Establishment And Application Of Effect Evaluation System For Damaged Forest Ecosystem Restoration

Since the 18 th National Congress of the Communist Party of China,the construction of ecological civilization has become an important task of the cause of socialism with Chinese characteristics.Nature reserves,as the basis of nature reserves system,are the core carrier for the construction of ecological civilization.Strengthening ecological protection and restoration of nature reserves is of great significance for promoting the construction of ecological civilization and ensuring national ecological security.As a forest-type nature reserve,Jinyun Mountain National Nature Reserve of Chongqing(hereinafter referred to as Jinyun Mountain)is an important part of nature reserves system of the Yangtze River Basin.However,Jinyun Mountain is located in the downtown area of Chongqing,and the special location determines that it undertakes the important task of meeting the needs of citizens for recreation and residents for production and living.With the continuous development of social economy,the contradiction between protection and development is becoming more and more prominent,which leads to different degrees of damage to forest ecosystem in Jinyun Mountain.The patchiness phenomenon of forest ecosystem has been obvious,which seriously affects the protection of biodiversity and the stability of ecological environment in the region.After realizing the great significance of ecological environment protection,relevant departments have carried out various forms of ecological restoration for the damaged forest ecosystem in Mount Jinyun.Intuitively,the effect of green restoration is conspicuous,but there is still a lack of scientific and effective evaluation in combination with the ecological effect.At present,there is no effect evaluation system for ecological restoration of damaged forest ecosystem in patches.Taking ecological restoration effects of damaged forest ecosystem in Jinyun Mountain as the main research object,this article analyses the effects of ecological restoration and damage reasons on soil physical and chemical properties,plant communities and soil microbial communities.On this basis,this article constructs an effect evaluation index system for ecological restoration of Jinyun Mountain,and this evaluation model is used to evaluate the effects of ecological restoration of damaged forest ecosystem.In this article,the suitability of ecological restoration technology patterns and the effects of ecological restoration under different ecological restoration time and damage reasons are preliminarily analyzed,and ecological restoration technology patterns suitable for different types of damaged forest ecosystems and Jinyun Mountain are proposed.This article is expected to provide ideas for the improvement of evaluation system for ecological conservation and restoration,and has a certain demonstration and reference significance for the improvement work of ecological restoration of similar nature reserves.The main results are as follows:(1)Natural disaster,unauthorized construction and abandoned mine are the reasons for the damage of forest ecosystem in Jinyun Mountain.The main reasons are unauthorized construction and abandoned mine.The ecological restoration techniques of the damaged forest ecosystem in Jinyun Mountain can be divided into three types:tree species selection technology,community structure design and optimization technology,and habitat modification technology.(2)For the damaged forest ecosystem caused by natural disaster,the restoration time span is long and stage is not obvious.For the forest ecosystem damaged by abandoned mine,the restoration time is 2 years.Therefore,the impacts of ecological restoration time on these two kinds of damaged forest ecosystems are not discussed.The soil,plant community and soil microbial community of the damaged forest ecosystem caused by unauthorized construction are affected by ecological restoration time to different degrees.With the increase of ecological restoration time,not only soil aeration and water holding capacity are being improved,but also contents of soil total phosphorus,available nitrogen,available potassium and organic matter are increasing.The composition of plant community is changing and the composition of life forms is approaching to that of natural community,with the increase of ecological restoration time.The species diversity of plant community is increasing with the increase of ecological restoration time,but could not reach the status of natural community in a short time.The community composition of soil bacteria and fungi will change with the increase of ecological restoration time,but the dominant phylum in the community will not change.Proteobacteria and Acidobacteria are the dominant bacteria phylum,and Ascomycota is the dominant fungi phylum.(3)Soil conditions after ecological restoration of unauthorized construction and abandoned mine are similar,but the aeration and water holding capacity of soil of unauthorized construction are better than those of abandoned mine,and the overall fertility of soil of abandoned mine is better than that of unauthorized construction.Although the compositions of plant communities after ecological restoration of unauthorized construction and abandoned mine are dominated by annual and biennial herbaceous plants,the overall restoration effect of plant community of unauthorized construction is better than that of abandoned mine.The community composition of soil bacteria and fungi of unauthorized construction is different from that of abandoned mine,but the most dominant phylum in community is the same.Proteobacteria is the dominant bacteria phylum,and Ascomycota is the dominant fungi phylum.(4)Combined with the actual situation of Jinyun Mountain,the weight of evaluation indexes is determined by Analytic Hierarchy Process(AHP)and other methods,and finally an effect evaluation model for damaged forest ecosystem restoration is established,which consists of 28 indexes from four aspects,including soil characteristics,plant community characteristics,soil microbial community characteristics and ecosystem stability characteristics.The evaluation model is applied to evaluate the restoration effect of representative ecological restoration sites in Jinyun Mountain.The result shows that the effects of ecological restoration of damaged forest ecosystem in Jinyun Mountain are significantly different.The restoration effects of restoration sites of natural disaster are better than those of the vast majority of unauthorized construction and abandoned mine.Moreover,when the restoration time is short,there is no obvious difference in restoration effects of restoration sites between abandoned mine and the unauthorized construction.The ranked order of restoration effects of restoration sites is AR1,BR7,AR2 > DR3,BR1 >BR4,BR5 > DR1,BR3,BR6,DR2,BR2.(5)Based on the research on the suitability of ecological restoration technology patterns,this article proposes that for the damaged forest ecosystem caused by natural disaster,with the characteristics of less human disturbance and high probability of natural vegetation restoration,the ecological restoration technology pattern is removal of residual trees;for the damaged forest ecosystem caused by unauthorized construction,with the characteristics of less human disturbance and general probability of natural vegetation restoration,the ecological restoration technology pattern is block land preparation + borrowed soil;for the damaged forest ecosystem caused by abandoned mine or unauthorized construction,with the characteristics of great human disturbance and low probability of natural vegetation restoration,the ecological restoration technology pattern is allocation of plant community(key technology)+ land preparation+ borrowed soil + control technology for alien invasive plant(auxiliary technology),which is suitable for most of the damaged forest ecosystem caused by human disturbance in Jinyun Mountain.In the aspect of allocation of plant community technology,this article recommends that for the damaged forest ecological system in unauthorized construction area of Jinyun Mountain,the plant species collocation pattern can be Gordonia acuminata(arbor layer)+ Chimonanthus praecox(shrub layer)+Dryopteris erythrosora(herb layer),Machilus nanmu(arbor layer)+ Ligustrum quihoui(shrub layer)+ Nephrolepis auriculata(herb layer),etc.;for the damaged forest ecological system in abandoned mine area of Jinyun Mountain,the plant species collocation pattern can be Trachycarpus fortune(arbor layer)+ Osmanthus fragrans(shrub layer)+ Urena lobata(herb layer),etc.