西藏生态移民安置村人类活动强度变化

针对生态移民如何影响安置地人类活动强度和生态承载能力的问题,结合生态足迹和人类占用的净初级生产力（Human Appropriation of Net Primary Production, HANPP）两种方法,分析生态移民安置对西藏拉萨河流域典型半农半牧村—白朗村人类活动强度变化的影响,为西藏生态移民搬迁和安置地的可持续发展提供科学依据。结果表明：①2010—2019年,白朗村人均生态足迹由2.79 hm²降至1.80 hm²,人均生态承载力由4.44 hm²降至2.47 hm²,生态足迹指数从移民迁入前的51.72%降为27.25%,白朗村生态系统由强可持续变为弱可持续;HANPP绝对量由20.17 g C/m²增长为34.01 g C/m²,HANPP占潜在净初级生产力的比率在10.09%至12.0%之间,土地利用变化导致的HANPP_luc不断上升并超过人类活动收获导致的HANPP_harv,半农半牧型产业偏向农业方向发展。②占村域面积11.46%的洪积平原地区,承担着2019年移民安置后72.96%的HANPP,新开垦耕地和人工草地减轻了山体草地放牧压力,使得村域人类活动强度更加集中,利于实现生态系统供给服务与调节服务的协同提升。③两种方法结果均表明移民安置明显增强了白朗村人类活动强度,其中生态足迹方法在可持续发展能力评价方面更直观,而人类占用的净初级生产力方法在人类活动强度的空间分析方面更具优势,二种方法具有互补性。后续移民安置区应根据当地生态承载力分配移民安置数量,并通过不同地形及植被类型之间供给服务和调节服务的合理分配,实现生态系统服务功能的协同提升。

Change of human activity intensity in ecological resettlement villages of Tibet

In view of the significant changes of human activity intensity and ecological carrying capacity (EC) caused by ecological resettlement, this study analyzed the impact of ecological resettlement on human activity intensity of typical semi-agricultural and semi-pastoral villages in the Lhasa River Basin of Tibet by using the methods of ecological footprint (EF) and human appropriation of net primary production (HANPP). The results show that the per capita ecological footprint of Bailang Village the case study village decreased from 2.79 hm² to 1.80 hm², and the per capita ecological carrying capacity decreased from 4.44 hm² to 2.47 hm² from 2010 to 2019. The ecological footprint index (EFI) value decreased from 51.72% to 27.25%, implying that the sustainability of the village has been weakened. The HANPP increased from 20.17 g C/m² to 34.01 g C/m², that is, HANPP in percent of potential net primary production ranges from 10.09% to 12.0%. Land-use induced human appropriation of net primary production (HANPP_luc) raised and exceeded biomass harvest (HANPP_harv), and the semi-agricultural and semi-animal husbandry industries tend to develop in the direction of agricultural dominance. The valley plain area, which accounts for 11.46% of the village area, bears 72.96% of the HANPP after resettlement in 2019. The newly reclaimed cultivated land and artificial grassland reduce the grazing pressure of mountain grassland, make the intensity of human activities in the village more concentrated, and help to realize the coordinated improvement of ecosystem supply services and regulation services. The results of the two methods show that the resettlement has significantly enhanced the intensity of human activities in Bailang Village. Ecological footprint is more specific in the evaluation of sustainability while HANPP has more advantages in spatial analysis and ecosystem function analysis, and the two methods are complementary. In the subsequent resettlement program, the number of resettlement villages shall be determined according to the local ecological carrying capacity, and the coordinated improvement of ecosystem service function shall be realized through the rational allocation of supply services and regulation services between different terrain and vegetation types. By comparing the characteristics of the two evaluation methods, this study provides a reference for the selection of human activity intensity evaluation indicators in other regions. It also provides a scientific basis for the relocation and sustainable development of ecological resettlement sites in Tibet.