Better late than never? Interannual and seasonal variability in breeding chronology of gentoo penguins at Stranger Point, Antarctica

Juáres, Mariana A.; Santos, Mercedes; Negrete, Javier; Santos, Maria Rita de Morais Chaves; Mennucci, Jorge Augusto; Rombolá, Emilce; Longarzo, Lucrecia; Coria, Néstor Rubén; Carlini, Alejandro R

doi:10.3402/polar.v32i0.18448

Cited by 12 publications

(19 citation statements)

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“…A clear decline in chinstrap penguin populations across the same region has also been established [6, 8, 9, 11–13]. However gentoo penguins, despite declining or showing a high degree of variability in the East Antarctic Peninsula [12] have otherwise shown an opposing response to the other two species with the majority of surveyed populations either remaining constant or increasing and expanding southwards [6, 8, 11, 12, 14–16]. …”

Section: Introductionmentioning

confidence: 99%

Population Size and Decadal Trends of Three Penguin Species Nesting at Signy Island, South Orkney Islands

et al. 2016

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We report long-term changes in population size of three species of sympatrically breeding pygoscelid penguins: Adélie (Pygoscelis adeliae), chinstrap (Pygoscelis antarctica) and gentoo (Pygoscelis papua ellsworthii) over a 38 year period at Signy Island, South Orkney Islands, based on annual counts from selected colonies and decadal all-island systematic counts of occupied nests. Comparing total numbers of breeding pairs over the whole island from 1978/79 to 2015/16 revealed varying fortunes: gentoo penguin pairs increased by 255%, (3.5% per annum), chinstrap penguins declined by 68% (-3.6% per annum) and Adélie penguins declined by 42% (-1.5% per annum). The chinstrap population has declined steadily over the last four decades. In contrast, Adélie and gentoo penguins have experienced phases of population increase and decline. Annual surveys of selected chinstrap and Adélie colonies produced similar trends from those revealed by island-wide surveys, allowing total island population trends to be inferred relatively well. However, while the annual colony counts of chinstrap and Adélie penguins showed a trend consistent in direction with the results from all-island surveys, the magnitude of estimated population change was markedly different between colony wide and all island counts. Annual population patterns suggest that pair numbers in the study areas partly reflect immigration and emigration of nesting birds between different parts of the island. Breeding success for all three species remained broadly stable over time in the annually monitored colonies. Breeding success rates in gentoo and chinstrap penguins were strongly correlated, despite the differing trends in population size. This study shows the importance of effective, standardised monitoring to accurately determine long-term population trajectories. Our results indicate significant declines in the Adélie and chinstrap penguin populations at Signy Island over the last five decades, and a gradual increase in gentoo breeding pairs.

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Section: Introductionmentioning

confidence: 99%

Population Size and Decadal Trends of Three Penguin Species Nesting at Signy Island, South Orkney Islands

et al. 2016

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“…Applying the method to a recently deployed network of time‐lapse cameras demonstrated its utility across monitoring sites and research teams, and, importantly, provided results consistent with known phenological variation due to colony latitude and plasticity among the pygoscelid penguins breeding in the Antarctic Peninsula region (Black, ; Hinke, Polito, Reiss, Trivelpiece, & Trivelpiece, ; Lynch, Fagan, Naveen, Trivelpiece, & Trivelpiece, ). In particular, the relatively high degree of plasticity in gentoo penguins relative to Adélie penguins has been shown for inter‐annual differences in phenology (Hinke et al., ; Juáres et al., ). This work extends that result to suggest intra‐annual plasticity is also higher in gentoo penguins than in Adélie penguins.…”

