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凋落叶在高山森林河流中的分解不仅是生态系统物质循环的重要内容,而且与森林养分流失以及下游水体环境密切相关,并可能受到冬季雪被变化和土壤季节性冻融的影响,但一直缺乏必要的关注。因此,以岷江上游高山森林4种代表性植物康定柳(Salix paraplesia)、高山杜鹃(Rhododendron lapponicum)、方枝柏(Sabina saltuaria)和四川红杉(Larix mastersiana)凋落叶为研究对象,采用凋落叶分解袋法,研究了一个冬季不同冻融时期(冻结初期、冻结期和融化期)的质量损失特征。经过一个冬季(162d)的分解,康定柳、高山杜鹃、方枝柏和四川红杉凋落叶分别完成了初始干重45.5%、18.9%、26.4%和23.8%的分解;除康定柳凋落叶质量损失在融化期最大外,其余3种凋落叶均表现为冻结初期最大;康定柳、方枝柏和四川红杉凋落叶质量损失与河流水环境的平均温度和正积温均表现出显著或极显著的正相关关系,且与河流流速和硝态氮显著正相关,而与河流pH显著负相关;高山杜鹃凋落叶质量损失除与HCO3-含量显著相关外,与河流水温及其它水质特征均无显著相关关系。这些结果表明高山森林河流流速及水环境特征显著影响了凋落叶分解及其相关的物质循环过程,但影响程度受到凋落叶特性的调控。
The decomposition of litter in the mountain forest is not only an important part of the ecosystem material circulation, but also is closely related to the loss of nutrients and the environment of the downstream water and may be affected by the change of snow in winter and the seasonal freezing and thawing of soil, but it has been lacking Necessary attention. Therefore, the litter of four representative plants, Salix paraplesia, Rhododendron lapponicum, Sabina saltuaria and Larix mastersiana in the upper reaches of the Minjiang River, Decomposition bag method, a winter freeze-thaw period (initial freeze, freeze and thaw) of the characteristics of mass loss. After one winter (162d) decomposition, the initial dry weight of 45.5%, 18.9%, 26.4% and 23.8% of the decomposition of Kangdingliu, Rhododendron rhodiolae, The losses were the largest in the thawing period, and the other three litters showed the largest in the initial freeze-thaw period. The mass loss of litter of Kangdingliu, Fangzhipibai and Sequoia sinensis showed significant or extremely significant positive correlation with the average temperature and positive temperature of the river water environment But negatively correlated with the pH of the river. The mass loss of Rhododendron fortunei leaves had no significant correlation with the water temperature and other water quality characteristics, except for the significant correlation with the content of HCO3- relationship. These results indicate that the flow rate and water environment characteristics of mountain forest rivers significantly affect litter decomposition and its related material cycle, but the degree of influence is controlled by the characteristics of litter.