不同土著草本群落对加拿大一枝黄花早期阶段入侵的抑制能力研究

    Capabilities of Native Herbosa Inhibiting Solidago canadensis at Early Stage of Its Invasion

    • 摘要: 为了解不同土著草本群落对加拿大一枝黄花(Solidago canadensis)的入侵抑制能力以及可能的机制,以杭州湾南岸湿地围垦区具有相同演替阶段的3 种优势土著草本白茅(Imperata cylindrical)、芦苇(Phragmitescommunis)和荻(Miscanthus sacchariflorus)群落为研究对象,以加拿大一枝黄花单优群落为参照,调查了不同群落中加拿大一枝黄花密度和地上部分生长(株高和基径)情况,测定了不同群落的光照水平和土壤理化性质,分析了土著群落中加拿大一枝黄花密度和地上部分生长与群落光照水平和土壤肥力的关系。结果表明:(1)土著群落显著降低加拿大一枝黄花密度(<0.05),白茅群落还显著降低加拿大一枝黄花地上部分生长(<0.05)。(2)土著群落降低了群落冠层光照水平,土著群落冠层中部光合有效辐射低于加拿大一枝黄花单优群落。白茅群落和荻群落盖度显著高于芦苇群落和加拿大一枝黄花群落(<0.05),冠层高度由大到小依次为荻、芦苇、加拿大一枝黄花和白茅;加拿大一枝黄花株高与其邻株株高间呈显著正相关(<0.001)。(3)土著群落土壤肥力低于加拿大一枝黄花单优群落,白茅群落土壤肥力最低,但多数指标与芦苇群落和荻群落差异不显著(>0. 05)。认为遮光可能是土著群落抑制加拿大一枝黄花早期入侵的主要机制,而较低的土壤肥力水平可能与光竞争协同作用进一步加剧了土著群落对加拿大一枝黄花扩散的抑制。通过筛选和培育那些能同时降低群落光照水平和土壤肥力水平的土著群落可有效抑制加拿大一枝黄花入侵。

       

      Abstract: Making use of native vegetation to inhibit spread of invasive species is a potential biological measure to control invasion of alien plant species. Solidago canadensis is one of the alien plant species that have been very invasive in recent years in the coastal area of Southeast China. To investigate capabilities of various native herbosa inhibiting spread of the invasive S. Canadensis, three native dominant grass species, i.e. Imperata cylindrical, Phragmites communis and Miscanthus sacchariflorus, that have the same succession stages were selected as subjects in the study.With patch of S. canadensis dominated community as control, density and growth (plant height and basal diameter) of S. Canadensis in the three native plant communities were surveyed and relationships of density and growth of S. canadensis in the native grass communities with illumination level and soil fertility were analyzed. Results show that (1) S. canadensis in the native grass communities was much lower in plant density, and even reduced growth in the I. cylindrical community (P<0.05); (2) the native grass communities reduced illumination level for S. canadensis .Photosynthetically active irradiation (PAR) in the middle of the canopy layer was lower in the native communities than in the S.canadensis community; I. cylindrical and M. sacchariflorus communities had much higher canopy coverage than P. communis and S.canadensis communities (P<0.05); in terms of canopy height, the four communities followed a decreasing order of M. sacchariflorus > P. communis > S.canadensis > I. cylindrical; S.canadensis was significantly and positively related to its neighboring native plants in plant height (P<0.05), and was also lower than M. sacchariflorus and P. communis. (3) soil fertility was lower in the native plant communities than in the S. canadensis community (P < 0.05), especially in the I. cylindrical community, which was the lowest in soil fertility, but not much different from the M. sacchariflorus and P. communis communities in most soil fertility indices (P>0.05). The findings suggest that shading of S.canadensis by native plants is the major mechanism of the latter inhibiting the former, meanwhile, it is very likely that lower soil fertility joining in synergy with light competition intensifies the inhibition of S. canadensis. It is, therefore, advisable to screen and cultivate native plants that may lower illumination level and soil fertility of the community simultaneously to effectively inhibit invasion of S.canadensis.

       

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