降水对鄂尔多斯高原克隆植物分布的影响

鄂尔多斯高原地处半干旱区到干旱区的过渡带。通过沿鄂尔多斯高原从东到西的天然降水梯度的样带调查,分析了克隆植物的分布特征与降水的关系。结果表明:克隆植物的物种数量、占物种总数的比例和重要值以及根状茎型克隆植物的物种数量均与降水量呈显著正相关。5种优势植物克氏针茅、本氏针茅、黑沙蒿、赖草和短花针茅均为克隆植物,它们的分布也受降水影响。克氏针茅的密度、本氏针茅的盖度和密度、黑沙蒿的高度、盖度和密度以及赖草的高度均与降水量呈显著正相关。然而,赖草的盖度以及短花针茅的高度、盖度和密度均与降水量成负相关。因此,克隆植物在鄂尔多斯高原植被中具有重要作用,而且其作用随着降水量的增加而加强。

Effects of precipitation on clonal plant distribution on Ordos Plateau

Ordos Plateau is located in an ecotone in a semi-arid to arid region. The distribution of clonal plants on Ordos Plateau was analyzed in relation to precipitation based on a dataset from plot and line transect sampling along a natural precipitation gradient from East to West. The results showed that clonal species number, ratio of clonal to total species number, importance value of clonal species, and the species number of rhizomatous clonal plants were significantly positively related to precipitation (P<0.05). Five dominant plants were all clonal, including Stipa krylovii, S. bungeana, Artemisia ordosica, Leymus secalinus, and S. breviflora. Their distribution was also affected by precipitation. The density of S. krylovii; coverage and density of S. bungeana; height, coverage, and density of A. ordosica; and height of L. secalinus were all significantly positively related to precipitation (P<0.05). However, the coverage of L. secalinus and height, coverage, and density of S. breviflora were negatively related to precipitation (P<0.05). Therefore, in the vegetation on Ordos Plateau, clonal plants had a relatively high importance value, which increased with increasing precipitation.