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Projected continent-wide declines of the emperor penguin under climate change
Abstract
Climate change has been projected to affect species distribution(1) and future trends of local populations(2,3), but projections of global population trends are rare. We analyse global population trends of the emperor penguin (Aptenodytes forsteri), an iconic Antarctic top predator, under the influence of sea ice conditions projected by coupled climate models assessed in the Intergovernmental Panel on Climate Change (IPCC) effort(4). We project the dynamics of all 45 known emperor penguin colonies(5) by forcing a sea-ice-dependent demographic model(6,7) with local, colony-specific, sea ice conditions projected through to the end of the twenty-first century. Dynamics differ among colonies, but by 2100 all populations are projected to be declining. At least two-thirds are projected to have declined by > 50% from their current size. The global population is projected to have declined by at least 19%. Because criteria to classify species by their extinction risk are based on the global population dynamics(8), global analyses are critical for conservation(9). We discuss uncertainties arising in such global projections and the problems of defining conservation criteria for species endangered by future climate change.
... All of those classed as endangered have population trends that are decreasing (Table 1). The populations' trend for emperor penguins is unknown (Table 1); however, various studies suggest that they will decline in the coming decades (Jenouvrier et al. 2009(Jenouvrier et al. , 2012(Jenouvrier et al. , 2014Trathan et al. 2011Trathan et al. , 2020. Indeed, it is recommended for the status of emperor penguins to be changed to vulnerable in the IUCN Red List due to the projected scenarios for this species (Trathan et al. 2020). ...
... However, the impact of global factors on penguins, such as climate change and how it may change in the future, is yet to be evaluated in numerous species (Gutt et al. 2015;Rintoul et al. 2018;Trathan et al. 2015;Xavier et al. 2017). Previous research suggests that ice-intolerant penguins (e.g., gentoo penguins) have expanded their range southward, whereas ice-obligate penguin species (e.g., emperor and Adélie penguins) may shift their distribution poleward in the future (Forcada and Trathan 2009;Jenouvrier et al. 2009Jenouvrier et al. , 2012Jenouvrier et al. , 2014McClintock et al. 2008). Such scenarios may vary regionally, as for example, Adélie penguins populations have been declining at the West Antarctic Peninsula, but increasing in the Ross Sea and some parts of the eastern Antarctica (Lynch et al. 2012;Trivelpiece et al. 2011). ...
... Indeed, projected changes for the twenty-first century are expected to have an impact in the feeding and foraging ecology of king penguins as well as their population sizes: foraging distance may increase (Cristofari et al. 2018), but detailed understanding is still not yet complete (Meijers et al. 2019). Also, based on long-term datasets, the projected impact of environmental change in emperor penguins will be negative, particularly following changes in the extent, formation, and persistence of sea ice, especially fast ice (Jenouvrier et al. 2014;Trathan et al. 2020). A climate-dependent demographic model projected that many colonies of emperor penguins would decrease from their current size by 2100 (assuming no emigration (Jenouvrier et al. 2014;Trathan et al. 2020)), and that including emigration may slow the anticipated global population decrease, but ultimately only delay it (Jenouvrier et al. 2017). ...
... All of those classed as endangered have population trends that are decreasing (Table 1). The populations' trend for emperor penguins is unknown (Table 1); however, various studies suggest that they will decline in the coming decades (Jenouvrier et al. 2009(Jenouvrier et al. , 2012(Jenouvrier et al. , 2014Trathan et al. 2011Trathan et al. , 2020. Indeed, it is recommended for the status of emperor penguins to be changed to vulnerable in the IUCN Red List due to the projected scenarios for this species (Trathan et al. 2020). ...
... However, the impact of global factors on penguins, such as climate change and how it may change in the future, is yet to be evaluated in numerous species (Gutt et al. 2015;Rintoul et al. 2018;Trathan et al. 2015;Xavier et al. 2017). Previous research suggests that ice-intolerant penguins (e.g., gentoo penguins) have expanded their range southward, whereas ice-obligate penguin species (e.g., emperor and Adélie penguins) may shift their distribution poleward in the future (Forcada and Trathan 2009;Jenouvrier et al. 2009Jenouvrier et al. , 2012Jenouvrier et al. , 2014McClintock et al. 2008). Such scenarios may vary regionally, as for example, Adélie penguins populations have been declining at the West Antarctic Peninsula, but increasing in the Ross Sea and some parts of the eastern Antarctica (Lynch et al. 2012;Trivelpiece et al. 2011). ...
... Indeed, projected changes for the twenty-first century are expected to have an impact in the feeding and foraging ecology of king penguins as well as their population sizes: foraging distance may increase (Cristofari et al. 2018), but detailed understanding is still not yet complete (Meijers et al. 2019). Also, based on long-term datasets, the projected impact of environmental change in emperor penguins will be negative, particularly following changes in the extent, formation, and persistence of sea ice, especially fast ice (Jenouvrier et al. 2014;Trathan et al. 2020). A climate-dependent demographic model projected that many colonies of emperor penguins would decrease from their current size by 2100 (assuming no emigration (Jenouvrier et al. 2014;Trathan et al. 2020)), and that including emigration may slow the anticipated global population decrease, but ultimately only delay it (Jenouvrier et al. 2017). ...
... Indeed, their long generation time (e.g. 16 years for the emperor penguin (Jenouvrier et al. 2014) but see review for penguins in Forcada and Trathan (2009)) makes evolutionary adaptability unlikely Trathan 2009, Cristofari 2016). This mismatch between the time they would require to adapt and the velocity of the changes is seriously threatening their future (Trathan et al. 2007, Tulloch et al. 2019, Rogers et al. 2020) even though populations of the same species disseminated around Antarctica may not respond uniformly due to regional differences in changes to the physical environment ). ...
... They are the tallest (ca. 80 cm -120 cm when the neck is fully stretched) and heaviest (up to 45 kg) living penguins (Stonehouse 1953), and their lifespan remains still unknown but estimated to be around 35-40 years (Jenouvrier et al. 2014). ...
... Juveniles will not return to their colony of origin and spend their first years of life at sea. Female emperor penguins will start breeding at 3-6 years of age, while males between 4-8 years (Jenouvrier et al. 2005(Jenouvrier et al. , 2014 (Orians and Pearson 1979), i.e. these predators have to commute between their breeding colony to feed their offspring and their feeding areas. The species is even the only central-place predator breeding in the middle of the austral winter (Ainley et al. 2005). ...
Iconic species used to raise public awareness, the Emperor penguin is first and foremost a top predator and umbrella species playing a pivotal role in Antarctic ecosystems. Standing at the forefront of climate upheavals, much remains to be learned about the ecology, distribution, and activities at sea of the species. Biologging allows to refine our understanding of the interactions between a species and the different components (biotic and abiotic) of its environment, in particular with a view of management, conservation, and assessment of the adaptive capacity of populations to face global change.In this study, we develop and share new equipment methods that increase equipment and data collection duration, while reducing the disturbance of the equipped individuals. By carrying out a spatio-temporal analysis of the data collected on individuals of different life-history stages, reproductive status, and from different colonies spanning around Antarctica, we investigate the species’ foraging behaviours and strategies and assess the influence of environmental conditions and habitat on these parameters. Such knowledge acquisition allows us to assess the degree of protection of the species at the scale of the Southern Ocean and to discuss strategic plans for conservation and management, such as the establishment of networks of Marine Protected Areas around the Antarctic continent.
... Starting in 2012, the International Union for Conservation of Nature listed the emperor penguin as Near Threatened due to climate change threats (BirdLife International, 2021). In 2008, the US Fish and Wildlife Service (FWS) determined that the emperor penguin did not warrant listing under the ESA, in part because of uncertainty in future predictions of sea ice conditions and a lack of significant population decline at the time (US Fish and Wildlife Service, 2008a) (Table 1) (Jenouvrier et al., 2009(Jenouvrier et al., , 2012(Jenouvrier et al., , 2014 were not designed to provide assessments relevant to any legal framework. The analysis described below is specifically tailored for decision-making under the ESA, and expands upon previous research by assessing the effects of annual extreme climate-related perturbations through exploration of various climate scenarios. ...
