为了研究浑善达克沙地丘间低地植物群落类型及其分布与土壤环境因子的关系,于2004年7~8月对浑善达克沙地丘间低地进行了植物群落学调查,共获取群落样方102个,其中草本植物群落样方99个,灌木样方3个。同时对每一个样方均取了土样,并分析了土壤的全氮、有机质、可溶性钾、钠的含量和土壤溶液的pH值。对在浑善达克沙地中部丘间低地获取的102个植物群落样方进行了分析,按照样方中建群种和优势种的重要值把它们归属于28个植物群落类型,分别以黄花蒿(Artemisia annua)、褐沙蒿(A. intramongolica)、沙地雀麦(Bromus ircutensis)、尖头叶藜(Chenopodium acuminatum)、大籽蒿(Artemisia sieversiana)、砂珍棘豆(Oxytropis gracilima)、狗尾草(Setaria viridis)、猪毛蒿(Artemisia scoparia)、冷蒿(Artemisia frigida)、寸草苔(Carex duriuscula)、糙隐子草(Cleistogenes squarrosa)、冰草(Agropyron cristatum)、克氏针茅(Stipa krylovii)、羊草(Leymus chinensis)、赖草(L. secalinus)、无芒雀麦(Bromus inermis)、草地风毛菊(Saussurea amara)、菊叶委陵菜(Potentilla tanacetifolia)、芨芨草(Achnatherum splendens)、马蔺(Iris lactea)、小红柳 (Salix microstachya)、芦苇(Phragmites australis)、拂子茅 (Calamagrostis epigejos)、鹅绒委陵菜(Potentilla anserine)、金戴戴(Halerpestes ruthenica)、星星草(Puccinellia tenuiflora)、水葱(Scirpus tabernaemontani)、碱篷(Suaeda glauca)为建群种。黄花蒿、沙地雀麦、猪毛蒿、褐沙蒿、尖头叶藜、大籽蒿、砂珍棘豆和狗尾草等群落分布于沙生环境,地下水位低,土壤溶液为中性,全氮和有机质平均含量低;冷蒿、糙隐子草、冰草、克氏针茅、寸草苔、羊草、赖草和菊叶委陵菜等群落分布于固定沙地,土壤的水分、全氮和有机质的含量都较高;无芒雀麦、草地风毛菊、鹅绒委陵菜、星星草和芦苇等群落分布于中生环境,地下水位高,土壤的养分含量也较高;芨芨草、拂子茅、马蔺、小红柳和金戴戴等群落分布于盐渍化的土壤上,地下水位较高,土壤溶液的酸碱度也较高;碱篷群落分布在盐碱化严重的湖边,土壤水分和盐分含量极高;水葱群落分布于湖边浅水沼泽中。对102个群落样方进行去趋势典范对应分析(Detrended canonical correspondence analysis, DCCA),结果表明DCCA排序轴第一轴(AX1)主要代表地下水位(GWL)的变化梯度;第二轴(AX2)主要代表土壤的全氮(TN)含量和有机质(ORG)含量的变化梯度;第三轴(AX3)则代表第三层土壤(20~30 cm)溶液的酸碱度(pH)值,即地下水位, 土壤有机质和全氮含量影响丘间低地植物群落的分布格局。

Aims Vegetation and soil surveys were conducted in the summer of 2004 to study the relationship between vegetation types and soil of inter-dune lowland of Otindag sand land. Of 102 vegetation samples collected, 99 were herb-dominated, the others shrub-dominated. We analyzed soils for total nitrogen, soil organic matter, soluble sodium, soluble potassium and pH. Vegetation samples were classified based on species composition and species functional groups. We used detrended canonical correspondence analysis (DCCA) to determine the main environmental factors related to the distribution of plant communities.

Methods The 102 samples were classified into twenty-eight groups dominated by Artemisia annua, A. intramongolica, Bromus ircutensis, Chenopodium acuminatum, A. sieversiana, Oxytropis gracilima, Setaria viridis, A. scoparia, A. frigida, Carex duriuscula, Cleistogenes squarrosa, Agropyron cristatum, Stipa krylovii, Leymus chinensis, L. secalinus, Bromus inermis, Saussurea amara, Potentilla tanacetifolia, Achnatherum splendens, Iris lactea, Salix microstachya, Phragmites australis, Calamagrostis epigejos, Potentilla anserine, Halerpestes ruthenica, Puccinellia tenuiflora, Scirpus tabernaemontani and Suaeda glauca.

Importunt findings The Artemisia annua, A. intramongolica, Bromus ircutensis, Chenopodium acuminatum, A. sieversiana, Oxytropis gracilima, Setaria viridis and A. scoparia associations are mostly distributed on sites often covered by quicksand. The level of the groundwater is low, the lixivium of the soil is neutral and the average soluble K⁺, Na⁺, total nitrogen and organic matter are low. Artemisia frigida, Cleistogenes squarrosa, Agropyron cristatum, Stipa krylovii, Potentilla tanacetifolia, Leymus secalinus, Carex duriuscula and L. chinensis associations are rooted mostly in stable sand, where soil water, organic matter and total nitrogen are high. Bromus inermis, Saussurea amara, Puccinellia tenuiflora, Phragmites australis and Potentilla anserine associations grow in wet sites, where organic matter and total nitrogen are relatively high. Achnatherum splendens, Iris lacteal, Calamagrostis epigejos, Salix microstachya and Halerpestes ruthenica associations are on saline sites that have high groundwater and alkalinity. The Suaeda glauca association occurs in a highly saline lake, where water and salinity levels are very high. The Scirpus tabernaemontani association occurs in a marsh. The first DCCA axis denoted gradients in ground water level (GWL) and factors related to ground water level such as pH, soluble sodium and soluble potassium. The second axis reflected gradients of total nitrogen and soil organic matter. The third axis reflected a pH gradient. Ground water level, pH, soluble sodium, soluble potassium, total nitrogen and soil organic matter significantly correlated with the distribution of plant communities.