Plant Diversity Response To Urbanization Gradient

This article preliminary study plant diversity within the three cities that are Wuhan,Huangshi and Ezhou, analysis plant diversity response to gradient of urbanization in different scales, Main results are as follows:1. As the acceleration of the process of urbanization,from village to suburb to city, the response of species composition of plant community to gradient of urbanization shows up:The number of Gymnosperms,Pteridophytes and Angiosperm gradually reduced in Ezhou and Huangshi city,while Pteridophytes dwindling,the number of Gymnosperms and Angiosperm on the rise.2.The three cities presents a trend that herbaceous layer>shrub layer> Arbor layer pattern. And distribution of tree layer and herbaceous layer shows up a positive trend, with a negative trend of shrub layer.The ratio of trees and shrubs to increase after reduction in Huangshi and Wuhan city,it increasing in Ezhou city,the ratio of herbaceous layer on the rise in Wuhan,but gradually decline in Ezhou and Huangshi city. Evergreen plant gradually growing in Ezhou and Wuhan,it increase after reduction in Huangshi;Diciduous plants gradually reduce in Wuhan,but increased first and then reduced in Huangshi,while gradually increased in Ezhou city.3.Within the scope of the three cities,the relationship of size between different level of families is:single specis familis> oligo-kind species familis> middle section species familis> larger branches species families. The different level of genera on gradient of urbanization in different cities is:single species genera> oligo-species genera> medium species genera> larger genera, but laeger genera have not yet found in the three city-wide.Phanerophyte plant have a distinct advantage in every city,and the distribution of Phanerophyte is the most in the ruralgradient,the Annual plant and Hemicryptophyte plant follwe it, the distribution of Cryptophyte is at the least.4.The analysis of Gleason index shows:within the three cities, the total average of species richness shows the trend that Huangshi> Wuhan>Ezhou. on the gradient of urbanization of the cities,species richness shows up the trend that village>suburban>urban area.5.The analysis of Shannon-wiener diversity index and Simpson index shows:The distribution of layers of plant communities were dissimilar in urbanization gradient. In Wuhan, diversity index of trees show up trend that urban> village>suburban, Bush show that village> suburb> urban; herbal shows up trends that suburb> city> rural.On gradient of Huangshi tree shows a suburb> village>city trend, shrubs are urban> village> suburban, herbal shows a village> suburb> urban trend. In Ezhou, Arbor show up a trend that urban> suburb> rural; shrub and herb are suburbs> village> urban.From the rangeability of plant biodiversity at all layers,the rangeability of tree layer was positively correlated with herbaceous,and inversely related with shrub layer.6.From the response of beta diversity index to the gradient of urbanization, we can know there is an obvious gradient structure in the similarity or difference of species on different gradient of urbanization.Through the similarity of species of different urbanization gradient, it can be arranged as follows:suburban-rural>urban-suburban> urban-rural.The similarity of plant speciesin diffrent gradient are the highest in Huangshi among the three cities, Wuhan in the lowest.The similarity of species in urbanization gradient of different cities all can be arranged as follows: Huangshi-Ezhou>Wuhan-Ezhou>Huangshi-Ezhou.