Structural,compositional and trait differences between the mature and the swamp meadow communities

Aims The mature meadows(MMs)and the swamp meadows(SMs)are the two most important ecosystems in the eastern Tibetan Plateau,China.Besides their substantial differences in terms of soil water conditions and thereby the soil oxygen and nutrients,however,little is known about the differences in community composition,struc-ture,traits and productivity between these two meadows.We par-ticularly ask whether light availability mediated by physical structure heterogeneity is a key determinant of the difference in community composition and productivity between these two meadows.Methods We examined the community structure,composition,aboveground net primary productivity(ANPP),light availability in understory and the community-weighted means(CWMs)for leaf morphological and physiological traits in 12 random plots(5 m×5 m)for each of the studied habitats.Important findings The results showed that plant community in the MM had higher variation in both vertical and horizontal structure and thus had more light availability in the understory.The MM had higher spe-cies richness and greater ANPP than the SM.The CWMs of leaf morphological and physiological traits for species in the MM fea-tured a fast-growing strategy(i.e.higher height,leaf area and net photosynthesis rate and lower nitrogen:phosphorus ratio),in con-trast to those in the SM.We also found that there were significant correlations between the CWM of traits and the ANPP,indicating that some key traits in these habitats have linked to community productivity.Our study also suggests that the heterogeneity in the community structure,which affects light availability in the under-story,may play an important role in determining the community composition and productivity.In conclusion,our study revealed significant differences in community structure,composition and traits between the MM and the SM,and the light availability that related closely to community structure is the key factor to deter-mine the composition and productivity of the community of these two habitats.