Naturalization and invasion of alien plants in Japan : Relationships among their origin, use, and time of introduction

• Published in: Japanese Journal of Conservation Ecology Vol. 13; no. 1; pp. 89 - 101
• Main Author: Muranaka, Takashi
• Format: Journal Article
• Language: Japanese
• Published: The Ecological Society of Japan 30.05.2008
• Subjects: Invasive alien species; Literature on alien plants; Literature review; Number of alien plants
• ISSN: 1342-4327; 2424-1431
• DOI: 10.18960/hozen.13.1_89

The specific traits (origin, use, introduction, and era) of naturalized vascular plants were examined. Of 2,237 introduced species, 1022 were weeds (ruderals), followed by ornamentals (863 species), medical plants (370), food plants (306), forage plants (224), plants that provided wood and other materials (161), or ground-cover (125). The species originating from East-Asia were mainly imported between 1601 and 1867 (Edo era), while those originating from Europe or North-America were mainly naturalized in 1868 - 1912 (Meiji era). The major use in the Edo era was as ornamentals, while the number of forage and ground-cover plants increased in the Meiji era. Of the ground-cover plants, 34.40% originated in Europe and 32.80% originated in East-Asia. Weeds (1,022 species) increased from the Edo era, and 36.69% of them were of European origin. The results suggest that when Japan opened after the Edo era, and again after World War II, large numbers of naturalized plants were introduced. The country of origin and use of the naturalized plants during each age roughly reflect the trade and industrial demand at that time.