| The ecological restoration and utilization of vegetation in the water-level-fluctuation zone of the Three Gorges Reservoir has always been the focus,difficulty and hotspot of the ecological environment construction and protection in the Three Gorges Reservoir area.The results showed that vegetation degradation was serious,the plants in the original habitat tended to be single optimal or even extinct,and the community structure was in an unstable stage far from the top level.The spatial distribution patterns and interspecific relationships of plant populations in the water-level-fluctuation zone of the Three Gorges Reservoir had got the attention of the scientific community.At present,the relevant studies are mainly focused on the lower section(Zigui-Fengjie),but the studies on the middle section(Fengjie-Fuling)and the upper section(Fuling-Jiangjin)have not been reported.At the same time,a large number of studies have proved that proper mowing disturbance can greatly reduce the growth redundancy and dead matter,and promote the positive succession of plant community,but if the mowing products are not properly recycled,it will lead to secondary pollution.Silage fermentation,as a common means of resource utilization,is applied to the recycling and utilization of the mowing products of dominant plants in the water-level-fluctuation zone of the Three Gorges Reservoir,which not only has good ecological value,but also has certain economic value for the development of animal husbandry industry.However,no relevant research has been reported so far.Therefore,this article proposed to upper middle section of the three gorges reservoir,the canal springs,pear xiangxi,stone bridge river and Meixi River and so on four main tributary river near down with plant as the research object,on the basis of the reference adjacent grid method,the niche breadth,niche overlap and interspecific correlation analysis of ecological characteristics,such as ability to reveal the use of plants to environmental resources or of dry-wet alternate environment adaptability,so as to the three gorges reservoir down with vegetation succession trend prediction and provide certain scientific basis for ecological restoration.At the same time,taking the representative dominant plant in the water-level zone of the Three Gorges Reservoir as the research object,the microflora dynamics of its silage fermentation process were analyzed by high-throughput sequencing technology,so as to explore a new way for the utilization of silage fermentation resources,and then provide a basis for the development of high-efficiency agriculture in the mountainous region of the Three Gorges Reservoir.The results showed that:(1)The distribution and species dominance of dominant plants were generally affected by site conditions and plant resistance to the environment.The study of the three gorges reservoir in the middle and upper reaches of different rivers found that:There were only Bidens bipinnata and Xanthium sibiricum in the 16 sample plots,which indicated that Bidens bipinnata and Xanthium sibiricum with wider niche could overcome different geographical environment and had strong adaptability to the middle gentle slope fluctuation zone,becoming the preferred dominant plants for ecological restoration of the middle gentle slope fluctuation zone.However,sedge,sorrel,mariqueter,wild fennel,acanthraxon hispidus,acanthraxon hispidus,acanthraxon hispidus and seleng argyra,which had a wider regional niche,became two endemic species in the land-level zone,and played an important role in the richness of regional species in the land-level zone.(2)Among the 105 species pairs in the study area of the water-level fluctuation zone of the Three Gorges Reservoir,66 pairs(62.85%)had an overlap value less than0.20.As a whole,the niche overlap of the plant community was small,which indicated that the competition between species was weak,the degree of community differentiation was obvious,and the plants were relatively independent.However,there are different topographic conditions in the water-level-fluctuation zones of the dry and tributaries near the estuaries of different rivers,and the plants have formed different dominant community structures due to their own selection and adaptation to the environment of the water-level-fluctuation zones.On the whole,the species number,biomass and niche overlap of dominant plants in the main stream were smaller than those in the tributaries.(3)Based on ?~2 test,Pearson correlation test,Spearman rank correlation test and population correlation analysis,we can see that the overall positive and negative correlation ratio of the gentle slope in the middle and upper reaches of the Three Gorges Reservoir is 1.09,showing a certain positive correlation.With the increase of altitude,the positive association between plants became more obvious,and the coexistence and development ability among species became stronger.Except that the positive correlation of sampling points in the tributaries of canals and rivers was slightly higher than that in the main stream,the positive correlation of sampling points in other main streams was stronger than that in the tributaries.(4)The results of dynamic study on the microflora of the silage fermentation of the root of the Three Gorges Reservoir showed that the relative abundance of Proteobacteria decreased from 91% in the early stage to 16% in the later stage,on the other hand,the relative abundance of Firmicutes increased from 0.86% in the early stage to 42%,and that of Actinobacteria increased from 5.45% in the early stage to35%.It can be concluded that the fermentation process of Ductus Root Silage can inhibit the growth of more harmful pathogenic bacteria to a certain extent and make the products develop in a beneficial direction. |
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