January 18, 2022 11:27 pm

Disappearing Arctic ice threatens seabird populations

A new study of Institute of Marine Sciences (ICM-CSIC) of Barcelona and the Norwegian Polar Institute (NPI) has revealed that the loss of sea ice threatens the future of Arctic seabird populations, most of which preferentially feed on fish and crustaceans found on the edges of sea ice.

The research, recently published in the specialized journal Diversity and Distributions, assesses the relationship between the retreat of sea ice in recent decades and the simultaneous decline in Arctic seabird populations, and provides some of the scant empirical evidence linking changes in the cryosphere ─the part of the terrestrial system where the water is in solid form─ with the population dynamics of the large predators of the Arctic.

This work provides empirical evidence that relates the changes in the cryosphere with the population dynamics of the species

“The Arctic is warming faster than any other region on Earth, leading to a very rapid and pronounced reduction in the extent, thickness and seasonal duration of the ice, which is expected to have major effects on wildlife in the Arctic. Arctic “, explains the NPI researcher Sebastien Descamps, which adds that “since the responses of populations of Arctic organisms to the lack of sea ice are not always direct, since different species and populations tend to respond differently, studies like this one are key to understanding the impact its loss in Arctic ecosystems. “

Decline in populations due to thaw

To carry out the study, the researchers traveled to the Svalbard Islands, a Norwegian archipelago located in one of the northernmost areas of the Arctic, to observe two of the most common seabirds in the Arctic area, the arao de Brünnich (Uria lomvia) and the tridactyl gull (Rissa tridactyla). Both basically feed on organisms associated with ice, and this makes them ideal species for evaluating the importance of ice conditions and the population dynamics of Arctic species.

During the period from 1988 to 2018, several colonies of these two species that nest in the archipelago were monitored and the size of their populations was evaluated. Thanks to this follow-up, both were found to have decreased since the mid-1990s.

The concentration of sea ice is associated with the size of the colonies of these birds with a lag of two years

The new analyzes carried out now not only reveal similar long-term trends in the dynamics of birds and sea ice, but also reveal that the concentration of sea ice is associated with the colony size with a lag of two years.

“We intuit that poor sea ice conditions in a given year lead to low food availability two years later. This would affect the probability of breeding and therefore the size of the colonies of gulls, guillemots and probably that of other predators that feed on prey related to it, “he details Francisco Ramirez, ICM-CSIC researcher.

Effects of climate change

While this study provides consistent evidence pointing to the Arctic thaw As a possible cause of the declines in the populations of these animals, the authors emphasize that variations in sea ice only explain a relatively small part of the observed changes in the size of the colonies, which suggests that there are other local or regional factors. that could affect population trends for gulls and guillemots.

The presence of glaciers can create key small-scale feeding areas that favor certain seabirds

In this sense, experts maintain that the presence of glaciers releasing large volumes of meltwater can create key small-scale foraging areas that favor certain surface-feeding seabirds, such as gulls. As a consequence, the impact of heating Ocean and sea melt on Arctic organisms can differ between species and geographic areas.

“All of this highlights the need to have monitoring programs long-term, comprehensive studies aimed at assessing the population dynamics of different Arctic species if we want to understand how climate change will affect this area in the future, “the researchers conclude.

Source:

Institute of Marine Sciences of the CSIC

Rights: Creative Commons.

Reference-www.agenciasinc.es

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