山西吕梁山亚高山草甸物种多样性的时空变化格局

在山西吕梁山系按照纬度从北向南依次选取马伦草原、荷叶坪、云顶山作为研究区,于2015、2016、2017年7月下旬进行亚高山草甸植被群落多样性调查,研究吕梁山亚高山草甸物种多样性不同年份、不同纬度的时空变化格局。结果表明:(1)吕梁山亚高山草甸群落中矮嵩草(Kobresia humilis)和珠芽蓼(Polygonum viviparum)、线叶嵩草(Kobresia capillifolia)和珠芽蓼、车前草(Plantago asiatica)和披碱草(Elymus dahuricus)分别为马伦草原、荷叶坪、云顶山的优势种,不同山地植物优势种和次优势种均以菊科(Asteraceae)、蔷薇科(Rosaceae)、莎草科(Cyperaceae)、禾本科(Gramineae)植物为主。(2)吕梁山亚高山草甸物种多样性在不同年份分布较为稳定,Pielou指数在连续3年内均无较大变化; Shannon-Wiener指数、Simpson指数和Patrick指数在2016年最高,同时该年份的降水天数也是最多,表明吕梁山亚高山草甸物种多样性在时间上呈现出受降水条件影响较大的变化格局。(3)吕梁山偏南部的云顶山多样性指数高于偏北部的马伦草原和荷叶坪,表明吕梁山亚高山草甸物种多样性在空间上表现出由北向南逐渐升高的变化格局。因此,吕梁山亚高山草甸物种多样性在时空上呈现出受降水条件影响较大,且由北向南逐渐升高的变化格局,降水条件和纬度梯度对该山地亚高山草甸物种多样性的时空变化格局产生了重要影响。

Spatial and temporal patterns of species diversity of subalpine meadows in the Lvliang Mountains, Shanxi Province

Based on latitude from north to south in the Lvliang Mountains, Shanxi Province, Malun Grassland, Heyeping, and Yunding Mountain were selected as study areas in this research. In 2015, 2016, and 2017, the species diversity of subalpine meadows was surveyed to determine the spatial and temporal patterns of different years and latitudes of subalpine meadow species in the Lvliang Mountains. The results showed that:(1) Kobresia humilis and Polygonum viviparum, Kobresia capillifolia and Polygonum viviparum, Plantago asiatica and Elymus dahuricus were the dominant species of Malun Grassland, Heyeping, and Yunding Mountain. The dominant and subdominant species in different regions were mainly from Compositae, Rosaceae, Cyperaceae, Gramineae, and the life forms were mainly perennial herbs; (2) the species diversity distribution was stable in different years. There was no visible difference in the Pielou index in three years. The Shannon-Wiener, Simpson, and Patrick indexes were the highest in 2016, which indicated that the species diversity of subalpine meadows in the Lvliang Mountains were affected by temporal variations in precipitation; (3) in the Lvliang Mountains, the species diversity of Yunding Mountain in the southern section was higher than that in Malun Grassland and Heyeping in the northern section. This indicated that the variation of species diversity of subalpine meadows in the Lvliang Mountains gradually increased from north to south. Therefore, the spatial and temporal patterns of species diversity of subalpine meadows in the Lvliang Mountains were obviously affected by precipitation and gradually increased from north to south.