Leaf And Fine Root Decomposition Of Common Fern Species In Subtropical Evergreen Broad-leaved Forest In Jinyun Mountain

Litter decomposition is the key ecological process of forest carbon and nutrients cycling.For a long time,the research on litter decomposition mainly focused on dominant tree species in forest,while less attention was paid to non-dominant species such as understory species in forest.In recent years,more and more studies have shown that understory plants exert important impact on the structure of ecological process of forest ecosystem,such as plant community recruitment and forest carbon and nutrients cycling.Although ferns are important components of the understory of subtropical forests and account for a large amount of biomass in the understory,little attention has been paid to their litter decomposition process.In order to further understanding the decomposition process and influencing factors of fern litter in subtropical forest,twelve fern species commonly found in Jinyun shan National Nature Reserve were selected in this study.Decomposition experiments were carried out by using the litterbag method to measure the decomposition rates of leaves and fine root,and the release dynamics of carbon,nitrogen and phosphorus of the litter after 113,198,386 and 586 days of decomposition were monitored.At the same time,eleven pairs of functional traits were measured in the leaves and fine root of these ferns,and whether the covariation patterns of there fern traits was similar to the plant economic spectrum that reported in seed plants is analyzed.We also analyzed whether the economic spectrum affected the decomposition rate of fern litter.The results are as follows.There is a significant covariantion between many functional traits of leaves and fine roots,and the plant economic spectrum similar to seed plants is found at the level of organs(leaves and fine roots)and the whole-plant.There are significant correlations between the fern economic spectrum and the decomposition rate of fern leaves and fine roots.The litter decomposition rate of the acquisitive resource strategy of fern species is faster,while that of the conservative resource strategy of fern species is slower.From the perspective of carbon and nutrient release patterns,the release rate of elements in leaves of most fern species is significantly higher than that of fine roots.The release of carbon,nitrogen and phosphorus in leaves is mainly a simple direct release mode,while the release of carbon,nitrogen and phosphorus in fine roots are very complex,such as direct release,enrichment-release-enrichment,and constant enrichment.We found that nitrogen or phosphorus release patterns was influenced by the initial tissue nitrogen or phosphorus concentrations respectively.Carbon remians between leaves and fine roots were significanlty correlated after 113,198 and 386 days decomposition in the filed,but not after 586 days.Phosphorus remians between leaves and fine roots were significanlty correlated after 198,386 and 586 days decomposition in the field,but not after 113 days.By contrast,there was no significant relationship of the nitrogen remians between leaves and fine roots during the entire decomposition process.The results of this study provide a reference for further quantifying the importance of fern to the cycling of forest carbon and nutrients in forest ecosystems.