... Our new analysis builds upon past work (Jenouvrier et al., , 2012(Jenouvrier et al., , 2014(Jenouvrier et al., , 2017, but integrates recent published knowledge about colony dynamics including models that reflect extreme perturbations, something hitherto not included. Specifically, our model includes the effect of sea ice concentrations on vital rates (survival and reproduction) and accounts for differences in the impact of sea ice concentrations on adult survival for males and females to project the intrinsic population growth rate at each colony ( Figure S2). ...
... Here, we present for the first time the regional population projections and Table S1 shows the details of the colony name included in each of the five regions. This model was built over a decade of research (Jenouvrier et al., , 2012(Jenouvrier et al., , 2014(Jenouvrier et al., , 2017; see Supplementary Methods) based on long-term dataset on breeding emperor penguins at Pointe Géologie (#35, Figure 1). This colony has been monitored every year from 1962 onwards allowing the estimation of breeding success and breeding pair number (Barbraud & Weimerskirch, 2001 Figure S2). ...
Species extinction risk is accelerating due to anthropogenic climate change, making it urgent to protect vulnerable species through legal frameworks in order to facilitate conservation actions that help mitigate risk. Here, we discuss fundamental concepts for assessing climate change risks to species using the example of the emperor penguin (Aptenodytes forsteri), currently being considered for protection under the US Endangered Species Act (ESA). This species forms colonies on Antarctic sea ice, which is projected to significantly decline due to ongoing greenhouse gas (GHG) emissions. We project the dynamics of all known emperor penguin colonies under different GHG emission scenarios using a climate-dependent meta-population model including the effects of extreme climate events based on the observational satellite record of colonies. Assessments for listing species under the ESA require information about how species resiliency, redundancy and representation (3Rs) will be affected by threats within the foreseeable future. Our results show that if sea ice declines at the rate projected by climate models under current energy system trends and policies, the 3Rs would be dramatically reduced and almost all colonies would become quasi-extinct by 2100. We conclude that the species should be listed as threatened under the ESA.
... Complementary examinations using MODIS imagery indicate that the island-grazing event of D29B was ephemeral, relocating northward without contact by August 5, whereas the grazing of D30A spanned an entire week. If the D30A had arrive a few months later, its sojourn could not only endanger colony safety but also force penguins to take longer foraging routes, incurring additional energy expenditure and reducing feeding frequency for chicks, thereby reducing adult survival and breeding success (Jenouvrier et al., 2014). ...
... Colonies 9-11 on the western side of the island have average depths less than 200 m and are thus prone to grounding, although they have experienced fewer historical iceberg visits. Data from Mapping Application for Penguin Populations and Projected Dynam- (Jenouvrier et al., 2014;Trathan et al., 2020). Facing an escalating threat of iceberg collisions or groundings, penguin colonies, like Clarence Island, situated within iceberg drift hotspots could be more vulnerable in the future. ...
During August and September 2023, three giant icebergs, each bigger than Paris, successively grazed Clarence Island in the northeast of the Antarctic Peninsula, a home to a population of over 100 000 penguins. This incident may serve as a clarion call for the increasing iceberg calving due to global warming and its subsequent impact on the Antarctic ecosystem. Here we investigate this unexpected event and employ historical records and probabilistic analyses of iceberg grounding to assess the degree of impact on penguin colonies of Clarence Island. Among the eleven colonies, there is one with low impact, eight with medium impact, and two with high impact. The low-impact colony, Cape Lloyd, is located in the northern part of the island, while the high-impact colonies, False Ridge and Pink Pool, are in the southeast. The eight medium-impact colonies are distributed along both the eastern and western coasts of the island. This study provides essential support for evaluating the impact of iceberg activity on penguin colonies. We argue that penguin colonies located in areas prone to iceberg drift, such as Clarence Island, may become more vulnerable to the heightened risk of iceberg collisions or groundings in the warming future. Therefore, we hope the public will become more aware of the grave impacts of climate change on penguins and underscore the urgent need for effective conservation strategies.
... This forms a feedback loop: climate change drives biodiversity loss, leading to more carbon emissions, worsening climate change. Biodiversity conservation is thus essential for climate mitigation [16][17][18][19][20]. ...
... However, this shift towards a "nexus thinking" approach has not been fully realized in policy design. Synergies can be enhanced by focusing more on how resources are extracted and promoting 20 regenerative practices. The EU Green Deal aimed to reflect the nexus approach, but more work is needed to manage trade-offs and synergies 36 . ...
This paper offers a comprehensive assessment of the "climate-biodiversity nexus" and the latest research. It also covers real-world developments. It delves into synergies and trade-offs between climate action and biodiversity protection, as well as the role of nature-based solutions (NBS) in addressing both crises. It highlights how biodiversity degradation reduces ecosystems' capacity to store carbon, intensifying climate change, while climate change accelerates biodiversity loss by pushing species beyond survival thresholds. The paper underscores the need for an integrated approach to biodiversity and climate. It uses examples like the potential collapse of the Atlantic Me-ridional Overturning Circulation (AMOC) and the tipping point's implications for ecosystems and species. It also reviews recent European Union policies and initiatives, such as the European Green Deal, which aim to balance climate mitigation with biodiversity conservation. Additionally, the paper examines corporate initiatives, such as Science-Based Targets for Nature (SBTN), which integrate biodiversity into sustainability strategies.
... We hypothesized that changes in population indices over 10 years would vary regionally, being positively correlated with sea ice conditions. Based on previous modelling work [27], we hypothesized that global population indices would be smaller in 2018 than in 2009. Our aim was to report these estimates (indices) as open data, and summarize population trends regionally, to quantify Southern Ocean environmental trends in relation to fast ice [28] and pack ice [29]. ...
... Because we are similarly capturing a subset of the population (and in our case, not the breeding population), the framework we present here may represent an index of demographic parameters for emperor penguins, such as breeding success, of which sustained changes would ultimately influence the unobservable breeding population of emperor penguins (during austral winter). Previously, model projections have predicted declines in the emperor penguin population through to the end of this century [27,54,55], but observations have been missing until now. In the absence of any estimates for emperor penguin vital rates, beyond those from one well-studied colony [2,56,57], metapopulation modelling remains challenging. ...
Like many polar animals, emperor penguin populations are challenging to monitor because of the species' life history and remoteness. Consequently, it has been difficult to establish its global status, a subject important to resolve as polar environments change. To advance our understanding of emperor penguins, we combined remote sensing, validation surveys and using Bayesian modelling, we estimated a comprehensive population trajectory over a recent 10-year period, encompassing the entirety of the species’ range. Reported as indices of abundance, our study indicates with 81% probability that there were fewer adult emperor penguins in 2018 than in 2009, with a posterior median decrease of 9.6% (95% credible interval (CI) −26.4% to +9.4%). The global population trend was −1.3% per year over this period (95% CI = −3.3% to +1.0%) and declines probably occurred in four of eight fast ice regions, irrespective of habitat conditions. Thus far, explanations have yet to be identified regarding trends, especially as we observed an apparent population uptick toward the end of time series. Our work potentially establishes a framework for monitoring other Antarctic coastal species detectable by satellite, while promoting a need for research to better understand factors driving biotic changes in the Southern Ocean ecosystem.
... Emperor penguins are an iconic symbol of Antarctica threatened by climate change [4][5][6][7] . There have been a number of studies linking this species' demography with sea ice loss driven by climate change, from initial studies showing the effects on breeding success 4 to losses of colony sites driven by long-term sea ice decline 8 or sea ice regime shift 9 . ...
