高寒地区多年生禾草混播草地的群落学特征研究

Community characteristics of mixed grassland with perennial grasses in Alpine Region of Tibetan Plateau

对青藏高原高寒地区天祝县金强河地区的 3年龄禾草混播草地进行了群落学特征研究。结果表明 ,栽培禾草比天然禾草约提前 15d返青 ,推后 10d成熟 ,整个生长期延长 2 5d左右 ;建植多年生禾草混播草地可以增加草地植被覆盖率 ,提高草地初级生产力 ,改善草地基况 ;多叶老芒麦和垂穗披碱草在群落中占优势地位 ,9类混播组合可以归为多叶老芒麦 (或垂穗披碱草 )单优群落和多叶老芒麦和垂穗披碱草共优群落两大类 ;全生长季内混播草群的生长速度呈倒“V”字型和倒“U”字型分布 ,草群的平均生长速度介于 0 5 5～ 0 .70cm·d-1;群落的物种多样性和丰富度随组分草种数目的增加而增加 ,均匀度则随草种数目增加而下降 ;人工禾草群落间优势种群的重叠程度越大 ,群落的相似程度越高。

The community characteristics of mixed grassland with 3-year old perennial grasses were studied in Jingqianghe region, one of the alpine regions on Tibetan Plateau. The results showed that cultivated grasses turned green on the 20th of April, 15d earlier than natural grasses, and became mature on the 15th of September, 10d later than the natural grasses, thus the growing period of the cultivated grasses was prolonged 25d compared with the natural grasses. The coverage, photomass and the basal conditions of the alpine grasslands were improved by establishing mixture grassland of perennial grasses in this region. In 9 combinations of the grasses, Elymus nutans and/or Clinelymus nutans dominated the communities. All the grass communties can be assorted as E. nutans or C. nutans single dominated communitires, and E. nutans and C. nutans co-dominated communities. The growth rate dynamics of the communities followed reversed 'V' or 'U' patterns, with average growth rate of the communties varied from 0.55～0.70 cm·d -1 in growing season. With increasing numbers of the grass compositions, the diversity and abundance of the cultivated community increased, although the eveness decreased. The similarity of different communities increased with the overlap extent of the grass compositions of the communities.