Process Of Patch Mosaics Of Mature Subtropical Monsoon Evergreen Broadleaved Forest In Hexi, Fujian, China

Community succession,as a core part of vegetation dynamic research,is one of the hot vegetation ecological research subjects.In the meantime,monsoon evergreen broad-leaved forest is a zonal vegetation type and an important part of land ecosystems in subtropic of the world.Based on the theories of vegetation ecology and restoration ecology,and also based on space-for-time substitution,detailed field investigation was conducted in the representative south subtropical monsoon evergreen broadleaved forest in Hexi,Fujian Provinve,China. Patch ecological charaeteristics such as plorristic composition,plant growth form and life form,patch structure,species diversity,comparison of patch similarity and succession dynamics were described in this paper.The results showed as followings:1.The total number of plant species in the eight study sites basically increased with patch age.During the 2nd to 6th year of the succession,the number of patch species fluctuated violently.When it came to the 10th year,the number of the plant species on the 154.8 m~2 of patch increased sharply to 92.And during the 21st to 30th year,species richness varied more slowly,approaching a possible plateau.2.The florae of successional patches were complex.With the development of succession, the number of families,genera and species increased.3.The species richness of every growth form group and life form group increased at the early stages and decreased at the late,the compositional proportion became more consistent over time.4.The dominant species of patches took a change of pioneer heliophytes degenerated and the mesophytes developed,and the dominant species of shrub layer were tree seedlings in the period before being climax patch.In conclusion,the importance value of shrub layer,herb layer and liana varied with the change of tree layer in different succession series,and the change of the microenvironment resulted in the variation of the dominant species in shrub layer,herb layer and liana.5.By pairwise comparison among patch 8(30a),7(21a),6(10a),5(6a),4(5a),4(4a),3(3a) and 1(2a) in respects of their coefficient of similarity and diversity in tree layer,shrub layer and herb layer,we can see that the coefficient similarity between patch 8(30a) and patch 7(21a) was close,therefore they should be considered to be in the similar succession series. The patch 8(30a) was approaching the stage of climax,and the period from patch 1(2a) proceeding to patch 6(10a) was the early stage of species invasion and patch formation.6.Species diversity increased during succession process.During the period from early succession to climax patch,species diversity rised gradually in tree,herb and liana layer and went down gradually in shrub layer.7.From analysis on the characteristics of the population structure during succession process,we concluded that the natural regeneration of Syzygium hancei under the forest went on relatively well.With the patch regeneration went on,the Syzygium hancei population will increase to a certain degree.While throughout the whole 30 years' succession,the seventh grade plant species never appeared.This phenomenon indicated that the patch 8(30a) has approached the climax,it just had a trend of developing and transiting to the climax.But it really was not a final climax patch.Also according to the dynamics of the number of Syzygium hancei,we can obviously observe the phenomenon of self-thinning and alien-thinning between populations in community during succession process.Meanwhile,the change of Castanopsis hystrix population and Syzygium hancei population shared something in common.8.At the beginning stage of succession,the successional mechanism was the "initial floristic composition hypothesis",and at the later stages,multiple mechanisms stimulated the succession together.9.The successional rate,management and conservation of Hexi south subtropical monsoon evergreen broadleaved forest and its study in the future were discussed,and also the suggestions were brought up.These studies will enrich the content of the responding mechanism of plant population and community after the disturbance,the rules of community succession,and restoration ecology in this area,and this paper is useful and referential to the restoration of degraded vegetation of south sub-tropical areas.