... Recent efforts to predict emperor penguin population trends from forecasts of sea ice loss have painted a bleak picture, showing that if present rates of warming persist over 90% of emperor colonies will be quasi-extinct by the end of this century 7 . Their populations have never been subject to large-scale hunting, or suffered from habitat loss, overfishing or other local anthropogenic interactions in the modern eara 5 and therefore, unusually for a vertebrate species, climate change is considered the only major driver of their long-term population change. Recent effort to provide additional protection and conservation measures in response to predicted population declines associated with projected sea ice loss have been partially successful but have failed at the Antarctic Treaty Consultative Meeting 10 . ...
The spring season of 2022 saw record low sea ice extent in Antarctica that persisted throughout the year. At the beginning of December, the Antarctic sea ice extent was tracking with the all-time low set in 2021. The greatest regional negative anomaly of this low extent was in the central and eastern Bellingshausen Sea region, west of the Antarctic Peninsula where, during November, some regions experienced a 100% loss in sea ice concentration. We provide evidence of a regional breeding failure of emperor penguin colonies due to sea ice loss using Sentinel2 satellite imagery. Of the five breeding sites in the region all but one experienced total breeding failure after sea ice break-up before the start of the fledging period of the 2022 breeding season. This is the first recorded incident of a widespread breeding failure of emperor penguins that is clearly linked with large-scale contractions in sea ice extent.
... Further, a biogeographical shift of diatoms and their zooplankton predators away from the SIZ northward towards the ACC, could cause Antarctic predators to travel further to consume prey and return it to their young during the breeding season. This, in combination with declining sea ice, could cause population declines in species such as the Emperor penguin (Jenouvrier et al., 2014). ...
... If phytoplankton blooms occur before zooplankton populations are sufficiently large to graze them down, more production may be exported out of the pelagic ecosystem, reducing flow of biomass to top predators. Mismatch in phenology would be further complicated by changing sea ice cover in the Antarctic SIZ, which is necessary for krill (Meyer et al., 2009) and many sea birds (Jenouvrier et al., 2014;Iles et al., 2020) and marine mammals (Bester et al., 2017). In short, the basic rearrangements of phytoplankton communities shown here for the CESM1-LE under climate change could have a multitude of cascading consequences for Antarctic ecosystems. ...
Southern Ocean phytoplankton production supports rich Antarctic marine ecosystems comprising copepods, krill, fish, seals, penguins, and whales. Anthropogenic climate change, however, is likely to drive rearrangements in phytoplankton community composition with potential ramifications for the whole ecosystem. In general, phytoplankton communities dominated by large phytoplankton, i.e., diatoms, yield shorter, more efficient food chains than ecosystems supported by small phytoplankton. Guided by a large ensemble of Earth system model simulations run under a high emission scenario (RCP8.5), we present hypotheses for how anthropogenic climate change may drive shifts in phytoplankton community structure in two regions of the Southern Ocean: the Antarctic Circumpolar Current (ACC) region and the sea ice zone (SIZ). Though both Southern Ocean regions experience warmer ocean temperatures and increased advective iron flux under 21st century climate warming, the model simulates a proliferation of diatoms at the expense of small phytoplankton in the ACC, while the opposite patterns are evident in the SIZ. The primary drivers of simulated diatom increases in the ACC region include warming, increased iron supply, and reduced light from increased cloudiness. In contrast, simulated reductions in ice cover yield greater light penetration in the SIZ, generating a phenological advance in the bloom accompanied by a shift to more small phytoplankton that effectively consume available iron; the result is an overall increase in net primary production, but a decreasing proportion of diatoms. Changes of this nature may promote more efficient trophic energy transfer via copepods or krill in the ACC region, while ecosystem transfer efficiency in the SIZ may decline as small phytoplankton grow in dominance, possibly impacting marine food webs sustaining Antarctic marine predators. Despite the simplistic ecosystem representation in our model, our results point to a potential shift in the relative success of contrasting phytoplankton ecological strategies in different regions of the Southern Ocean, with ramifications for higher trophic levels.
... The Antarctic sea ice plays a crucial role in Earth's climate system. Its freezing, melting, and transport not only impact atmospheric and oceanic circulation (Bader et al., 2013;Haumann et al., 2016;Zhang et al., 2024) and marine ecosystems (Jenouvrier et al., 2014) but also place constraints on human activities such as fisheries, tourism, and scientific expeditions in the Southern Ocean. Since August 2016, there has been a dramatic reduction in Antarctic sea ice extent (SIE) accompanied by sizable interannual variability (Hobbs et al., 2024), indicating that the Antarctic sea ice has shifted to a new state (Purich & Doddridge, 2023). ...
In this study, the subseasonal Antarctic sea ice edge prediction skill of the Copernicus Climate Change Service (C3S) and Subseasonal to Seasonal (S2S) projects was evaluated by a probabilistic metric, the spatial probability score (SPS). Both projects provide subseasonal to seasonal scale forecasts of multiple coupled dynamical systems. We found that predictions by individual dynamical systems remain skillful for up to 38 days (i.e., the ECMWF system). Regionally, dynamical systems are better at predicting the sea ice edge in the West Antarctic than in the East Antarctic. However, the seasonal variations of the prediction skill are partly system‐dependent as some systems have a freezing‐season bias, some had a melting‐season bias, and some had a season‐independent bias. Further analysis reveals that the model initialization is the crucial prerequisite for skillful subseasonal sea ice prediction. For those systems with the most realistic initialization, the model physics dictates the propagation of initialization errors and, consequently, the temporal length of predictive skill. Additionally, we found that the SPS‐characterized prediction skill could be improved by increasing the ensemble size to gain a more realistic ensemble spread. Based on the C3S systems, we constructed a multi‐model forecast from the above principles. This forecast consistently demonstrated a superior prediction skill compared to individual dynamical systems or statistical observation‐based benchmarks. In summary, our results elucidate the most important factors (i.e., the model initialization and the model physics) affecting the currently available subseasonal Antarctic sea ice prediction systems and highlighting the opportunities to improve them significantly.
... Jenouvrier et al., 2012), dispersal (e.g. Jenouvrier et al., 2012Jenouvrier et al., , 2014Urban et al., 2012), competition (e.g. Adler et al., 2012), biophysical mechanisms (e.g. ...
Many ecological systems dominated by stochastic dynamics can produce complex time series that inherently limit forecast accuracy. The ‘intrinsic predictability’ of these systems can be approximated by a time series complexity metric called weighted permutation entropy (WPE). While WPE is a useful metric to gauge forecast performance prior to model building, it is sensitive to noise and may be biased depending on the length of the time series. Here, we introduce a simple randomized permutation test (rWPE) to assess whether a time series is intrinsically more predictable than white noise.
We apply rWPE to both simulated and empirical data to assess its performance and usefulness. To do this, we simulate population dynamics under various scenarios, including a linear trend, chaotic, periodic and equilibrium dynamics. We further test this approach with observed abundance time series for 932 species across four orders of animals from the Global Population Dynamics Database. Finally, using Adélie (Pygoscelis adeliae) and emperor penguin (Aptenodytes forsteri) time series as case studies, we demonstrate the application of rWPE to multiple populations for a single species.
We show that rWPE can determine whether a system is significantly more predictable than white noise, even with time series as short as 10 years that show an apparent trend under biologically realistic stochasticity levels. Additionally, rWPE has statistical power close to 100% when time series are at least 30 time steps long and show chaotic or periodic dynamics. Power decreases to ~10% under equilibrium dynamics, irrespective of time series length. Among four classes of animal taxa, mammals have the highest relative frequency (28%) of time series that are both longer than 30 time steps and indistinguishable from white noise in terms of complexity, followed by insects (16%), birds (16%) and bony fishes (11%).
rWPE is a straightforward and useful method widely applicable to any time series, including short ones. By informing forecasters of the inherent limitations to a system's predictability, it can guide a modeller's expectations for forecast performance.
