Niche Of Main Species In Populus Purdomii Community In Wulongdong National Forest Park

Qinling Mountain is the geography and climate separatrix in china, it suitable for various survival and reproduction because of its complex and changeable terrain. So the research of plant communities in WuLongDong National Forest Park, located in the south slope of Qinling Mountain, would be typical and representative. Using Populus purdomii community from WuLongDong National Forest Park as object, this paper analyzed all the data from sample plot and local forestry department, researched the niche of dominant species in Populus purdomii community in WuLongDong National Forest Park.Two niche breadth methods(Shannon-Wiener, Levins) were used to analyze the niche breadth of main species in arbor layer, shrub layer, herbal layer respectively, the two methods had the same result about niche breadth in arbor layer. The permutation order of niche breadth in arbor layer was: Populus purdomii > Carpinus turczaninowii > Betula utilis > Pinus armandi > Ostrya japonica > Cornus controversa > Lindera obtusiloba > Acer truncatum > Quercus aliena BI. var. acuteserrata >Betula albo-sinensis. The permutation order of niche breadth both in shrub layer and herbal layer by two methods had a slight difference, but the basic order stay the same. The reason of the unanimous result was that species with wide niche breadth had a large number and high important values in Populus purdomii community, they used space and resource fully, so they took wider niche breadth, while some dispersive species with little amount and weak ability of utilizing and adapting took narrow niche breadth.According to result of niche overlap in arbor layer, shrub layer and herbal layer, there were 81 pairs of plant species overlapped niche, accounting for 90% in total, the species with niche overlap index above 0.03 reached 64, accounting for 71.1% in total. The several species with wide niche breadth had higher niche overlap index, while species with narrow niche breadth had lower niche overlap index. Niche overlap index in shrub layer had the same result with that in herbal layer, the possible reason was that species with wide niche breadth had close ecological characteristic and similar adaption for habitat, so their niche overlapped a lot. Species with little amount and narrow niche breadth only had smaller ecological accommodation, they had little chance to overlap, so their niche overlap index was low. According to the results of niche similarity in arbor layer, shrub layer and herbal layer, there were 24 pairs of species in arbor layer whose niche similarity proportion above 0.5, accounting for 53.3% in total; 31 pairs of species in arbor layer whose niche similarity proportion above 0.3, accounting for 68.9% in total. There were 9 pairs of species in shrub layer whose niche similarity proportion between 0.5 and 0.6; 42 pairs of species in shrub layer whose niche similarity above 0.3, accounting for 63.63%. Results showed that dominant species in arbor layer in Populus purdomii community had higher niche similarity proportion. Species with wide niche breadth also had high niche similarity proportion, species with narrow niche breadth only had low niche similarity proportion.This paper studied the niche of main species in Populus purdomii community in WuLongDong National Forest Park, analyzed main species'sharing ability for resource and the relationship among different species, provided necessary base for further research on dynamics, structure and function of local forest ecosystem.