基于景观格局的丘陵山区耕地生态风险评价——以重庆市潼南区为例
Ecological Risk Assessment of Cultivated Land Based on Landscape Pattern: A Case Study of Tongnan District, Chongqing
杨恒 张星山 宫泽奇 惠云婷 王天一 马雯秋 王海翼 杨敏丽 尤泳
作者信息
摘要
［目的/意义］丘陵山区农田宜机化整治会改变耕地景观格局、高程、坡度、微地貌等，评价其生态风险 为后续整治工作提供数据参考具有重要意义。本研究的目的为评价丘陵山区农田宜机化整治对耕地生态风险的改 变情况以及探究生态风险与耕地坡度之间的关系。［方法］以重庆市潼南区20个县为评价单元，基于2010年和 2020年土地利用数据，采用ArcGIS 10.8和Excel软件计算景观格局指数，通过熵权法确定各指数的权重并构建生 态风险评价模型，揭示生态风险时序空间变化特征；基于数理统计原理，对生态风险与坡度进行相关性分析，探 究生态风险与坡度的关系。［结果和讨论］2010年和2020年两个时期，干扰度指数由0.97下降为0.94，耕地整体 抗干扰能力增强；脆弱度指数由2.96增加为3.20，耕地结构更加脆弱；生态风险值由3.10下降为3.01，耕地生态 安全性提高。两个时期生态风险区域主要以低风险区和较低风险区为主，低风险区面积增加6.44%，较低风险区 面积增加6.17%，中风险区面积增加24.4%，较高风险区面积减少60.70%，高风险区面积增加16.30%，耕地生态 安全区域相对增加。耕地坡度主要以2°~25°为主，耕地坡度小于15°时坡度面积占比与生态风险值呈负相关，耕 地坡度大于15°时坡度面积占比与生态风险值呈正相关关系，坡度处于5°~8°、15°~25°、25°以上时坡度面积与生 态风险值呈极显著相关。农田宜机化整治应重点关注潼南区南部区域，并集中于耕地坡度处于5°~8°和15°~25° 区域。［结论］通过评价潼南区农田宜机化整治前后耕地生态风险并分析生态风险与耕地坡度的相关性，表明农田 宜机化整治可以降低耕地生态风险，耕地坡度面积占比可作为精准指导农田宜机化整治的重要依据，潼南区宜机 化整治工作应重点关注耕地坡度处于5°~8°和15°~25°区域。
Abstract
[Objective]Farmland consolidation for agricultural mechanization in hilly and mountainous areas can alter the landscape pattern, elevation, slope and microgeomorphology of cultivated land. It is of great significance to assess the ecological risk of cultivated land to provide data reference for the subsequent farmland consolidation for agricultural mechanization. This study aims to assess the ecological risk of cultivated land before and after farmland consolidation for agricultural mechanization in hilly and mountainous areas, and to explore the relationship between cultivated land ecological risk and cultivated land slope. [Methods]Twenty counties in Tongnan district of Chongqing city was selected as the assessment units. Based on the land use data in 2010 and 2020 as two periods, ArcGIS 10.8 and Excel software were used to calculate landscape pattern indices. The weights for each index were determined by entropy weight method, and an ecological risk assessment model was constructed, which was used to reveal the temporal and spatial change characteristics of ecological risk. Based on the principle of mathematical statistics, the correlation analysis between cultivated land ecological risk and cultivated land slope was carried out, which aimed to explore the relationship between cultivated land ecological risk and cultivated land slope. [Results and Discussions]Comparing to 2010, patch density (PD), division (D), fractal dimension (FD), and edge density (ED) of cultivated land all decreased in 2020, while meant Patch Size (MPS) increased, indicating an increase in the contiguity of cultivated land. The mean shape index (MSI) of cultivated land increased, indicating that the shape of cultivated land tended to be complicated. The landscape disturbance index (U) decreased from 0.97 to 0.94, indicating that the overall resistance to disturbances in cultivated land has increased. The landscape vulnerability index (V) increased from 2.96 to 3.20, indicating that the structure of cultivated land become more fragile. The ecological risk value of cultivated land decreased from 3.10 to 3.01, indicating the farmland consolidation for agricultural mechanization effectively improved the landscape pattern of cultivated land and enhanced the safety of the agricultural ecosystem. During the two periods, the ecological risk areas were primarily composed of low-risk and relatively low-risk zones. The area of low-risk zones increased by 6.44%, mainly expanding towards the northern part, while the area of relatively low-risk zones increased by 6.17%, primarily spreading towards the central-eastern and southeastern part. The area of moderate-risk zones increased by 24.4%, mainly extending towards the western and northwestern part, while the area of relatively high-risk zones decreased by 60.70%, with some new additions spreading towards the northeastern part. The area of high-risk zones increased by 16.30%, with some new additions extending towards the northwest part. Overall, the ecological safety zones of cultivated relatively increased. The cultivated land slope was primarily concentrated in the range of 2 to 25. On the one hand, when the cultivated land slope was less than 15, the proportion of the slope area was negatively correlated with the ecological risk value. On the other hand, when the slope was above 15, the proportion of the slope area was positively correlated with the ecological risk value. In 2010, there was a highly significant correlation between the proportion of slope area and ecological risk value for cultivated land slope within the ranges of 5 to 8, 15 to 25, and above 25, with corresponding correlation coefficients of 0.592, 0.609, and 0.849, respectively. In 2020, there was a highly significant correlation between the proportion of slope area and ecological risk value for cultivated land slope within the ranges of 2 to 5, 5 to 8, 15 to 25, and above 25, with corresponding correlation coefficients of 0.534, 0.667, 0.729, and 0.839, respectively. [Conclusions]The assessment of cultivated land ecological risk in Tongnan district of Chongqing city before and after the farmland consolidation for agricultural mechanization, as well as the analysis of the correlation between ecological risk and cultivated land slope, demonstrate that the farmland consolidation for agricultural mechanization can reduce cultivated land ecological risk, and the proportion of cultivated land slope can be an important basis for precision guidance in the farmland consolidation for agricultural mechanization. Considering the occurrence of moderate sheet erosion from a slope of 5 and intense erosion from a slope of 10 to 15, and taking into account the reduction of ecological risk value and the actual topographic conditions, the subsequent farmland consolidation for agricultural mechanization in Tongnan district should focus on areas with cultivated land slope ranging from 5 to 8 and 15 to 25.关键词
农田宜机化整治/耕地/生态风险评价/景观格局Key words
farmland consolidation for agricultural mechanization/cultivated land/ecological risk assessment/landscape pattern引用本文复制引用
杨恒,张星山,宫泽奇,惠云婷,王天一,马雯秋,王海翼,杨敏丽,尤泳.基于景观格局的丘陵山区耕地生态风险评价——以重庆市潼南区为例[EB/OL].(2024-07-17)[2026-04-05].https://chinaxiv.org/abs/202407.00190.学科分类
农业科学研究/环境科学基础理论/环境管理
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