... Previous studies provide valuable information about how future environmental change is likely to affect the global emperor penguin population (e.g. Jenouvrier et al. 2014Jenouvrier et al. , 2020. Based on long-term projections of loss of habitat and habitat quality (Jenouvrier et al. 2009), the International Union for Conservation of Nature uplisted the species from Least Concern to Near Threatened in 2012 (BirdLife International 2024). ...
As a species highly reliant on stable fast ice as a breeding platform, emperor penguins are increasingly challenged in their breeding attempts due to changes in fast ice conditions. We collated habitat information of 27 emperor penguin colonies in East Antarctica (43°-167°E) from 2018 to 2023 using European Space Agency Sentinel-2 satellite images. Our objective was to examine the variability in habitat and ice conditions and associated repercussions for colony location and breeding success. Variables, such as location, colony movement and inter-annual variability in these parameters, were used to assess the adaptability of emperor penguins when local conditions change markedly. The major challenge emperor penguins currently face throughout Antarctica is untimely loss of breeding habitat resulting in increased or complete breeding failure, as observed in 8 colonies at least once during the study. One small colony at the West Ice Shelf lost its breeding area and has not been seen since 2021. The inter-annual movement of some colonies demonstrates the species’ adaptability and the need for ongoing monitoring of the global emperor penguin population using satellite imagery. We highlight caveats, such as availability of suitable satellite images and movement of colonies, that need to be accounted for to ensure sound interpretation of the monitoring findings. Ongoing Antarctic-wide monitoring is essential to quantify the impact of changing fast ice conditions on emperor penguins and also the cumulative impacts of other threats such as disease. The information presented is to provide background and empirical data for researchers, policy makers and managers.
... Determining the preferred foraging habitats used by emperor penguins is important, given that their primary breeding and foraging habitats are projected to decline over the next decades (e.g. Jenouvrier et al. 2014Jenouvrier et al. , 2017Jenouvrier et al. , 2021. So far, most studies have focused upon changes in the breeding habitat (fast ice), but here we focus upon the preferred foraging and moulting habitat during summer; that is, the seasonal pack ice. ...
We tracked adult emperor penguins from Rothschild Island, west Antarctic Peninsula in 2015/2016 during a summer with extensive sea ice of long duration, contrasting with past years of reduced sea ice extent associated with the recent, rapid, warming trend across the region. We fitted ARGOS PTT devices to penguins of unknown breeding status. Of 33 penguins tracked, nine returned to the colony, presumably to provision offspring. Their foraging trips lasted 9.6 ± 3.7 days, with maximum distances of 75 ± 45 km from the colony within coastal waters. Also, 18 instruments transmitted until the initiation of the annual moult. Penguins travelled at ~ 2.3 km h⁻¹ before slowing for moult. Post-moult, some devices continued to transmit, with speeds of ~ 0.8 km h⁻¹, plausibly due to ice drift, which is rapid in this region. Penguins remained within the seasonal sea ice throughout, staying within 100 km of land, and generally within 5 to 10 km of features (open water, polynyas, leads, icebergs) that offered potential access to the ocean. Penguins were unlikely to have been constrained by the extensive sea ice habitat in 2015/2016. Similar habitats would also have been available in most years of the satellite record (since 1979); however, the moult locations in 2015/2016 would not have been available in many years, and penguins would have needed to find alternative moult locations during some years. Despite uncertainties, the moult period is a critical time for emperor penguins, particularly as sea ice declines, potentially affecting adult survival.
... In many species, juveniles migrating for the first time show a greater spread of directions than adults, so juveniles more frequently end up outside the usual route for their po pulation (Newton, 2008). Much of the global emperor penguin population is potentially under long-term threat because of climate change in the form of reduced sea-ice concentration and thickness and duration of sea-ice cover (Ainley et al., 2010;Trathan et al., 2011;Jenouvrier et al., 2014). In this context, these long dispersal routes may also be considered in terms of a potential search for new breeding habitats (Jenouvrier et al., 2017;Hrbáček et al., 2018). ...
We provide information on vagrant and visitor bird species recorded in the Fildes Region (King George Island, South Shetlands, Antarctic) during the long-term bird monitoring programme between the 1979–1980 and 2022–2023 seasons. The total ice-free territory covers approximately 35 km2, making it one of the largest ice-free areas in the Western Antarctic Peninsula region. In addition to 13 breeding and one potentially breeding bird species, we recorded 28 non-breeding bird species. Of these non-breeding bird species, we defined 18 as vagrants and 10 as visitors. The vagrant and visitor bird species recorded were representatives of the families Spheniscidae, Diomedeidae, Procellariidae, Pelecanoididae, Laridae, Ardeidae, Scolopacidae, and Anatidae. Furthermore, we include information on the frequency of observations of bird species that do not breed in the study area. Most frequently observed were white-rumped sandpiper, cattle egret, emperor penguin, macaroni penguin, and king penguin. These data contribute to knowledge of rare birds in the Antarctic. Together with similar studies, this information may provide valuable clues to unusual environmental conditions that allow vagrants to reach regions beyond their usual distribution range. Furthermore, long-term data on rare bird sightings can indicate a potential expansion of the breeding range of individual species. Such studies may be relevant for the evaluation of environmental changes that are already occurring as a result of current climate change, e.g., changes in sea ice cover or food web structures.
... It is worth noting that reduction of NPP may propagate up the food chain and could have larger impacts on the entire Ross Sea ecosystem. As the Ross Sea is one of the few locations around Antarctica where Emperor Penguins, a threatened species, may be able to survive in future climate scenarios (Jenouvrier et al 2014(Jenouvrier et al , 2019, it is especially relevant to understand the relationships between physical and biological systems in this region that could impact species that the Ross MPA is intended to protect. Both male and female Emperor Penguins require access to open water throughout the winter months to feed at sea (Jouventin and Dobson 2018). ...
This study investigates winter polynyas in the southern Ross Sea, Antarctica where several polynyas are known to form. Coastal polynyas are areas of lower sea ice concentration and/or thickness along the coast that are otherwise surrounded by more extensive, thicker sea ice pack. Polynyas are also locations where organisms can exploit both the ice substrate and pelagic resources. Using a self organizing map algorithm, we identify polynya events in the Community Earth System Model Version 2 Large Ensemble (CESM2-LE). The neural network algorithm is able to identify polynya events without imposing an ice concentration or thickness threshold, as is often done when identifying polynyas. The CESM2-LE produces a wintertime polynya feature comparable in size and location to the Ross Sea polynya, and during polynya events there are large turbulent heat fluxes and export of sea ice from the Ross Sea. In the CESM2-LE polynya event frequency is projected to decrease sharply in the later twentyfirst century, leading to increasing sea ice concentrations and thicknesses in the region. The drivers of the polynya frequency decline are likely both large scale circulation changes and local atmosphere and ocean feedbacks. If declines in wintertime polynya frequency over the twentyfirst century do occur they may impact Antarctic Bottom Water formation and local net primary productivity. Thus, better understanding potential local and unexpected sea ice changes in the Ross Sea is important for both assessing climate system impacts and ecological impacts on the Ross Sea ecosystem, which is currently protected by an internationally recognized marine protected area.
... Emperor penguins (Aptenodytes forsteri) breed on land-fast sea ice, making them particularly vulnerable to the impact of global warming (1)(2)(3)(4)(5)(6). For breeding, stable land-fast sea ice (or fast ice), which is sea ice anchored to land, ice shelves, or grounded icebergs, is required (5,7). ...
Emperor penguins ( Aptenodytes forsteri ) are under increasing environmental pressure. Monitoring colony size and trends of this Antarctic seabird relies primarily on satellite imagery recorded near the end of the breeding season, when illumination levels are sufficient to capture images, but colony occupancy is highly variable. To correct population estimates for this variability, we develop a phenological model that accurately predicts the number of breeding pairs and fledging chicks, as well as key phenological events such as arrival, hatching and foraging times, from as few as six data points from a single season. The ability to extrapolate occupancy from sparse data makes the model particularly useful for monitoring remotely sensed animal colonies where ground-based population estimates are very rare or unavailable.
