非表示:
キーワード:
invasive macrophyte; Amazonia; genetic distance
要旨:
The water hyacinth Eichhornia crassipes (Mart.) Solms is one of the 100 world’s worst invaders. Native to tropical freshwaters of tropical South America, with a putative origin in the Amazon basin and the Pantanal of western Brazil, the water hyacinth is nowadays distributed worldwide. In tropical regions, E. crassipes escaped into local environments and spread out into the freshwaters proliferating aggressively mainly by means of vegetative reproduction. Due to its ability to double its biomass within only 12 days, it rapidly covers whole waterbodies and destroys ecosystems. Several independent anthropogenic introductions into the tropics worldwide took place. Given the environmental and economical dangers related to the expansion of E. crassipes, the role of botanical gardens as initiators of invasions and of other anthropogenic migration factors, such as missionaries and colonists in the past as well as tourists, nurseries, private and commercial internet trade must be taken seriously. The dangers linked to the expansion of this highly aggressive species with high growth rates and no local enemies should not be underestimated, especially in view of a further increase of its expansion and favourable growth conditions in formerly non-suited habitats as a consequence of climatic changes
