城市扩张与耕地保护耦合对陆地生态系统碳储量的影响——以湖北省为例

城市扩张对生态系统的影响可以分为城市扩张对生态用地的直接挤占以及为补充城市扩张占用的耕地对生态用地二次挤占两个连锁的过程。以往的研究大多只关注城市扩张对生态系统的直接影响,忽略了城市扩张与耕地保护耦合的间接影响。针对这一问题,采用GIS空间分析方法和InVEST模型定量评估了2000年至2015年湖北省城市扩张与耕地保护耦合对陆地生态系统碳储量的影响。结果显示:(1)城市扩张与耕地保护耦合导致湖北省陆地生态系统碳储量减少40.90 Tg;(2)由城市扩张与耕地保护耦合导致的陆地生态系统碳储量的减少量中,耕地保护传导作用间接导致的占比31%。结果表明,城市扩张与耕地保护的耦合是导致生态系统碳储量减少的主要原因之一。忽视城市扩张通过耕地保护的传导作用对生态系统碳储量的间接影响,会导致城市扩张对陆地生态系统碳储量的影响被严重低估。

Impact of cascading processes of urban expansion and cropland reclamation on the ecosystem of a carbon storage service in Hubei Province, China

Urban expansion has an impact on ecosystems and results in the loss of ecological lands. The occupation of ecological lands includes two processes:directly by urban expansion, and indirectly because of the compensation for croplands that are lost during urbanization. Many researches have discussed the direct impact of urban expansion on ecosystems; however, most of them have ignored the impacts of cascading processes of urban expansion and cropland reclamation. Therefore, we have explored the impacts of the cascading processes of urban expansion and cropland reclamation on the ecosystem of a carbon storage service in Hubei during 2000-2015 by means of the GIS spatial analysis method and InVEST model. The results show that during 2000 and 2015:(1) the reduction of carbon storage resulting from the impacts of cascading processes of urban expansion and cropland reclamation was 40.90 Tg; (2) the indirect impact from cropland reclamation accounted for 31% of reduction of carbon storage. Our study indicates that the main cause of carbon storage decrease is the impact of the cascading processes of urban expansion and cropland reclamation. Furthermore, ignoring the impact of cropland reclamation can lead to an underestimation of the decrease of carbon storage.