Teaser
The Emperor penguin becomes the Southern Ocean’s canary in a coal mine through remote sensing its annual breeding success.
... It is worth noting that reduction of NPP may propagate up the food chain and could have larger impacts on the entire Ross Sea ecosystem. As the Ross Sea is one of the few locations around Antarctica where Emperor Penguins, a threatened species, may be able to survive in future climate scenarios (Jenouvrier et al, 2014(Jenouvrier et al, , 2019, it is especially relevant to understand the relationships between physical and biological systems in this region that could impact species that the Ross MPA is intended to protect. Both male and female Emperor Penguins require access to open water throughout the winter months to feed at sea (Jouventin and Dobson, 2018). ...
This study investigates winter polynyas in the southern Ross Sea, Antarctica where several polynyas are known to form. Coastal polynyas are areas of lower sea ice concentration and/or thickness along the coast that are otherwise surrounded by the thicker ice pack, and polynyas are locations where organisms can exploit both the ice substrate and pelagic resources. Using a self organizing map algorithm, we identify polynya events in the Community Earth System Model Version 2 Large Ensemble (CESM2-LE). The neural network algorithm is able to identify polynya events without imposing an ice concentration or thickness threshold, as is often done when identifying polynyas. The CESM2-LE produces a wintertime polynya feature comparable in size and location to the Ross Sea polynya, and during polynya events there are large turbulent heat fluxes and export of sea ice from the Ross Sea. In the CESM2-LE polynya event frequency is projected to decrease sharply in the later 21st century, leading to increasing sea ice concentrations and thicknesses in the region. The drivers of the polynya frequency decline are likely both large scale circulation changes and local atmosphere and ocean feedbacks. Changes in wintertime polynya frequency over the 21st century may impact local net primary productivity, which has the potential for cascading effects up the food chain. Improving understanding of the biogeophysical relationships will be important for assessing how the Ross Sea ecosystem, which is currently protected by an internationally recognized marine protected area, may be vulnerable in the future in unexpected ways.
... Conservation and management of these animals relies on understanding their distributions, how these relate to the bio-physical environment (Reisinger et al., 2018); and how these distributions may alter in a changing marine environment (Pecl et al., 2017). Predicting how distributions of species may change is critical in predicting their potential for adapting to climate-related environmental change (Jenouvrier et al., 2014;Rose et al., 2010). ...
Anthropogenic climate change is resulting in spatial redistributions of many species. We assessed the potential effects of climate change on an abundant and widely distributed group of diving birds, Eudyptes penguins, which are the main avian consumers in the Southern Ocean in terms of biomass consumption. Despite their abundance, several of these species have undergone population declines over the past century, potentially due to changing oceanography and prey availability over the important winter months. We used light‐based geolocation tracking data for 485 individuals deployed between 2006 – 2020 across 10 of the major breeding locations for five taxa of Eudyptes penguins. We used Boosted Regression Tree modelling to quantify post‐moult habitat preference for southern rockhopper (E. chrysocome), eastern rockhopper (E. filholi), northern rockhopper (E. moseleyi) and macaroni/royal (E. chrysolophus and E. schlegeli) penguins. We then modelled their redistribution under two climate change scenarios, Representative Concentration Pathways RCP4.5 and RCP8.5 (for the end of the century, 2071 – 2100). As climate forcings differ regionally, we quantified redistribution in the Atlantic, Central Indian, East Indian, West Pacific, and East Pacific regions. We found sea surface temperature and sea surface height to be the most important predictors of current habitat for these penguins; physical features that are changing rapidly in the Southern Ocean. Our results indicated that the less severe RCP4.5 would lead to less habitat loss than the more severe RCP8.5. The five taxa of penguin may experience a general poleward redistribution of their preferred habitat, but with contrasting effects in the i) change in total area of preferred habitat under climate change ii) according to geographic region and iii) the species (macaroni/royal vs rockhopper populations). Our results provide further understanding on the regional impacts and vulnerability of species to climate change.
... The predicted future distribution under the SSP5-8.5 scenario showed an extreme declining trend that ranged between complete loss and significant reduction of suitability. This trend is similar to those found in other studies investigating climate change impacts on seabirds [4,6,62]. During model projection, extrapolation and clamping were allowed. ...
The Socotra Cormorant (Phalacrocorax nigrogularis) is a regionally endemic seabird that is vulnerable due to human disturbance and habitat degradation. This study aimed to predict the potential current and future marine distribution of the species under different climate change scenarios using environmental variables affecting distribution using MaxEnt. Occurrence data were collected over several years using satellite tagged adults in the Arabian Gulf. The current model showed large areas of high suitability, mainly in the Arabian Gulf and in the Red Sea, where 31,300 km2 or 48% of total highly suitable areas existed. These areas are currently not utilized by the species. The future model predicted a sharp decline in suitable areas with 73% loss under the SSP5-8.5 climate change scenario of 2050 (extreme scenario). Nevertheless, the Red Sea is predicted to still hold considerable moderately suitable areas. Suitable areas increased around the Socotra archipelago. The model did not include biological variables due to lack of fish distribution data. Two variables, namely, mixed layer thickness and sea floor depth, explained most of the species’ distribution. These variables significantly influence nutrient cycling and forage fish distribution patterns, which in turn influence seabird distributions. Thus, the model could be useful in predicting the distribution of Socotra cormorants. However, the model outcomes should be interpreted with caution as potential areas of future expansion of the species to be further tested and validated. Conserving these areas as a precaution might encourage the Socotra Cormorant to colonize the region and persist in the future under the most extreme climate change scenarios, given that small forage fish that are eaten by the species are abundant in the predicted areas outside of the Arabian Gulf.
... An important challenge in the study of population fluctuations is to reveal the link between demographic parameters and climatic variables, mediated by their influence on foraging resources [1][2][3]. It is difficult, however, to single out the effect of a single climatic variable on a given biological system because variables can act directly [4], indirectly through multiple paths [5], alone [6] or in combination with others [7]. ...
Large-scale climatic indices are extensively used as predictors of ecological processes, but the mechanisms and the spatio-temporal scales at which climatic indices influence these processes are often speculative. Here, we use long-term data to evaluate how a measure of individual breeding investment (the egg volume) of three long-lived and long-distance-migrating seabirds is influenced by i) a large-scale climatic index (the North Atlantic Oscillation) and ii) local-scale variables (food abundance, foraging conditions, and competition). Winter values of the North Atlantic Oscillation did not correlate with local-scale variables measured in spring, but surprisingly, both had a high predictive power of the temporal variability of the egg volume in the three study species, even though they have different life-history strategies. The importance of the winter North Atlantic Oscillation suggests carry-over effects of winter conditions on subsequent breeding investment. Interestingly, the most important local-scale variables measured in spring were associated with food detectability (foraging conditions) and the factors influencing its accessibility (foraging conditions and competition by density-dependence). Large-scale climatic indices may work better as predictors of foraging conditions when organisms perform long distance migrations, while local-scale variables are more appropriate when foraging areas are more restricted (e.g. during the breeding season). Contrary to what is commonly assumed, food abundance does not directly translate into food intake and its detectability and accessibility should be considered in the study of food-related ecological processes.
