Habitat destruction, climate change biggest contributors, says International Union for Conservation of Nature
The migratory monarch butterfly, a sub-species of the monarch butterfly that travels around 4,000 kilometres across America each year, has been classified ‘endangered’ in the International Union for Conservation of Nature (IUCN) Red List of Threatened Species July 21, 2022.
Habitat destruction and climate change are mainly responsible for pushing the insect towards extinction, the global biodiversity monitor said. The species has been on IUCN's watchlist for some years now, but the official classification was put on hold to direct conservation efforts to species that need that faced a graver threat.
Monarchs, the most recognisable species of butterfly, are important pollinators and provide various ecosystem services such as maintaining the global food web. Their population in the continent has declined 23-72 per cent over the last decade.
The number of the western monarchs, which live west of the Rocky Mountains, reduced 99.9 per cent, falling to only 1,914 butterflies in 2021 from 10 million in the 1980s. The population of the eastern monarchs that migrate from eastern United States and Canada — the bigger group — also shrunk 84 per cent from 1996-2014.
Read more: Decline in monarch butterfly population not because of migration: Study
Most of these butterflies winter in the California coast and forests in central Mexico. A smaller population of the species is also found in countries like Australia, Hawaii and India.
“Legal and illegal logging and deforestation to make space for agriculture and urban development has destroyed substantial areas of the butterflies’ winter shelter in Mexico and California,” IUCN noted.
These butterflies follow a unique lifestyle: They traverse the length and breadth of the American continent twice a year, feasting on nectar from a variety of flora. But they breed in only one particular plant — the milkweeds. The monarch larvae feed on this species on hatching.
The removal of this breeding ground by farmers because they are ‘weed’ is an important driving factor for the dwindling numbers.
In the 2000s, glyphosate, a weedicide, was widely used in farms in the Midwest, Anna Walker, member of the IUCN SSC Butterfly and Moth Specialist Group and Species Survival Officer at the New Mexico BioPark Society, told The New York Times. This killed much of the milkweed, where the female monarchs lay their eggs, she added.
Climate change has made the conditions worse by making storms and droughts more intense and disrupting flowering cycles, according to conservationists. The authors observed:
Drought limits the growth of milkweed and increases the frequency of catastrophic wildfires, temperature extremes trigger earlier migrations before milkweed is available, while severe weather has killed millions of butterflies.
IUCN’s alarming announcement was not without hope. Conservation efforts such as protecting wintering grounds and breeding sites have led to a small, but necessary, increase in the monarch count.
Broader policy changes to reduce deforestation and mindless urbanisation as well as contain climate change are the need of the hour, the global body noted.
But more focused strategies such as “planting native milkweed and reducing pesticide use to supporting the protection of overwintering sites”, are imperative for a significant and sustainable rebound of the monarch population, IUCN suggested.
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