Research On The Landscape Ecological Effects Of Regional LUCC Based On RS And GIS

Land Use and Cover Change (LUCC) is an interdisciplinary programmatic scientific research collaboratively initiated by two international projects—IGBP and IHDP. It aims to reveal the processes of the interplay between environmental system that mankind depends on and developing production system (agrarianization, industrialization and urbanization, etc.). As the main reason for land degradation, land use and ground cover change directly relate to biological diversity of the ecological system and global climate change, and influence the ecological system’s capacity for human needs through by changing its service functions. Targeting at the hot topics covered in LUCC research, this thesis explores LUCC changes on landscape scale in Miyun Reservoir within the past 10 years, reveals its temporal and spatial evolution laws and internal driving mechanism, and evaluates the ecological effects of landscape in the study area. Based on RS and GIS technology and the theoretical method of landscape ecology, this thesis has completed the LUCC information extraction from the study area with the help of decision tree method assisted by non-remote sensing information categorization, which takes Landsat TM images as the main data in Miyun County in 2003 and 2013; then one selects landscape metrics, analyzes and reveals temporal and spatial patterns of landscape characteristics and laws of evolution, and further explores the evolution of land use landscape pattern based on the driving mechanism of the social, cultural and economic factors. Based on temporal and spatial evolution models of land use, this thesis quantitatively analyzes changes in the quantity and quality of LUCC, explores its evolution, and reveals the space phenomena, evolution processes and driving mechanism of LUCC in the study area. From the perspective of landscape spatial pattern stability, it evaluates the environmental effects of LUCC, builds sensitivity evaluation model of ecological environment with such variables as ecological sensitivity, ecological elasticity and ecological pressure, and explores the functional mechanism between LUCC and ecological environment as well as ecological vulnerability. Finally, it discusses the ecological restoration and reconstruction of different fragile ecological zones based on the qualitative zoning of ecological functions, proposes targeted measures for Miyun’s ecological construction, and provides technical support and theoretical basis for land use and ecological restoration in Miyun couThe following substantiate the details and conclusions of this research project.(1)A multisource spatial database is built through the collection and analysis of NDVI, Landsat TM, topography and geology data. Based on the features of the study area, a land classification system as well as ground material type interpretation signs are established. This thesis adopts decision tree method together with fieldwork records to classify the data group of 2003 and 2013, with the classification accuracy reaching 88.33% and 86.35%, and kappa coefficients 0.8565 and 0.8374 respectively.(2)Landscape types in the study area are unevenly distributed and the differences of patch number are prominent in 2003 and 2013. Forest area takes up the greatest proportion, with the ratios of 48.24% and 59.18%, controlling the overall landscape structure, functional and dynamic processes in the study area; anthropogenic landscape (residential industrial landscape) accounts for 7.95% and 7.12% in 2003 and 2013; the ratio of semi-natural landscapes (unused land) are 18.39% and 11.11%. Therefore, the overall landscape is dominated by woodland scattered with waters, grassland and residential industrial land. In addition to outside factors and natural conditions, the landscape pattern is influenced by its location, important sources of drinking water in Beijing, population, level of economic development and regional industrial structure of the study area.(3)By calculating the landscape pattern indexes, all of NP, PD, AWMSI and IJI indexes show a decreasing trend while CONTAG index shows an increasing trend from 2003 to 2013, which proves that the number of landscape patches has reduced, the degree of fragmentation has slowed, the shape of surface landscape patches has simplified, spatial distribution tends to be concentrated, the closeness of spatial distribution has increased, overall regional ecological environment quality has been improved, and landscape ecological function has got some play. SHDI and SHEI index show a decreasing trend, while DI shows an increasing trend. This indicates that the degree of equilibrium between the overall distribution of different landscapes have been reduced throughout the study area, the domination of one type or several types of landscape has been strengthened, the control on the overall landscape has been enhanced, and richness and complexity of the regional landscape has been reduced.(4)The analysis of principal component based on the evolution of the driving mechanism of LUCC landscape shows that characteristic value of the first principal component is 8.521 and the contribution rate of explained variance is 77.459%, mainly reflecting the social and economic development factors; the contribution rate of the second main component is 88.146%, reflecting the rural population; the contribution rate of the third main component is 7.516%, reflecting the urban population. A quantitative analysis reveals that economic development and demographic factors are the two dominant driving factors in promoting LUCC landscape evolution in the study area, and this serves as the innovative points of this thesis.(5)The calculation based on Miyun County LUCC and its ecological service functions shows that the total value of the ecological services has increased by 38.89 × 1011 yuan from 2003 to 2013. The value of forest ecosystem services have increased the most--43.34 ×1011 yuan, and accounts for the most proportion, respectively 72.66% and 77.65%, both exceeding 70%, which occupies a dominant position in the absolute value of ecosystem services in the entire region; the second is waters, with its ecosystem services occupying 13.99%and 13.28% of the total area; the ecological service value of lawn ecosystem has declined the most, namely 10.48 ×1011 yuan, and the value of residential industrial land accounts for the smallest proportion, only 0.11% and 0.09%.(6)Another two innovative points of this thesis lie in the establishment of the model between vegetation coverage data collected by fieldwork and regional environmental vulnerability evaluation, and also in the creation of the function between vegetation coverage and environmental vulnerability which can be demonstrated as follow.There is a high relativity between vegetation coverage and environmental vulnerability. They present a negative correlation and their correlation coefficient reaches 0.8588. It displays that the rate of vegetation coverage is largely depended on regional environmental vulnerability, and the latter can be reached through the model when given the former.(7)Based on three basic indicators including ecological sensitivity, ecological elasticity and ecological pressure, a sensitivity evaluation model of ecological environment is established. Natural break method is adopted to complete environmental vulnerability classification, namely:micro-degree vulnerable, low-degree vulnerable, moderately vulnerable, highly vulnerable and extremely vulnerable. In 2003, the proportion of moderately vulnerable area occupied the most, followed by the micro-degree vulnerable area, with the area ratio 40.43% and 37.00; in 2013, the proportion of micro-degree vulnerable areas accouts for the most, followed by low-vulnerable areas, with the area ratio 48.57% and 28.59%; the ratio of the extremely vulnerable area is minimal--1.78% and 1.28% respectively. Based on the Markov model, the prediction on the future variation tendency of ecological vulnerability in Miyun County shows that the ratios of the area of extremely, highly, moderately and low-degree vulnerable regions have continued to show a downward trend, while the area of micro-degree vulnerable areas continues to increase, with the final area ratio reaching 53.01%.