... Most observed impacts were assessed with low evidence, but high agreement, and focused on plants and insects. Impacts described included abundance changes and extirpations (Jenouvrier et al., 2014), altitudinal range shifts (Koide et al., 2017), increased invasive alien species' abundance and extent in Madagascar (H76, 77), Balearic (H51) and Pacific islands (Ghulam, 2014;Silva-Rocha et al., 2015;Goulding et al., 2016;Dawson et al., 2017), increased temperature affecting physiology, body size and behaviour of frogs in the Caribbean (H20) (Narins and Meenderink, 2014) and phenological alterations (Fontúrbel et al., 2018). One positive observation was the high resilience to recovery of intact forest ecosystems to tropical cyclones within Caribbean (H20) and Pacific islands (medium confidence) (Keppel et al., 2014;Marler, 2014;Shiels et al., 2014). ...
... The most effective actions to protect the emperor penguin from anthropogenic impacts would be a reduction in greenhouse gas emissions [31,32] as well as the establishment of MPAs throughout its habitat range [31]. Long-lived seabirds, emperor penguins reach sexual maturity between 4 and 8 years [33,34]. However, little is known about the first years at sea of the species, even though the survival of this age class referred as 'juvenile' is crucial for the viability of the global population [33,35]. ...
To protect the unique and rich biodiversity of the Southern Ocean, conservation measures such as marine protected areas (MPAs) have been implemented. Currently, the establishment of several additional protection zones is being considered based on the known habitat distributions of key species of the ecosystems including emperor penguins and other marine top predators. However, the distribution of such species at sea is often insufficiently sampled. Specifically, current distribution models focus on the habitat range of adult animals and neglect that immatures and juveniles can inhabit different areas. By tracking eight juvenile emperor penguins in the Weddell Sea over 1 year and performing a meta-analysis including previously known data from other colonies, we show that conservation efforts in the Southern Ocean are insufficient for protecting this highly mobile species, and particularly its juveniles. We find that juveniles spend approximately 90% of their time outside the boundaries of proposed and existing MPAs, and that their distribution extends beyond (greater than 1500 km) the species' extent of occurrence as defined by the International Union for Conservation of Nature. Our data exemplify that strategic conservation plans for the emperor penguin and other long-lived ecologically important species should consider the dynamic habitat range of all age classes.
... Except for Antarctic petrels, the current status and trends of most seabird species breeding in DML or using the marine area outside DML remains largely unknown. Data from the longest-studied population of emperor penguins at Terre Adélie coupled with future levels of sea ice variability modelled under various climate change scenarios demonstrated that not only is the demographic trajectory of the species highly dependent upon variability in sea ice, but that the DML coastline is predicted to be the region most likely to experience the greatest levels of sea ice variability into the future (Jenouvrier et al. 2014). Despite this apparent threat, there are no available data on emperor penguin populations in DML and their current trend is unknown. ...
Despite the exclusion of the Southern Ocean from assessments of progress towards achieving the Convention on Biological Diversity (CBD) Strategic Plan, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) has taken on the mantle of progressing efforts to achieve it. Within the CBD, Aichi Target 11 represents an agreed commitment to protect 10% of the global coastal and marine environment. Adopting an ethos of presenting the best available scientific evidence to support policy makers, CCAMLR has progressed this by designating two Marine Protected Areas in the Southern Ocean, with three others under consideration. The region of Antarctica known as Dronning Maud Land (DML; 20°W to 40°E) and the Atlantic sector of the Southern Ocean that abuts it conveniently spans one region under consideration for spatial protection. To facilitate both an open and transparent process to provide the vest available scientific evidence for policy makers to formulate management options, we review the body of physical, geochemical and biological knowledge of the marine environment of this region. The level of scientific knowledge throughout the seascape abutting DML is polarized,
with a clear lack of data in its eastern part which is presumably related to differing levels of research effort dedicated by national Antarctic programmes in the region. The lack of basic data on fundamental aspects of the physical, geological and biological nature of eastern DML make predictions of future trends difficult to impossible, with implications for the provision of management advice including spatial management. Finally, by highlighting key knowledge gaps across the scientific disciplines our review also serves to provide guidance to future research across this important region.
... For example, with continued lengthening thaw season and diminishing sea ice in the Arctic, polar bear distributions may shift away from prey dependent on sea ice such as ringed seal pups, and toward prey on solid ground, such as snow geese eggs (117), a shift that could reduce polar bear body condition and survival and increase competition with land-based brown bears (118). In Antarctica, receding glaciers have enabled more breeding habitat and increased abundances of Adélie penguins in some areas (119), whereas continued sea ice decline is detrimental to emperor penguin breeding habitat and populations (120). Multiple SAI scenarios predict diminished seasonality in high latitudes, with warmer winters and cooler summers, resulting in sea ice decreasing during winter and increasing during summer (32). ...
Making informed future decisions about solar radiation modification (SRM; also known as solar geoengineering)—approaches such as stratospheric aerosol injection (SAI) that would cool the climate by reflecting sunlight—requires projections of the climate response and associated human and ecosystem impacts. These projections, in turn, will rely on simulations with global climate models. As with climate-change projections, these simulations need to adequately span a range of possible futures, describing different choices, such as start date and temperature target, as well as risks, such as termination or interruptions. SRM modeling simulations to date typically consider only a single scenario, often with some unrealistic or arbitrarily chosen elements (such as starting deployment in 2020), and have often been chosen based on scientific rather than policy-relevant considerations (e.g., choosing quite substantial cooling specifically to achieve a bigger response). This limits the ability to compare risks both between SRM and non-SRM scenarios and between different SRM scenarios. To address this gap, we begin by outlining some general considerations on scenario design for SRM. We then describe a specific set of scenarios to capture a range of possible policy choices and uncertainties and present corresponding SAI simulations intended for broad community use.
... There is also evidence of an increase of breeding attempts of king penguins in Antarctic Peninsula suggesting an expansion in their distribution (Petry et al. 2013, Juarés et al 2017, Borowicz et al. 2020). Finally, based on genomics, population sizes of emperor penguins also expanded in the warming period after the Last Glacial Maximum (Cole et al. 2019), but more recent declines at the Antarctic Peninsula and East Antarctica (see next subsection) are projected to shift their distribution pole ward during the 21st century (Jenouvrier et al. 2014). ...
... Penguins are observed and predicted to drastically abandon or relocate their breeding colonies in response to the climate change. By the end of 21 st century nearly all colonies of the Emperor penguin would experience substantial population decline of more than 90% (Jenouvrier et al., 2009(Jenouvrier et al., , 2014(Jenouvrier et al., , 2021. As a sea-ice dependent species, Ad elie penguins are observed to decrease in number at almost all locations on the Antarctic Peninsula (Lynch et al., 2012) due to reduced sea-ice extent. ...
As a result of climate changes, penguins are predicted to be at risk of losing their breeding habitats. Changes in penguin colony distribution suggest that some colonies have withstood environmental changes better than others, serving as initial post-glacial settlements or refuges in adverse climatic conditions. Here we have synthesized over 200 dates (including 91 new dates) of penguin remains and of guano in 107 ornithogenic profiles from abandoned nests on Inexpressible Island, one of the longest persisting Adélie penguin colonies in Antarctica, to investigate the dynamics of population size and the role of this island in the ecological history of this species. The results indicate that, following the retreat of Ross Ice Shelf, the Adélies first colonized this island at ∼8.6 kyr BP, documenting the earliest known breeding site in the Ross Sea since deglaciation. During ∼7-3 kyr BP the reconstructed population on Inexpressible Island was generally consistent with the change in pack ice, reaching relative peaks at 5.5–5.0 and 4.0–3.5 kyr BP. After brief decline at 3.5–3.0 kyr, substantial enlargement of the penguin colony occurred between 3.0 and 1.5 kyr BP, attributed to the immigration from the abandoned colonies along the Scott Coast. During this time, the persistent efficiency of Terra Nova Bay polynya offered conditions favourable to the expansion of the penguin population on Inexpressible Island, which probably represented a refuge area under increased coastal sea-ice. This longest-dwelling penguin colony may provide a valuable refuge for the Adélie penguin if the recurrent Terra Nova Bay polynya persists under future climatic and environmental changes, as occurred in the past.
