1 Tahrcountry Musings: Estimating the population of Emperor penguins using a single synoptic survey

Sunday, April 15, 2012

Estimating the population of Emperor penguins using a single synoptic survey

In this piece of path breaking research, the researchers attempted to estimate the population of emperor penguins (Aptenodytes fosteri) using a single synoptic survey. They examined the whole continental coastline of Antarctica using a combination of medium resolution and Very High Resolution (VHR) satellite imagery to identify emperor penguin colony locations. Where colonies were identified, VHR imagery was obtained in the 2009 breeding season. The remotely-sensed images were then analysed using a supervised classification method to separate penguins from snow, shadow and guano. Actual counts of penguins from eleven ground truthing sites were used to convert these classified areas into numbers of penguins using a robust regression algorithm

Four new colonies were discovered. The location of three previously suspected sites was confirmed. Total number of emperor penguin breeding colonies was put at 46. The researchers estimated the breeding population of emperor penguins at each colony during 2009 and provide a population estimate of ~238,000 breeding pairs. This is against the last previously published count of 135,000–175,000 pairs). The researchers say based on published values of the relationship between breeders and non-breeders, this translates to a total population of ~595,000 adult birds.

The researchers contend that their work now provides a comprehensive estimate of the total breeding population that can be used in future population models and will provide a baseline for long-term research.

Citation: Fretwell PT, LaRue MA, Morin P, Kooyman GL, Wienecke B, et al. (2012) An Emperor Penguin Population Estimate: The First Global, Synoptic Survey of a Species from Space. PLoS ONE 7(4): e33751. doi:10.1371/journal.pone.0033751

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