[Assessment and early warning of land ecological security in rapidly urbanizing coastal area: A case study of Caofeidian new district, Hebei, China].

Assessment and early warning of land ecological security (LES) in rapidly urbanizing coastal area is an important issue to ensure sustainable land use and effective maintenance of land ecological security. In this study, an index system for the land ecological security of Caofeidian new district was established based on the Pressure-State-Response (P-S-R) model. Initial assessment units of 1 km x 1 km created with the remote sensing data and GIS methods were spatially interpolated to a fine pixel size of 30 m x 30 m, which were combined with the early warning method (using classification tree method) to evaluate the land ecological security of Caofeidian in 2005 and 2013. The early warning level was classed into four categories: security with degradation potential, sub-security with slow degradation, sub-security with rapid degradation, and insecurity. Result indicated that, from 2005 to 2013, the average LES of Caofeidian dropped from 0.55 to 0.52, indicating a degradation of land ecological security from medium security level to medium-low security level. The areas at the levels of insecurity with rapid degradation were mainly located in the rapid urbanization areas, illustrating that rapid expansion of urban construction land was the key factor to the deterioration of the regional land ecological security. Industrial District, Shilihai town and Nanpu saltern, in which the lands at the levels of insecurity and sub-security with rapid degradation or slow degradation accounted for 58.3%, 98.9% and 81.2% of their respective districts, were at the stage of high early warning. Thus, land ecological security regulation for these districts should be strengthened in near future. The study could provide a reference for land use planning and ecological protection of Caofeidian new district.