... In only one species (northern gannet) was breeding success predicted to increase under the future climate scenario. Our results build upon previous findings that have demonstrated the importance of climate on breeding success and other vital rates in seabirds globally, but which have tended to focus on single breeding colonies or species (Jones et al. 2007, Barbraud et al. 2011, Jenouvrier et al. 2014, Monticelli et al. 2014, Carroll et al. 2015, Christensen-Dalsgaard et al. 2018; but see Sydeman et al. 2021) or on abundance, not vital rates (Johnson et al. 2013). Very few studies have estimated future vital rates for seabirds under projected future climates (but see Carroll et al. 2015) or across broad regions such as the North Sea (but see recent review by Pearce-Higgins 2021). ...
Europe has set ambitious green energy targets, to which offshore renewable developments (ORDs) will make a significant contribution. Governments are legally required to deliver ORDs sustainably; however, they may have detrimental impacts on wildlife, especially those already experiencing declines due to climate change. Population viability analysis (PVA) is the standard method for forecasting population change in ORD assessments, but PVAs do not currently account for climate effects. We quantified climate effects on seabird breeding success for 8 UK species breeding in the North Sea. We assessed the potential for seabirds to mitigate climate-driven changes in breeding success by accessing wider resources through increased foraging ranges around colonies. We demonstrate strong links between breeding success and climate in 5 species. In 4 of these species, future climate projections indicated large declines in breeding success relative to current rates. Only one species was predicted to increase breeding success under future climate. In all 5 species, there was limited opportunity for species to increase breeding success by expanding foraging ranges to access more suitable future climatic conditions. Climate change will have significant ramifications for future breeding success of seabirds breeding in the North Sea, an area undergoing extensive and rapid offshore renewable energy development. We recommend 3 methods for including climate-driven changes to seabird breeding success within ORD assessments: development of predictive climate-driven habitat use models to estimate ORD-wildlife interactions; delivery of a new ORD assessment framework that includes dynamic predictions of climate-driven habitat use and demography of wildlife populations; and consideration of climate-driven changes in the implementation of compensatory measures.
... Most importantly, we define disturbance as a sudden event impacting the structure of the population (Capdevila, Stott, et al., 2020;Stott et al., 2011); however, perturbations can also alter the vital rates of a population (e.g. Capdevila et al., 2019;Jenouvrier et al., 2014). Changes in the vital rates will alter the stable structure of the population, generating discrepancies between the actual population structure and the stable structure. ...
... Most importantly, we define disturbance as a sudden event impacting the structure of the population (Capdevila, Stott, et al., 2020;Stott et al., 2011); however, perturbations can also alter the vital rates of a population (e.g. Capdevila et al., 2019;Jenouvrier et al., 2014). Changes in the vital rates will alter the stable structure of the population, generating discrepancies between the actual population structure and the stable structure. ...
Accelerating rates of biodiversity loss underscore the need to understand how species achieve resilience—the ability to resist and recover from a/biotic disturbances. Yet, the factors determining the resilience of species remain poorly understood, due to disagreements on its definition and the lack of large‐scale analyses. Here, we investigate how the life history of 910 natural populations of animals and plants predicts their intrinsic ability to be resilient. We show that demographic resilience can be achieved through different combinations of compensation, resistance and recovery after a disturbance. We demonstrate that these resilience components are highly correlated with life history traits related to the species’ pace of life and reproductive strategy. Species with longer generation times require longer recovery times post‐disturbance, whilst those with greater reproductive capacity have greater resistance and compensation. Our findings highlight the key role of life history traits to understand species resilience, improving our ability to predict how natural populations cope with disturbance regimes.
... Emperor penguin is a relevant empirical example to test our theoretical prediction that long lived species (comparable to species 4) may permit an earlier detection of the time at which the signal of anthropogenic climate change emerges from the noise of natural climate variability (Fig. 3, section 4.2). Penguins are threatened by future climate change as most of their breeding colonies will be endangered by 2100 if greenhouse gases continue their current course [Jenouvrier et al., 2020[Jenouvrier et al., , 2014[Jenouvrier et al., , 2021. These declines occur through projected loss of Antarctic sea ice, which affects survival and reproduction. ...
Climate impacts are not always easily discerned in wild populations as detecting climate change signals in populations is challenged by stochastic noise associated with natural climate variability, variability in biotic and abiotic processes, and observation error in demographic rates. Detection of the impact of climate change on populations requires making a formal distinction between signals in the population associated with long-term climate trends from those generated by stochastic noise. The time of emergence (ToE) identifies when the signal of anthropogenic climate change can be quantitatively distinguished from natural climate variability. This concept has been applied extensively in the climate sciences, but has not been explored in the context of population dynamics. Here, we outline an approach to detecting climate-driven signals in populations based on an assessment of when climate change drives population dynamics beyond the envelope characteristic of stochastic variations in an unperturbed state. Specifically, we present a theoretical assessment of the time of emergence of climate-driven signals in population dynamics (ToEpop). We identify the dependence of ToEpop on the magnitude of both trends and variability in climate and also explore the effect of intrinsic demographic controls on ToEpop. We demonstrate that different life histories (fast species vs. slow species), demographic processes (survival, reproduction) and the relationships between climate and demographic rates, yield population dynamics that filter climate trends and variability differently. We illustrate empirically how to detect the point in time when anthropogenic signals in populations emerge from stochastic noise for a species threatened by climate change: the emperor penguin. Finally, we propose six testable hypotheses and a road map for future research.
... Drawing on similar studies looking at climate sensitivities for marine mammals in the Arctic (Laidre et al., 2008), we build on the study by Siniff et al. (2008), to explain important habitat variables for each seal species. We discuss implications of a marine protected area (MPA) in one of the important climate refugia in the Southern Ocean (Jenouvrier et al., 2014;Teschke et al., 2020), the Weddell Sea. ...
The impacts of climate change in Antarctica and the Southern Ocean are not uniform and ice-obligate species with dissimilar life-history
characteristics will likely respond differently to their changing ecosystems. We use a unique data set of Weddell Leptonychotes weddellii and crabeater seals' (CESs) Lobodon carcinophaga breeding season distribution in the Weddell Sea, determined from satellite imagery. We contrast the theoretical climate impacts on both ice-obligate predators who differ in life-history characteristics: CESs are highly specialized Antarctic krill Euphausia superba predators and breed in the seasonal pack ice; Weddell seals (WESs) are generalist
predators and breed on comparatively stable fast ice. We used presence–absence data and a suite of remotely sensed environmental variables to build habitat models. Each of the environmental predictors is multiplied by a ‘climate change score’ based on known responses to climate change to create a ‘change importance product’. Results show CESs are more sensitive to climate change than WESs. Crabeater seals prefer to breed close to krill, and the compounding effects of changing sea ice concentrations
and sea surface temperatures, the proximity to krill and abundance of stable breeding ice, can influence their post-breeding foraging success and ultimately their future breeding success. But in contrast to the Ross Sea, here WESs prefer to breed closer to larger colonies of emperor penguins (Aptenodytes forsteri). This suggests that
the Weddell Sea may currently be prey-abundant, allowing the only two air-breathing Antarctic silverfish predators (Pleuragramma antarctica) (WESs and emperor penguins) to breed closer to each other. This is the first basin-scale, region-specific comparison
of breeding season habitat in these two key Antarctic predators based on real-world data to compare climate change responses. This work shows that broad-brush, basin-scale approaches to understanding species-specific responses to climate change are
not always appropriate, and regional models are needed—especially
when designing marine protected areas.
