金沙江头塘小流域5种人工林种子库研究

Species Diversity of Five Plantation Communities in Toutang Small Watershed of Jinsha River

为研究金沙江头塘小流域土壤种子库状况,对5种典型人工林植被样地采集土样做种子萌发试验,以期为金沙江植被恢复提供更新预测。结果表明,(1)5块样地共萌发植物22科,41种植物。其中,草本植物占绝大多数,有34种,占82.930%;灌木4种,占9.756%;乔木有3种,占7.317%。(2)萌发的种子密度由大到小排序为:上层、中层、下层。上层的种子密度显著大于中层和下层,中层和下层所含种子的数量差别较小。(3)种子储量最大的是云南松与华山松混交林,为933粒/m^(2),种子储量最少的是云南松林,仅为399粒/m^(2)。(4)5种类型人工林土壤种子库物种丰富度由大到小的顺序为:云南松与华山松混交林、华山松林、旱冬瓜林、云南松林、圣诞树林。(5)土壤种子库与地面组成植被之间有一定的相似性,相似性系数变动范围为0.2222~0.5000。除旱冬瓜林相似性系数较低外,其余样地的相似性系数计算结果表现为地上植被和土壤种子库为中等相似。

For understanding the status of soil seed bank and providing updated prediction for vegetation restoration in Toutang small watershed of Jinsha River,soil samples were collected from five typical plantations for seed germination test.The results showed that:(1)there were 22 families of plants,41 species of plants.Among them,the vast majority was herbaceous plants,with 34 species,accounting for 82.930%;shrubs,with 4 species,accounting for 9.756%;and trees,with 3 species,accounting for 7.317%.(2)The order of the density of seed germination was upper layer,middle layer and lower layer from high to low.The density of upper seeds was significantly higher than the middle and the lower.There was little difference in terms of number of seeds at middle layer and lower layer.(3)The largest seed reserves was Pinus yunnanensis-Pinus armandi mixed plantation with 933 grains/m^(2),the lowest seed reserves was P.yunnanensis with only 399 grains/m^(2).(4)The richness of species was in the order of P.yunnanensis×P.armandi,P.armandi,Alnus nepalensis,P.yunnanensis and Acacia dealbata.(5)There were some similarity between soil seed bank and vegetation composition,and the similarity coefficient was 0.2222~0.5000.Except for the low similarity coefficient of A.nepalensis,the calculation results of the similarity coefficients of other plots showed that the above-ground vegetation and soil seed band were moderately similar.