Ecological Study On The Evergreen Broadleaved Forest In Meihuashan National Nature Reserve Of Fujian

Evergreen broad-leaved forest(EBLF) is an important kind of forest vegetation on the surface of earth,developing under subtropical humid climatic conditions.In China's subtropics,as a result of relative subtropical monsoon,atmospheric circulation, sea-land geographical position and existence of Qin-Tibet plateau,it comes into being subtropical humid climate and most largest area evergreen broad-leaved forest of the world,that is principal part of EBLF and significant species gene pool.Evergreen broad-leaved forest plays an important role in the global biological diversity,ecological balance,harmonious and continuable development between human society and nature. Meihuashan National nature reserve of Fujian is located in the evergreen broad-leaved forest area,and is the key terrene biodiversity region with international significance in China.Based on transect and sample plot field investigations,this paper is mainly targeted at studies on present status and distribution,species composition,floristic characteristics,community types,community dominance and similarity,community physiognomy and structure,species diversity characteristic and variational disciplinarian through altitude of EBLF in Meihuashan National Nature Reserve of Fujian with modern ecological analysis methods.The results were as follows:(1) The EBLF in Meihuashan National Nature Reserve of Fujian is located in two sides of valley or slope of middle hill at 350m～1300m altitude in sheet distribution. There are different community formation and association under different altitude,terrain and condition of soil.For example,Castanopsis carlesii community distributed below 1000m altitude;Castanopsis fissa community,Castanopsis lamontii community, Castanopsis fabri community and Castanopsis fordii community distributed between 600m～1000m;and Michelia maudiae community,Altingia gracilipes community distributed above 1000m,and so on.(2) According to the classific system of China Vegetation,the community of EBLF in Meihuashan National Nature Reserve of Fujian may be divided into 23 types, which are pertained to typical EBLF(subdivision) evergreen broad-leaved forest of China,those are belong to Castanopsis Formation Group,Cyclobalanopsis glauca Formation Group,Machilus Formation Group,Schima Formation Group,Altingia Formation Group,Michelia alba Formation Group.Such as:Cyclobalanopsis glauca community,Castanopsis carlesii community,Castanopsis eyrei community,Altingia gracilipes community,Schima superb community,Machilus thunbergii community,and the like.(3) There is 228 seed plant species,which are belong to 156 genera,87 families in EBLF.Through analyzing geographical distribution types of families,genera,and species,the type of tropic distributing families(including Pantropic,Tropic & Subtropic East Asia & South Tropic America disjuncted,Old World Tropics,Tropic Asia to Tropic Australasia Oceania,Tropic Asia),which quantity account for 55.17%,the quantity of North Temperate distributing families account for 16.09%,the quantity of East Asia & North America disjointed distributing families only account for 3.45%;the type of the Pantropic topped the genera,followed by Tropic Asia.,and then East Asia & North America disjointed,North Temperate,Old World Tropics,East Asia,Tropic Asia to Tropic Australasia,Tropic Asia &(South)Tropic America disjuncted,Tropic Asia to Troppic Africa,Endemic to China and Old World Temperate,the characteristic of geography may be summarized as multiple types age-old origin,transitional belt markedness and little man-made influence;the dominant species of arbor layer belongs to Fagaceace,Lauraceace,Magnoliaceae and Hamaelidaceace etc.,and the dominant species of shurb layer belongs to Camelliaceae,Aquifolliaceae,Myrsinaceae,Rosaceae, Rubiaceae,et al.;the elements endemic to subtropical China occupied a high percentage of tree species,such as Castanopsis eyre,Castanopsis tibetana,Schima superb, Lithocarpus hancei,Phoebe sheareri,Neolitsea aurata var.chekiangensis, Rhododendron latoucheae,et al.It showes that the EBLF of Meihuashan National nature reserve is a endemic type of EBLF at east part of subtropic area in China.