E-Paper
One in 5 migratory species at risk of extinction: UN data
One in five migratory species is threatened with extinction, with 44% experiencing population decline, according to the UN's first State of the World's Migratory Species report. Of the species covered by the UN's Convention on Migratory Species, 82% listed as being in danger of extinction are threatened, including 97% of migratory fish. Habitat fragmentation caused by dams is a significant threat to freshwater migratory fish, particularly in India. Other pressures on migratory species include habitat loss, pollution, climate change, and obstacles to migration such as infrastructure and disturbance from industrial development.
One in five species that migrate are threatened with extinction and a substantial proportion of them — 44% — is undergoing population decline, United Nations’ first State of the World’s Migratory Species report has said.
The UN’s Convention on Migratory Species covers around 1,189 species, including terrestrial, aquatic and avian migratory animals and their fates are linked inevitably to the delicate ecological balances, at present being upset by human activity and the climate crisis.
When considering the appendices under the Convention on Migratory Species separately, 82% of appendix I species — these are defined as being in danger of extinction throughout all or a significant portion of their range — are threatened with extinction and 76% have a declining population.
Around 18% of appendix II species (not as endangered as appendix 1) are globally threatened, with almost half (42%) showing decreasing population trends. The current situation and trajectory of migratory fish is of particular concern, with nearly all (97%) listed fish species threatened with extinction, the report has flagged.
The report has cautioned that habitat fragmentation caused by dams in river systems is one of the most significant pressures facing freshwater migratory fish, including in India. Only 37% of the world’s long rivers (>1,000 km) have high levels of connectivity over their entire length, while the rest have dams and other artificial river infrastructure.
Habitat fragmentation resulting from dams is currently greatest in the Indian sub-continent, Europe, East Asia, North America and Southern Africa. In the near future, connectivity within tropical river systems, such as the Amazon, Mekong and Congo basins, is predicted to come under increasing pressure from new dams.
“Levels of extinction risk are rising across CMS-listed species as a whole. Between 1988 and 2020, 70 CMS species showed a deterioration in conservation status, substantially more than the 14 species that showed an improvement in conservation status. Extinction risk is also escalating across the wider group of migratory species not listed in CMS,” the report said.
An analysis produced for the report identified 399 globally threatened and near-threatened migratory species (mainly birds and fish) that are not yet listed in the CMS appendices but need protection.
The deteriorating status of migratory species is being driven by intense levels of anthropogenic pressure — or factors attributed to human activity.
Habitat loss, degradation and fragmentation (primarily driven by agriculture), and overexploitation (hunting and fishing, both targeted and incidental) are among major threats.
Pollution including pesticides, plastics, heavy metals and excess nutrients, as well as underwater noise and light pollution, also impact these species.
Climate change too is expected to increase over the next few decades, not just as a direct threat to species but also as an amplifier of other threats such as habitat loss, degradation and fragmentation, the report said.
Obstacles to migration range from physical infrastructure, like roads, railways, fences and dams; disturbance from industrial development, and shipping traffic, also threaten migratory species.
Over the past 30 years, 70 migratory species, including the steppe eagle, Egyptian vulture and the wild camel — have become more endangered.
Only 14 species have recorded an improvement in conservation status, including blue and humpback whales, the white-tailed sea eagle and the black-faced spoonbill. Migratory sharks, rays and sturgeons — are facing a high risk of extinction.
Large colonies of the straw-coloured fruit bat for example, known to play a role in the dispersal of Iroko (Milicia), an economically important timber, however, is threatened by deforestation and hunting for wild meat.
Tropical regions are seeing a higher rate of decrease in abundance of migratory species. An average decrease in abundance between 1970 and 2017 ranged from -66% in Asia to -27% in Africa. But, in South America, there is an average 90% increase in abundance compared to the baseline.
Many marine migratory species listed in the CMS appendices, including marine mammals and some species of sharks and rays, are very sensitive to pressure from exploitation due to their inherently low reproductive capacity, the report said. Incidental catch is a huge threat to them and cross coastal regions of the tropics and subtropics, the use of migratory cetaceans, crocodilians, manatees, dugongs and marine turtles for consumption or bait (aquatic wild meat) is also widespread.