Section: Discussionmentioning

confidence: 96%

Estimating nest‐level phenology and reproductive success of colonial seabirds using time‐lapse cameras

et al. 2018

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Abstract1. Collecting spatially extensive data on phenology and reproductive success is important for seabird conservation and management, but can be logistically challenging in remote regions. Autonomous time-lapse camera systems offer an opportunity to provide such coverage.2. We describe a method to estimate nest-level breeding phenology and reproductive success of colonial pygoscelid penguins using photographs from time-lapse cameras. The method derives from stereotypical patterns of nest attendance, where predominantly two adults are present before and during laying, but switch to one adult during incubation. The switch approximates the date of clutch completion and is estimated by fitting a smoothing spline to daily nest attendance data, identifying candidate dates that switch from two adults to one and selecting the date when the first derivative of the spline is minimized. Clutch initiation and hatch dates are then estimated from the mean, species-specific interval between laying (pygoscelid penguins typically lay two eggs) and the duration of the incubation period. We estimated these intervals for each species from historical field data. The phenology is adjusted when photographs indicate egg or chick presence prior to their estimated lay or hatch dates. The number of chicks alive in each study nest on its crèche date determines reproductive success estimates. The method was validated with concurrent direct observations for each species and then applied to a camera network in the Antarctic Peninsula region to demonstrate its utility.3. Mean egg laying and incubation intervals from direct observations were similar within species across sites. In the validation study, the mean clutch initiation, hatch and crèche dates were generally equivalent between photographs and This article has been contributed to by US Government employees and their work is in the public domain in the USA. | Methods inEcology and Evoluঞon HINKE Et al. | INTRODUC TI ONData on reproduction, including breeding phenology and nest success, are important for management and conservation of seabirds globally (Cairns, 1987;Constable, de la Mare, Agnew, Everson, & Miller, 2000;Cury et al., 2011). In particular, breeding phenology and reproductive success data from seabirds are thought to indicate general conditions of marine ecosystems (Cairns, 1987) and represent important components for the development of 4. The method accurately estimated phenology and reproductive success relative to direct observations and appears well-suited to operationalize regional time-lapse camera networks. The estimation method should be applicable for other seabirds with stereotypical nest attendance patterns from which breeding phenology could be estimated. K E Y W O R D SAntarctica, camera, monitoring, penguin, phenology, reproductive success, seabird, time-lapse | 1855Methods in Ecology and Evoluঞon HINKE Et al. peak attendance of adults at the colony level was synchronized at the start of laying in Adélie penguins Pygoscelis adeliae. Here, we extend this ...

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“…The gentoo penguins exhibited life-history strategies that help reduce seasonal and interannual variability in breeding success. Their plasticity in reproductive phenology and the selection of better nesting sites might contribute to maintaining the breeding success under adverse local conditions (Juáres et al 2013). In contrast, the Adélie penguins are less flexible in their reproductive chronology and exhibited high nesting site fidelity, suggesting that this species was unable to cope with the adverse effects of snow (Juáres 2013).…”

Section: Discussionmentioning

confidence: 99%

Adélie penguin population changes at Stranger Point: 19 years of monitoring

et al. 2015

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The Adélie penguin (Pygoscelis adeliae) breeding population at Stranger Point, King George Island (25 de Mayo), increased in number from 1965/66 until 1980/81 after which it started to decrease almost continuously up to the present. A significant decrease in the number of breeding pairs and chicks crèched was observed between 1995/96 and 2013/14 (75% and 78%, respectively), although the rate of this decrease has slowed since 2006/07. Over the last seven years, larger interannual fluctuations were recorded in the number of breeding pairs and chicks in crèches, as well in the breeding success. The values for the index of breeding success during 2007/08, 2009/10 and 2012/13 were low and this parameter showed higher temporal fluctuation in the period 2007/08 to 2013/14. The reduction in breeding success and the number of chicks reared to crèche will unfavourably impact on future population size at Stranger Point through the reduction of new recruits. Although Adélie penguin population trends on the Antarctic Peninsula are linked to the marine environment variability (i.e. reduction in sea ice affecting the availability of prey), breeding success is also influenced by the amount of snow fall which has increased in recent years.

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Better late than never? Interannual and seasonal variability in breeding chronology of gentoo penguins at Stranger Point, Antarctica

Cited by 12 publications

References 54 publications

Population Size and Decadal Trends of Three Penguin Species Nesting at Signy Island, South Orkney Islands

Population Size and Decadal Trends of Three Penguin Species Nesting at Signy Island, South Orkney Islands

Estimating nest‐level phenology and reproductive success of colonial seabirds using time‐lapse cameras

Adélie penguin population changes at Stranger Point: 19 years of monitoring

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