三峡库区腹地山区农业景观格局动态变化与转型

山区农业景观格局动态分析有利于厘清农业景观发展的动态轨迹与方向,对农地用途的合理规划和管理有重要意义。本文提出了山区农业景观格局转型理论框架,并在三峡库区草堂溪流域进行了实证研究,从整体—微观的角度解析2000—2018年期间,以坡耕地、撂荒地和果园为代表的农业景观格局转型特征。研究发现：① 果园沿河谷的扩张和撂荒地在较高海拔处的扩张明显压缩了坡耕地的空间,这导致区域景观多样性的整体增强,而在局部地形上的差异明显,斑块破碎但聚集度增强;② 研究区农户耕种范围内的农业景观格局转型主要表现为耕—果转换型、综合型、部分撂荒型和撂荒型4种模式,各模式揭示了山区农业景观格局的不同发展阶段;③ 在以社会经济因素为主的驱动下,三峡库区山区的农业景观格局转型具有双向性,表现为以传统均衡分布的纯粮种植景观向河谷生态经济双赢的经果林景观和较高海拔的撂荒地转变。研究结果揭示了近年来中国山区农业景观格局演变的独特性,对库区山区农村土地利用和农业生态系统的深入认识以及库区乡村发展和生态环境的改善均有启示意义。

Dynamic changes and transformation of agricultural landscape pattern in mountainous areas:A case study in the hinterland of the Three Gorges Reservoir Area

Analyzing the agricultural landscape pattern in mountainous areas is conducive to clarify the dynamic change and development direction of the agricultural landscape, and is of great significance to rational planning and management of agricultural land. This paper proposes a theoretical framework for agricultural landscape pattern transformation in mountainous areas, and conducts an empirical study in the Caotangxi watershed, Three Gorges Reservoir Area (TGRA). Transformation characteristics of agricultural landscape pattern during 2000-2018 represented by sloping farmland, abandoned land, and orchard are analyzed from a holistic-local perspective. The research findings show that the orchard expanded along river valleys, and the abandoned land expanded at high elevations in the case study, leading to a reduction in sloping farmland. Therefore, there are differences in the regional landscape at the holistic and local levels. In other words, this phenomenon enhances the region's holistic landscape diversity but causes the fragmentation and aggregation of landscape patches in local areas. Meanwhile, the agricultural landscape pattern transformation within the farmers’ farming range in the study area is mainly manifested in four modes, including sloping farmland-orchard conversion, comprehensive conversion, partial abandonment and complete abandonment. Different transformation modes reveal different development stages of the mountainous agricultural landscape pattern. Generally, driven by socioeconomic factors in mountainous areas of TGRA, the agricultural landscape pattern transformation is bidirectional. The attribute is expressed as the transformation from the traditional grain-planting landscape with even distribution to the ecological-economic win-win orchard in valleys and the transformation from sloping farmland to abandoned land in high-elevation areas. Overall, the results reveal the uniqueness of agricultural landscape pattern evolution in China's mountainous areas in recent decades, which has enlightenment for the in-depth understanding of rural land use and agricultural ecosystems in mountainous areas of the reservoir area, and the improvement of rural development and ecological environment.