69 invasive species of plants and animals threaten native species

Scientists have identified 69 invasive species of plants and animals in Bangladesh that are becoming a major threat to the native species.

Among the species, 51 percent have been identified as deadly invasive. A recent study published in the science journal Global Ecology and Conservation this month revealed this.

The study was conducted by researchers from five universities in Bangladesh, the United States, Australia and Germany on the exotic species of plants and animals in Bangladesh.

They also identified 300 foreign species of plants in the country. According to the survey, there are 46 invasive species of plants, five species of insects, one species of snails and one species of birds in the country.

As Bangladesh had been a crucial route for international trade, foreign traders and tourists came to the country since ancient times. They brought seeds of their local fruits, grains and shrubs from their own country.

The International Union for Conservation of Nature (IUCN) has compiled a list of the world's 100 most invasive species of plants and animals. The list includes the identified 69 species including water hyacinth, Assam creeper, Swarnalata, lantana and Bon Motmotia.

Among them, 28 species have been imported from North America, 17 from other Asian countries, 9 from Africa and 7 from Australia. Among them, 38 species of plants came before independence.

Sharif-e-Mukul, a senior research fellow at the Sunshine Coast University in Australia, said, “Separate researches have been done on different species of plants and animals in Bangladesh. We have evaluated these studies and presented an overall list and diagram. In order to meet the sustainable development goals and maintain the natural balance of Bangladesh, we need to know which species of trees and animals are harmful to our country's ecosystem. '

According to the report on the threat of the invasive species in Bangladesh, two species of ants, tilapia, African catfish and grass carp have become too aggressive. The native small fish cannot survive in open and closed reservoirs due to these fish.

In Bangladesh, herbaceous trees were brought mainly for beautification during the British colonial rule. Similarly, water hyacinth was brought from Brazil. Other harmful plants including Assam vine were brought in the same manner.

In the 80's, rapidly growing trees, including acacia and mahogany, were brought here from Australia and Africa as part of social afforestation and tree plantation programmes. These trees became popular in Bangladesh due to the timber price and fast growth. The common people in the villages too planted these trees on their land. They were prioritised in various programmes including tree plantation programmes along both sides of the roads.

Similarly, in the 90's, commercial fish farming in ponds became popular in Bangladesh. At this time, bighead carp of China, grass carp, African catfish, Thai koi were brought to the country. However, commercial cultivation of African catfish has been banned in country due to aggressiveness of the fish. However, the research team thinks that these have been mixed with other local varieties here.

Farid Uddin Ahmed, executive director of non-government organisation Arannayk Foundation, differed saying most of the fruits popular here came from abroad. He, however, said it was not right to have any foreign species of trees in the natural forests of Bangladesh. "No one can be prevented from planting exotic trees commercially on their own land, but a complete survey should be conducted on all the alien species of plants in Bangladesh. It should be evaluated how much they are good or bad for the environment."

Asked about this, Chief Conservator of Forests Amir Hossain Chowdhury told Prothom Alo, "The forest department has planted trees in 17,000 hectares of land in last two years. All of the trees were indigenous.”

“The Forest Department and the Bangladesh National Herbarium have started a comprehensive survey of the foreign invasive species affecting native species in Bangladesh. We will be able to make a clear decision about these trees after it,” he said.

According to research report, if the invasive species of trees and animals are not controlled, the native species will gradually become extinct.

Bangladesh has signed the UN Convention on Biological Diversity that stated, native and indigenous species must be protected. Conservation of native species has also been stressed in the sustainable development goals.

*This report, originally published in Prothom Alo print edition, has been rewritten in English by Nusrat Nowrin.