Effects of litter accumulation on plant communities in fenced desert steppe

摘要

The litter decomposition plays an important role in nutrient circle of grassland ecosystem, the water holding ability of litter and physical and chemical characteristics have been studied exclusively over the past century However, the effect of litter accumulation on plant community in desert steppe under fenced condition was little known. In this study, four typical plant communities were employed to identify the effects of litter accumulation on plant communities. The results showed the trend of litter accumulation amount in the four different types of plant communities was best represented by Birk model. The accumulation of litter had different effects on the number of seedlings. When litter accumulation reached 300-400 g cm(-2), green-up dates advance 7 days. The amount of seedling germination and the number of plant species reached a peak. Meanwhile, plant density coverage, average height, richness, and evenness reached maximum values. It was concluded that when opposite fencing time was about 6 years, and the optimum amount of litter accumulation was about 300-400 g cm(-2), which could advance the green-up dates and increase the number of plant seedlings, and also improve or maintain community stability. Such a notion has to be taken into account for the development of an improved policy for environmental management in desert steppe.