基于土地利用变化的沂河流域景观格局与径流关系的分析

Analysis of the relationship between landscape pattern based on land use change and runoff in Yihe River Basin

关键词:  沂河流域  土地利用变化  景观格局  径流  相关性

Key words:  Yihe River Basin  land use change  landscape pattern  runoff  correlation

摘要:

为探究流域径流量和景观格局变化的关系，基于沂河流域土地利用数据和实测径流资料，运用景观格局指数分析方法和统计分析方法在景观水平和斑块类型水平方面分析流域土地利用景观格局变化与径流量的相关关系。结果表明:1)1961—2015年，流域年径流量相比于年降水量其波动幅度及下降趋势更显著，这说明流域年径流变化除受到降水因素影响外，还受到土地利用变化等人类活动的影响。2)1975—2015年，流域土地利用类型以耕地为主，其次林地、建设用地和草地所占比例较大，再次是水域，而未利用地面积最少；土地利用变化主要表现为耕地和草地迅速减少，建设用地和林地快速增加，水域和未利用地有不同程度的增加；流域景观格局破碎化程度增大、斑块形状趋于复杂、连通性趋于减弱、景观异质性增高。3)在斑块类型水平上，径流量与斑块数量(NP)和斑块密度(PD)相关性较小，随着斑块破碎化程度的增加有先减少后增大的微弱趋势；径流量与斑块结合度指数(COHESION)相关性也较小，与最大斑块指数(LPI)有较强的相关性，随着斑块连通程度、景观优势种丰度的增加呈现先增加后减小的趋势。在景观水平上，径流量与多样性指数(SHDI)、景观形状指数(LSI)、蔓延度指数(CONTAG)显著相关，与景观分离度指数(DIVISION)的相关不显著，随景观类型多样性、斑块形状复杂度、斑块聚集度、景观分割度的增加呈现先增加后减小的趋势。

Abstract:

To explore the relationship between land use landscape pattern change and runoff in the landscape level and patch type level, the landscape pattern index analysis method and statistical analysis method were carried out based on the land use data and measured runoff data of the Yihe River Basin. The results showed that: 1)From 1961 to 2015, the fluctuation and decline trend of annual runoff was more significant than that of annual precipitation. This indicated that the annual runoff change was not only affected by precipitation, but also by human activities such as land use change. 2)From 1975 to 2015, the land use type of basin was mainly cultivated land, followed by forest land, construction land and grassland, which accounted for a large proportion, followed by water area, with the least area of unused land; Land use change was mainly manifested in the rapid decline of cultivated land and grassland, the rapid increase of construction land and forest land, and the increase of water area and unused land to varying degrees. The landscape pattern of the watershed was more fragmented, the patch shape tended to be complex, the connectivity tended to be weakened, and the landscape heterogeneity increased. 3)At the level of plaque type, the correlation between runoff and NP and PD was small. With the increase of the degree of plaque fragmentation, there was a weak trend of decreasing first and then increasing; The correlation between runoff and COHESION was also small, and there was a strong correlation between runoff and LPI. With the increase in patch connectivity and the abundance of dominant species, it showed a trend of increasing first and then decreasing. At the landscape level, the runoff was significantly correlated with SHDI, LSI and CONTAG, and runoff was not significantly correlation with DIVISION. With the increase of landscape type diversity, patch shape complexity, patch aggregation and landscape segmentation, runoff showed a trend of increasing first and then decreasing.