Abstract: Carex peat mire is widespread in high latitude regions of northern hemisphere. Hummock microtopography is a pervasive feature ofCarex peat mire and the difference of microenvironment inside and outside tussocks created byCarex may lead to spatial heterogeneity in litter decomposition. A litter decomposition experiment through litterbag method was conducted to study the spatial heterogeneity of litter decomposition inside and outside tussocks in aCarex schmidtii peat mire in Changbai Mountain, Northeast China. Results showed that patterns of litter dry weight loss inside and outside tussocks were consistent throughout the study. The total litter dry weight loss and decomposition rate inside tussocks were lower than that outside tussocks (21.70%±2.25% vs. 40.20%±4.22%; 0.0012±0.0001 d^-1 vs. 0.0021±0.0001 d^-1). Litter dry weight loss from the litterbags with large mesh inside and outside tussocks was 1.81%±0.32% and 2.91%±0.30% higher than that from the small mesh litterbags, respectively. The contribution of soil microorganisms to the litter decomposition rates inside and outside tussocks were 6.37 times and5.65 times that of soil fauna, respectively. However, the contributions of soil fauna and soil microorganisms to the litter decomposition rates outside the tussocks were 1.79 times and 1.59 times that inside the tussocks, respectively. Correlation analysis demonstrated that the dry weight loss of litter was significantly positively related with the accumulated temperature (P<0.05). The litter dry weight loss was negatively related with the water level inside tussocks (P<0.05), but positively related with the water level outside tussocks (P<0.05). The results suggested that soil temperature and soil water content were different between positions inside and outside tussocks, which affected the distribution and structure of fauna and microorganisms, and further affected litter decomposition rate. The water regime outside tussocks was a key environmental factor affecting litter decomposition inCarex peat mire.

Key words: Xiongan New Area, urbanization., remote sensing ecological index, ecological quality