Although Adélie, chinstrap and gentoo penguins share their western Antarctic Peninsula breeding grounds, new research has discovered that rising temperatures have been affecting the breeding cycles of the three species in different ways.
Tracking penguin colonies
Professor Heather Lynch and her colleagues from Stony Brook University used a combination of fieldwork and satellite imagery to track colonies of the three penguin species and monitor how their breeding cycles were affected by the region’s warming temperatures.
Currently, the Antarctic is considered to be one of the world’s most rapidly warming regions and is one of the areas most impacted by global climate change.
Shifting breeding cycles
According to Lynch’s research, warmer temperatures cause a shift in the breeding cycle, causing the Peninsula’s penguin inhabitants to lay their eggs earlier. The researchers found that the resident gentoo penguin population is able to adapt more quickly to this change, with these birds able to bring their egg laying dates forward by almost twice as much as the Adélie or chinstrap penguins.
Lynch believes this may allow the gentoo penguin to better compete for the best nesting space. In addition, the gentoo prefers areas with less sea ice, and has been able to migrate further south into the Antarctic as the sea ice shrinks as a result of the warming temperatures.
While gentoo penguins are year-round residents on the Antarctic Peninsula, Adélie and chinstrap penguins migrate to the Peninsula to breed. The researchers believe that the Adélie and chinstrap penguins are not aware of the local conditions in the region until they arrive, and have not been able to advance their breeding cycles as rapidly as the gentoo penguin.
Chinstrap and Adélie penguins also rely more heavily on sea ice due to their dependence on Antarctic krill, a species which lives under the sea ice for parts of its lifecycle, for food.
Changing penguin populations
As a result of changing conditions in the region, the number of gentoo penguins has been increasing on the Antarctic Peninsula, while populations of both Adélie and chinstrap penguins have noticeably dwindled in recent years.
Analyses carried out by Lynch and her team have confirmed that populations of the Adélie penguin have decreased at almost all of its breeding locations on the Antarctic Peninsula. The researchers have also helped to resolve previous contradictory studies that suggest that the chinstrap penguin may benefit from decreasing sea ice, and have instead shown that populations of this species are also decreasing in the region.
Read the Stony Brook University press release about Lynch’s work.
For more information on the Antarctic visit ARKive’s Antarctic ecoregion page.
Helen Roddis, ARKive Species Text Author