Warmer waters, less food and reproductive “stress”: this is how global warming pushes the albatross to “divorce”

The effect of climate change that is not expected: global warming also affects the divorce ofalbatross with a black eyebrow, known until then as perennial and monogamous. Because if we already knew that the main cause of divorce is due to the reproductive failure of a couple, it turns out today that, whether or not these large seabirds manage to give birth, as the water temperature also increases the chance of a couple ‘breaking out’. It is the result of the study of a group of researchers from the universities of Lisbon, of Montana andExeter, as well as those of the Environmental Research Institute of South Atlantic and the Center for Marine and Environmental Sciences of Portugal, published in the journal of the Royal Society, that they have been examining since 2003 15,500 breeding pairs black-browed albatrosses that breed a New Island, in the Falklands. “This is the only growing population in the South Atlantic, but this link between climate change and divorce could be another cause for concern if confirmed in other populations of albatrosses, especially other species. slowly disappearing. due to factors such as the impact of fishing or exotic species, ”he explains to ilfattoquotidiano.it Francesco Ventura, Italian researcher at the University of Lisbon and co-author of the research.

Reproduction and divorce of albatrosses When this seabird – scientific name Thalassarche melanophris – it has to breed, in summer it goes to the mainland for about four months. And it always comes back to the same nest: some of the black-eyed albatrosses studied have paired with the same partners since the start of the research, that is to say almost twenty years. A “divorce” occurs if from one year to the next the members of a couple have both survived but at least one of them reproduces with another partner. “We know that couples who fail to reproduce (especially if the egg does not hatch) have a very good chance of divorce. five times higher than those who manage to make the chick survive, ”adds Ventura, who has been with the research team for four years. But during the study, it was realized that during certain breeding seasons there was a spike in divorce cases. “If on average we are talking about 3-4%, it went from a minimum of1% to a maximum of8% – he said – and we found out that it happened regardless of whether breeding was successful or not, even when the sea temperature changed on the balance of the pair. So we asked ourselves questions and formulated hypotheses ”.

The link with climate change From the ritual: when the female lays the egg, in fact, during the incubation period, the parents take turns in the hatching to get food. The increase in water temperature has a first effect on the abundance of prey because warmer waters are less rich and productive, so animals have more difficulty finding food. “The first consequence, as an indirect link between high temperature and divorce – explains Ventura – is that in more difficult times, reproduction is hampered by the fact that trips to find food must be prolonged, which makes reproduction more difficult synchronization. between male and female who alternate between brooding and prey hunting ”. But, according to the researchers, there are two other direct effects of climate change: Ventura – in more difficult years, animals pay a higher reproduction cost, it takes more time to regain energy during the winter and can arrive late on land for the next breeding season. Second, still in unfavorable conditions, the members of the couple stress more, making the female believe the male. unable to bring reproduction to success ”. Hence the choice to change partners. “On the other hand, we already knew – adds the researcher – that the female obtains greater benefits in terms of reproductive success after a divorce, compared to what a male specimen does”. But the most worrying aspect “is that interruptions in the reproductive processes of monogamous populations could represent a hitherto neglected consequence of global warming which, therefore, as temperatures rise, could have even more negative effects in the world. decades to come, especially on populations. of albatross more to limit numerically ”.

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