柳杉种植对黔西南喀斯特山区金发藓沼泽植物群落和储水功能的影响

Effects of artificial Cryptomeria fortunei forests on the plant community and water content of a Polytrichum commune bog in a karst region in southwestern Guizhou Province, China

藓类沼泽对喀斯特山区生物多样性维持和水源涵养有重要作用,需加强人工林种植对喀斯特山区藓类沼泽生态功能影响的研究。以黔西南典型金发藓沼泽为研究对象,分析了人工柳杉林对林下金发藓植物群落和金发藓沼泽储水功能的影响。主要研究结果为:1)柳杉种植对金发藓植物群落有负面影响。随柳杉密度增加,林下金发藓植物群落的盖度、平均高度和物种多样性显著下降;2)表层土壤含水量是金发藓沼泽储水量的主要贡献者。柳杉种植显著提高了干季表层土壤的含水量,但高密度柳杉林显著降低了雨季表层土壤的含水量;柳杉种植未对干季金发藓含水量造成影响,低密度柳杉林显著提高了雨季金发藓植物的含水量;3)柳杉密度对金发藓沼泽生态系统储水量的影响存在明显季节差异:在雨季呈负影响,在干季呈正影响;4)柳杉种植有利于维持金发藓沼泽储水能力的稳定性,尤其是当柳杉密度较低时这种效果更明显。表明人工柳杉林对金发藓沼泽的影响是非线性的,合适密度的柳杉种植可提升金发藓沼泽的储水能力。

Moss bogs dominated by bryophytes play important roles in the maintenance of biodiversity and water resource in karst regions.There is limited knowledge about the effects of artificial forests on the ecological functions of moss bog ecosystems.To understand the effects of artificial Cryptomeria fortunei forests on the plant community and water content of a Polytrichum commune bog,we chose a typical P.commune bog in a karst region in southwestern Guizhou Province to conduct field surveys.We found that,1)the artificial C.fortunei forest negatively affected P.commune communities.The cover,average height,and species richness of the P.commune community decreased significantly with increasing density of C.fortunei.2)Surface soil contributed most to the water content of the bog ecosystem.The C.fortunei forest significantly improved water content in the surface soil in the dry season.High?density C.fortunei forest significantly reduced the water content in the surface soil in the rainy season.The C.fortunei forest did not affect the water content of the P.commune in the dry season.Low?density C.fortunei forest improved the water content of the P.commune in the rainy season.3)There were seasonal variations in the effects of C.fortunei forest on the water content of P.commune bog ecosystems,i.e.,a negative relationship in the rainy season was noted,but this shifted to a positive one in the dry season.4)The C.fortunei forest was beneficial for maintaining the stability of water content of the bog ecosystems,especially when the density of C.fortunei was not too high.This suggests that the effects of artificial C.fortunei forest on P.commune bog were nonlinear.Water content of the P.commune bog can improve if the density of C.fortunei is reasonable.