The migratory Monarch Butterfly (Danish plexippus plexippus) is known for its spectacular annual journey of more than 4,000 kilometers from the United States and Canada to the breeding sites in Mexico, an impressive journey that has made the species famous. Like all insects, the lepidoptera faces multiple dangers due to human activity, to the point that the International Union for Conservation of Nature (IUCN) has just added it to its Red List of Threatened Species in the category of endangered (only there is another above: critically endangered).

The update of the exhaustive list also warns that all surviving species of sturgeon in the northern hemisphere, also migratory, are in danger of extinction due to prey and poaching. The good news stars the tiger (Panthera tigris), of which more specimens have been found than was thought to exist in the world. With this review, the Red List includes 147,517 species, of which 41,459 are in danger of extinction.

The Migratory Monarch Butterfly population has been reduced by between 22% and 72% over the last decade, warns the IUCN. Behind the decline is logging, both legal and illegal, which occurs to make room for agriculture and urban development, leading to deforestation and the destruction of butterfly wintering areas. Added to this are pesticides and herbicides, true poisons for all kinds of insects, and droughts, which increase the risk of fires and limit the growth of milkweed, the plant on which monarch butterfly larvae feed. In addition, Lepidoptera begin migration earlier, pushed by the increase in temperature due to global warming, when milkweed is not yet available.

The dark future of sturgeons

The IUCN assessment has found that the decline of sturgeons has not been stopped: 100% of the world’s 26 sturgeon species are in danger of extinction, compared to 85% in 2009. The Yangtze sturgeon (Acipenser dabryanus) has gone from critical to endangered status and another 17 species are now critically endangered, three are endangered and five are vulnerable. The extinction of the Chinese paddlefish (Psephurus sword). Sturgeon face poaching, so stricter enforcement of the illegal sale of sturgeon meat and caviar is “essential,” the IUCN says. Reservoirs and dams are a brake on their reproduction, and the warming of river water due to climate change also affects them. Measures can be taken, which are key to the conservation of the species, warns the IUCN: restore the channels and build working fish passages, in addition to repopulating.

More tigers than previously thought

The tiger population, which remains in the endangered category, appears to be stable or increasing, the IUCN determines in this update. It is estimated that today there are between 3,726 and 5,578 tigers in the wild worldwide. This figure represents an increase of 40% since the last evaluation of tigers that was carried out in 2015. The improvement is due to the fact that monitoring has been reinforced, which has made it possible to locate more specimens than previously thought. To which we must add that the conservation projects are working. Recovery, therefore, is possible as long as those efforts are maintained, the organization says. This species also faces poaching; to the capture of their prey, which affects their diet, and to the fragmentation and destruction of their habitat due to the expansion of agriculture and urban development.

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