評估種植冇骨消和野棉花能否有效抑制大花咸豐草族群

Abstract

大花咸豐草 (Bidens pilosa var. radiata) 是多年生、入侵臺灣的植物；而臺灣目前主要用「移除法」控制入侵植物。在本研究中，我先做田間調查以了解移除是否可有效控制大花咸豐草；在移除北投樣區 (優勢物種為大花咸豐草) 內的植物後，觀察且測量樣區內植物群落的消長，發現一年生植物會先成為優勢物種，當其逐漸死亡，多年生的大花咸豐草會再次成為優勢物種；因此只靠移除不能有效控制大花咸豐草。根據前人研究，在實施移除法後，若能再搭配種植原生植物，可能是抑制入侵植物的有效方式。冇骨消 (Sambuscus chinensis) 和野棉花 (Urena lobata) 為臺灣常見的多年生原生植物，其種子大小與大花咸豐草之種子相當；本研究接著比較這兩種原生植物和大花咸豐草的種子發芽速率、小苗生長速率和成熟植株生理及生長表現，並測試這兩種原生植物之組織水溶液萃取液是否會抑制大花咸豐草，以評估如果移除大花咸豐草後再種植這兩種原生植物是否可以抑制大花咸豐草的族群數量。結果顯示，雖然大花咸豐草的發芽率比野棉花高，但野棉花的發芽速率較大花咸豐草快，此現象在高溫 (30 ̊C/25 ̊C) 較顯著；冇骨消在播種後11天內沒有發芽。在冬季，小苗栽植六周後野棉花的植株高度、葉片面積和總生物量都顯著高於大花咸豐草。在夏季，小苗在栽植六周後，野棉花的植株高度和總生物量和大花咸豐草相似，然而在持續栽植三個月後，野棉花成熟植株的總生物量比大花咸豐草高；而冇骨消小苗在栽植六周後與大花咸豐草有相似的總生物量，但植株高度小於大花咸豐草。本研究沒有發現野棉花和冇骨消的組織水溶液萃取液可以有效抑制大花咸豐草的種子發芽率或小苗生長。根據實驗結果推測，在夏季移除大花咸豐草後再播撒野棉花種子或種植野棉花小苗可能可以抑制大花咸豐草的數量；而移除大花咸豐草後再播撒冇骨消種子或種植冇骨消小苗可能無法抑制大花咸豐草的族群數量。

Bidens pilosa var. radiata is a perennial invasive plant in Taiwan. Eradication is the most often used method to inhibit the spread of invasive plants in Taiwan. In this research, I conducted a field survey to examine whether the method is applicable to control the population of B. pilosa var. radiata. After eradicating all plants growing in a farm, in Peitou, dominated by B. pilosa var. radiata, I found that annual species dominated the plots at the beginning of the succession but they died out soon, and subsequently, B. pilosa var. radiata became dominant again. Therefore, eradication alone cannot control the population of B. pilosa var. radiata. According to previous studies, planting suitable native species might be able to prevent the invasion of invasive plants after their removal. Sambucus chinensis and Urena lobata are two native perennial species producing seed size compatible to B. pilosa var. radiata. In the second part of this study, I evaluated whether planting these two native species could inhibit the population size of B. pilosa var. radiata after its eradication. I compared seed germination, seedling growth, physiological and growth traits of the three species and also investigated allelopathic effects. Results of seed germination experiments revealed that among the three species, B. pilosa var. radiata had the highest germination percentage, U. lobata had the fast germination rate at the temperature of 30 ̊C/25 ̊C, while S. chinensis did not germinate during the incubation period of 11 days. During the six weeks of culture period in winter, seedlings of U. lobata had higher plant height, accumulated more biomass and more leaf area than those of B. pilosa var. radiata. In summer, seedlings of U. lobata and B. pilosa var. radiata had similar plant height and biomass at the end of the 6-week of culture period. When the culture period was extended to 3 months, U. lobata accumulated more biomass than B. pilosa var. radiata. S. chinensis had similar biomass but lower plant height than B. pilosa var. radiata after 6 weeks of culture period. In general, I did not find that aquatic extracts of S. chinensis and U. lobata had apparent effect on seed germination and growth of B. pilosa var. radiata. According to these results, I suggested that sowing the seeds or planting the seedlings of U. lobata might be able to control the population size of B. pilosa var. radiata after the eradication treatment in summer. However, S. chinensis might not be a good candidate for the application.