金沙江上游干旱河谷植被

为了解金沙江上游奔子栏到羊拉约130 km河段范围内干旱河谷的植被特征, 作者采用样带与典型样方相结合的方法, 对该河段进行了植物群落调查。结果显示: (1)研究区域记录到野生维管植物51科95属111种(含种下等级), 其中, 蕨类植物4科4属6种; 无裸子植物; 被子植物中双子叶植物40科71属84种; 单子叶植物7科20属21种。(2)群落物种以草本为主, 达67种, 占总物种数的60.36%; 生活型以地面芽植物为主, 占总物种数的32.43%, 矮高位芽次之, 占27.93%; 叶型以微型和小型叶为主, 微型叶有30种, 占统计总数(50种)的60%, 小型叶有11种, 占总数的22%。(3)用双向指示种分析方法可将93个样方分为5个群系。分布最广、物种丰富度最高的是小叶荆 + 小叶野丁香(Form. Vitex microphylla + Leptodermis pilosa var. microphylla)群系。(4)根据对该河谷区域的气候特点、干旱程度、植被特征(植株矮化、叶片小、植物毛被发达、植株具刺、部分植物有吸湿反应性特征等)的分析, 综合植物群落的外貌、结构、物种构成和植物形态, 可以确认金沙江上游干旱河谷植被具有亚热带荒漠植被类型的 特征。

Desert vegetation in dry valleys of the upstream of Jinsha River

In order to understand the vegetation characteristics of dry valleys in the upstream of Jinsha River, a field survey was conducted by using transect and sampling surveys with 93 plots from September to October of 2011. Results showed that: (1) There were 111 vascular plant species belonging to 95 genera in 51 families, including 6 ferns belonging to 4 genera in 4 families, and 84 species of dicotyledon belonging to 71 genera in 40 families, 21 species of monocotyledon belonging to 20 genera in 7 families. (2) Five main life forms: Nanophanerophyte, Hemicryptophyte, Chamaephyte, Therophyte and Geophyte, can be recognized, of which Hemicryptophyte was the most dominant, occupying 32.43% and Nanophanerophyte accounted for 27.93% of the total. The dominant leaf size belonged to nanophyll and microphyll, accounted for 60% and 22%, respectively. (3) 93 sampling plots can be classified into 5 community types using a two-way Indicators Species Analysis. The species richness of herbs were higher than shrubs, and the richness of the Formation Vitex microphylla+Leptodermis pilosa var. microphylla was the greatest and also distributed most widely. (4) The vegetation in the dry valleys of the upstream of Jinsha River can be regarded as subtropical desert.