黄土丘陵沟壑区沟道土地整治对乡村人地系统的影响

深入开展土地整治对区域乡村人地系统的影响研究对于优化土地整治模式、促进乡村振兴具有积极意义。该文以延安市某典型小流域为例,结合高分影像数据、景观格局分析和人文实地调查,从土地利用、景观格局、生态安全、社会响应和综合研判等角度探讨了黄土丘陵沟壑区沟道土地整治对当地乡村人地系统的影响。研究表明:1)在土地整治工程措施的作用下,沟道底部及其两侧的台地、坡耕地、灌木林地和草地大多转变为高产稳产的坝地,部分灌木林地由于生物措施转变为生态功能更强的乡土适生林地;坝地和林地分别增加159.06 hm2和69.75 hm2,灌木林地、草地和坡耕地分别减少112.37、63.26和59.06 hm2。2)坝地平均斑块面积和凝聚度增加,生产功能提升;乔木林地和灌木林地的景观指数、斑块凝聚度指数均保持在较高水平,生态功能稳定;流域整体的景观破碎化程度降低,景观趋于多样化和均衡化发展,景观抗干扰能力和生态系统稳定性得到提升。3)从生态安全效应来看,流域植被和生态环境明显改善,土壤侵蚀显著减少,防洪能力明显提升,但局部存在生态安全隐患。4)人类活动对流域地理环境变化有所响应,土地规模化、农业机械化、就业兼业化和非农化程度提高;但仍存在农业结构单一、效益不高等问题。应着力创新"共同商议、协同推进"的乡村治理机制,进而发挥土地整治综合效能,促进流域乡村转型与振兴。

Impacts of land consolidation on rural human-environment system in typical watershed of loess hilly and gully region

Abstract: Land fragmentation and low productivity are the prominent problems facing China''s agricultural development. Land consolidation has become an important policy tool aiming at solving these problems in China. In addition, the development of land consolidation projects will inevitably have a certain impact on the local rural regional system, especially the local ecological environment and social and economic development. Study on the impact of land consolidation on the evolution of rural human-environment system is of positive significance for optimizing land consolidation model and promoting rural revitalization. Taken a typical small watershed in Yan''an city as the case study area, in this paper, we explored the impact of gully land consolidation on local human-environment system from the perspectives of land use, landscape pattern, ecological security, social response and comprehensive evaluation, based on high-resolution image data, landscape pattern analysis and field investigation. The results showed that due to the gully land consolidation, the terraces, sloping fields, shrub land and grassland at the bottom and both sides of the gully were mostly converted to high quality check dam land. Some of the shrub land were converted to more ecologically suitable native forest due to biological measures. The check dam land and forest land increased by 159.06 hm2 and 69.75 hm2, respectively. While the shrub land, grassland and sloping land decreased by 112.37, 63.26 and 59.06 hm2, respectively. In addition, the average patch area and patch cohesion index of the check dam land increased, and the function of production also improved. The landscape shape index and patch cohesion index of forestland and shrub land kept at a high level, and thus their ecological function was stable. At the watershed level, the fragmentation degree of landscape decreased, the landscape tended to be more diversified and balanced, and the anti-jamming capability of landscape and stability of ecosystem improved. Moreover, in terms of the ecological security effects, vegetation cover, ecological environment and capacity of flood control improved significantly, and soil erosion decreased significantly. However, there were still some ecological risks. And finally, human activities responded more or less to the changes of geographical environment of watershed. The scale of agricultural production, agricultural mechanization, diversity and non- agriculturalization of employment increased; but there were still some problems that needed to be addressed, such as very unitary of the structure of agriculture, the low efficiency of agriculture production. This paper suggested that more efforts should be made to innovate the rural governance mechanism of "mutual deliberation and collective action", thereby exerting the comprehensive effectiveness of gully land consolidation and promoting the transformation development and revitalization of the watershed. At the same time, this study also suggested strengthening the investigation, monitoring and evaluation of the effects of gully land consolidation on local environment so as to ensure that it produced more positive ecological effects.