A new report has warned that 49 per cent of global migratory species populations protected under the Convention of Migratory Species (CMS) are declining, having decreased five per cent in just two years.
The interim update on the landmark United Nations State of the World’s Migratory Species of 2024 noted that globally, 24 per cent of species face extinction — an increase of 2 per cent compared to the 2024 report.
Viewed as a whole, these updated statistics present a concerning picture: the total number of CMS-listed species that have decreasing population trends now stands at 592, or almost half (49 per cent) of all CMS-listed species, up from the 44 per cent reported in the State of the World’s Migratory Species, the authors said.
Bird flu or Highly Pathogenic Avian Influenza (HPAI) H5N1 has emerged as a major threat, causing mass mortality in a range of species, namely Critically Endangered African Penguins (Spheniscus demersus), Vulnerable Humboldt Penguins (Spheniscus humboldti) and Near Threatened Peruvian Pelicans (Pelecanus thagus) in South America, Near Threatened Dalmatian Pelicans (Pelecanus crispus) in Europe, and Vulnerable Hooded (Grus monacha) and Red-crowned Cranes (Grus japonensis) in Asia.
Mass mortality events have also been recorded in CMS-listed aquatic mammals, such as the South American Sea Lion (Otaria byronia) and the South American Fur Seal (Arctocephalus australis).
“Although the long-term impacts of HPAI are uncertain, these disease outbreaks have added to the pressures already faced by migratory species. The emergence of HPAI is especially concerning for long-lived migratory species that are sensitive to any increases in mortality,” the report noted.
The new warnings will be presented to the 15th Meeting of the Conference of the Parties to the Convention on the Conservation of Migratory Species of Wild Animals (CMS COP15), a legally binding UN treaty, in Campo Grande Brazil March 23-29.
The week-long COP is one of the most important global meetings for wildlife conservation. The report noted that billions of individual aquatic, avian, and terrestrial wild animals migrate across lands, rivers, oceans and skies. They are essential to the well-functioning of nature and to human well-being, pollinating plants, transporting nutrients, regulating ecosystems, controlling pests, storing carbon and sustaining livelihoods and cultures worldwide.
It stated that since the previous analysis, which used version 2022-23 of the IUCN Red List, 386 of the 1,200 CMS-listed species have been re-assessed, excluding species that were listed at COP14.
The interim report said thirty-four (9 per cent) of the 386 re-assessed CMS-listed species have been re-classified to a different IUCN Red List category since 2022. Twenty-six of these species have shifted to a more threatened category, while seven species have moved to a less threatened category. The total number of globally threatened CMS-listed species now stands at 284, representing 24 per cent of all CMS-listed species, up slightly from the 22 per cent reported in the first State of the World’s Migratory Species.
“Nineteen (73 per cent) of the 26 species that have recently moved to a more threatened category are now categorised as Critically Endangered, Endangered or Vulnerable. Of these 19 globally threatened species, 12 were previously categorised as Least Concern or Near Threatened in the preceding assessment. A further seven species were previously categorised as globally threatened but have shifted to an even more threatened category,” it noted adding four of these species are now Endangered and three are now Critically Endangered.
It observed that eighteen (69 per cent) of the 26 CMS-listed species that moved to a more threatened category are migratory shorebirds, of which nine are now assessed as Vulnerable. At least 14 of these species have been confirmed as undergoing a deterioration in their global conservation status since 1988 that can be attributed to increased threats, rather than improvements in information, the report said.
Meanwhile it noted that seven CMS conservation species showed improved status out of which four were identified as bird species.
The other species included Scimitar-horned Oryx (Oryx dammah) in Chad with an estimated population of nearly 575 individuals in 2022 has been re- categorised from Extinct in the Wild to Endangered.
The Saiga Antelope (Saiga tatarica) populations in Kazakhstan have rebounded spectacularly in parts of their range after disease outbreaks during the 2010s, moving the species from globally Endangered to Near Threatened.
The Mediterranean Monk Seal (Monachus monachus) has been moved from Endangered to Vulnerable owing to improved population with a population under 1,000 individuals.
The authors said that updates to the IUCN Red List have also resulted in changes to population trends of CMS-listed species. “Excluding the ten entirely new species and subspecies that were added to the CMS Appendices at COP14, the overall proportion of CMS-listed species with an increasing or stable population trend has declined from 43 per cent (520 species) to 38 per cent (459 species) since the first State of the World’s Migratory Species,” it said.
They attributed the change to largely have been driven by the 67 Appendix II birds that have been re-assigned from the “stable” to the “decreasing” category, as indicated by the transitions.
“This indicates that many species that were previously considered to be stable are actually decreasing; importantly, the number of species considered to have an “unknown” trend has remained roughly constant,” it added.
The growth in the number of species with decreasing populations is likely to reflect the integration of additional long-term trend data within IUCN Red List assessments rather than abrupt decreases during the time period since COP14, the report stated.
It noted that among terrestrial, avian and marine CMS, the expansion of linear infrastructure such as roads, railways, fences, pipelines in addition to climate change, habitat loss, degradation and fragmentation have further pushed these populations at risk of further decline.
For instance, it said for example, between 2002 and 2021, mobility declined significantly for the Mongolian Gazelle (Procapra gutturosa), a nomadic species that makes some of the longest distance movements ever recorded. Increasing traffic volume leading to a loss of connectivity appears to be a key factor in the decline.
The Mara-Loita Blue Wildebeest (Connochaetus taurinus) population declined by 75 per cent since the late 1970s after land use changes were permitted throughout their range.
“The main pressures facing raptors in Africa and Eurasia are habitat loss and illegal taking, including hunting and trapping, intentional and unintentional poisoning, and taking for belief-based use, along with electrocution and collisions with energy infrastructure,” the report found.
It said that pronounced long-term declines in the populations of many migratory shorebirds have also occurred in the East Asian-Australasian flyway, in the East Atlantic flyway (particularly species breeding in the Arctic and boreal regions), and at coastal sites in India. The main threats affecting shorebird populations globally include the loss and deterioration of key habitats, including at stopover and non-breeding sites, unsustainable taking, disturbance, and climate change-driven shifts in the suitability of conditions at breeding sites.
In terms of sharks and rays it said, “Taking a regional perspective, the most pronounced increases in extinction risk for sharks and rays have occurred in the tropical Atlantic Ocean, the Northern Indian Ocean, the Indo-West Pacific Ocean and the Mediterranean and Black Sea regions. Regional populations of wide-ranging sharks and rays may rebound, if science-based fisheries management approaches are implemented.”
Overfishing and bycatch is also identified a threat for sharks and rays along with degradation of coastal habitats while climate change including ocean warming, acidification and potential deoxygenation is also documented to add pressure ion coastal and pelagic species.