关键词: 大兴安岭, 坡度, 化学计量, 火烧年限, 养分循环

Abstract: By using Landsat TM as the main data source, and with the help of GIS and ENVI 4.4 software, the spatial information of the natural wetland, constructed wetland, and non-wetland in the Dagu estuary of Jiaozhou Bay in 1986, 2002, and 2010 was extracted, and, based on the principles and methods of landscape indices, the ecological safety index was constructed, aimed to quantitatively analyze the dynamic changes of the landscape in the study area, and elucidate the area’s ecological safety status and related driving mechanisms under the changes of landscape pattern. From 1986 to 2010, due to the natural and anthropogenic double interferences, the land area of Dagu estuary was diminishing. The amount of patches increased, dominant landscape disappeared, and landscape tended to be complicated, fragmentized, and separated. The interference of human activities on the landscape became more and more obvious. There was a negative correlation between the landscape interference index and ecological safety index. The loss degree of each landscape increased, while the ecological safety index decreased, with the landscape of river and reed wetland having the largest deterioration degree. The areabased landscape ecological safety was in the order of nonwetland > constructed wetland > natural wetland. To some extent, the newly established forest plantations and the newly integrated Shaohai East Lake artificial wetland park offset the ecological loss in the study area, alleviated the conflict between the area’s ecological conservation and economic growth, and developed a new way to protect the wetland.

Key words: fire history, nutrient cycle, Great Xing’an Mountains, slope, stoichiometry.