钢铁厂旧址自然恢复过程中植物类型研究

Investigation of Heavy Metals Hyperaccumulators in the Process of Natural Recovery on a Steel Plant Site

调查了广州钢铁厂搬迁3 a后旧址上的植被自然恢复情况,统计了群落中的植物种类组成、生活型组成和各种植物的重要值,分析了植物群落的多样性指数和均匀度指数,比较了植物的重金属耐受性。结果发现,在调查的6个样方中,共有26种植物,分属于14科,其中菊科和禾本科植物数量最多,没有发现豆科植物。植物生活型组成以一二年生和多年生草本植物为主,共21种,占80.77%,极少灌木和乔木,表明群落处于次生演替的初级阶段。群落中的植物重要值差异较小,以蜈蚣草(Pteris vittata)的重要值最大,为32.10;其次是少花龙葵(Solanum americanum)、苎麻(Boehmeria nivea)、蟛蜞菊(Sphagneticola calendulacea),它们的重要值也大于20;其余14种植物重要值小于10。群落中优势种不明显,表明群落的组成较复杂。群落内植物覆盖度平均仅27.16%,物种多样性指数为0.93,均匀度指数为0.89。群落内植物数量多而个体矮小,导致群落的多样性指数与均匀度指数较高而覆盖度较低,表明植物种子萌发受到重金属胁迫较小,而植物生长受重金属胁迫较大。群落中超富集植物仅有蜈蚣草、少花龙葵和蟛蜞菊3种,有8种植物对重金属具有一定耐受性。对于钢铁厂旧址的生态恢复,可利用具有生态修复功能的植物构建符合景观需要的乔-灌-草相结合的生态-经济型植物群落。

Vegetation in the process of natural recovery on the 3-year site after the relocation of Guangzhou Steel Plant was investigated, plant species composition, life form composition, important value of various plants, diversity index and evenness index of the plant community were analyzed, and heavy metal tolerance of species was compared. Results showed that in 6 plots, there are 26 species belonging to 14 families, of which the number of Compositae and Gramineae plants are the most,but Leguminosae plants are not found. About the plant life form, 21 species, accounting for 80.77%, are annual or biennial and perennial grasses, rarely shrubs and trees, indicating the vegetation is in the primary stage of the secondary succession. Impor-tant value of these species differ little, with the maximum 32.10 of Pteris vittata, followed by Solanum americanum, Boehmeria nivea and Sphagneticola calendulacea, whose important value are greater than 20; important value of the rest 14 species are less than 10. Dominant species in the community are not obvious, which indicates that the composition of the community is more complex. The average plant coverage is 27.16%, the species diversity index is 0.93 and evenness index is 0.89. The plant number is large but the plant height is short, leading to higher species diversity index and evenness index, but lower coverage. It indicates that plant seed germination is small influenced by heavy metal stress, but plant growth is larger influ-enced by heavy metal stress. There are 3 heavy metals hyperaccumulators, which are Pteris vittata, Solanum americanum and Sphagneticola calendulacea. Other 8 species have certain tolerance to heavy metals. For ecological restoration of steel plant site, plants with remediation function can be used to construct plant landscape to tree, shrub and grass combination of eco-e-