Stay-at-home penguins have advantage as temperatures rise

Gentoo penguin feeding its chick
by Liam Q, on Flickr.
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ANTARCTICA - Three penguin species that share the Western Antarctic Peninsula for breeding grounds have been affected in different ways by the higher temperatures brought on by global warming, according to Stony Brook University Ecology and Evolution Assistant Professor Heather Lynch and colleagues. The work by Lynch and her team is contained in three papers that have been published online in Polar Biology, Ecology and Marine Ecology Progress Series.

Lynch and her colleagues used a combination of field work and, increasingly, satellite imagery to track colonies of three penguin species – Adélie, chinstrap and gentoo. The Adélie and chinstrap migrate to the peninsula to breed, while the gentoo are year-round residents.

The Antarctic is considered one of the world’s most rapidly warming regions. Warmer temperatures move up the breeding cycle, causing the penguins to lay their eggs earlier. The resident gentoo population is able to adapt more quickly and advance their “clutch initiation” by almost twice as much as the other species. Lynch believes this may allow them to better compete for the best nesting space. The Adélie and chinstrap are unaware of the local conditions until they arrive to breed and have not been able to advance their breeding cycles as rapidly.

In addition, the gentoo prefer areas with less sea ice, and have been able to migrate further south into the Antarctic as the sea ice shrinks. The chinstrap and Adélie species rely more heavily on the abundance of Antarctic krill, which require sea ice for their lifecycle.

The result – the gentoo numbers are increasing while the other two species have noticeably dwindling populations on the Antarctic Peninsula.

The scientists have uploaded their satellite imagery of penguins and other species that live or breed in the polar regions to Google Earth. Lynch said the use of Google Earth has helped to “democratise the science” in that anyone can view the images.

Satellite imagery has advanced the science of tracking penguin populations, drastically reducing the time needed to do a census and even helping to find previously unknown colonies. What took weeks to accomplish through field work can now be done in hours through the use of satellites.

The three online papers are:
Spatially integrated assessment reveals widespread changes in penguin populations on the Antarctic Peninsula, Lynch, Heather J., Ron Naveen, Philip N. Trathan, and William F. Fagan. In press, Ecology. 
Differential advancement of breeding phenology in response to climate may alter staggered breeding among sympatric pygoscelid penguins, Heather J. Lynch, William F. Fagan, Ron Naveen, Susan G. Trivelpiece, Wayne Z. Trivelpiece, Marine Biology Progress Series.
Detection, differentiation, and abundance estimation of penguin species by high-resolution satellite imagery, Heather J. Lynch, Richard White, Andrew D. Black and Ron Naveen, Polar Biology.

Source
SBU professor tracks Antarctic penguin breeding cycles, Stony Brook News, 21 March 2012