Spatial Distribution Characteristics Of Nitrogen And Phosphorus Contents In Leaf-litter Of Different Tree Species In A Subtropical Evergreen Broad-leaved Forest

Litter plays an important role in the nutrient cycle of forest ecosystem.Species with different distribution patterns have different nutrient utilization strategies,and the nutrient content of litter leaves may also be different,but the related research is less.The spatial distribution characteristics and influencing factors of the nutrients in leaf-litter are closely related to the coexistence of species and the nutrient cycle of forest ecosystem.In this study area,the subtropical evergreen broad-leaved forest community has high-level diversity,and all species coexist well.It is of great significance to study the spatial distribution characteristics of nutrient content of different distribution species in this area for further understanding of forest community and nutrient dynamics.Based on the 20 ha dynamic monitoring sample plot in Tiantong,this study selected six species with large difference in distribution range and region,measured the nitrogen and phosphorus content of leaf-litter in the litter peak of each species.The spatial distribution characteristics of nitrogen,phosphorus content and stoichiometric ratio in leaf-litter were analyzed through the terrain factors and terrain types.Then the effects of soil factors and community factors on the nutrient content and stoichiometric ratio of leaf-litter were explored.The main results and conclusions are as follows:1)The results showed that the nitrogen and phosphorus contents in leaf-litter of generalist species were significantly lower than that of the specialist species,and the stoichiometric ratio of the leaf-litter of the generalist species was significantly higher than that of the specialist species.This indicate that the generalist species might adapt to different habitats through low nutrient requirements;The nutrient contents in leaf-litter of the deciduous species were significantly different between topography types,while the evergreen species did not show significant correlation with topography.This indicated that evergreen species have strong adaptability to environment.2)The variation coefficient of nutrients in leaf-litter of the generalist species was significantly higher than that of the specialist species,and the variation coefficient of phosphorus content in leaf-litter was significantly higher than that of nitrogen content.The variation coefficient of the generalist species was not significantly different between different topography types,while the specialist species showed significantly different.This indicated that the generalist species adapt to different environmental conditions by changing the nutrient utilization strategy,while the specialist species was more suitable for a specific habitat.In addition,the coefficient of variation of nitrogen content in leaf-litter of Liquidambar formosana was significantly higher than that of other species,which may be related to the specificity of pioneer species.3)Through the analysis of the influencing factors of nutrient content and stoichiometric ratio of leaf-litter,it is found that all species are affected by soil factors and community factors to some extent,but there is a large difference between species,and there is no significant law.The obvious characteristic is that the explanation degree of influencing factors of generalist species is small(R~2<0.2),while that of specialist species is large(R~2>0.5),which indicates that the strategy of leaf litter utilization of generalist species is more dependent on the genetic characteristics of species.In conclusion,this study found that the generalist species may adapt to different environmental conditions through the low nutrient content of leaf-litter and the large variation of nutrient utilization strategy in different habitats,which provides a basis for the further study of community dynamics and nutrient cycling.