The Effects of Weather and Ice Conditions on Breeding in Adélie Penguins

Varying the timing of reproduction in response to local environmental conditions is a key factor influencing reproductive success. We used 19 yr (1991 to 2009) of data on breeding chronology and reproductive success of Adélie penguins Pygoscelis adeliae and gentoo penguins P. papua at King George Island, Antarctica to compare clutch initiation dates (CIDs), hatch rates, and crèche rates at population and individual levels. The CIDs of both species occurred earlier with warmer October temperatures, but gentoo penguins adjusted CIDs twice as much per °C of temperature as Adélie penguins. Gentoo penguins also exhibited lower variances in hatch and crèche rates than Adélie penguins, suggesting that greater ability to respond to ambient conditions can buffer reproductive success. Mixed-effects models revealed that individual-and yearspecific random effects on the overall population mean best accounted for observed variation in CIDs, with some individuals routinely breeding earlier than others. However, individual differences in the relative timing of breeding provided no advantage for long-term reproductive success. The results suggest that, among gentoo and Adélie penguins, plasticity in CIDs with respect to environmental conditions is primarily a population-level rather than an individual-level response. Energetic constraints of contrasting migratory and fasting behaviors likely contribute to the different abilities to respond to warming spring temperatures. Overall, larger responses of gentoo penguin CIDs to October temperature and lower variability in reproductive success, despite reduced reproductive success with delayed breeding, suggests that gentoo penguins are better equipped than Adélie penguins to adjust to rapid warming in the Antarctic Peninsula ecosystem.KEY WORDS: Phenology · Adélie · Gentoo · Climate change · Migrant Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 454: 91-104, 2012 92 should exhibit higher and/or less variable reproductive success relative to those less able to respond to ambient conditions. In the present study, we compared the response in breeding chronology to changing environmental conditions in the Antarctic Peninsula region of 2 species of Pygoscelis penguins that have exhibited long-term divergent trends in abundance. We specifically investigated the relative importance of population-versus individual-level plasticity on reproductive success among Adélie penguins P. adeliae and gentoo penguins P. papua.The Antarctic Peninsula region is currently undergoing rapid environmental changes, including increased air and sea temperatures (Meredith & King 2005, Turner et al. 2005a, declines in the duration of winter sea ice (Stammerjohn et al. 2008), and increases in frequency and amount of precipitation (Turner et al. 2005b, Thomas et al. 2008. These environmental factors are important for penguins, as they can influence marine primary production (Schofield et al. 2010), food distribution (Loeb et al. 1997), and physical cond...

Section: Other Factors That Limit Breeding Successmentioning

confidence: 99%

Flexible reproductive timing can buffer reproductive success of Pygoscelis spp. penguins in the Antarctic Peninsula region

Hinke

Polito²,

Reiss³

et al. 2012

“…Adélie penguins are considered ice-obligate over winter , Ainley 2002 and are closely associated with sea ice in summer , Ainley 2002. During incubation this species commonly forages 200 km or more from its breeding colonies (Davis & Miller 1992, Kerry et al 1995a).…”

Section: Foraging Ranges During Breeding and Environmental Constraintsmentioning

confidence: 99%

“…Proximity of Adélie penguin colonies to polynyas provides crucial access to foraging grounds during spring as well as opportunities for faster travelling rates and wider distribution of foraging birds , Arrigo & van Dijken 2003, Ainley et al 2004. Penguins tracked during incubation in this study walked directly to the nearest margin of the Taylor Glacier polynya before moving northwards into the pack ice, using the polynya as access to the pack ice zone rather than as a foraging locality per Large Adélie penguin breeding colonies are only found in regions where fast ice typically breaks out from the Antarctic coastline before or soon after chicks hatch , Ainley 2002. The presence of excessive fast ice or heavy pack ice during the chick rearing period restricts access to prey, resulting in reduced breeding success in years of extensive ice cover (Yeates 1968, Ainley & LeResche 1973, Spurr 1975, Whitehead et al 1990, Irvine et al 2000, Clarke et al 2002.…”

