Species in decline


What’s Happening to the Monarch Butterfly Population?, NYTimes, March 20, 2020Researchers don’t know if the smaller populations of monarchs are not making it to breeding sites, not finding plants to nourish them along the way, or not able to find mates.

Worldwide decline of the entomofauna: A review of its drivers, Biological Conservation, April 2019Biodiversity of insects is threatened worldwide. Here, we present a comprehensive review of 73 historical reports of insect declines from across the globe, and systematically assess the underlying drivers. Our work reveals dramatic rates of decline that may lead to the extinction of 40% of the world’s insect species over the next few decades. In terrestrial ecosystems, Lepidoptera, Hymenoptera and dung beetles (Coleoptera) appear to be the taxa most affected, whereas four major aquatic taxa (Odonata, Plecoptera, Trichoptera and Ephemeroptera) have already lost a considerable proportion of species. Affected insect groups not only include specialists that occupy particular ecological niches, but also many common and generalist species.


The Big Apocalyptic Bird Story Everyone Read This Week May Have Missed Some Necessary Nuance, Mother Jones, Sept 28, 2019Todd Arnold, a conservation biologist at the University of the Minnesota who studies bird population dynamics, made a similar point. “If you take away the 40 biggest decliners from the dataset, then what’s left behind is hundreds of birds, some of which are declining, some of which are increasing. But, on average, the increases outweigh the declines,” Arnold said.

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