A Comparrative Study Of The Evergreen Broad-Leaved Forest Community Structure In Wuyanling Community And Gutianshan Community

This paper comparatively studied the community structures of the evergreen broad-leaved forests in Wuyanling National Nature Reserve and Gutianshan National Nature Reserve, including the community appearance and vertical structure, community composition, floristic composition, species diversity and evenness, size structures and community similarity, The main conclusions are as follows:1、Both Wuyanling community and Gutianshan community have Castanopsis eyrei、Schima superba and Machilus thunbergii as their co-edificato species, which resulted in their similar appearances.. There is no significant difference between the two communities. The canopies both appear as dark green, interspersed with light green crowns the tree crowns mostly are irregular, and the seasonal change of appearences are not obvious;2、Both community show distinct vertical layers,,and the vertical structures can both be divided as Canopy layer(=15m), Subcanopy layer(=5m) and Undergrowth(<5m) according to the height and growth form of the species;3、Both of the Wuyanling community and Gutianshan community are very rich in species composition. There are179kinds of woody plants in wuyanling community, belonging to47families and89genera, including3families、3genera and3species of gymnosperms, and43families86genera and176kinds of Angiosperms; there are143kinds of woody plants in gutianshan community, belonging to44families and95genera, including3 families and3genera and3species of gymnosperms and140kinds of Angiosperms, which belonging to41families and92genera.4、The floristic elements Analysis of the two communities showed that, there are a total of12and11categories on the floristic elements of woody plants in Gutianshan and Wuyanling, respectively. The tropical types of wuyanling community and gutianshan community are45genera and50genera, respectively. temperate distribution types are51genera and41genera respectively, and each community has three kinds of Chininese endemic genera. Both communities have obvious north-south transition in the floristic composition, wuyanling community contains more temperate elements, and Gutianshan community contains rich tropical elements.5、Wuyanling and gutianshan have50392and16812individuals respectively, the abundance of Wuyanling community is about three times as Gutianshan. The density of Wuyanling is much bigger than in Gutianhan, When the sampling area is40000m2, there are33500individuals in wuyanling community, An average of8,375individuals per hectare, while there are only13000individuals in gutianshan community,3250individuals per hectare, there are2.6times of difference between two communities.6、The dominant species in the two communities are obvious and the compositions are similar, such as Castanopsis eyrei、Schima superba and Machilus thunbergii, and these species play the major role in building the structures and forming the environments of the two communities.7、After analysing the number of individuals of different species in both communities, the result showed that, the abudance distributions are very unevenly distributed in both communities, Pielou index equals0.018in Wuyanling and0.026in Gutianshaan. Both communities have a large proportion of rare species (species with less than one individual per hectare),Wuyanliing has forty eight rare species while gutianshan has thirty two.8、The species-area curves showed that Gutianshan has a smaller Minimum sampling area than wuyanling community. the number of species of the two communities rise rapidly with the initial stage of sampling area increases. After the sampling area reaches36600m2in Wuyanling, the number of species tends to stabilize with sampling area increases, the number of species increases by only nine when sampling area is60000m2. While in Gutianshan inclusion of95%of the species in the community requires only25600m2of sampling area then tends to stabilize, and increased by only seven species when sampling area reaches50000m2.9、Size structures of the two communities show a gradually decreasing from class one to class five, most of the individuals belong to the smallest diameter class, and the number of individuals gradually reduce with the increase of the diameter class. The size class structures of the dominant tree species in Wuyanling are leaf skewed normal distribution, the abundance of medium-sized (7.5=DBH<22.5cm) individuals are bigger than saplings or old trees, indicating poor regeneration.while in Gutianshan, the saplings and medium-sized individuals are very abundant, indicating good regeneration. The dominant shrub size structure in both communities are shaped like a "L", the populations tend to growth.10、Wuyanling community and gutianshan community are very similar in species composition, the Jaccard similarity coefficient is0.40and the SΦrenson similarity coefficient is0.58, and they are more similar in family composition and genera composition, the family similarity coefficient is0.60(Jaccard similarity coefficient) and0.75(Sφrenson similarity coefficient), the genera similarity coefficient is0.55(Jaccard similarity coefficient) and0.71(Sφrenson similarity coefficient). Indicating that the genetic relationship of Wuyanling community and Gutianshan community is very closely related in species composition.