A new study published in Proceedings of the Royal Society B has provided evidence of the effect of environmental conditions on the longevity of relationships — among a population of albatrosses. It suggests that environmental conditions cause splits between black-browed albatrosses in the South Atlantic, which otherwise have long-term monogamous relationships.
So, how exactly can a changing environment cause these birds to split up? The researchers say “divorce” is triggered by breeding failure and that it yields some reproductive benefits, particularly for females which are more likely to find new partners and attain a higher breeding success. They say their results suggest divorce in long-lived monogamous sea populations is an adaptive strategy.
The researchers analysed a long-term demographic dataset of the black-browed albatross population in the Falkland Islands, a group of remote islands in the South Atlantic about 483 km from the South American mainland. The researchers’ objective was to see if “divorce” was affected by environmental variability over the years. They collected data on their breeding behaviour starting 2003 from New Island, Falklands, which is home to about 15,500 pairs of albatrosses.
The study says the “divorce rate” in the study population varied substantially across years and was directly modulated by temporal environmental variability. Higher “divorce rates” were recorded in lower-quality years, it says.
“Our work provides, to our knowledge, the first evidence of a significant influence of the prevailing environmental conditions on the prevalence of divorce in a long-lived socially monogamous population,” it says.
It says all the modelling techniques adopted consistently show that “divorce” is triggered by breeding failure, “but, crucially, that it is also promoted by environmental harshness”.
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“Hence, in light of the dramatic extent of the current climatic changes, the environmentally driven disruptions of the breeding processes of socially monogamous populations might represent an overlooked consequence of global change, with repercussions on demography and population dynamics,” the authors note.