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Eco-risk assessment of land use in Tianjin City.

XIAO Lin, TIAN Guang-jin**   

  1. (State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China)
  • Online:2014-02-10 Published:2014-02-10

Abstract: This paper formulated land use eco-risk index at the landscape scale based on Tianjin’s land use dynamics from 1990 to 2005, then analyzed spatiotemporal differentiation characteristics of Tianjin’s land use eco-risk and its response to land use change by means of spatial statistics method and elasticity theory. The results indicated that changes in land use structure and quantity were complex. Transitions from both cropland and water to construction land were the main forms of land use change, as is prominently shown by the slump in cropland and surge in construction land. Land use eco-risk exhibited significant spatiotemporal variations. With great expansion of construction land, high ecorisk areas rose while low eco-risk areas decreased. Eco-risk areas at five levels had tended to be consistent by 2005. The eco-risk level was higher in downtown while lower in suburb regions, appearing as a ring-laminar layout on the whole. The land use eco-risk intensity in northern Jixian County and the eastern coastal zone was notably lower than the other regions. The transformation and mergence of different land use types caused the increasing spatial correlation distance of eco-risk index. The spatial correlation of land use eco-risk was significantly positive, besides the fact that its global and local spatial differentiation kept expanding. The response elasticity of eco-risk to land use change varied spatiotemporally, which was most highly positive in both Jixian County and Baodi District while the lowest in both inner city and Hangu District. As the land use ecorisk increased, its response elasticity to land use change showed a reverse development. The factors influencing land use eco-risk became more diversified.

Key words: Radarsat, QuickBird, object-based, synthetic aperture radar, support vector machine.