Wednesday 4 April 2012

Antarctic warming changing penguin breeding cycles, and success

Gentoo happier than Adelie & Chinstrap
March 2012. 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.
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.
Rapid warming 
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.
Gentoo numbers booming, Chinstrap and Adelie declining
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 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 (MEPS).
http://www.wildlifeextra.com/go/news/gentoo-chinstrap.html

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