition, HQ decreased 0.47, accounting for 88.68% of the mean HQ in HBO region in 1990. The modes of edge expansion and leapfrog expansion had the greatest impacts on ESs in HBO region. During 1990-2013, the decreases of CP, MP and CS caused by edge expansion accounted for more than 60% of the total decrease of ESs in HBO. The losses of MP caused by leapfrog expansion accounted for more than 1/3 of the total losses of ESs in HBO region. The large-scale decreases of cropland and grassland during the urban growth of edge expansion and leapfrog expansion were the main causes for the losses of ESs. Thus, we suggest that effective utilization and management of urban land with respect to urban growth of edge expansion and leapfrog expansion are needed to reduce the impacts of urban expansion on ESs in HBO region.