流域景观格局对江西省粮食生产服务的影响机制和分区调控

    Influence mechanism and zonal regulation of watershed landscape pattern on grain production services in Jiangxi Province of China

    • 摘要: 流域作为天然的生态系统,探究流域景观格局对粮食生产服务的时空影响机制,可通过景观格局优化的方式提升粮食生产服务供给,维护粮食安全。该研究以江西省为研究区,测度了2000、2005、2010、2015、2020年5期粮食生产服务(grain production,GP)的空间分布;从形状、面积、空间分布3个维度测度流域单元景观格局特征;利用时空地理加权回归模型探究景观格局变化对粮食生产服务的影响机制;并基于影响机制的空间异质性提出景观格局的分区调控建议。结果表明:1)2000—2020年间,江西省粮食生产服务重心由鄱阳湖平原向西南延伸,形成以平原、盆地为中心的聚集分布特征。2)2000—2020年间,景观格局指数变化方向和程度存在较大差异,斑块密度、景观形状指数分别上升5.35%、1.39%;平均斑块面积、景观联通度指数分别下降5.14%、0.68%,景观格局趋于复杂化、破碎化和分散化。3)GP时空演变特征是众多因素共同作用的结果,各景观驱动因素对GP影响呈现出片状或带状空间分布规律。其中耕地面积、水域密度、水域形状对GP主要具有正向作用;水域面积、林地密度、草地形状对GP主要具有负向作用。4)总结各景观因子系数空间分异特征,将研究区划分为赣东北季风区;鄱阳湖平原区;中部主产区;南部丘陵区4个聚类区域,并提出相应的区域景观调控建议。研究结果可为江西省流域粮食生产服务提升与景观格局调控提供参考,并加强调控措施在研究单元的针对性。

       

      Abstract: Landscape patterns have posed a great impact on the natural ecosystem and food production after land use and urbanization. This study aims to explore the spatial and temporal influence mechanisms of watershed landscape patterns on food production services. The food production services were supplied to maintain food security after landscape pattern optimization. Taking Jiangxi Province as the study area, the spatial distribution of grain production (GP) was measured for five periods in 2000, 2005, 2010, 2015, and 2020; The patch density (PD), the mean patch size (MPS), the patch cohesion index (COHESION), and the landscape shape index (LSI) were selected to measure the landscape pattern of the watershed unit, in terms of shape, area and spatial distribution; A systematic investigation was implemented to explore the influence mechanism of landscape pattern on the GP services using spatiotemporal geographically weighted regression model; According to the spatial heterogeneity of influence mechanism, the landscape zones were divided to regulate the landscape pattern. The results show that: 1) The overall supply of food production services showed a fluctuating upward trend from 2000 to 2020, and then fell back in 2015. There were large differences in the capacity of food production services in various basins. The center of gravity was extended from the Poyang Lake Plain to the southwest. The aggregated distribution was observed in the center of the plains and basins. The GP presented the descending pattern of Poyang Lake Plain > Jitai Basin > Gannan Hills > Northwestern Low Hilly Area. 2) There was a more heterogeneous pattern of landscape during the period of 2000-2020. The zoning control of the landscape was then implemented, according to the influence mechanism. There was a great variation in the direction and degree of the landscape pattern index. The patch density and landscape shape index increased by 5.35% and 1.39%, respectively; While the average patch area and landscape connectivity index decreased by 5.14% and 0.68%, respectively. The landscape pattern tended to be complicated, fragmented, and dispersed. The fragmentation of landscape was roughly presented as the distribution pattern of “high in the plains and basins, low in the mountains and hills; high in the north of Gan, low in the south of Gan”. 3) The spatial and temporal evolution of GP was attributed to the joint action of many factors. Each driving factor on the GP landscape shared the piecewise or bandwise pattern of spatial distribution. Among them, cultivated land area, water density, and water shape posed the positive effects on the GP, whereas, the negative effects were observed in the water area, woodland density, and grassland shape. 4) According to the spatial differentiation of landscape factor coefficients, the study area was divided into four clustering areas, namely, northeast Gan monsoon, Poyang Lake plain, central main production, and southern hilly. Furthermore, regulation suggestions were proposed for these regional landscapes. The finding can also provide a strong reference to enhance the food production services and landscape pattern regulation in Jiangxi watersheds.

       

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