非洲狗尾草与紫茎泽兰的竞争效应

 【目的】明确非洲狗尾草与紫茎泽兰种间竞争关系，探索紫茎泽兰替代控制和其入侵地生态修复的途径和策略。【方法】采用野外生态学的试验方法，建立不同密度的非洲狗尾草和紫茎泽兰单种与混种种群小区，定量分析其相对生长速率和竞争能力。【结果】非洲狗尾草单株生物量、相对产量（RY）和竞争平衡指数（CB）均显著高于紫茎泽兰对应指标，竞争效应参数相对产量总和（RYT）显著小于1；随着各处理种群密度的增大，上述关系愈加明显。在混种处理20、45和175株/m2密度条件下，紫茎泽兰单株总生物量比其在单种处理对应密度条件下的单株生物量分别降低了33.0%、38.5%和70.1%，而非洲狗尾草单株生物量在各密度间无显著变化。在混种处理条件下，非洲狗尾草生物量根茎比显著小于在单种处理其根茎比，而紫茎泽兰其根茎比显著大于在单种处理其根茎比。【结论】非洲狗尾草与紫茎泽兰之间呈现很强的竞争作用，非洲狗尾草地上部分相对竞争力比紫茎泽兰强。在较高密度的生长模式下，两物种混种群落经过长期的竞争演替，紫茎泽兰可能会被非洲狗尾草成功取代。

Competitive Effects Between Ageratina adenophora(Asteraceae) and Setaria sphacelata(Gramineae)

Abstract:【Objective】 The experiment was conducted to investigate the intra- and inter-specific competition interaction between Ageratina adenophora (Sprengel) R. King & H. Robinson and Setaria sphacelata (Schum) Stapf ex Massesy cv. Narok at different densities and its succession in the field, and to further explore the methods of controlling the invasive weed A. adenophora displaced by S. sphacelata.【Method】 We grew two perennial grasses species (A. adenophora and S. sphacelata) for 2 yr in monoculture and in mixture on an experimental densities gradient. The above- and blow-ground biomass of two species were measured and the growth response and relative competitive ability were discussed.【Result】 The biomass total and relative yield (RY) and competitive balance index (CB) of S. sphacelata were significant higher than those of A. adenophora, the relative yield total (RYT) was significant lower than 1. The relationships mentioned above become more obvious with density decreasing. The total biomass of A. adenophora at the densities of 19, 46 and 174 plants/m2 in mixture decreased by 33.0%、38.5％ or 70.1% compared to those in monoculture, respectively. However, the total biomass of S. sphacelata at the same density between in monoculture and in mixture showed no significant difference. The ratios of root mass: shoot mass of S. sphacelata in mixture were significant lower than those in monoculture. However, the ratios of root mass: shoot mass of A. adenophora in the mixture were significant higher than those in monoculture.【Conclusion】There was significant mutual antagonism between A. adenophora and S. sphacelata. Compared to A. adenophora, the relative competitive ability of S. sphacelata was higher which decreased heavily the growth of A. adenophora mainly by shoot competition. It will be a good strategy for controlling of A. adenophora and restoring its invaded habitats by S. sphacelata in the future.