Study On Community Structure And Dominant Species Functional Traits Of Evergreen Broad-leaved Forest In Shaiwandashan

The forest is the main body of the terrestrial ecosystem,and the plant community is the producer of the forest ecosystem,which plays an important role in maintaining the stability and development of the system.Plant functional traits are the carrier connecting community,environment and material cycle process.The species composition and community structure of woody plants with DBH≥1 cm in a 1 hm~2 evergreen broad-leaved forest sample plot in Shiwandanshan were analyzed,and the functional traits and relative growth rates of 12 dominant species were analyzed.Conclusions are as follows:(1)The species richness of evergreen broad-leaved forest in Shiwanddashan is high,and there are 132 species of woody plants with DBH≥1 cm,belonging to 87 genera and 46 families.The overall diameter class and tree height structure of the community showed an inverted"J"type,and the vertical structure of the community was obvious,and the regeneration status was good.The dominant species were mainly middle and small size trees,which could maintain the dominant position in the community.Most of the dominant species in the community showed aggregation distribution with obvious habitat preference,and the extent of aggregation distribution was affected by scale and population abundance.Most of the dominant relationships were positive and could coexist stably in the community,while the repellent competition relationship appeared in understory shrubs.(2)The dominant species in the community have high plasticity in leaf functional traits and relatively stable branch traits.The inter and intra specific variation coefficients of fresh leaf weight,dry leaf weight,leaf area,and specific leaf area are large,indicating a greater competition among species for obtaining light resources.The plasticity of functional traits of trees is greater than that of shrubs and small trees,and the reason for this result is related to the vertical spatial distribution position of individual trees in the community.(3)The trade-offs between functional traits of different plant groups are manifested as thin leaves,large specific leaf area,high leaf moisture content,high branch moisture content,and low dry matter content of understory plants,adopting a"low input resource acquisition"strategy;However,canopy plants with better lighting conditions have thicker leaves,smaller specific leaf area,lower leaf moisture content,lower branch moisture content,higher leaf dry matter content,and leaf tissue density,adopting a"high input resource conservation"strategy.(4)There is a significant correlation between plant functional traits of dominant species.The tradeoff relationship between branch traits and leaf traits was that the branch with high water content had larger specific leaf area,higher leaf water content,lower leaf tissue density,lower leaf dry matter content,and lower leaf dry weight.With high branch density,the leaf thickness was thick,the leaf water content was low,the leaf tissue density was high,the leaf dry matter content was high,and the specific leaf area was small.(5)The relationship between ecological strategies and growth strategies of dominant species was as follows:"low input-resource acquisition"strategy had a faster growth rate,while"high input-resource conservation"strategy had a slower growth rate.Between ecological strategies and spatial distribution patterns,the functional traits of populations with similar distribution locations tended to be the same resource acquisition type.On the other hand,too similar ecological niche leads to competition for access to limited resources,which leads to different resource access types for functional traits.In summary,the evergreen broad-leaved forest in the 100000 Dashan Mountains is rich in species.The sample plot community is mainly composed of small diameter standing trees,lacking large diameter standing trees.The community density is high,and the dominant position of dominant species is not obvious.The community has strong secondary vitality,and the dominant species coexist stably in the community.The ecological strategies of dominant species are closely related to their spatial distribution patterns and growth strategies,and populations with similar ecological strategies have similar spatial distribution patterns and growth strategies;But when the ecological niche of species is too similar,the ecological strategies of species tend to be different;Plant functional traits can provide a reasonable explanation for the growth,survival,and competition of species to a certain extent.