Dynamical research of ecological security based on ecological footprint in Nanyang city

The author applies the ecological footprint method to evaluate the sustainable development and ecological security of Nanyang city from the time series by the great span. The paper constructs the new evaluation index system of ecological security and introduces the model of ecological tension index, ecological occupancy index and ecological economic coordination index. Taking Nanyang city as a case study, the paper introduced the concepts of change rates and scissors difference to quantitatively analyze the trends of EF and BC and the difference between both trends in a long time series and index system of ecological security from 1997 to 2004 for Nanyang city. Among 7 years from 1997 to 2004, the results showed that the per capita ecological footprint of Nanyang gradually increased, while the per capita ecological capacity appeared to be a reducing trend in the same period. It resulted in the increasing trend of per capita ecological deficit in 7 years. In addition, the ecological tension index and the ecological occupancy index increased, but the ecological economic coordination index declined in the same time. The results indicated that the sustainable development model of Nanyang was not optimistic, the ecological environment was at risk and the social economic development did not go with ecological environment.