The Community Structure On Chaparral Forest Of Danxia Landform In Fujian Province

In this paper,community structure of 4 different formations and 8 different associations in 4 Danxia landform,Fujian Wuyi Mountain National Nature Reserve,Jiangshi Provincial Narure Reserve,Taining World Nature Heritage Site and Guanzhai Mountain National Geological Park are studied.The species composition,species diversity,floristic composition and geographical elements,ecological niche and interspecific association are analyzed.The main results are as follows:1.The constructive species of typical chaparral in Fujian Danxia landform were Quercus,Q.phillyraeoides and Q.oxyphylla.In addition,Buxus sinica was constructive species of not typical chaparral and the Juniperus formosana was constructive species of coniferous chaparral.The chaparral was mainly dominated by hard-leaf plants,which had characters of drought and cold resistance.There were large differences among chaparral of Danxia landform in the number of families,genera and species composition.2.In species diversity,the index varied from association to association.Overall,the index of Q.phillyraeoides formation and Q.oxyphylla formation in Danxia landform were similar and they were different from J.formosana formation and B.sinica formation in Danxia landform.The diversity index was higher in chaparral of Danxia landform than chaparral of non-Danxia landform while the Pielou evenness index was higher in non-Danxia landform than Danxia landform.3.At the family level,the tropical and temperate elements took dominant position,which revealed transitional characteristics from tropical to temperate.At the generic level,temperate components were richer,which had the proportion of over 40%.But the tropical and subtropical elements were still dominant.The proportion of tropical components was lower in Q.phillyraeoides formation than Q.oxyphylla formation.The proportion of temperate components was lower in Q.oxyphylla formation than Q.phillyraeoides formation.The proportion of tropical components was negatively correlated with the altitude.4.Top 4 of ecological niche breadth on the gradients of elevation and slope was J.formosana,Photinia serrulat,Q.oxyphylla,Q.phillyraeoides.These 4 species had higher niche similarity.There was no correlation between niche breadth and niche overlap.The niche overlap of chaparral in Danxia landform was low-level overlap,which revealed that competition among species in guilds was not fierce.The overlap level between Q.phillyraeoides and Q.oxyphylla was low.They tended to form single species dominancy forest and there was a small possibility that they formed mixed forest.5.In interspecific association of dominant species,tree layer was not significantly positive correlation,with 48.9%positive association species pair,33.3%negative association species pair,13.3%species pair independent from each other.The undergrowth layer was not significantly negative correlation.There was 42.1%positive correlation species pair,45%negative connection species pair and 12.9%species pair independent from each other.