Drafting Science, May 1 (EFE) .- Bird populations are experiencing a strong decline worldwide and North America has lost more than 25 % of all reproductive birds since 1970. Now, a new study confirms that, in addition, in this subcontinent they are decreasing more in areas where they should be thriving.
The latter is one of the main conclusions of a work led by scientists from the University of Cornell, United States, which is published in Science and that advances on the map of this avene decrease, which has been studying for years. And it does so thanks, in part, to citizen science and the application of a specialized deep learning model.
For the new work, the researchers of the Ornithology Laboratory of the University of Cornell gathered data from more than 36 million observations of shared birds in the Ebird program, of the aforementioned laboratory, in addition to multiple environmental variables.
The analysis revealed a mosaic complex of local population dynamics.
General descent
Thus, general trends show that 75 % of bird species are decreasing throughout their distribution area – and 65 % significantly.
However, population descents are not uniform throughout that area; Almost all species (97 %) had some areas where populations are increasing, a positive sign that can help guide conservation measures.
It should be noted that bird populations are reducing more quickly in places where they remain more abundant, precisely where they should prosper.
83 % percent of the species that examined (in total 495 between 2007 and 2021) are losing a higher percentage of their population where the authors emphasize. This pattern suggests that “even the bastions of bird populations are no longer safe.”
Ecological stress
The descents are especially serious in birds that are raised in meadows and arid areas, and are more closely linked to local abundance than to the geographical position within the distribution area of a species.
This points to ecological stress – climate change and loss of habitats – as the main motor of the decline. Habitats that house abundant populations may be more vulnerable to these pressures, while marginal habitat species may be more resistant.
“It’s not just about small changes, but about populations that decrease where they were very abundant before. Places that previously offered an ideal habitat and climate are no longer adequate, “adds researcher Alison Johnston.
Background
These results are continuation of others in the same direction. For example, a 2019 article also published in Science reported a accumulated population loss of almost 3,000 million birds in Canada and the United States since 1970.
“The 2019 document told us that we have an emergency and now with this work we have the necessary information to create an answer plan,” summarizes Johnston, for whom an effective conservation requires knowing where populations are decreasing more.
“This type of small -scale information and in large geographical areas is the one that was missing and it is exactly what we need to make intelligent conservation decisions,” says Amanda Rodewald.
Detailed cartography will help conservation organizations and politicians to better guide their efforts to protect species in decline.
However, the work reveals stability spot
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