All species of sturgeon-like fish are endangered
(ORDO NEWS) — The International Union for Conservation of Nature published the first update of the lists this year.
The most notable changes have been the endangered status of a migratory subspecies of monarch butterflies, as well as a reassessment of the status of sturgeons. Now all 25 living species of sturgeons, shovelnose paddlefish are endangered species.
The decline in the number of these fish is associated with the construction of dams on rivers, poaching and climate change. In addition, many species of birds, primarily Australian endemics, have received new statuses.
The International Union for Conservation of Nature and Natural Resources (IUCN) has been collecting information on the status of tens of thousands of species and subspecies of animals, plants, fungi and other living organisms for about sixty years.
Each of them is assigned a certain status depending on how great the risk of its extinction is. For example, numerous and widespread species such as humans (Homo sapiens) or the gray rat (Rattus norvegicus) are classified as Least Concern (Least Concern, LC).
More rare get the status close to a vulnerable position (Near Threatened, NT). They are followed by vulnerable (Vulnerable, VU), endangered (Endangered, EN) and on the verge of extinction (Critically Endangered, CR) species (all of which are sometimes collectively referred to as endangered or threatened with extinction (disappearance)).
Finally, there are separate categories for extinct in nature (Extinct in the Wild, EW) and extinct (Extinct, EX) species, as well as for species for which there is not enough data to assess the position (Data Deficient).
Several times a year, IUCN updates the lists by adding species that did not previously have conservation status and by revising the status of species already included. For example, last year the list was updated three times: in March, September and December. Two upgrades are planned for 2022. The first of them was published on the twenty-first of July.
One of the main differences in the new version of the list is the elevated conservation status of monarch butterflies (Danaus plexippus). In general, this species is not threatened with extinction, so it has retained the status of causing the least concern.
However, in the migratory North American subspecies D. p. plexippus things are getting worse. The number of these butterflies wintering in California and Mexico has declined markedly over the past decades.
Migratory monarchs are thought to have suffered due to the disappearance of caterpillar food plants, overuse of pesticides, and climate change. In the current update, the subspecies has received the status of endangered.
However, it is obvious that not all entomologists will agree with such an assessment. For example, a recent analysis of 26 years of data showed that, despite the decline in the number of these insects in wintering areas,
IUCN specialists also revised the status of sturgeon fish (Acipenseriformes). The plight of this group has long been of concern to scientists: according to a 2009 estimate, 85 percent of the 26 species of sturgeon, beluga, shovelnose and paddlefish that existed at that time were threatened with extinction due to dam building, poaching and climate change.
However, it now appears that the decline in many species has been greater than previously thought. As a result, four North American species of sturgeon – lake (Acipenser fulvescens), Pacific (A. medirostris), American Atlantic (A. oxyrinchus) and white (A. transmontanus), whose populations were previously considered stable, received the status of vulnerable and endangered. Thus, now all living sturgeon are classified as endangered species.
The status of some sturgeons, which were already considered endangered, have been upgraded. Sterlet (A. ruthenus) has been upgraded from vulnerable to endangered, and Siberian sturgeon (A. baerii) has been upgraded from endangered to critically endangered.
Finally, the Yangtze River sturgeon A. dabryanus is declared extinct in the wild (however, it has been bred in captivity since the 1970s), and the Chinese paddlefish (Psephurus gladius), which lived in the same river, is extinct.
In addition, the update affected several mammal species, including the Syrian hamster (Mesocricetus auratus) (it was declared endangered species) and the tiger (Panthera tigris) (it remained endangered, but its population estimate was raised by 40 percent, to 3726-5578 individuals) and about two hundred species of birds. In particular, the cryptic Great-billed Warbler (Acrocephalus orinus), thought to be extinct for 130 years, has been designated a species of Least Concern.
A number of Australian bird species affected by natural vegetation clearing and the catastrophic wildfires of 2019-2020 have been upgraded. Feathered endemics of the Queensland rainforests that were previously considered common, such as Victoria’s shield-bearing bird of paradise (Lophorina victoriae) and golden bowerbird (Prionodura newtoniana), have also received higher status.
Recent studies have shown that due to climate change, their ranges are shifting higher into the mountains, and their numbers are rapidly declining.
However, the populations of some Australian birds have grown thanks to protection, which has allowed them to be assigned lower conservation statuses. For example, Albert’s lyrebird (Menura alberti) and Gouldian’s finches (Chloebia gouldiae) have been given Least Concern status.
All changes that were made to the IUCN list in 2022 can be found at the link.
Some species that have survived only in zoos and nurseries manage to return to the wild. For example, in early June, ornithologists released eight captive-bred blue macaws (Cyanopsitta spixii) in northeastern Brazil. These birds have not been seen in their native forests for more than twenty years.
—
Online:
Contact us: [email protected]
Our Standards, Terms of Use: Standard Terms And Conditions.
