In 1847, and after several investigations, the German biologist Carl Bergmann postulated one known rule, according to which animals homeotherms —Able to maintain their temperature—were morphologically larger in colder climates (and vice versa), establishing a correlation between ambient temperature and body mass.
With this maxim in mind, the Vitek Jirinec, researcher of Louisiana State University (USA) studied 77 species of birds non-migratory species from the Amazonian understory —our protagonists of # sciencealobestia— to discover that the average body size of some of them has diminished over the past 40 years, in response to increasingly hotter and drier conditions.
“Our results indicate that in our study site the climate is changing and, at the same time, so is the morphology of the birds exposed to these climatic conditions”, highlights SINC Jirinec.
According to the work, published in Advances in Science, all species studied in a virgin area of the Amazon currently have a lower average mass than in the early 1980s and, of those studied, 61 also show an average increase in wing length.
All species studied in an Amazon virgin area currently have a lower average mass than they had in the early 1980s
To show that the long-term decrease in body mass was related to a temperature increase, Jirinec and his team measured the variations between body mass, wing length and the relationship between the two, comparing them to seasonal patterns of precipitation, finding that the morphology of the studied birds also varied in the short term, which “ It’s more evidence that shape and size [de las aves] it is related to temperature and rain”, indicates Jirinec.
Morphological adaptation over the decades
The study notes that tropical birds in the heart of the world’s largest rainforest are rapidly evolving in response to the pressures of man-made climate change, and to cement that claim, scientists have reanalyzed the region’s 50-year climate data obtained thanks for the Project of Biological Dynamics of Fragmented Forests (BDFFP) in the Brazilian Amazon.
The authors then compiled the body mass measurements of about 15,000 birds and the wing length and the wing mass ratio of over 11,000 birds studied in this area throughout. four decades, comparing their morphological variations with abundance data in the number of individuals.
Changes in the shape and size of Amazonian birds are related to climate change
The team found that all 77 species showed an average decrease in body mass, and that 36 of them appeared to have lost nearly one. 2% of your body weight per decade since 1980. All species showed an average reduction in their wing mass proportion, and 61 of them showed an average increase in wing length during this period.
For Jirinec, the greatest contribution of his article is to demonstrate that changes in the shape and size of Amazonian birds are related to climate change, and that the actions that contribute to its acceleration around the world reverberate in places as “immaculate” as the Amazon forest, highlighting the global magnitude you purchased this process.
Rights: Creative Commons.