Growth and decomposition characteristics of Sphagnum in a subalpine wetland, southwestern Hubei, China

AimsWe investigated the growth and decomposition of Sphagnum, a principal plant involved in peat accumulation in wetlands, in subtropical wetlands. MethodsWe selected a Sphagnum-dominated wetland in southwestern Hubei Province as the study area.In situ growth and litter decomposition experiments in different microhabitats were carried out, and the chemical composition of litter was measured in laboratory to examine the processes of its growth and decomposition. Important findingsThe average height of Sphagnum in hummock and hollow were 2.9 and 2.7 cm, and the net production was 270.94 and 370.88 g•m -2 , respectively, after 12 months.Growth time and microhabitats significantly affected on the height growth and the net production, and there was an interaction between time and microhabitats.However, the growth trend in two microhabitats was significantly different.The average growth rate of Sphagnum under the two microhabitats (July to October 2017) was 0.33 mm•d -1 , which was higher than that in the cold temperate zone.In addition, the decomposition time had an significant effect on the decomposition amount of Sphagnum, and the residual rate decreased first and then increased with time.By the end 12-month period, the final residual rates in hollow, hummock and pool were 100.67%,90.54% and 85.63%, respectively.The content of carbon (C), carbon nitrogen (N) ratio (C:N) and polyphenols in the litters decreased, while the nitrogen content increased.During the first 3 months of decomposition, a significant difference of decomposed litter was found between the microhabitats, but no significant difference later on.