Evaluation Of Karst Ecosystem Health And Its Simulation Prediction

The residues of carbonate rocks after weathering are the main source of soil in karst areas.Due to the slow soil formation rate,shallow soil layer and fragile soil environment in karst areas,there are very few residues after weathering of carbonate rocks,and the soil formation rate is extremely slow.This leads to a series of ecological and environmental problems,which threaten the restoration of ecosystem health in karst areas and the sustainable development of the region.Therefore,soil problems are the first issues that need to be considered in the diagnosis and research of Karst Ecosystem Health(KEH).However,in the past,general and universal ecosystem health diagnosis methods have not considered the problems of soil thickness and soil formation rate in carbonate rock areas,and the spatial pattern,evolution trend and influencing factors of KEH are still unclear,which affects the status of KEH Future scenario simulation and early warning and forecasting work,thereby restricting regional ecological restoration and sustainable development.To this end,this article uses VORS model,carbonate dissolution model,spatial autocorrelation analysis method,trend analysis method,geographic detector,Spearman correlation analysis and partial correlation analysis based on global karst database,meteorological and hydrological data and lithology data to study the temporal and spatial distribution patterns of global and karst ecosystem health from 2000 to 2015,reveal its temporal and spatial evolution characteristics,explore the main influencing factors and driving mechanisms that affect ecosystem health,and simulate and predict future scenarios.The main conclusions are as follows:(1)In terms of spatial distribution,the high values of the global ecosystem health index are concentrated near the equator and within the Tropic of Cancer(0～13°N,0～18°S),and the highest value in this region reaches 0.52;in terms of quantity,it is relatively healthy Almost all countries account for more than 50%,but its area is far less than 50%.In terms of changing trends,areas with improved global ecosystem health(45.37%)accounted for 9.26% less area than degraded areas(53.63%).(2)It was found that the proportion of the area of the global karst ecosystem health level below the medium level is as high as 75.91%.Although the general ecosystem health diagnosis method is widely used,however,KEH without considering the soil formation rate is overestimated by 90%.In addition,areas with improved karst ecosystem health levels(34.46%)accounted for 1.38% more area than degraded areas(33.08%).(3)In 42% of the karst regions of the world,the rate of soil formation makes a positive contribution to the health of the ecosystem,and 28% of the region makes a negative contribution.In China’s karst areas,the area where the soil formation rate contributes positively to ecosystem health reaches 57%,and the negative contribution is about 28%.In short,whether it is a global or Chinese karst,SFR’s effect on the health of karst ecosystems is mainly a positive contribution.(4)It reveals that the health of ecosystems in the global karst region will gradually improve in the next five years.However,when the soil formation rate is not included in the ecosystem health diagnosis index system,the area of relatively healthy areas(6.38%)will increase in the next five years is 7.3 times of the increase rate when the soil formation rate is included(0.87%),and the degree of restoration is much greater than when the soil formation rate is not considered.It can be seen that the soil formation rate may limit the health of the ecosystem in the karst area.(5)Average annual precipitation and soil moisture play a key role in ecosystem health on a global scale,and their correlations are 0.574 and0.399,respectively.In karst areas,the addition of soil formation rate enhances the correlation between rainfall,soil moisture and ecosystem health index.The results of interactive detection and analysis show that social and economic factors act as bridges,and they connect and strengthen the influence of other factors.In summary,the impact of soil formation rate on KEH cannot be ignored.Considering the strong geological background restriction characteristics of karst ecosystems,the soil formation rate is included in the karst area ecosystem health diagnosis and risk identification index system to make it more accurate and more accurate.Comprehensively reflect the health of the karst ecosystem,so as to better serve the ecosystem health assessment and macro management in the karst area.