新疆博格达山北坡岩面生壳状地衣群落特征及其与环境因子的相关性

Characteristics of saxicolous crustose lichen community on northern slope of Bogda Mountain in Xinjiang and its correlation with environmental factors

以盖度为指标,应用双向指示种分析(TWINSPAN)和除趋势对应分析(DCA)法对分布于新疆博格达山北坡的岩面生壳状地衣群落进行分类;采用Sφrensen相似性系数和Jaccard相似性系数分析各群丛的种类相似性,并应用典范对应分析(CCA)法探讨供试区域岩面生壳状地衣群落的种类分布与环境因子的关系。结果表明:从供试区域的15个样地中共鉴定出岩面生壳状地衣21种,隶属于3目7科13属,其中盖度在7%以上的种类仅4种,其他种类的盖度均在5%以下。依据TWINSPAN和DCA分析结果,可将该岩面生壳状地衣群落划分为4个群丛,即亚洲平茶渍+粉瓣茶衣+小多盘衣群丛(Assoc. Aspicilia asiatica+Lobothallia alphoplaca+Myriolecis hagenii)(群丛1)、青海茶渍+白边平茶渍群丛(Assoc. Lecanora kukunorensis+Aspicilia sublaqueata)(群丛2)、地图衣+绿黑地图衣群丛(Assoc. Rhizocarpon geographicum+Rhizocarpon viridiatrum)(群丛3)和石墙原类梅+亚凹网衣群丛(Assoc.Protoparmeliopsis muralis+Lecidea subconcava)(群丛4),分别包含15、11、9和18种岩面生壳状地衣。各群丛的种类相似性和多样性存在明显差异。群丛1和群丛4的种类相似性最高,Sφrensen相似性系数和Jaccard相似性系数分别为0. 441和0. 650;群丛1和群丛3的种类相似性最低,Sφrensen相似性系数和Jaccard相似性系数分别为0. 294和0. 227。群丛1至群丛4的Shannon-Wiener多样性指数依次为1. 483、1. 804、0. 318和2. 954。CCA分析结果显示:第1、第2和第3排序轴的贡献率分别为30. 0%、22. 4%和17. 5%,包含总信息量的69. 9%;种类分布与环境因子的相关系数分别为0. 980、0. 940和0. 873。第1排序轴与坡度、海拔、光照程度和人为干扰程度呈正相关,与岩石长度和坡向呈负相关,且与坡度的相关性最高;第2排序轴与岩石长度和光照程度呈正相关,而与海拔、坡度、坡向和人为干扰程度呈负相关,且与坡向的相关性最高;第3排序轴与海拔和光照程度呈正相关,而与坡度、坡向、岩石长度和人为干扰程度呈负相关。研究结果显示:新疆博格达山北坡岩面生壳状地衣群落的种类分布主要受坡向、坡度、岩石长度和光照程度等因子影响,而人为干扰程度和海拔则无明显的影响效应。

Taking coverage as an indicator, saxicolous crustose lichen community on northern slope of Bogda Mountain in Xinjiang were classified by using two-way indicator species analysis （TWINSPAN）and detrended correspondence analysis （DCA） methods. Species similarities of each association were analyzed by using similarity coefficients of Srensen and Jaccard, and relationship of species distribution of saxicolous crustose lichen community with environmental factors was studied by using canonical correspondence analysis （ CCA） method. The results show that 21 saxicolous crustose lichen species belonging to 13 genera in 7 families of 3 orders are identified from 15 plots in tested area in total, in which only coverage of 4 species is higher than 7%, while coverage of other species is lower than 5%.According to TWINSPAN and DCA analysis results, saxicolous crustose lichen community can be classified into 4 associations, including Assoc. Aspicilia asiatica ＋ Lobothallia alphoplaca ＋ Myriolecis hagenii （Assoc. 1）, Assoc. Lecanora kukunorensis＋Aspicilia sublaqueata （Assoc. 2）, Assoc. Rhizocarpon geographicum ＋ Rhizocarpon viridiatrum （ Assoc. 3 ）, and Assoc. Protoparmeliopsis muralis ＋ Lecideasubconcava （ Assoc. 4 ）, which contain 15, 11, 9, and 18 saxicolous crustose lichen species,respectively. There are evident differences in species similarity and diversity of each association. Species similarity between Assoc. 1 and Assoc. 4 is the highest, and similarity coefficients of Srensen andJaccard are 0. 441 and 0. 650, respectively; species similarity between Assoc. 1 and Assoc. 3 is thelowest, and similarity coefficients of S.rensen and Jaccard are 0. 294 and 0. 227, respectively. Shannon.Wiener diversity index from Assoc. 1 to Assoc. 4 is 1. 483, 1. 804, 0. 318, and 2. 954, respectively. TheCCA analysis result show that contribution rates of axis 1, axis 2, and axis 3 are 30. 0%, 22. 4%, and17. 5%, respectively, including 69. 9% of the total information; correlation coefficients of speciesdistribution with environmental factors are 0. 980, 0. 940, and 0. 873, respectively. Axis 1 shows positivecorrelations with slope, altitude, light degree, and human disturbance degree, but negative correlations with rock length and aspect, and the correlation with slope is the highest; axis 2 shows positive correlations with rock length and light degree, but negative correlations with altitude, slope, aspect, and human disturbance degree, and the correlation with aspect is the highest; axis 3 shows positive correlations with altitude and light degree, but negative correlations with slope, aspect, rock length, andhuman disturbance degree. It is suggested that species distribution of saxicolous crustose lichencommunity on northern slope of Bogda Mountain in Xinjiang are mainly affected by aspect, slope, rock length, and light degree, while human disturbance degree and altitude have no obvious effect.