Analysis of Land Ecological Safety Evaluation of Harbin City Based on Principal Component Analysis

Land ecological security is relation to the overall regional ecological environment sustainable development.Evaluation index system has been constructed according to Harbin City land resources situation,from three aspects including nature,economy,and society by selecting 21 indices which have close relation with land ecological security.Land ecological security situation of Harbin City from 2001 to 2008 was analyzed by using the principal component analysis method,safety threshold was set and preliminary discussed finally.The results of the study show that land ecological security situation of Harbin City is at the trend of degressive fluctuations from 2001 to 2008,but overall is at a safety level.Specific land ecological security changes of Harbin City can be divided into several levels: at a security level before 2002;the land ecological security was in the inflection point in 2003,and then safety levels have been going down to 2007,during this period,although the level performed a little rise in 2005,the general trend is degressive;the security level was somewhat better until 2008.Land ecological levels had been in a wave state and had insecure trend in recent years.