广东省1990—2020年耕地景观破碎度时空变化特征及其驱动机制

The Spatial-temporal Changes of Cropland Fragmentation and its Driving Mechanisms in Guangdong Province from 1990 to 2020

  • 摘要: 在城镇化发展背景下, 耕地破碎化已成为制约农业现代化和规模化发展的关键问题之一, 严重威胁着我国粮食生产安全。基于景观格局指数等多种方法, 评估1990—2020年广东省耕地区、县尺度的景观破碎度, 并分析其动态变换特征, 以最优参数地理探测器和方差膨胀系数检验法识别耕地景观破碎度的主要影响因子, 揭示其时空演变的驱动机制。结果表明: 1) 1990—2020年广东省耕地破碎度总体呈小幅下降—持续上升—迅速降低的趋势, 破碎度高值集中于粤西, 低值集中于粤北, 随时间变化破碎度高值由粤西和粤东转移至珠三角; 2)农林牧渔总产值、城镇化率和GDP等社会经济因子对广东省耕地破碎度演变影响显著, 其中农林牧渔总产值是最主要的影响因素; 3)驱动机制方面, 产业结构调整是导致耕地破碎化的关键动力, 耕地“非粮化”及土地利用类型转变进一步加剧了破碎化程度, 生态及耕地保护重视度的提高对耕地破碎化起到减缓作用。研究结果可为广东省高标准农田的建设及耕地利用效率的提高与管理措施的调整提供参考。

     

    Abstract: Under the context of urbanization, cropland fragmentation has emerged as a critical issue constraining agricultural modernization and large-scale development, posing a significant threat to food production security in China. This study employed a comprehensive evaluation model integrating the landscape pattern index, entropy method, and Pearson correlation coefficient test to assess the spatio-temporal evolution of cropland fragmentation at the district and county levels in Guangdong Province. Additionally, the land use transfer matrix was utilized to analyze the dynamic changes in cropland, while the variance inflation factor (VIF) test and geographic detector method were applied to identify the key drivers of cropland landscape fragmentation. The results show that: 1) Temporally, cropland fragmentation in Guangdong Province exhibited a trend of "slight decline — continuous increase — rapid decrease", with substantial fluctuations over time. Spatially, the cropland fragmentation index was highest in western Guangdong and lowest in northern Guangdong. Western Guangdong experienced the most significant changes, while northern Guangdong remained relatively stable, indicating pronounced spatial disparities in fragmentation. Over time, the fragmentation pattern evolved into a radial distribution extending outward from the Pearl River Delta, with the high-fragmentation zones shifting from western and eastern Guangdong to the Pearl River Delta. 2) The evolution of cropland fragmentation was significantly influenced by the gross output value of agriculture, forestry, animal husbandry, and fishery (GOV-AFAF); urbanization rate; GDP; altitude; slope; average annual precipitation; kernel density; and proximity to roads. Among these, socioeconomic factors—particularly GOV-AFAF, as well as urbanization rate and GDP—played a dominant role. GOV-AFAF was identified as the most critical factor, underscoring that socioeconomic dynamics are the primary inhibitors of cropland fragmentation in Guangdong Province and a key determinant of its spatial variability. 3) Four typical driving mechanisms were identified for the evolution of cropland landscape fragmentation in Guangdong Province: First, exemplified by Yunan County, the implementation of cropland-to-forest conversion programs reduced fragmented cropland patches on hillsides, promoting more consolidated cropland distribution. Second, as observed in Lianzhou City and Huangpu District, industrial restructuring and rapid socioeconomic development led to insufficient emphasis on cropland protection. Third, illustrated by Gaozhou City, enhanced policy interventions for cropland protection mitigated fragmentation. Fourth, typified by Yangchun City, adjustments in crop cultivation and land use transitions resulted in a net reduction of cropland area.

     

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