Section: Foraging Ranges During Breeding and Environmental Constraintsmentioning

confidence: 99%

“…Adélie penguins are known to moult on large ice floes, ice bergs and sheltered areas of land (Ainley 2002), but how far they range from their breeding sites at this time of year is virtually unknown. Penguins foraging prior to moult are no longer provisioning offspring and are thus free to travel further from the colony to search for food.…”

Section: Foraging Ranges During Breeding and Environmental Constraintsmentioning

confidence: 99%

See 1 more Smart Citation

Environmental conditions and life history constraints determine foraging range in breeding Adélie penguins

Clarke¹,

Emmerson²,

Otáhal³

2006

Foraging movements of Adélie penguins are constrained both by environmental conditions (e.g. sea ice cover) and life history factors (e.g. regular offspring provisioning). We describe within season changes in foraging range, trip duration and body condition of Adélie penguins nesting at Béchervaise Island, East Antarctica, in the context of these constraints. Penguins were satellite tracked over multiple seasons during the incubation, guard, crèche and pre-moult phases of their annual cycle. They ranged farthest during incubation when sea ice was extensive and shortest during the guard stage when chicks were small and sea ice limited in extent. Prior to their annual moult the birds foraged hundreds of kilometres to the west and east of their breeding sites. A recurrent polynya facilitated access to the sea early in the season when ice cover was extensive. Kernel analyses showed that penguins foraged most intensively close to the colony, along submarine canyons and at the continental shelf break. Increases in foraging range, as the chick rearing period progressed, were consistent with changing energy requirements of adults and chicks and likely intraspecific competition. Whilst provisioning their offspring, penguins adopted a variable combination of time minimising and food maximising foraging behaviour in which choice of foraging rule was determined largely by adult body condition.

“…Adélie penguins are a sea-ice-dependent species throughout their circumpolar range (Ainley et al 1983, 1994, Fraser et al 1992, Fraser & Trivelpiece 1996, but only in the mid-to northern WAP is the diet of this species dominated by Euphausia superba (Volkman et al 1980, Fraser & Trivelpiece 1996. In continental Antarctica, Adélie penguins rely more on the Antarctic silverfish Pleuragramma antarcticum and the krill E. crystallorophias, 2 species with a more on-shelf distribution than E. superba (Clarke et al 1998, Ainley 2002. Compared to continental Antarctica, the WAP continental shelf is very narrow, sea ice is less prevalent annually, and important hydrographic features such as Circumpolar Deep Water (the most voluminous water mass carried by the Antarctic Circumpolar Current) occur relatively close to shore (Hofmann et al 1996.…”

Section: Introductionmentioning

confidence: 99%

A predator's perspective on causal links between climate change, physical forcing and ecosystem response

Fraser¹,

Hofmann²

2003

234

242

ABSTRACT:The mechanisms by which variability in sea ice cover and its effects on the demography of the Antarctic krill Euphausia superba cascade to other ecosystem components such as apex predators remain poorly understood at all spatial and temporal scales, yet these interactions are essential for understanding causal links between climate change, ecosystem response and resource monitoring and management in the Southern Ocean. To address some of these issues, we examined the longterm foraging responses of Adélie penguins Pygoscelis adeliae near Palmer Station, western Antarctic Peninsula, in relation to ice-induced changes in krill recruitment and availability. Our results suggest that (1) there is a direct, causal relationship between variability in ice cover, krill recruitment, prey availability and predator foraging ecology, (2) regional patterns and trends detected in this study are consistent with similar observations in areas as far north as South Georgia, and (3) largescale forcing associated with the Antarctic Circumpolar Wave may be governing ecological interactions between ice, krill and their predators in the western Antarctic Peninsula and Scotia Sea regions. Another implication of our analyses is that during the last 2 decades in particular, krill populations have been sustained by strong age classes that emerge episodically every 4 to 5 yr. This raises the possibility that cohort senescence has become an additional ecosystem stressor in an environment where ice conditions conducive to good krill recruitment are deteriorating due to climate warming. In exploring these interactions, our results suggest that at least 1 'senescence event' has already occurred in the western Antarctic Peninsula region, and it accounts for significant coherent decreases in krill abundance, predator populations and predator foraging and breeding performance. We propose that krill longevity should be incorporated into models that seek to identify and understand causal links between climate change, physical forcing and ecosystem response in the western Antarctic Peninsula region.