基于土地多功能的黄土丘陵沟壑区生态保护与发展情景评估及多主体模拟

The scenario assessment of ecological protection and development in the Loess Hilly and Gully area based on land use functions and agent-based modelling

黄土高原丘陵沟壑区生态环境脆弱,近几十年生态保护工程的实施带来显著的生态恢复效果,也对农户的生计策略与区域粮食安全产生了影响。刻画生态脆弱区人-地系统复杂响应过程,可以为区域可持续的土地利用管理模式提供依据。研究从土地多功能出发,着眼于黄土丘陵沟壑区河谷川地、梁峁区域、黄土塬地、土石山地以及城郊区域等不同的典型地貌类型与代表区域,采用多层次利益相关者参与式的评估框架,以农户的耕地利用行为及生态工程影响与未来发展为切入点,设置惯性发展情景、发展优先兼顾生态情景、农业优先兼顾生态情景以及生态优先兼顾发展情景,构建多智能体模型对区域土地利用与土地多功能的时空变化开展模拟。主要结果表明:(1)生态优先兼顾发展情景综合影响最高且对各维度影响相对均衡,而农业优先兼顾生态情景对区域土地的经济维度的功能和社会维度具有更为明显的提升效应;(2)根据土地多功能空间变化模拟结果,区域土地利用破碎化明显且耕地的撂荒对全域土地多功能均表现出明显的限制作用,农业优先兼顾生态情景中土地功能发生下降的面积最少;(3)发生土地功能下降的区域主要分布在土地质量较差、坡度处于5—15°范围内、地形起伏度较大以及距离道路较远的区域;本研究刻画了黄土丘陵沟壑区不同典型地貌区域的差异化土地利用系统特征,为生态保护工程实施背景下的土地管理与区域可持续利用发展提供参考。

The hilly and gully areas of the Loess Plateau have been affected by natural disasters such as soil erosion and drought for thousands of years.The implementation of ecological protection projects in recent decades has brought significant ecological restoration effects,but also affected the farmers′livelihood strategies,which furtherly threatened the regional food security,ecological security,and sustainable development.In order to describe the complex response process of the human-land system,this study selected the different typical landform types in the Loess Hilly and Gully area and focused on the land use functions(LUFs)with a multi-level stakeholder participatory evaluation framework.We analyzed the farmland using behavior of farmers,the impact of ecological restoration project,and further development strategies.Four scenarios were set,including business as usual scenario,development priority scenario,agricultural development priority scenario,and ecological protection priority scenario.A multi-agent model was constructed to predict the spatio-temporal changes of regional land use and land use functions under different scenarios.The main results show that:(1)the ecological priority scenario has the highest comprehensive impact and has a relatively balanced beneficial impact on each dimension,while the agricultural development priority scenario has a more obvious effect on the economic and social dimensions of LUFsꎻ(2)According to the simulation results of spatial change of LUFs,regional land use fragmentation is obvious and the abandonment of cultivated land shows a significant restriction on the LUFs in the whole area.The agricultural development scenario has the least LUFs declined area.(3)The area where the land function declines distributed mainly in areas with poor land quality,a slope within the range of 5-15°,the great the terrain undulation,and away from the road.This study describes the differentiated land use characteristics of different typical landforms in Loess Hilly and Gully area,and provides a specified reference for land management and regional sustainable development in the context of balancing the ecological protection and local development.