Spatio-temporal Evolution and Optimization of Landscape Ecological Risk in Karst Mountainous Areas

[Objective]The ecological vulnerability and landscape ecological risk of karst mountainous areas have increased as a result of enhanced disturbance of natural resources by human activities.This paper aimed to explore the characteristics of ecological risk evolution under different landscape patterns in the region,with a view to providing reference for land classification protection,sustainable use of resources and regional ecological risk optimization in karst mountainous areas.[Method]Taking Huangping County,a typical karst mountainous area,as an example,eight evaluation factors of natural and landscape patterns were selected to construct a landscape ecological risk evaluation model,to quantitatively explore the spatio-temporal evolution of landscape ecological risk and the trend of risk level transfer in the study area from^(2)010-2018,and to reveal the complex relationship between ecological risk and topography in karst mountainous areas.[Result]①From 2010 to 2018,land use types changed to different degrees,with the most amount of woodland transferred out(1627.37 hm^(2))and the most amount of construction land transferred in(1303.93 hm^(2));a total of 3552.31 hm^(2) of land was transferred,with a change ratio of 2.13%,and there was a significant conversion between construction land,arable land,and woodland.②From 2010 to 2018,the landscape ecological risk in the study area changed significantly,and the landscape ecological risk index decreased from 0.3441 to 0.1733,showing an upward and then downward trend;the landscape ecological risk of the whole region was dominated by low-risk and lower-risk zones,and the ecological risk level generally shifted from a high level to a low level,and the ecological environment was improved.③There was a negative correlation between ecological risk and topographic position,and high-risk zones were mainly distributed among low topographic zones;with the change of time,the advantage of risk level for the selection of topography was gradually weakened,and the influence of anthropogenic factors on the ecological risk of the landscape was becoming more and more prominent.[Conclusion]This paper can provide theoretical basis for land use optimization and ecological protection in karst mountainous areas.

Ecological risk assessment and ecological security pattern optimization in the middle reaches of the Yellow River based on ERI+MCR model

The middle reaches of the Yellow River represent an important area for the protection and development of the Yellow River Basin.Most of the area of the river basin is within the Loess Plateau,which establishes it as a fragile ecological environment.Firstly,using high-resolution data of land use in the watershed from the past 30 years,landscape ecological risk(LER)sample units are defined and an ecological risk index(ERI)model is constructed.Kriging interpolation is used to display the LER spatial patterns,and the temporal and spatial evolution of risk is examined.Secondly,the spatial evolution of land use landscape change(LULC)is analyzed,and the correlation between land use landscape and ecological risk is discussed.Finally,Based on the LER model,a risk-based minimum cumulative resistance(MCR)model is established,and a comprehensive protection and management network system for the ecological source-corridor-node system designed.The results suggest that in the past 30 years,LER has a high spatial correlation and areas with extremely high ecological risks are concentrated in northwest and southeast areas of the region,of which the northwest area accounts for the highest proportion.Risk intensity is closely related to the spatial pattern of land use landscape.ERI values of forestland,grasslands,and unused land and farmland are low,medium,and high,respectively.The trend of risk evolution is“overall improvement and partial deterioration”.Man-made construction and exploitation is the most direct reason for the increase of local ecological risks.The high ecological-risk areas in the northwest are dominated by deserts which reduce excessive interference by human activities on the natural landscape.Recommendations are:high-quality farmland should be protected;forestland should be restored and rebuilt;repair and adjust the existing ecosystem to assist in landscape regeneration and reconstruction;utilize the overall planning vision of“mountain,water,forest,field,lake,grass,sand”to design a management project at the basin scale;adhere to problem-oriented and precise policy implementation.

The Spatio-temporal Evolution of Ecological Risk and Its Drivers in the Weihe River Basin Landscape from 1990 to 2020

The Weihe River Basin has a significant number of tributaries and a delicate ecological environment.Understanding the spatial and temporal evolution and determinants of landscape ecological risk in the Weihe River Basin(WRB)can improve the scientific protection and development of its watershed ecosystems.This study is based on land use statistics from the WRB for a 30-year period represented by 1990,2000,2010,and 2020.An initial model for the assessment of landscaping ecological hazards was created using the software that was also used to generate the landscape ecological risk index,such as ArcGIS 10.4 and Fragstats 4.2-64.Next,the spatial and temporal evolution of landscape ecological risk in the vicinity of the study area was characterized by the trajectory of the center of gravity migration and the spatial autocorrelation of GeoDa.Finally,Geodetector was used to analyze ecological risk drivers in the landscapes.According to the findings,the high-risk and relatively high-risk regions are steadily expanding,while the low-risk and relatively low-risk areas dominate the ecological risk landscape in the WRB.Within the Weihe River Basin,Xianyang and Xi'an are the areas to which the high-risk centers of gravity are migrating.Positive spatial correlations were found between the landscape ecological hazards in the study area,most prominently in the form of high-high and low-low aggregations.The primary drivers are the interplay between the GDP component,temperature,and elevation as a single factor.