彬长矿区不同地表沉陷类型下植物群落特征

Characteristics of plant community in different types of coal mining subsidence in BinChang mining area

地表沉陷是煤炭开发过程对生态环境造成严重损害的形式之一,直接或间接地影响植物分布与群落结构。本研究以陕西彬长矿区不同地表沉陷类型下植物群落为对象,调查植物群落组成、生产力和多样性等变化特征,探讨不同沉陷类型植物群落特征的变化规律及其机理。结果表明:1)彬长矿区植被以菊科、禾本科、豆科植物为主,植物生长型构型以多年生草本为主,水分生态类型以中旱生植物为主;沉陷扰动造成了一年生草本、多年生草本和中旱生植物比例增加,中生植物比例显著下降,而灌木和乔木比例变化不明显。2)不同沉陷类型下塬面裂缝区植物群落结构变化不显著,塬面台阶状沉陷区、沟谷边缘裂缝区和台阶状沉陷区植物群落物种数、盖度、生物量、物种密度、物种多样性显著下降。3)依据植物群落损害程度,将彬长矿区不同沉陷类型分为3类:轻微损害区,包括塬面裂缝区;中等强度损害区,包括塬面台阶状下沉区和沟谷边缘裂缝区;强烈损害区,包括沟谷边缘台阶状下沉区。

Subsidence is one of the most serious forms of coal mining process on environment,which directly and indirectly affects plant species distribution and community structure.In this study,we investigated the characteristics of plant community in different types of coal mining subsidence in Bin-Chang mining area to understand the responses of plant community to coal mining subsidence and underlying mechanisms.The results showed that families in Bin-Chang mining area were mainly Compositae,Gramineae,and Legumes,the main plant growth forms were perennial herb,and the water ecological type was dominated by meso-xerophytes.Disturbance of mining subsidence increased proportions of annual grass,perennial herbs and meso-xerophytes,decreased the proportion of mesophytes,but had no effect on the proportion of shrubs and trees.The disturbance of surface crevasse in the tableland area did not cause significant change in plant community structure,but the number of species,coverage,biomass,species density and biodiversity index of plant community were significantly lower in stepped subsidence area and surface crevasse area at ravine edge.According to the damage of plant communities,the subsidences in Bin-Chang mining area could be divided into three types:slightly damaged area,including surface crevasse in tableland area;medium damage area,including stepped subsidence area in tableland area and surface crevasse area at ravine edge;strong damage area,including stepped subsidence area at ravine edge.