市域尺度耕地景观格局演变时空过程模型研究

Landscape pattern change is the intuitively spatial reflection of the scale and quality variation of farmland system. Researches about the spatio-temporal variation of farmland scale and spatial organization based on landscape model, which had been the regular method in exploring the process of farmland landscape pattern change. However, disadvantages including the accurate reflection of the recessive process of farmland landscape, description of the farmland landscape function and model validation are the most common problems found in current studies. This project aims to 1) classify farmland landscape structures and recognize farmland landscape function depending on the integration of geographic distance attenuation law and ecological edge effect. Then the spatio-temporal model of farmland landscape pattern evolution will be developed by the coupling of the temporal variation of farmland structure and spatial transition of landscape function. 2) By constructing the index models about farmland landscape degradation and stability of grain yield, the developed model will be validated according to the consistency between farmland degradation and grain yield from temporal perspective. 3) Through the classification of farmland types and developing the evaluation model about potential productivity of farmland at city scale, the developed model will be validated depending on the corresponding relations among the landscape structure, function and potential productivity of farmland. Based on the spatio-temporal model of farmland landscape pattern evolution process, the farmland landscape structure and function would be accurately described and it would provide theoretic and technical method support to farmland protection and spatial regulation optimizing.

耕地景观格局变化过程是耕地规模与质量波动的直观时空表现形式。以景观模型为基础，通过时序规模变化与空间组合变化探索耕地景观格局演变时空过程规律已成为常规技术手段。然而，当前研究在准确反映耕地景观隐性过程、刻画耕地景观功能、验证模型有效性等方面存在不足。本研究拟1）集成地理距离衰减定律和生态边缘效应理论，实现耕地景观结构分类，识别耕地景观功能，耦合时序结构变化与空间功能转换过程，研发耕地景观格局演变时空过程模型；2）构建耕地景观退化度和粮食生产稳定度指数模型，根据耕地景观退化度与粮食生产稳定性的一致性判断，验证时间维度模型有效性；3）划分耕地类型，构建市域尺度耕地生产潜力评价模型，基于耕地景观结构、功能与耕地系统生产潜力之间的响应关系，验证空间维度模型有效性。通过建立的耕地景观时空过程模型，可准确刻画耕地景观结构与功能特征，为保护耕地资源、优化耕地空间管控格局等提供理论与技术方法支撑。

长期以来，耕地资源保护一直是我国的基本国策。然而，以土地资源输出为代价的经济发展策略引发了严重的耕地非粮化和非农化现象，直接影响到我国粮食安全根基。研究耕地时空演变机理，分析耕地资源保护与空间发展响应关系，是实现耕地资源永续利用和高效保护的关键。对此，项目基于地理距离衰减定律和生态边缘效应理论，构建了多尺度耕地景观结构分类体系，构建了像元水平景观结构分类模型，研发并验证了耕地景观格局演变时空过程模型，实现了耕地景观隐性过程和结构功能的准确刻画。研究结果表明，从耕地景观单元空间位置差异与邻接关系的角度开展耕地景观结构分类，符合地理事物的空间变化规律，可以科学地反映耕地景观格局变化及其所产生的生态效应。此外，同一地理环境背景的耕地景观类型相互转变过程中，耕地景观本身的生产功能也随之产生异变。通过集成耕地景观格局时序变化规律与空间功能结构演变过程，研究实现了像元水平耕地景观格局时序变化与空间演替的过程耦合，揭示了多尺度多情景驱动的农业空间演变机理，实现了耕地景观格局隐性演变过程的空间刻画，为耕地景观生态功能识别提供了精细化空间分析方法。目前，上述成果已推广应用于长沙、合肥、深圳、常州、芜湖等地耕地资源保护和永久基本农田划定研究，助力形成了“四位一体”的城市周边耕地资源管控方法。