河北地区黄顶菊土壤种子库特征及其对替代控制的响应

Characteristics of Soil Seed Bank of Flaveria bidentis and Its Response to Control with Replacement Plants in Hebei, China

土壤种子库在退化生态系统的恢复以及植被更新过程中发挥重要的作用。2001年黄顶菊（Flaveria bidentis）入侵河北地区，对当地生态系统造成了严重危害。为明确其潜在危害，调查了其在河堤与荒地两个典型生境中的土壤种子库特征。结果表明，（1）两种生境中地上植被均以黄顶菊最为丰富，频度达100%。河堤及荒地黄顶菊种子总储量分别达12527和13947 ind.·m-2，占整个种子库的88.05%及96.32%；黄顶菊种子库与植被间物种相似系数（S）分别为0.55（河堤）和0.40（荒地），属于中等及偏低相似水平。（2）黄顶菊种子多集中于上层土壤中（0-2 cm）中，且随土层深度的增加而减少，但土壤中层和下层（2-10 cm）中仍有近50%的黄顶菊种子。（3）在3次取样中，黄顶菊种子主要集中于4月份与6月份采集的土样中，8月份较少。本研究利用紫穗槐（Amorpha fruticosa）与沙打旺（Astragalus adsurgens）两种植物替代控制黄顶菊，分析了黄顶菊对替代控制后的响应，结果发现第2年控制效果优于第1年，其密度、单株结实量、土壤种子储量均极显著低于同期对照（P〈0.01；）其次，其余生态指标如株高、分枝数、生物量等均受到不同程度的抑制，因此利用这两种替代植物可以限制黄顶菊的繁殖与扩散。该研究对黄顶菊的综合持续控制具有一定的实践指导意义。

The soil seed bank plays an important role in the restoration of degraded ecosystems and vegetation renewal,Flaveria bidentis has caused serious damage to the native ecological system since its first occurrence in Hebei province of China in 2001. We surveyed the characteristics of soil seed bank ofF. bidentisin two habitats riverbank and wasteland. The results showed that, （1） F. bidentiswas the most abundant species in two habitats with its 100% frequency. The seed density ofF. bidentis was 12527 and 13947 ind.·m-2, accounting for 88.05% and 96.32% of the soil seed bank in riverbank and wasteland respectively, the species similarity coefficient （s） betweenF. bidentis seed bank and vegetation was 0.55 （riverbank） and 0.40 （wasteland）, belongs to the medium and lower similarity level, respectively. （2） The seeds ofF. bidentis was decreased with the increasing of soil depth, seed density in the 0-2 cm soil layer was the highest, followed by the 2-5 cm layer while the 5-10 cm depth had the lowest seed density. （3） The seeds ofF. bidentis can be mainly collected in April and June, fewer in August. In addition, we replacedF. bidentis by using Amorpha fruticosa andAstragalus adsurgensand investigeted its responses. The results indicated that effect of replacement control was better in the second year than the first year, the density, seed yield and soil seed reserve ofF. bidentis were decreased significantly after two years （P〈 0.01）, and the other ecological indicators ofF. bidentis such as the height, number of branches and biomass were inhibited by different degrees, thus it can limit the propagation and spread ofF. bidentis by using these two kinds of substitutive plants. The results and findings in the present study can help in the sustainable management ofF. bidentis.