Many seabirds are now acutely threatened. However, it is particularly difficult to protect species that spend a large part of their lives on the high seas, because the areas required for this cannot be easily identified. Researchers have now discovered such an area in the middle of the North Atlantic by tracking seabirds. It is visited intensively every year, at times more than four million seabirds stay there. Such a large concentration of birds on the high seas has never been detected before.
Whether hawk-sku, guillemot or fulmar – many seabirds are doing badly and their populations are shrinking. Some of them suffer from the effects of marine pollution and overfishing, which makes it difficult for them to forage. Others are affected by the ongoing destruction of their breeding areas by human activity or have to move to new areas due to climate change. In principle, protected areas could help to protect endangered bird species and their habitats more effectively and to safeguard biodiversity.
Searching for clues with tracking data
The problem, however, is that many species of seabirds travel far and wide and migrate thousands of kilometers through national and international waters. In order to survive, they depend on the preservation of several very different and sometimes widely spaced areas and ecosystems. Because if one were only to protect their breeding area, but not the areas in which they look for food, the birds would still not be able to survive in the long run. It is therefore particularly difficult to identify suitable areas for seabird sanctuaries. “As a result, seabirds are one of the most endangered groups of vertebrates, with almost half of all species experiencing a decline”, explains Johannes Lang from the Justus Liebig University in Giessen.
To change that, Lang and an international team led by Tammy Davies from the nature conservation organization BirdLife International have now evaluated the observation and population data of 23 seabird species and supplemented them with tracking data that had been fed into a central database of BirdLife International. This data is based on electronic location methods in which the movements of birds are tracked over a longer period of time, for example using a GPS tracker. The research team evaluated a total of 2188 routes of 23 seabird species in the Atlantic area.
Largest known collection of birds on the high seas
This revealed an area in the North Atlantic that seems to play a prominent role for most of the species examined. This “hotspot” is located in the middle of the North Atlantic between the 41st and 53rd degrees of latitude north and the 31st to 42nd degree of longitude west. It extends from the offshore sandbanks of Newfoundland to the Azores. “We estimate that between 2.9 to five million birds use this area over the course of a year,” report Davies and her team. “This is the first time that a seabird accumulation of this size has been detected anywhere on the high seas.” The area has both feeding grounds and 56 breeding colonies of the species examined.
However, the mapped seabird species mainly stay there outside of their breeding season. This is one of the reasons why the number of birds in this North Atlantic hotspot is high, especially in winter. In three seabird species – the southern polar skua, the hawk skua and the dark shearwater – more than 60 percent of the total global population is staying in the North Atlantic hotspot at this time and hibernating there, as the scientists report. Another five of the species found in this area are also endangered worldwide – this refuge could therefore be particularly important for them. “Protection could help reduce current and future threats to species in this area,” says Lang.
According to the research team, this newly discovered seabird hotspot in the North Atlantic should be made a protected area as a matter of urgency. “Given the large number of seabirds and the stability of this hotspot, we believe that this area should be protected all year round as part of a marine reserve,” said Davies and her colleagues. After all, the area belongs to the areas of the North Atlantic that are already being considered as a marine reserve by the OSPAR Commission (Oslo-Paris-Convention on the protection of the North-East Atlantic).
Source: Justus Liebig University Giessen; Technical article: Conservation Letters, doi: 10.1111 / conl.12824