松嫩平原碱化草甸恢复演替系列的群落种子流分析

对松嫩平原碱化草甸恢复演替系列4个群落优势种种子源库、土壤种子库及幼苗库进行了比较,建立了种子流模型.结果表明:演替初期虎尾草群落优势种种子源库密度最大,为(446182±180455)粒.m-2,分别是演替中期星星草群落的7.2倍、演替后期星星草 羊草群落的11.4倍、演替顶极羊草群落的164.8倍.土壤种子库和幼苗库密度均以虎尾草群落最大,分别为(63650±14541)粒.m-2和(39160±15192)株.m-2,羊草群落最小,分别为(14310±7686)粒.m-2和(790±745)株.m-2,大体呈随着恢复演替进程而递减的趋势.全体演替系列群落输出的实生苗均以虎尾草为主,占79.8%～100%.在种子流中,优势种的种子源库向土壤种子库输入率在10%～35%之间,输出率差异则较大,虎尾草群落高达62.3%,但星星草群落和羊草群落均没有优势种的幼苗输出.

Seed flows of restoration succession series communities in alkaline meadow of Northeast China Songnen Plain

After compared the source seed bank, soil seed bank, and seedling bank of the dominant species in four communities of restoration succession series in alkaline meadow of Songnen Plain, the model of seed flows was established. At early succession stage, the density of dominant source seed bank in Choris virgata community arrived its maximal value 446,182 +/- 180,455 seeds x m(-2) being 7.2 times of that in Puccinellia tenuiflora community at intermediate succession stage, 11.4 times of that in P. tenuiflora + Leymus chinensis community at later succession stage, and 164.8 times of that in L. chinensis community at climax succession stage. The densities of soil seed bank and seedling bank were all the maximal in C. virgata community, which were 63,650 +/- 14,541 seeds x m(-2) and 39,160 +/- 15,192 seedlings x m(-2), while the minimal in L. chinensis community, being 14,310 +/- 7,686 seeds x m(-2) and 790 +/- 745 seedlings x m(-2), respectively, representing a decreasing trend with the restoration. In the seedling banks of all communities in the restoration succession series, C. virgata was dominant, with its percentage ranged from 79.8% to 100%. In the seed flows, the input from dominant source seed banks to soil seed banks was only 10%-35%, while the output differed significantly at different succession stages, being the highest (62.3%) in C. virgata community and none in P. tenuiflora and L. chinensis communities.