Research On Plant Diversity And Value Assessment In The Purple Mountain In Nanjing

Applying sample-plot survey methods, this paper analyzed species composition, basic characteristics, species diversity of the main forest communities in the Purple Mountain based on 24 sample-plots. To further understand the forest biodiversity and dynamics of the Purple Mountain, we carried on the forest community survey along the same 31 belt transects in Spirit Valley, Nanjing, in July,2010. The changes of flora, community structure, species diversity and age structure of the forest in Spirit Valley were studied, by comparing the data collected in 1951, 1981,2002 and 2010. Based on the positioning observation data of City Forest Ecosystem Research Station in the yangtze river delta of Jiangsu, the value of the forest biodiversity in the Purple Mountain was estimated by using the related theories and methods in evaluation on the vlue of the forest biodiversity studies. The assessment of the forest biodiversity evaluation in the paper included the value of water storage, soil conservation, carbon fixation and oxygen release, environment purification, nutritious substances accumulation, biodiversity conservation and forest recreation. Followings are the main results.(1)The important value, Simpson index, Shannon-wiener index, Pielou evenness index and Sorenson similarity coefficient were applied to study the main forest communities in the Purple Mountain. The result showed that Simpson index, Shannon-wiener index, Pielou evenness index of the broad-leaved mixed community were highest among six forest communities, while diversity indexes of Phyllostachys pubescens community were the lowest and the other four were in a little distance. The order of diversity indexes of three layers in the community of Liquidambar formosana, Quercus variabillis, Pinus thunbergii was:shrub layer> herb layer> tree layer. And in conifer and broad-leaved mixed forest, as well as broad-leaved mixed forest, the order of diversity indexes of three layers was:shrub layer> tree layer> herb layer. Moreover, the order of diversity indexes of three layers in Phyllostachys pubescens community was:herb layer> shrub layer> tree layer. Sorenson similarity coefficient showed that, Pinus thunbergii and Phyllostachys pubescens community shared the least species, while conifer and broad-leaved mixed forest and broad-leaved mixed forest shared the most species.(2)The changes of flora, community structure, species diversity and age structure of the forest in Spirit Valley were studied, by comparing the data collected in 1951,1981,2002 and 2010. In general, the result showed that the number of species, Shannon-Wiener index, Pielou index all increased, while the number of individuals, Simpson index both decreased. The number of species decreased from 75 in 1951 to 50 in 1981, then increased to 73 in 2002, and now increased to 105 in 2010. The number of stumpage changed from 441 in 1951 to 413 in 1981, and then to 439 in 2002, being 1211 in 2010. While the number of saplings changed from 4712 in 1951 to 44130 in 1981, and then to 7372 in 2002, being 2148 in 2010. Population of the pioneer species at the early stage, Pinus massoniana, declined over time because of poor regeneration. It was first replaced by intolerant broad-leaved species, such as Pistacia chinensis and Liquidambar formosana, which were then replaced by relatively tolerant species, such as Quercus variabilis and Quercus fabri. At present, Osmanthus fragrans, Phoebe sheareri, Liquidambar formosana, Quercus variabilis, Quercus fabri have been the commonly dominant species in the forest of Spirit Valley, Nanjing. And deciduous broad-leaved forests have succeeded gradually to deciduous and evergreen broad-leaved mixed forests.(3)Evaluation on the value of the forest biodiversity in the Purple Mountain was carried out in the paper, including the value of water storage, soil conservation, carbon fixation and oxygen release, environment purification, nutritious substances accumulation, biodiversity conservation and forest recreation. The results showed that the vlue of the forest biodiversity in the Purple Mountain added up to 4.35 billion yuan. And the order of them was:forest recreation(52.88%)> water storage(25.19%)>carbon fixation and oxygen release(8.78%)>environment purification (5.05%)>nutritious substances accumulation(3.62%)>biodiversity conservation(2.76%)>soil conservation(1.73%).