VietNamNet Bridge - Dozens of invasive alien species that have been developing in Vietnam have been difficult to control because of high costs needed to eliminate infestations.

At a workshop on biodiversity conservation in Can Tho City in late August, Truong Thi Nga from the Can Tho University’s Environment & Natural Resources Faculty spoke about the list of 100 invasive alien species which cause serious consequences and the list of the new alien species in Vietnam. 

In Vietnam, they include Pleco (Hypostomus plecostomus), red-ear turtle (Trachemys scripta elegans), hamster and fresh water lobster (Procambarus clarkii).

Nga said that alien species had serious consequences, including hyacinth (Eichhornia crassipes), yellow snail (Pomacea canaliculata), beaver (Myocastor coypus bonariensis), mot cung dot (Trogoderma granarium) and mai duong (Mimosa pigra).

Mimosa pigra, sourced from the American tropical forest, appeared in Vietnam in mid-20th century. At first, it grew sporadically in the southwestern region, but later, it has been growing well in many localities. 

Dozens of invasive alien species that have been developing in Vietnam have been difficult to control because of high costs needed to eliminate infestations.

In Tram Chim Tam Nong of Dong Thap province alone, there are 2,000 hectares of Mimosa pigra.

Mimosa pigra causes big changes in local vegetational cover and harms local flora and fauna. Its acid amin mimosine is harmful to many animal species, according to Nga.

It is very difficult and costly to kill Mimosa pigra because the plant grows strongly on any type of land, while its seeds can go along streams and spread out. It can reproduce strongly after burning and sprouts easily from root cuttings.

It cost $11 million to control Mimosa Pigra in the northern part of Australia in 1997. Vietnam has to spend VND50-100 million a year to kill the trees in Tram Chim Tram Nong, but it has not succeeded.

As for yellow snail, imported to Vietnam in 1975, hundreds of billions of dong have been spent to kill the harmful species, which included $250,000 worth of aid from FAO. The snails still can be seen everywhere on fields.

In 1995 a ‘yellow snail boom’ in Vietnam occurred when the harmful snails could be found on 15,000 hectares of rice and vegetable fields, rivers and canals. 

Yellow snails, eating rice and vegetables, can multiply and spread very quickly. They change the "food webs" in the ecosystem, while it is prone to interbreed with native snails, thus depleting indigenous genetic resources.

In Can Tho City alone, according to Nguyen Minh The, deputy director of the city Department of Natural Resources and the Environment, six typical invasive alien plant species and five animal species that cause negative impact on people’s lives have been discovered.


Chi Nguyen