Bangladesh is a country of about 143,999 square kilometres (km2 ) and is bordered by India in the west, north, and east except for a small portion in the southeast by Myanmar (Figure 1). The entire south is occupied by the Bay of Bengal. Geographically, the country is located between 88o 01’E and 92o 41’ East longitude, and between 20o 34’ and 26o 33’ North latitude (Rashid 1991). The majority of the country’s land is formed by river alluvium from the Ganges and the Brahmaputra and their tributaries, which consists mostly of flood plains (80%) with some hilly areas (12%) (Sohel et al. 2015). More than fifty transboundary rivers feed into the country, effectively creating the world's second largest riverine drainage basin, the Ganges-Brahmaputra-Meghna (GBM) basin, and the largest delta of the world (Hofer and Messerli 2006). Bangladesh enjoys a tropical monsoon climate, which is characterized by high temperatures, heavy rainfall, excessive humidity, and fairly marked seasonal variations (Brammer 2016). There are three distinct seasons in the country: a hot, humid summer from March to June; a cool, rainy monsoon season from June to October; and a cool, dry winter from October to March. Maximum summer temperatures range between 30°C-40°C. April is the warmest month whilst January is the coldest month with an average temperature of about 10°C all over the country. Biodiversity in Bangladesh Although a small country, Bangladesh is exceptionally endowed with a rich biodiversity due to its unique geophysical location (Mukul et al. 2018). An estimated 5,700 species of angiosperms alone, including 68 woody legumes, 130 fiber yielding plants, 500 medicinal plants, 29 orchids, 3 gymnosperms and 1,700 pteridophytes has been recorded from the country (Islam 2003). The country also possesses a rich faunal diversity although many are now under different degrees of threats due to changing climate and anthropogenic pressure (Mukul et al. 2019, 2012; Alamgir et al. 2015). Approximately 138 species of mammals, 566 species of birds, 167 species of reptiles, 49 species of amphibians, 708 species of marine and freshwater fish, 2,493 species of insects, 19 species of mites, 164 species of algae (and seaweed) and 4 species of echinoderms have so far been recorded from the country (IUCN 2015). Invasive alien species in Bangladesh A complete and reliable inventory of invasive alien species is still lacking in Bangladesh. The majority of the exotic species were introduced into the country without any proper documentation (Barua et al. 2001). There are also contradictions in the definition and the use of the term IAS in Bangladesh, and not all the exotics are harmful (Mukul et al. 2006). Table 3 provides a list of common IAS in Bangladesh based on secondary literature. Most of the IAS in the country were brought by settlers, invaders, seamen, and traders. Few of the invasive species, mainly plants, were introduced during the colonial period as an ornamental species for their aesthetic value (Mukul et al. 2006). Perhaps the first widely introduced IAS in Bangladesh is Water Hyacinth (Eichhornia crassipes) which was brought from Brazil during the British colonial period (Barua et al. 2001). In recent years, deliberate preferences of fast-growing, high-yielding cultivars over native species caused the introduction of some potentially harmful exotic species in the country (Hossain 2009). The introduction of Acacia and Eucalyptus from Australia during the 1980s created several controversies in the country. All the species belongs to these two genera are proven to be rivals to the endemic flora and found to be environmentally unfriendly (Ameen 1999). The initial list of IAS prepared by Zabala (1990) of angiospermic flora of the country listed nine species, i.e. Acacia auriculiformis, A. mangium, Albizia falcataria, Dalbergia sisso, Eucalyptus camaldulensis, E. brassiana, Leucaena leucocephala, Swietenia macrophylla, S. mahagony, although not all of them fulfill the criteria of IAS.