基于景观格局视角的土地整治对农地细碎化影响评价研究

EVALUATION OF FARMLAND FRAGMENTATION DUE TO THE IMPACT OF LAND CONSOLIDATION BASED ON THE VIEW OF LANDSCAPE PATTERN

以江西省宜丰县土地整治项目区为例,选择斑块类型、景观类型、廊道特征3类景观格局指数,从景观格局视角定量评价土地整治对农地细碎化的影响。研究表明:(1)水田的斑块密度由8.916 1个/hm^2下降至8.423 4个/hm^2,平均斑块面积由0.075 1 hm^2提升至0.076 9 hm^2,边缘密度由1 203.431 8降低至1 127.134 7,面积加权的平均形状因子由1.238 6下降至1.216 3,最大斑块指数由0.17%上升至0.18%,景观格局指数均得到不同程度改善;但旱地除面积加权的平均形状因子以外,其他指标均表明旱地趋于细碎化。(2)土地整治导致项目区破碎化程度加剧,斑块数量由3 530个提升至4 175个,平均斑块面积由0.070 6 hm^2增加至0.059 7 hm^2,面积加权平均形状因子由1.672 3增加至1.816 0,最大斑块指数由2.06%降低至2.01%。(3)土地整治优化了农村道理和沟渠布局,廊道特征指数均有不同程度改善。但农村道路和沟渠的修建割裂了斑块,是导致项目区破碎化程度加剧的主要原因。因此,在土地整治规划设计中需要注重旱地、农村道路、沟渠的景观格局设计,达到有效治理农地细碎化和提高土地整治景观生态效益的目的。

Taking a land consolidation project of Yifeng County, Jiangxi Province as an example, we conducted quantitative evaluation on farmland fragmentation due to the impact of land consolidation based on the view of landscape pattern. We selected three types of landscape pattern indices, including patch-level indices, landscape-level indices, and characteristic indices of corridors. The results showed that the patch density of paddy field decreased from 8.9161 per hectare to 8.423 per hectare, the edge density of paddy field decreased from 1203.4318 to 1127.1347, and the area-weighted mean shape index of paddy field decreased from 1.2386 to 1.2163, the mean patch size increased from 0.0751 hectare to0.0769 hectare and the largest patch index of paddy field increased from 0.17 percentage to 0.18 percentage. However, the drylands became fragmented, suggested by negative landscape pattern indices except the area-weighted mean shape index.Land consolidation led to fragmentation of the landscape pattern in the study area. The total number of patches increased from 3530 to 4175. The mean patch size increased from 0.0706 hectare to 0.0597 hectare. The area-weighted mean shape index of paddy fields decreased from 1.6723 to 1.8160. The largest patch index decreased from 2.06 percentages to 2.01 percentages. While characteristic indices of corridor improved, because of the land consolidation optimized the layout of rural roads and ditches, the construction of the corridor, such as rural roads and ditches, led to negative effects on the segmentation of landscape pitches. It is the principal cause of aggravation of fragmentation of landscape pattern. To effectively control the farmland fragmentation and improvement of the ecological benefit of land consolidation, the land consolidation planning should pay more attention on the consolidation of daylands, and the design of the layout of the corridors, such as rural roads and ditches.