A recent study revealed that the high temperatures is causing changes in these animals
A study from the American Ornithological Society assured that increasing temperatures might cause birds to shrink. This new data seems to confirm various biologist’s hypothesis about the link between colder climates and animals with larger bodies. This is because the animals in these areas adapted in order to reduce heat loss. However, it is known that these changes are a result of evolution.
The study conducted by the AOS is a step forward in understanding how temperatures affects animals in modern times, where climate change is modifying habitats.
The research The Auk: Ornithological Advances investigated the European House Sparrows that is located in different climates throughout Australia and New Zealand, "since their introduction in the mid-19th century, to show that this trend in birds might actually be due to the effects of high temperatures during development. Raising new alarms about how populations might be affected by global warming". Also, the researchers also warned that the change in the average adult body size could, potentially, affect the birds' fitness.
The study collected data from 30 populations of birds in Australia and New Zealand, two countries affected by the high temperatures over the past years. According to the results, a rise in the temperature is essential during breeding season for there to be noticeable size change.
"Our results suggest that higher temperatures during the breeding season could reduce body size through developmental plasticity, which could be considered in combination with or as an alternative to selection", explained the investigators.
Sadly, the changes in the animals’ size is not the only problem linked to climate change. The findings predict "the hotter the climate during breeding could drive significant changes in morphology among populations".
Samuel Andrew, professor in Macquarie University and some colleagues, captured and measured approximately 40 adult House Sparrows from 30 locations. The maximum the temperatures rise during summer (when birds breed) can predict the adult body size. The investigation also revealed that the decrease in the temperatures during winter doesn't affect the size of the birds.
"If variation in body size is linked directly or indirectly to adapting to different climates, then body size could be useful for monitoring the extent to which bird populations are capable of adapting rapidly to changing climates”, stated Andrew. "Our work on this common species helps us to understand the adaptive responses of birds to a changing climate and their constraints, and this fundamental knowledge will help future workers and managers focus their work on other species and potentially identify those species most at risk from climate change."
According to Whitman College's Tim Parker, an expert who was not involved with the research, "this is not a new idea, but it has been largely ignored by those who have assumed that most morphological variation in birds is due to evolved adaptive variation. We need more work on the direct effects of temperature variation on development in endotherms”.
Latin American Post | Santiago Gómez Hernández
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