Evaluation of ecological security of coastal saline land in Hebei

Severe soil salinization and fragile ecological environment are characteristic features of coastal saline land. It is therefore very important to analyze the state of ecological security of coastal saline land and the driving mechanisms in order to lay the basis for struc-tural land adjustment and land function upgrade. Based on the land use types, a classification standard of land use ecological security (LUES) in coastal saline area of Huanghua City, Hebei Province was developed. LUES values in 2000, 2005 and 2010 were calculated in Huanghua City, and key land use types were explored. Based on the above results, we selected 16 indicators (including LUES) combining with TM data and socio-economic data for 2000-2010, coupling with Erdas, ArcGIS and Fragstats platforms, to construct the P-S-R land ecological security evaluation model, and then used this model to evaluate the state of land ecological security status in Huanghua City. The results showed that: (1) LUES value for Huanghua City was 0.458-0.466 during the period of 2000-2010, LUES was at critical security state; and there was an urgent need to control the areas of construction land, salty land and heavily saline land. (2) Improvement of LUES in Huanghua City was mainly due to the decreased of soil salinization. Positive ecological effects of decrease in both moderate and severe saline land areas, and increase in lightly saline land areas exceeded the negative ecological effects of increase in construction land areas. (3) The land ecological security index (LESI) of Huanghua City showed a rising trend year by year, and the safety state improved from less secure (LESI=0.431) in 2000 to safe (LESI=0.666) in 2010. (4) The stress index (P) decreased, while the response index (R) increased year by year. For 2010, R contributed the most to LESI (45.3%), which indicated that the developed measures reduced ecological risk of land in the study area. The results provided a scientific basis for ecological utilization of land in Huanghua City.