Migratory species most vulnerable to plastic pollution, finds UN report

Plastic pollution poses a threat to migratory species that dwell on land and in freshwater habitats, especially in the Asia-Pacific region, a UN report published on Tuesday highlighted.

It showed that pollution from plastics increases the vulnerability of already endangered species such as Gangetic and Irrawaddy dolphins, Asian elephants, and Black-footed Albatrosses.

The report, released by the United Nations Convention on the Conservation of Migratory Species of Wild Animals (CMS), focused for the first time on the impacts of plastic pollution on animals, birds, and aquatic beings in the Asia-Pacific region.

The study focussed on the Ganges and Mekong river basins, which together contribute an estimated 200,000 tonnes of plastic pollution to the Indian Ocean and the Pacific Ocean every year.

Not only does plastic pollution endanger the lives of the species through entanglement but it can also impact the food web in the form of the ingestion of microplastics.

The study found that species protected under the CMS are impacted by plastic pollution in river ecosystems and on land, including freshwater species, land animals, and birds, which researchers said were often overlooked victims of humanity's expanding trash crisis.

The UN report, ahead of the crucial summit of the International Union for the Conservation of Nature (IUCN), which will include a motion calling for an end to marine plastic pollution by 2030, as well as the Convention on Biological Diversity (CBD) summit in October this year, highlighted that air-breathing freshwater mammals are particularly at risk from plastic pollution. Entanglement in the plastic waste can prevent them from reaching the surface, leading to drowning.

With an estimated 3,500 individuals remaining in the wild, the Gangetic dolphins were recently rated as the second-most vulnerable species at risk of entanglement and negative effects from discarded fishing gear in the Ganga river.

In the Mekong delta, the drowning of Irrawaddy dolphins, estimated to be less than 100, owing to entanglement in nets is rampant. Both these species of dolphin are classified as 'endangered' on the IUCN Red List.

Dugong, another marine mammal protected by the CMS in the Asia-Pacific region, is often seen to drown after getting entangled in fishing nets or ingesting microplastics, with India and Thailand contributing to most of their deaths.

While most plastics are used and disposed of on land, most research on the impacts of plastic pollution has focused on marine ecosystems. Terrestrial environments are particularly under-represented in plastic pollution research globally. However, evidence indicates that plastic ingestion is likely to be adversely impacting a wide variety of animals on land.

“Since most plastic pollution is generated on land, it is unfortunately not surprising that it is impacting migratory and other animal species that live on land and in freshwater environments," executive secretary of CMS, Amy Fraenkel said.

Protected under CMS since the 13th Conference of the Parties in 2020, the Asian Elephant has been observed scavenging on rubbish dumps in Sri Lanka and ingesting plastic in Thailand.

With nearly 500 species, birds represent over 80% of the CMS-listed species in the Asia-Pacific region, and there is significant evidence for bird interaction with plastics.

The report also said migratory seabirds, such as Black-footed Albatrosses and Laysan Albatrosses, may not be able to tell plastic from prey when flying over the ocean and can accidentally eat floating debris.

This means the plastic could build up in their guts or be passed on to their chicks when they regurgitate food for them, it said.

Migratory birds such as the Black-faced Spoonbill and the Osprey have been observed making nests out of plastics, using fishing lines, and shipping debris, often resulting in the entanglement of their chicks.

"Clearly, we have huge gaps in the scientific literature of the threats of plastic pollution on many species. We need more research to better identify risks to these species, and take appropriate steps to address them," Fraenkel said.

The report pointed out that discarded fishing gear and kite strings are among the major threats. This is especially the case for aquatic species, but also for mammals and birds which encounter these discarded materials on land.

Apart from the discarded fishing gear, kite strings are especially an issue for land birds and have been estimated as the second-most frequent source of plastic hazards.

“Actions to address this global issue have fallen far short of what is needed”, Fraenkel said, adding, “The focus has thus far been on clean up in our oceans, but that is already too late in the process. We need to focus on solutions and prevention of plastic pollution upstream.”

The report found that migratory species are likely among the most vulnerable to plastic pollution. Migratory species will encounter a wider range of different environments including ones that are industrialized and highly polluted, leading to the possibility of higher exposure to plastics and associated contaminants.

Plastic pollution is a growing global problem. Global capacity to manage plastic pollution is not keeping pace with projected growth in the plastics market.

According to a recent study in Science, by 2030, even with ambitious reduction measures, up to 53 million metric tonnes of plastics could enter aquatic ecosystems annually, and if no improved measures are taken, this figure could reach 90 million tonnes annually. This, combined with the longevity of plastics, means that global environmental contamination is likely to continue to increase dramatically for some years to come.

“Bringing the science closer to policy-making is our shared mission,” said Dechen Tsering, UN Environment Programme’s regional director for Asia and the Pacific.

Of concern is that the long-term implications for organisms, ecosystems, the food web, and human health are as yet unclear. Understanding the extent and drivers of negative effects on organisms and ecosystems because of plastic exposure and ingestion should be a research priority, given the ubiquity of plastics.