Variable vital rates and the risk of population declines in Adélie penguins from the Antarctic Peninsula region

Abstract

Abstract. Predicting population responses in changing environments is an important task for ecologists.In polar regions, climate warming, loss of sea ice, and more frequent anomalous events suggest that further reductions in ice-dependent animal populations are likely. We assess the risk of near-term (30-year) depletion of an Ad elie penguin (Pygoscelis adeliae) population with a stochastic matrix model parameterized with 30 yr of data from the Copacabana colony on King George Island, Antarctica. The model was fitted to nest census data by estimating correction factors for survival rates estimated from a multi-state mark-recapture model. We modeled future survival and fecundity scenarios during the projection period (2012-2041) based on a two-state Markov chain that randomly assigned survival rates and reproductive success from their respective historical distributions to represent "good" and "poor" years. Monte Carlo simulation was used to estimate population trajectories across a range of progressively worse survival conditions. The results suggest that, given historical distributions of survival and reproductive success, a limited scope for recovery of the population is present, commensurate with recent stabilization in population size at the study site. However, our projections mainly suggest that the Ad elie penguin population will decline if the frequency of years with poor survival remains at, or increases above, its 30-year mean. The risk of local depletion within 30 yr, defined according to International Union for Conservation of Nature categories for endangered and critically endangered species, was 33% for >90% declines, but near 100% for 50% declines given status-quo conditions. As survival conditions worsen, the risk of substantive depletions rose rapidly. Given expectations of further environmental and ecosystem changes in the northern Antarctic Peninsula region, continued declines in Ad elie penguin population size at the northern extent of their range should be expected.

Variability and change in the west Antarctic Peninsula marine system: Research priorities and opportunities

“…Populations of icedependent Adélie and chinstrap penguins have declined significantly (e.g. Figure 14; Ducklow et al 2013;Hinke et al 2017a;Juares et al 2015;Trivelpiece et al 2011) and the only Emperor penguin colony at the WAP has been lost due to changes in seasonal sea ice duration (Trathan et al 2011). Southward shifts of the maritime climate, displacing the Antarctic climate, have also increased precipitation and snow accumulation, which reduces the survival of Adélie penguin chicks (Carlini et al 2009;Chapman et al 2011).…”

Long-term observations from Antarctica demonstrate that mismatched scales of fisheries management and predator-prey interaction lead to erroneous conclusions about precaution

“…2), the posterior predictive distributions from our model indicate that any performance index, including recruitment, would be less than its long-term mean with a probability of 0.77 (Table 1). An increased probability of poor recruitment raises the risk of population declines, as has been shown for Adélie penguins 31 . Although penguins may compensate so that their performance is not reduced after the birds are "challenged", e.g.…”

Study of fauna population changes on Penguin Island and Turret Point Oasis (King George Island, Antarctica) using an unmanned aerial vehicle

“…Moreover, some authors suggest that further reductions in the icedependent Adélies population are likely if the frequent climate anomalous events continue (Ainley et al 2010;Hinke et al 2017). …”