Evolutionary and ecological aspects of some Antarctic and sub-Antarctic penguin distributions

Abstract

Penguins probably originated in the core of Gondwanaland when South America, Africa, and Antarctica were just beginning to separate. As the continents drifted apart, the division filled with what became the southern ocean. One of the remaining land masses moved south and was caught at the pole by the Earth's rotation. It became incrusted with ice and is now known as East Antarctica. Linking it to South America was a series of submerged mountain ranges that formed a necklace of islands. The northern portion of the necklace, called the Scotia Arc, is now the "fertile crescent" of the Southern Ocean. The greatest numbers and biomass of penguins are found here as well as that of krill, the primary prey species of most penguins, and many other marine predators. Today penguins are found throughout the sub-Antarctic islands and around the entire Antarctic continent. Using satellite transmitters and time-depth recorders, while taking advantage of the parental dedication of breeding birds, numerous investigators have described foraging habits of several species of penguins. The information obtained is labor intensive and costly so that studies are restricted to certain species, areas and seasons. Here I review the patterns evident among six of the most abundant and completely studied of the penguins. The variation in behavior is considerable from those species that seldom dive deeper than 20 m in search of prey to those that will dive to depths >500 m to catch mesopelagic fish and squid. Foraging trips from breeding colonies vary among species and with the season. Often the birds travel no more than 30 km and at other times the trips may exceed 600 km. Sub-Antarctic species often reach more productive waters near or within the Antarctic Polar Front zone, where the mixing of Antarctic and sub-Antarctic waters provide rich resources for their prey. Antarctic species usually remain close to shore, along the continental slope, or near the sea ice edge. Less is known about penguins during the pelagic phase between breeding cycles. What we do know is surprising in regard to their dispersal, which ranges from hundreds to thousands of kilometers from the breeding colonies.

The Basal Penguin (Aves: Sphenisciformes) Perudyptes devriesi and a Phylogenetic Evaluation of the Penguin Fossil Record

“…Thus, a shift in feeding ecology may be an important factor in the success of Spheniscidae. Potential drivers of this shift remain untested, but two intriguing possibilities include the development of the biomass-rich ''fertile crescent'' of the Southern Ocean created by the circumpolar current in the early Neogene (Kooyman, 2002) and competition with marine mammals (Simpson, 1976;Olson, 1985;Warheit and Lindberg, 1988 (Cody Fraser, personal commun.). Older specimen numbers are listed in parentheses to aid comparisons with previous work (e.g., Marples, 1952;Simpson 1971b;Ksepka et al, 2008 AMNH 3274, 3276, 3285, 3287, 3289, 3295, 3297-3298, 3316, 3321, 3323, 3330, 3336, 3340, 3343-3344, 3349, 3352, 3355, 3358;MUSM 257, Acosta Hospitaleche et al (2008 single (0); bipartite (1).…”

Life Hung by a Thread: Endurance of Antarctic Fauna in Glacial Periods

“…Additionally, the Antarctic ice sheet had thickened during the LGM and therefore depressed the continent isostatically, so that the average water depth of the Antarctic shelf during the LGM was probably deeper than 280 m. This is confirmed by the numerous occurrences of raised beaches along the present Antarctic coast, which date back to the time of post-LGM ice retreat and have raised by isostatic uplift in response to ice sheet thinning (e.g., Conway et al 1999, Takada et al 2003, Bentley et al 2005. Consequently, penguins had to move to subantarctic regions in order to breed successfully (Ainley 2002), which should have implied competition with modern subantarctic penguin species occupying very similar ecological niches (Kooyman 2002). Due to the sea-level drop during the last glacial period, ideal alternative breeding grounds for Antarctic penguins might have been the Patagonian shelf, which unfortunately remains submerged today and is thus difficult to sample for radiocarbon dating of potential LGM penguin colonies.…”

Biological invasions in the Antarctic: extent, impacts and implications

“…These threats are serious, as the ice-free areas of Antarctica support a large proportion of the world's seabird species (Chown, Gaston & Williams, 1998 a ;Woehler et al, 2001 ;Kooyman, 2002), and their biotas, though species poor (Gressitt, 1970 ;Chown et al, 1998b ;Vernon, Vannier & Tréhen, 1998 ;Convey, 2001a), include a high proportion of endemic taxa (lichens -Øvstedal & Smith, 2001 ; liverworts -Bednarek-Ochyra et al, 2000 ; flowering plants - Greene & Walton, 1975 ;mites -Pugh, 1993 ;springtails -Greenslade, 1995 ;insects -Gressitt, 1970 ;Chown, 1990 ;nematodes -Andrássy, 1998). Human influence has increased rapidly.…”