Landscape Ecological Security Assessment Considering Three Dimensional Information

Ecological security is the premise of the stable development of society and the foundation of other systems.Landscape ecological security is to discuss the ecological security of a region from the perspective of landscape ecology,which can intuitively reflect the structure and composition of the ecosystem.It is one of the important areas of regional ecological security research.At present,most of the research on regional landscape safety is based on two-dimensional plane data.The regional complex geomorphological differentiation and three-dimensional spatial features are not reflected,which affects the objectivity of the analysis results.Taking Daye City,Hubei Province as an example,the regional landscape ecological security evaluation method considering three-dimensional information is explored to provide scientific basis for regional sustainable development.Using ENVI,ArcGIS and other platforms,the paper analyzes the dynamic changes of landscape in the three stages of Daye City in 1995,2005 and 2015,and constructs the landscape ecological security evaluation index system from four perspectives: landscape function,landscape structure,landscape stability and landscape stress.The effects of three-dimensional topography on landscape pattern and ecological security are divided into two categories: direct impact and indirect impact.Direct impact refers to the influence of surface area and perimeter difference in three-dimensional case.Indirect influence refers to the influence of redistribution of the light,temperature,water,and soil caused by three-dimensional topographic relief.The sunshine hours are used to reflect the light and temperature condition to correct the material product function of the land.The general soil erosion equation is used to reflect the soil and water conditions to correct the ecological security maintenance function of the land.The results show that:(1)The overall landscape change in 2005-2015 is stronger than that in 1995-2005.(2)The landscape ecological security level of Daye City is the largest in the Grade II,followed by Grade III and Grade I,and Grade IV and Grade V are small.From 1995 to 2015,the change in safety level was mainly due to the decrease in the proportion of Grade I and Grade II,and the increase in the proportion of Grade III.The descending trend of the flat and low mountains is the most obvious,and the ecological state of the hills and steep hills is relatively stable.(3)The characteristics of the change of landscape ecological security index in Daye City are as follows: The rising area is the least,it distributed sporadicly in the northern hills and the low mountains in the middle of Daye City;The descending areas are mainly distributed in the flat in east and middle and the low mountains in the southeastern part of Daye City.The fluctuanting area is mainly distributed in the flat in the north,the gentle hill in the west and the steep hill in the middle of Daye City.