岷江中下游生态景观格局变化

Change of landscape pattern in middle and lower of Minjiang River

以生态景观理论为基础,地理信息与遥感技术为支撑,对三期遥感影像数据,1990年和2002年TM数据、2014年ETM+数据进行土地覆被变化监测,景观格局指数定量分析,面积转移矩阵统计,对9种社会与自然驱动力因素降维转化,分析景观格局变化主要驱动力因素,研究结果表明:(1)研究区内景观类型面积排序:林地>草地>农田>水域>居民地>裸地。1990—2014年期间林地所占比例由78.03%下降到68.97%,农田比例由6.85%上升到10.91%。居民地所占比例升高了4.1%。(2)农田发生变化的区域主要分布在岷江、大渡河两侧以及西南山地附近。林地减少的区域主要在岷江、青衣江、大渡河交汇的西北部。1990—2002年,林地分别向草地和农田转化了14061.0 hm^2和13891.0 hm^2;此外,水域向裸地转化了214.3 hm^2。2002—2014年,林地向草地、农田、居民地分别转化了3932.0 hm^2、3240.0 hm^2、801.0 hm^2;同时草地景观向农田、居民地进行了转化,分别为10164.0 hm^2、826.0 hm^2。(3)PC1和PC2主成分载荷超过0.8的变量中,导致区域景观发生变化的主要驱动力因子是农业耕作面积扩大和城市化进程。

Background, aim, and scope The three rivers＇ （Minjiang River, Daduhe River, and Qingyi River） intersection area is located in the southeast of Sichuan Province and the lower reaches of Minjiang River. The area is rich in animal and plant resources, and ecological landscape diversity. It is an important scientific research and ecological protection area in our country. However, in recent years, the regional landscape type has changed, so it is necessary to study how the landscape type change？ What are the driving forces？ What are the ecological impacts？ Materials and methods In this paper, using three period （the year of 1990, 2002 and 2014） remote sensing images combined with natural and social assistance data to monitor landscape change based on RS andGIS technology, and extracting the index of different types of landscape, and calculating the transfer matrix to count the landscape area, using the PCA method to point out that the driving force of landscape pattern change. Results The results showed that： （1） The landscape area sort： forestland 〉 grassland 〉 farmland 〉 water area 〉 urban land 〉 bare land in the study area. The advantage landscape was forestland and the proportion fell to 68.97% from 78.03%, farmland increased to 10.91%, and urban land raised 4.1%, from 1990 to 2014. （2） The change of farmland mainly distributed on the Minjiang, Daduhe River and southwest mountains, forestland area decreased, mainly in the northwest. From 1990 to 2002, forestland converted to grassland and farmland with a value of 14061.0 hm2 and 13891.0 hm2 respectively, moreover, the conversion amount from water area to bare land was about 214.3 hm2. From 2002 to 2014, forestland converted to grassland, farmland and urban land, and the conversion amount is 3932.0 hm2, 3240.0 hm2, 801.0 hm2 respectively. Grassland converted to farmland, urban land, the conversion amount is 10164.0 hm2, 826.0 hm2. Grassland transferred amount was negative. （3） Among the values that is greater than 0.8, in principal component loading matrix, the main driving force of the regional landscape change was the expansion of farming area and urbanization. Discussion Multi-temporal remote sensing was used to monitor the landscape change, improved the timeliness of monitoring results. However, the time and spatial resolution of image is not very high, and the factors that lead to landscape change are diverse and complex, so, we can analysis of different driving forces with partition in the interaction area. Conclusions Overall, the landscape had an obvious change, and the expansion of urbanization and agricultural area were the main driving force factors in three rivers interaction area. Remote sensing and GIS technology greatly improve the efficiency and accuracy of landscape change monitoring and driving force analysis. Recommendations and perspectives The study objectively reflect the changes and driving forces of the ecological landscape in the interaction area, and provide scientific data support for the regional ecological protection.