Abstract

Identification, inventory and impact assessment of Invasive Alien Species (IAS) in different land use types in five districts of Bangladesh was made. In this extensive survey of more than 100 transects, a total of 21 most abundant species of herbaceous weeds have been recorded. From these, seven invasive alien species, Ageratum conyzoides, Eichhornia crassipes, Eupatorium odoratum, (Chromolaema odorata.) Ipomoea carnea, Lantana camara, Mikania micrantha and Parthenium hysterophorus have been identified. These invasive alien species belonged to four families. A very significant impact of these invasive alien species was detected on the number of species in different land use types (road side, low land, fallow land, homestead and railway track). The presence of alien species always reduced the number of associated species, in most cases significantly so. The existence of phenotypic variation in the morphological and reproductive characters of the invasive alien species from the different sites indicates their ability to invade and adapt to new habitats.
 
 Key words: Invasive alien species, Bangladesh, weeds.