A Demonstration Study On The Restoration Of Degraded Sub-alpine Plant Communities In Shangri-La

The restoration and rehabilitation of vegetation in degeneration of ecosystem are the key research contents of restoration ecology.It is acknowledged that the health of ecosystem is quite crucial to the protection of biodiversity and the long-term sustainable development of human society.The sub-alpine region is situated in the northwest of Yunnan Province of China,where the complex and diverse geographical environment and climate have nurtured the rich and diverse wildlife resources in that area.However,over the years,a large number of natural resources have been exploited by human with its development and the deforestation even more serious than before,which lead to grave consequences,such as the serious regional degradation of sub-alpine forest communities,the rapid decrease of wildlife resources,the decrease of natural forest of area and quality,and the fragile ecosystem.To restore and reconstruct sub-alpine ecosystem in that region,we take the Chunzong village in Shangri-la city as research object,Investigate soil seed banks of degraded forest communities,utilizing the method of different plant functional groups to match planting and selecting 4 pieces of sample soil with basically similar degradation degree,geographic location(1.3 hectares per block)for the restoration experiment.For each sample plot,we configuration the different restore sample area:Sample area 1(enclosed,Local Arbor,Shrub,Herb plant configuration planting restoration),Sample area 2(contrast),sample area 3(enclosed,Natural recovery),Sample area 4(enclosure,Planting of native irrigated grass plants was restored).Next,we take multisequential monitors to the situation of vegetation restoration when comparing the effect of different recovery mode,so as to make regional sub-alpine degraded forest estate optimized.Meanwhile,we can offer the theoretical and technological foundation for the ecology restoration and construction of Shangri-la's sub-alpine forest zone as well as provide practical experience and scientific basis for selecting vegetation species of regional vegetation restoration.In this study,a total of 4 community sample surveys conducted on the restored plots is as follow:in April 2018(before planting and enclosure),in August 2018 and in April and August 2019.We have gained the data of species composition of phytocoenosium,diversity,vegetation coverage,plant growth and survival rate of the four plots and so on,collecting soil sample for five times in April 2018(before planting and enclosed),and in August and April,August and December,2019.Then we back to the lab for the determination of soil sample chemical properties,and make the experiments for analyzing degradation plot before planting and enclosing,exploring different plant functional group of configuration between 4 samples in plant community plant diversity,species,plant coverage,plant growth and soil chemical properties change with the recovery process.The results show that:(1)The average density of soil seed Banks in the degraded sub-alpine forest community was 700.5±215.5 seeds/m~2,but the`similarity between soil seed Banks and above-ground vegetation was low.Few seeds in the soil seed Banks germinated and grew into above-ground vegetation,and soil seed bank plants contributed little to the above-ground vegetation renewal.The herbs in the soil seed bank and above-ground plants were mainly annual and perennial Rosaceae,Asteraceae Bercht and Gramineae,while the woody plants in the above-ground plants were mainly Salicaceae,Fagaceae,Rhamnaceae and Pinaceae,but they did not appear in the soil seed bank,the soil lacks the provenance basis of vegetation restoration,indicating that the natural renewal ability of forest communities in the region was insufficient.(2)In the four recovery sample plot,as the recovery process progressed,except natural blank control sample area 2,sample area 1,sample area 3 and sample area 4community coverage,species diversity,plant growth are steady upward trend,and the community coverage,species diversity,plant growth are the sample area 1>sample area 4>sample area 3>sample area 2.The results showed that the restoration effect of enclosure was better than that of natural restoration,the restoration effect of artificial planting was better than that of enclosure,and the restoration effect of planting functional groups of arbor,shrub and grass was better than that of shrub and grass.(3)In the four restoration plots,with the advancement of the restoration process,except for the natural blank control sample area 2,the soil chemical properties ware showed obvious for sample area 1,sample area 3 and sample area 4.The specific performance is as follows:the soil pH is steadily advancing to the original forest pH;the organic matter content is fluctuating and rising,and the degree of change is ample area 1>ample area 4>ample area 3;Total phosphorus and available phosphorus content showed a steadily increasing trend,and the rising rate was ample area 1>ample area 4>ample area 3;Hydrolysis of sex of nitrogen,total nitrogen,available potassium and total potassium content showed a gradual downward trend,and the rate of decline was ample area 1>ample area 4>ample area 3.The results showed that the effect and improvement effect on soil chemical properties in the two years of restoration were as follows:Native trees,shrubs and herbs were better than native shrubs and herbs,and native shrubs and herbs were better than natural ones.(4)Among the 4 groups of configuration diversity of plant functional sample,sample area 1 collocation planting the Pinus densata,Piptanthus nepalensis and nitrogen-fixing herb growth and survival rate were higher than Picea asperata Mast,Cotoneaster microphyllus and nitrogen-fixing herb growth and survival rate;Sample area 4 collocation and nitrogen fixation of herbaceous plant of Piptanthus nepalensis and trees growth and survival rate higher than Cotoneaster microphyllus and nitrogen-fixing herb growth and survival rate.The results showed that the restoration effect of sub-alpine degraded plant communities with Pinus densata,Piptanthus nepalensis and nitrogen fixation herbs was the better,while that of regions with high rocky desertification with Piptanthus nepalensis and nitrogen fixation herbs was the better.The results of this study support the“near-nature forestry”restoration theory.In the short term,the restoration strategies of degraded sub-alpine plant communities in Shangri-La should be combined with planting different native species as a technical means,using of native trees,shrubs and grass(enclosed,Pinus densata,Piptanthus nepalensisr and herbs)or native shrubs,grass(enclosed,Piptanthus nepalensis,herbs)for vegetation restoration.In addition to human intervention in vegetation restoration and reconstruction,local people's awareness of environmental and ecological protection should be raised,and the productive forces of local forest land,agriculture and animal husbandry should be balanced with the development of social economy.