(4) Physiognomy is one of obvious features of a community,and mainly,reflects on life-form and leaf features of the community.Through analyzing the life-form spectrum and leaf-class spectrum,it can be descried that phanerophytes were absolutely dominant in the life-form spectrum and their quantity accounted for 81.2%in Meihuashan National nature reserve EBLF,and among phanelophytes,quantity of microphamerophytes was the most,followed by macrophanertophytyes, nanophanerpphytes,and mesophanerophtyes.The quantity of hemicryptophytes and geophytes accounted for 7.8%and 7.1%,There are few chamaephytes,and therophytes. Leaf features are a significant indicator of physiognomy,reflecting not only the ecological environment of the community but also the history of the community.It is evident that the EBLF in Meihuashan National nature reserve of Fujian,in terms of Rauakiarer's leaf-size hierarchy,microphyils(47.7%) are more than mesophylls(43.5%), and nanophylls(5.9%) and macrophylls(2.9%) are very small in quantity.In EBLF of Meihuashan National Nature Reserve of Fujian,leaves of thin-leathery and herbaceous texture are of dominance,which quantity accounted for 45.6%and 43.5%,followed by leathery leaves,and leaves of other textures are few,and little difference between smooth margin leaves and nonsmooth margin leaves.So the microphylls,mesophylls, leathery,evergreen,and smooth margin leaves;phanerophytes is main factors which determine physiognomy of EBLF in Meihuashan National Nature Reserve.(5) EBLF of Meihuashan National Nature Reserve of Fujian manifests clear stratification and there are mainly four layers,viz.a arbor layer,a shrub layer,a herbaceous layer as well as plants growing between layers.The height of the arbor layer is from 10 to 25m,and its coverage is roughly 90%.The arbor layer is chiefly made up of evergreen broad-leaved macrophanerophytes,in which dominant tree species were Castanopsis eyrei,Cyclobalanopsis glauea,Castanopsis fabri,Lithocarpus glabra, Castanopsis carlesii,Castanopsis fargesii,Schima superb Altingia gracilipes,et al.The height of the shrub layer is lower than 2m,and its coverage is roughly 30%.The shrub layer is chiefly made up of the species of Rhedodendron,Eurya,Vacciniu,Camellia, Ilex,Myrsina,et al.The height of the herbaceous layer is less than lm,and its coverage is roughly from 10%to 30%.The herbaceous layer is chiefly made up of the species of Carex,Oplismenus,Alpinia,Woodwardia,Hicriopteris,Dieranoperis,Dryopteris et al. Plants growing between layers are lianas,not so abundant as those in tropical rainforest,.Such as Smilax,Toddalia,Embelia,Fissistigma,Cayratia,Ficus,Actinidia, Militia et al.In addition,there is some aerophyte,such as lichen,moss,and orchid.(6) To measure species diversity of EBLF community in Meihuashan National nature reserve with species richness,Pielou index,Simpson index,and Shannon-Wiener index,the results indicates that community abundance degree was 61 species on the average,the average quantity of Species richness index,simpson index, Shannon-Wiener index and Pielou index,account for 11.3836,4.5291±0.4371, 3.4864±0.2551,and 0.5315±0.0687;the changes trend of all kinds of diversity index in altitude are the same,which belongs to "mid-altitude bulge";the highest value of species richness and Shannon-Wiener index appear at 700～900m altitude,and lowest value appear at 1100～1300m altitude;the community diversity of different layer is the shrub layer(including tree seedlings,saplings,and plants between layers)＞tree layer＞herb layer in species richness and Shannon-Wiener index.(7) Measuringβdiversity of EBLF community in Meihuashan National Nature Reserve of Fujian with total number of species,average number of species,species number in common,Sφrenson index,Jaccard index,Cody index,and species richness of arbor layer,the results show that plantβdiversity monotony decrease,but there is some difference among different index,the changes of total number of species,average number of species,species number in common,and species richness of tree layer, increase at first and then decrease slowly in altitude;Sφrenson index,Jaccard index,and Cody index,increasing slowly at first and then decreasing in haste.(8)Through analysing of similarity index and dominance of community of EBLF community in Meihuashan National nature reserve,the results indicate:the similarity value of species in arbor layer which control physiognomy and structure of community is lower;the value of dominance of community which composed by single constructive species is higher than that of combined community;the dominant species in arbor layer and liane are more distinctness,the stability of those layer in community is higher also;the characteristic of community dominance between plots of EBLF in Meihuashan Nature Reserve showes the mode of "middle bulge".