Evaluation And Prevention Of Regional Land Ecological Risk

The current situation of global land degradation and ecological security remains critical.The situation of land ecological security in China is especially severe compared with many countries in the world.Unreasonable land use and resource development have caused irreversible damage to the land ecosystem and endangered the human living environment and development.Risk assessment of land ecosystems provides a valuable tool for scientifically evaluating the impact of current human and natural activities on land and its ecological effects,thus providing an important means of achieving the sustainable use of land resources.This paper is based on the requirements of land resource management and extends the theory,method,and technology of ecological risk evaluation to the land ecological risk evaluation field at the regional level.Empirical research was conducted in the traditional mining city of Daye in Hubei Province.This research provides the basis for reference in realizing the ecological protection and sustainable use of resources.The following specific content and conclusions were drawn.(1)Survey of land ecological problemsWe discussed the mainland ecological problems of Daye and determined the risk receptors and ecological endpoints at the regional level on the basis of long-term field investigation,data analysis,and expert group discussion on the land ecological environment in Daye.We selected major sources of land ecological risks and analyzed various possible risk stress factors.We discussed the transfer process of regional land ecological risks,constructed the exposure-response analysis conceptual model of regional land ecological risks,and revealed the mechanism of land ecological degradation risks based on the type and characteristics of economic development activities in Daye.It has a positive significance for land use planning and ecological protection.(2)Land ecological risk evaluation based on comprehensive evaluation conceptual modelWe constructed the index system of land ecological risk evaluation at the regional level and analyzed the temporal and spatial characteristics of the regional land ecological risk in Daye based on the risk level of the risk source and the vulnerability of the land ecosystem.The main results are as follows.(i)The area of regions with high land ecological risk is approximately 168km2,which comprises 10.10%of the land area.The risk index is generally between 0.22-0.38.(ii)The area with extremely high land ecology risk and vulnerability is distributed in the north and southeastern regions.The vulnerability index is between 0.68 and 0.77,which constitute 3.13%of the region.(iii)The spatial distribution of the integrated ecological risk presents obvious spatial variability.Areas with extremely high risk represent 13.83%,which is approximately 230 km2 and are mainly distributed in the eastern and midwestern ore belt and the central mining processing belt of Daye,which risk indexes are from 0.13 to 0.23.High-risk areas account for approximately 21.35%,which involves an area of 355 km2 and are mainly distributed in Luoqiao,Jinshan Street,the City North Economic Development Zone in the northern city center,and Chengui in the central region.Areas with moderate risk comprise approximately 33.79%of the entire region,with an area of 562 km2,and are mainly agricultural.Areas with low risk represent approximately 31.03%of the entire region,with an area of 516 km2,and are mainly distributed in the forest area in the southern and southeastern part of Daye.We used the expert evaluation method to perform uncertainty analysis and resolve the uncertainty factors of the risk evaluation.The present study proposes the differential risk management countermeasures on the basis of the different risk patterns and according to the different risk source categories and land use status and then provides decision-making basis for regional land ecological protection and sustainable resource management.(3)Evaluation of regional land ecological risk based on the relative risk modelThe relative risk model(RRM)was introduced into the regional land ecological risk evaluation.The evaluation area was divided into six risk sub-regions by applying the model to the target area,the city of Daye.The exposure-response relationship between the risk source and the ecological endpoint was quantified.The risk level of each sub-area was evaluated,and the spatial heterogeneity of the land ecosystem was emphasized,thereby providing new ideas on evaluating regional land ecological risk under multi-pressure.The results show that(i)risk sub-regions 2 and 4,as the traditional iron-coal mining and mining processing zones,are in a high-risk state;(ii)mining is the largest risk source in the region,followed by solid waste dumping and urbanization;(iii)habitat removal is the strongest stress factor,followed by accumulating organic pollutants and heavy metals;(iv)lake habitat suffered from the largest potential threat among the eight habitat receptors;(v)significant health threats,soil pollution,and decline in landscape aesthetics value are the end of the maximum risk pressure.The Monte Carlo simulation technology,which is widely used globally,established the uncertainty analysis of the evaluation results of regional land ecological risk.The uncertainty analysis results of land ecological risk evaluation in Daye were presented,and the uncertainty problems specifically reflected by the Monte Carlo simulation curve were discussed.This research recommended the ecological risk management for different risk sub-areas,risk categories,and habitat receptor management perspective.(4)Development of land ecological risk prevention and decision-making tool based on spatial Bayesian modelingBayesian networks combined with geographic information system was used to develop spatial decision-making tools for land ecological risk prevention at regional scale and was applied to the traditional mining city of Daye in Hubei Province.The present study constructed a model of land ecology degradation at the regional level given several expert group discussions.The model reveals the complex mechanism of the ecological risk in Daye.We divided the state of the variables in the network on the basis of a large number of prior knowledge architecture,at the same time,multiple seminars introduced to design the probability distribution(condition probability table,CPTs)between variables to improve the design efficiency of model parameters,thereby reducing the uncertainty of subsequent simulation.Four scenarios,that is,land resource supply,land ecological environment protection,maintaining land productivity,and urban development transformation,were designed for risk decision simulation based on the value orientation of different land resource stakeholders.The results show that(i)appropriate urbanization plan can minimize the shortage of land resources;(ii)strict control over mining and enclosure culture in lakes can effectively control soil and water environment deterioration;(iii)high-strength protect habitats and prevent soil degradation can maintain land productivity;(iv)strict control of mining can effectively improve the quality of living environment The results of spatial simulation show the ecological benefits of decision-making behavior and provide the optimal decision-making reference for regional land ecological risk prevention and management.The sensitivity analysis reveals that the mining industrial point source discharge and irrigation node are most sensitive to the degradation of soil quality;industrial point source pollution is not the most sensitive to deterioration of water quality,except large areas of aquaculture;the impact of surface damage and heavy metal pollution of soil on the threat to human safety and health is obvious.Moreover,land reclamation in lake districts and solid waste dumping demonstrate a penetrative influence on the multi-level node.This paper discussed the evaluation technology system of the regional land ecological risk based on regional scale,comprehensive evaluation of multi-index land ecological risk,land risk evaluation based on RRM,risk prevention decision-making tool based on spatial Bayesian modeling and handling uncertainties.This paper also introduces the direction and goal of further research work.