Community Structure And Function Of Typical Forest Vegetations In Pearl River Delta

The research on community structure and relevant function of representative Everygreen Broadleaved forest in the Pearl River Dealta were important scientific significance,which provide a reference for the development of urban forest ecological theory and the construction of beautiful town.Based on the Evergreen broad-leaf community characteristics of Guangzhou,Shunde district in Foshan city,Zhongshan in the Pearl River Delta,0.60,0.24,1.2,0.60,0.36,0.36,0.12,0.48,0.12,0.36,0.12 hm~2 evergreen broad-leaf forests of Dafu Mountain,Tianhe Park,Ersha island,Baiyun Mountain,Maofeng Mountain,Nansha and The airport highway in Guangzhou city,Jiaoshiling Park in Zengcheng,Wugui mountain and Zimaling Park in Zhongshan city,Longfeng mountain in Shunde district,Foshan city were investigated respectively by the ecosystem community ecological methods.The community ecological parameters and stoichiometry of soil and leaves were measured by vegetation quantitative ecological methods and chemometrics methods.Forest plots were classified as different vegetations by between-group average clustering analysis.Species composition,size class,species diversity,the niche breadth of main arbor populations,main species niche similarity and association,ecological environmental functions of different vegetation types were systematically analyzed.The difference reflecting similar associated characteristics and environmental burthen effects among different vegetation types would provide a good theoretical basis for the construction and evaluation of the near-natural forests and beautiful city forests landscape as a typical example.The main results were as follows:(1)The 38 forest plots(30m×40m)were classified as 22 formations,i.e.: Acacia mangium formation,Liquidambar formosana formation,Machilus breviflora+Castanopsis fissa formation,Schima spp+Machilus pingii formation,Celtis sinensis+Machilus pingii formation,Michelia alba +Eucalyptus citriodora formation,Michelia chapensis+Amygdalus communis formation and so on.They were classified as Evergreen Broadleaved Secondary Forest(EBSF),Evergreen Broadleaved Artificial and Natural Forest(EBANF)and Evergreen Broadleaved Plantation(EBP)according to the stand origin differences.(2)The woody plants of three vegetation types were composed of 168 species,belonging to 62 families and 118 genus.The top 5 families were sequentially Leguminosae,Lauraceae,Theaceae,Moraceae,Myrtaceae.And the top 3 genera were sequentially Ficus,Litsea,and Ilex.The IV≥2.0% dominant species were Albizia falcataria,Machilus breviflora,Kahaya seegalesis and so on,14 species.The woody plants of EBSF,EBANF,and EBP were respectively composed of 77,66,and 94 species,belonging to 35 families and 49 genera,33 families and 25 genera,42 families and 75 genera respectively.The IV≥2.0% dominant species of EBSF were Machilus breviflora,Castanopsis fissa,Cinnamomum porrectum,and so on,10 species.The IV≥2.0% dominant species of EBANF were Schima spp,Machilus pingii and so on,15 species.The IV≥2.0% dominant species of EBP were Albizia falcataria,Kahaya seegalesis and so on,14 species.The generic coefficients sequentially showed an increasing trend from EBSF to EBANF to EBP,which reflecting a inverse trend on the species variability.The control action of dominant species to the vegetation types showed that: EBSF>EBP>EBANF.(3)The average DBH of three vegetation types showed an increasing trend sequentially from EBSF to EBANF to EBP.The diameter-class structure of EBSF and EBANF were recognized as Standard,bimodal inverse “J” type respectively.Howere,the EBP were irregular.Highly significant and positive correlations between H and DBH were found in three vegetation types respectively.An extremely significant and positive linear correlation between DBH and H was characterized by H = 0.6227 DBH + 2.003(R2 = 0.8199,p<0.01)in EBSF.And extremely significant and positive power correlation between DBH and H was characterized by H= 1.4858(DBH)0.7608(R2 = 0.8687,p<0.01)and H = 1.8081(DBH)0.6134(R2 = 0.6546,p<0.01)respectively.The average growth rate decreased sequentially form EBSF to EBANF to EBP.(4)The Shannon-Wiener index,Gleason index and Pielou index were characterized by EBSF>EBANF>EBP.The same character was showed on the SW index and Gleason index of tree layer,while the Pielou index was characterized by EBANF>EBSF>EBP.The SW index and Gleason of shrub layer were: EBSF>EBP>EBANF,while,the Pielou index showed: EBP>EBSF>EBANF.Three indexes of shrub layer had a higher value than tree layer in EBSF and EBP,and it was converse in EBANF.(5)20 dominate populations of woody plants showed an insignificant positive association in EBSF and EBANF.The interspecific associations of 190 species-pairs were similar conclusion of insignificant positive association analyzed by χ2 correction test,percentage co-occurring(PC)and association coefficient(AC),and the EBSF was more significant.(6)The average niche breadth value of main tree populations were characterized by Machilus breviflora+Castanopsis fissa community>Michelia alba +Eucalyptus citriodora community>chima spp+Machilus pingii community among three communities.The same characteristic was showed on the niche similarity of main tree species-pairs.It was EBSF>EBANF in the two vegetation types.(7)The forest soil Org.C,TN,TScontents and N:P value were progressive increase from EBP to EBAFN to EBSF in the city scale.However,the soil TP contents and C:N value were progressive decrease.The forest leaf Org.C,TN contents and N:P value were progressive increase with the order from EBP to EBANF to EBSF.However,the leaf TS TP contents and N:P value were non-significant between three vegetation types.