Land Use Change And Land Ecological Security Evaluation In Zhoushan Archipelago

Land resources have been important spatial for human survival and development since ancient times.Land ecological security is a necessary external guarantee for maintaining regional sustainable development.In the new century of vigorously developing the blue economy,the maintenance of island land ecological security plays a strong role in realizing the orderly development of island resources and the high-quality development of the marine economy.However,due to the single structure of the ecosystem,islands have significant fragility.Under the effects of natural disasters and human disturbance,the ecosystem is likely to be unbalanced,and the ecosystem is difficult to self-recover,if ecological security is severely challenged.Zhoushan Archipelago is the largest archipelago city in the country,and land resources suitable for development and utilization are scarce.In recent years,with the advancement of the urbanization of Zhoushan Archipelago,the development of the marine economy on the island has led to a rapid increase in demand for land on the island.The continuous expansion of construction land and a large number of natural shoreline of islandis have been lost,and the spatial pattern of island land use has undergone significant changes,the security issue then became prominent.Therefore,scientific planning and utilization of the limited land resources of Zhoushan Archipelago,as well as the coordination of the contradiction between the development of the marine economy and the utilization of the land resources of the islands,have become an urgent problem to be solved in the development of the marine economy of Zhoushan Archipelago.This article takes Zhoushan Archipelago as the research area,and based on the visual interpretation of the 4 Landsat TM/ETM+/OLI remote sensing image data in 2005,2010,2015and 2018,the time and space of land use in Zhoushan Archipelago from 2005 to 2018 are obtained.Based on the change situation,the basic land use database of Zhoushan Archipelago from 2005 to 2018 was established.Using dynamic model,transfer matrix model and other methods to analyze the evolution of the spatial and temporal pattern of land use in Zhoushan Archipelago.Based on the“PSR”evaluation model,20 evaluation indicators were selected to construct land ecological security evaluation system for Zhoushan Archipelago.The grid was used as the evaluation unit,and the comprehensive index method and GIS spatial overlay analysis method were used to obtain Zhoushan Archipelago land ecological security index.Based on this,the land ecological security grading evaluation was carried out,and the research results show:(1)Significant changes in land use.Forest,arable land,and construction land are the main types of land use in Zhoushan Archipelago.From 2005 to 2018,the land use of the Zhoushan Archipelago changed significantly,and the area of forest was in a state of continuous reduction,the area of forest decreased from 606.62km~2 in 2005 to 558.94km~2 in 2018;the area of arable land was in a state of continuous reduction,the area of arable land decreased from 409.62km~2 in2005 to 295.17km~2 in 2018;construction area continued to increase,construction land area of117.23 km~2from 2005 to 2018 increased to 293.92 km~2.The single dynamic degree of soil was the highest among the 7 land types;from 2015 to 2018.Zhoushan Archipelago has an uneven spatial distribution of various types of transfers from 2005 to 2018.Among them,the change of water to construction land is the most obvious and presents patchy distribution.Forest turns to grassland,and arable land turns to construction land.(2)There are differences in the degree of land use.From 2005 to 2018,the land use index of the 4 districts of Zhoushan Archipelago all showed an upward trend.The changes in land use in Zhoushan Archipelago from 2005 to 2010,2010 to 2015,and 2015 to 2018 ranged from 0.28to 14.07,and the changes in land use in 4 districts were significant.The land use change rate of Zhoushan Archipelago in 2005-2010,2010-2015,2015-2018 is between 0.04%-1.59%,the 4districts have a small gap in land use change rate.The land use change rate of Putuo District is generally lower than that of the other three districts,and the change rate of land use in Daishan District fluctuates slightly.(3)The overall land ecological security index shows an upward trend.From 2005 to 2018,the 4 districts of Zhoushan Archipelago have a relatively safer land ecological security level,and the land ecological security index is generally increasing.The average land ecological security index of Zhoushan Archipelago from 2005 to 2018 was 0.58,0.54,0.58,0.57.The land ecological security index of Zhoushan Archipelago has not changed significantly in the past 13years,and the overall trend has been decreasing first and then increasing.In 2010,affected by the significant expansion of construction land in Zhoushan Archipelago,the land ecological security index of the 4 districts was affected to a certain extent,and the land ecological security index dropped significantly.(4)The regional differences in land ecological security are quite significant.From 2005to 2018,the 4 districts of Zhoushan Archipelago have significant differences in land ecological security index,and they are mainly based on safer and critically safe areas.Shengsi district has the highest land ecological security index and relatively good land ecological environment status;Dinghai District has the lowest land ecological security index and land ecological environment status is relatively bad.The land ecological security index of Putuo District and Daishan District is between the land ecological security index of Shengsi District and Daishan District.Based on the main problems in the ecological security of the land in Zhoushan Archipelago,it is proposed to implement integrated island management,improve the level of island governance,guide island residents and tourists to participate in protection,form a multi-party protection body,strengthen the construction of island supervision and punishment mechanism,and modernize island supervision.Countermeasures and suggestions are intended to provide reference and reference for island ecological management.