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Researching In The Species Diversity Character Of Vegetation Within Ningbo

Posted on:2007-08-04Degree:MasterType:Thesis
Country:ChinaCandidate:X F FangFull Text:PDF
GTID:2120360185962313Subject:Ecology
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Ningbo is located in eastern China, and it belongs to the monsoon climate of subtropical zone, its zonal vegetation is typical evergreen broad-leaved forest. Since the long time and intensive human disturbance, nowadays the vegetation of Ningbo has presented a massively degraded situation, and formed a pattern which degraded vegetation distributed as the main part with the EBLF scattered in. After the investigation of vegetation in Ningbo and the arrangement of some existing data in the same region, we intended to reveal and compare the character of species diversity of the EBLF and its degraded communities there. We even established a RBF (Radial Basis Functions) artificial neural network to forecast and simulate the transformation of plant species diversity within Tiantong - Dongqian lake. Based on these works, we reached 7 conclusions as follows:(1) The species richness of EBLF (29.28) was significant higher than that of its degraded communities (23.67, P<0.001). Among the 5 types of degraded communities, the richness rank was: Evergreen and deciduous broad-leaved mixed forest > Broad-leaved and conifer mixed forest > Deciduous broad-leaved forest > Conifer forest > Shrub. So it could be concluded that the species richness of Evergreen and deciduous broad-leaved mixed forest, which was the most similar as the EBLF, was the highest, and the shrub which was the most serious degeneration, its species richness was the lowest. Theses results showed that as the degree of vegetation degeneration aggravating, the species diversity within the communities would decline significantly.(2) Species-area relationship can also reflect the species diversity character of one vegetation type. When we fitted the species-area curve of EBLF and its degraded communities in Ningbo, we found that the Logistic model was thebest model, their expressions were as follows:For EBLF communities: S =For Degraded communities: S =...
Keywords/Search Tags:Species diversity, degraded communities, evergreen broad-leaved forest, stepwise multiple regression, environmental and land use factors, species-area curve, RBF artificial neural network
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