| Viburnum belongs to the family Adoxaceae,an important part of the plant community in subtropical forest ecosystem,and is also a genus of ornamental shrubs of development value.In order to identify the dominant species of Viburnum with high ornamental value in southwest Hubei province,and to explore the current situation,dynamics and spatial distribution pattern of Viburnum population,it will be beneficial to the development,utilization and conservation of the localization of Viburnum,as well as important for the maintenance of species diversity and ecological balance in the region.In this study,three forest dynamic monitoring plots(27 hm~2)were set up in the subtropical evergreen deciduous broad-leaved mixed forest in the Jinzi Mountains State Forest Farm,the Mulinzi and the Qizimeishan National Nature Reserve in southwest Hubei Province to investigate the Viburnum resources.The dominant ornamental species of wild Viburnum in southwest Hubei were determined by AHP.Taking the dominant species as the research object,using the method of space instead of time,the age structure,dynamic quantitative analysis,static life table and related curves of its population were studied.To clarify the population structure and dynamic characteristics of dominant Viburnum and explore its future development potential.And the spatial distribution pattern and spatial correlation of dominant species were analyzed by using pair correlation function.The main research are as follows:1.Based on the data of the large plots,13 species of wild Viburnum were found in the three large plots,and there were significant differences in distribution and population size of Viburnum.The number of Viburnum plants in the sample plot was8198,and the total number was Jinzi Mountains>Mulinzi>Qizimeishan.The number of individuals in V.betulifolium,V.setigerum,V.dilatatum,V.erosum,V.sympodiale,and others was relatively small.2.Based on the ornamental characteristics,resource value and development potential of 13 species of Viburnum,a comprehensive evaluation model of ornamental plant resources in southwest Hubei province was constructed by AHP.Thirteen Viburnum species were divided into three grades according to the comprehensive score.There were 5 species in the first order,including V.betulifolium,V.setigerum,V.dilatatum,V.erosum,V.sympodiale.There were 6 species of secondary including V.cylindricum,V.schensianum,V.henryi.The third level species such as V.plicatum and V.plicatum f.tomentosum.3.The age structure of the five Viburnum species displays as the pyramidal type summarized from population structure and dynamic analysis.The number of individuals of each population is large at the young stage(89.48%of V.erosum in Jinzi Mountains,76.38%of V.betulifolium,67.24%of V.erosum in Mulinz,62.11%of V.dilatatum,56.53%of V.sympodiale,58.44%of V.setigerum),and only a small proportion of individuals(0.18%of V.erosum in Jinzi Mountains,0.85%of V.betulifolium,3.29%of V.erosum in Mulinzi,3.97%of V.dilatatum,8.37%of V.sympodiale,2.79%of V.setigerum)in the older stage.The young stage plants of five Viburnum species all have strong growth potential but are sensitive to external disturbances.The survival quantity of the five Viburnum species was decreasing monotonically with increasing age class presented by static life tables.Except for V.setigerum,the life expectancy reaches a peak at the younger age,all other Viburnum species populations reach the peak at the middle age.The change trend of mortality rate and disappearance rate are similar,but the fluctuation of disappearance rate and mortality curve are different among different species.The survival curves are tended to be Deevey-Ⅱtype.The four survival function curves show that all five Viburnum species populations exhibited a substantial decrease in the early stage,stabilization in the middle stage,and decline in the late stage.4.The study of spatial distribution pattern and spatial correlation showed that the distribution of Viburnum and its growth stages was clustered at a small scale,but the degree of aggregation gradually decreased with the increase of scale,and the distribution gradually shifted to uniform or random distribution.The young and young age of Viburnum showed a positive correlation in small scale.In the larger scale,the five Viburnum species showed different spatial correlation characteristics at different growth stages,but mainly showed a positive correlation or no correlation overall.In conclusion,in order to develop and utilize wild Viburnum plants in southwest Hubei province,it is suggested that the species with abundant resources should be selected first,while the species with few numbers in the wild should be protected more.The development and utilization of Viburnum plants should be scientific and feasible in accordance with local conditions.If the resource reserves are rich,artificial thinning can be properly carried out at the young stage to improve the conservation rate.At the stable stage of middle age,the dominant species can be screened for proper development and utilization.If the resource reserve is low,it require doing strengthened protection.This is of great significance to the maintenance of species diversity,the protection and sustainable development of plant germplasm resources in this region. |
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