泥炭沼泽不同植物群落中地表糙度变化及其影响机制

Changeness of the surface roughness distribution of different plant communities and its biological mechanism

地表糙度是衡量地表径流形成的一个重要指标.以东北区典型泥炭沼泽—金川泥炭沼泽为例,考虑地表坡度影响,用链条法对不同群落中糙度系数指标进行计算,并以泥炭沼泽中物种多样性、踏头个数以及踏头形态差异变率系数为主,初步分析泥炭泥泽地表糙度的变化机制,结果表明:在芦苇-臌囊苔草群落、臌囊苔草群落和油桦-臌囊苔草-泥炭藓群落三个植物群落中,糙度系数指标的变化与群落中物种丰富度和生物多样性变化相一致;糙度系数变化与踏头个数呈负相关关系,与踏头形态差异变率系数呈正相关关系.说明物种多样性越小,生态优势度越大,优势种植物越少,踏头个数越多,踏头形态变率系数越小,微地貌形态发育相对较一致,糙度系数越小;反之,则地表糙度系数越大.

Surface roughness was an important indicator for the formation of surface runoff. This paper takes peat mire of Northeast Jinchuan peat mire as an example, considering impacts of surface slope to measure the roughness index with the chain method in different plant communities. Based on the plant richness, the number of hummock and the coefficient of variation of the hummock forms, we analyzed the mechanism of the changes of surface roughness. The results showed： in three Phragmites australis-Carex schmidtii community, Carex schmidtii community and Betula ovilifolia-Carex schmidtii-Sphagnum palustre community, roughness coefficients changed consistently with changes of species richness and biodiversity of the communities. The changes of the roughness were negatively correlated with number of the hummocks, and positively correlated with coefficient of variation of the hummock forms. It showed that, the smaller the species richness, the larger the ecological dominance; the fewer the dominant plant, the more the number of the hummocks; and the smaller the coefficient of variation of the hummock forms, the more consistence the forming of the micro-geomorphologic relief and the smaller the roughness coefficient. Otherwise, the roughness coefficient became bigger.