... Most emperor penguin colonies are difficult to access due to their location on remote sections of Antarctic fast ice, and very few of the 66 known colonies (Fretwell & Trathan, 2020) are available to survey using ground counts or aerial surveys Barbraud & Weimerskirch, 2001;Kooyman & Ponganis, 2017;Richter, Gerum, Schneider, et al., 2018). However, gaining empirical understanding of population change at multiple spatial scales is critical, as modelling studies suggest that most breeding colonies will be quasi-extinct by 2100 under 'business as usual' emissions scenarios (Jenouvrier et al., 2014, resulting in dramatic declines in the global population size, even under optimistic dispersal scenarios (Jenouvrier et al. 2017). The ability to apply the baseline population provided by Fretwell et al. (2012) to monitor population trends will improve our understanding and predictions of emperor penguin populations at multiple spatial scales, which is critical for conservation . ...
Very high‐resolution satellite (VHR) imagery is a promising tool for estimating the abundance of wildlife populations, especially in remote regions where traditional surveys are limited by logistical challenges. Emperor penguins Aptenodytes forsteri were the first species to have a circumpolar population estimate derived via VHR imagery. Here we address an untested assumption from Fretwell et al. (2012) that a single image of an emperor penguin colony is a reasonable representation of the colony for the year the image was taken. We evaluated satellite‐related and environmental variables that might influence the calculated area of penguin pixels to reduce uncertainties in satellite‐based estimates of emperor penguin populations in the future. We focused our analysis on multiple VHR images from three representative colonies: Atka Bay, Stancomb‐Wills (Weddell Sea sector) and Coulman Island (Ross Sea sector) between September and December during 2011. We replicated methods in Fretwell et al. (2012), which included using supervised classification tools in ArcGIS 10.7 software to calculate area occupied by penguins (hereafter referred to as ‘population indices’) in each image. We found that population indices varied from 2 to nearly 6‐fold, suggesting that penguin pixel areas calculated from a single image may not provide a complete understanding of colony size for that year. Thus, we further highlight the important roles of: (i) sun azimuth and elevation through image resolution and (ii) penguin patchiness (aggregated vs. distributed) on the calculated areas. We found an effect of wind and temperature on penguin patchiness. Despite intra‐seasonal variability in population indices, simulations indicate that reliable, robust population trends are possible by including satellite‐related and environmental covariates and aggregating indices across time and space. Our work provides additional parameters that should be included in future models of population size for emperor penguins. Most emperor penguin breeding colonies are projected to be quasi‐extinct by 2100 under ‘business as usual’ emissions scenarios and thus it is now critical to gain empirical evidence of population changes. Very high‐resolution satellite images (VHR) provide us unprecedented, remote access to monitor emperor penguin populations. Our study is the first to address the cause of uncertainties in emperor penguin population estimates derived via VHR, and to account for uncertainty to optimize population estimates. We found that (i) the assumption within Fretwell et al. (2012) that a single VHR image of an emperor penguin colony is a reasonable representation of the colony size for that year was violated, and that (ii) environmental and satellite‐related covariates helped determine population indices, in an effort toward realistic population estimates. This work has major implications for the future assessment of emperor penguin responses to climate change.
... The habitats of Emperor and King penguin have shrunk significantly as a result of climatic warming and penguin populations have decreased dramatically. By 2100 at least two-thirds of Emperor colonies are projected to have declined by >50% compared to their current size (Jenouvrier et al., 2014), and 70% of the presentday 1.6 million King penguin breeding pairs are expected to have relocated or disappeared (Cristofari et al., 2018;Kintisch, 2020). In addition, a southward contraction in the range of Ad elie penguins in the Antarctic Peninsula is likely over the next century (Lynch et al., 2012), and Ad elie penguins on Litchfield Island near the Palmer Station had already disappeared completely in 2007 (Fraser et al., 2013). ...
Drastic climate change is widely believed to threaten the ecological security of penguins. Previous studies have concluded that penguins on the Scott Coast, southern Ross Sea, disappeared from ∼2000 yr BP; two opposite hypotheses of “cooling” and “warming” have been proposed for the disappearance. Here, by identifying penguin guano and remains such as eggshell fragments, bones and feathers in a sediment profile from Dunlop Island, we found that this island was not abandoned at ∼2000 yr BP. In addition, sedimentological evidence from Cape Ross deduced the permanent snow/ice cover at ∼1700 yr BP, which is consistent with a Neoglacial cooling period on the Scott Coast. We suggest that Neoglacial cooling caused the widespread abandonment of penguin colonies on the Scott Coast, by the increased coastal sea ice and/or snow/ice accumulation. However, penguins persisted at particular localities due to specific topographical or oceanic conditions shielding them from the impacts of snow and ice.
... Many species are moving toward the poles and mountain tops to escape increasing temperatures (Chen et al., 2011;Lenoir & Svenning, 2015;Pecl et al., 2017) or seeking refugia in the landscape (Keppel et al., 2012;Reside et al., 2014). For species that rely on specific habitats, changes over this century are expected to have dire consequences for populations, such as species dependent on ice environments, such asemperor penguins (Aptenodytes forsteri), Adelie penguins (Pygoscelis adeliae), and polar bears (Ursus maritimus; Kovacs, Lydersen, Overland, & Moore, 2011;Jenouvrier et al., 2014;Cimino, Lynch, Saba, & Oliver, 2016;Jenouvrier et al., 2020). However, species responses to climate change have been varied and complex, with some thriving in new environments (Ling, Barrett, & Edgar, 2018), or demonstrating unexpected redistribution (Archaux, 2004;Fei et al., 2017;Lenoir et al., 2019). ...
Climate adaptation is an emerging practice in biodiversity conservation, but little is known about the scope, scale, and effectiveness of implemented actions. Here, we review and synthesize published reports of climate adaptation interventions for iconic fauna. We present a systematic map of peer‐reviewed literature databases (Web of Science and Scopus); however, only nine climate adaptation actions targeting iconic fauna were returned. In the grey and informal literature, there were many instances of practical intervention within our scope, that were not uncovered during traditional systematic search methods. The richness of actions reported in commercial news, government and non‐government organization media outlets and other online sources vastly outweighs the limited studies that have been robustly evaluated and reported in the scientific literature. From our investigation of this emerging field of conservation practice, we draw insights and pen a series of recommendations for the field moving forward. Key recommendations for future adaptation interventions include: the sharing and publishing of climate‐related conservation interventions, the use of standardized metrics for reporting outcomes, the implementation of experimental controls for any actions undertaken, and reporting and evaluation of both failures and successes. New Zealand sea lion pups get stuck in muddy wallows/bogs on Campbell Island so the Department of Conservation installed artificial ramps to help them climb out.
... The colonies sampled were divided into at least four metapopulations, with the colonies in the Ross Sea being one of them. The world's largest breeding colonies of both emperor (Fretwell et al., 2012) and Adèlie (Lynch and LaRue, 2014) penguins are located in the Ross Sea, which is also the only region with a predicted stable or increasing population of emperor penguins (Jenouvrier et al., 2014). Genetic tools revealed that the assumption of all colonies being demographically connected was incorrect (Younger et al., 2017). ...
The current attrition of biodiversity extends beyond loss of species and unique populations to steady loss of a vast genomic diversity that remains largely undescribed. Yet the accelerating development of new techniques allows us to survey entire genomes ever faster and cheaper, to obtain robust samples from a diversity of sources including degraded DNA and residual DNA in the environment, and to address conservation efforts in new and innovative ways. Here we review recent studies that highlight the importance of carefully considering where to prioritize collection of genetic samples (e.g., organisms in rapidly changing landscapes or along edges of geographic ranges) and what samples to collect and archive (e.g., from individuals of little-known subspecies or populations, even of species not currently considered endangered). Those decisions will provide the sample infrastructure to detect the disappearance of certain genotypes or gene complexes, increases in inbreeding levels, and loss of genomic diversity as environmental conditions change. Obtaining samples from currently endangered, protected, and rare species can be particularly difficult, thus we also focus on studies that use new, non-invasive ways of obtaining genomic samples and analyzing them in these cases where other sampling options are highly constrained. Finally, biological collections archiving such samples face an inherent contradiction: their main goal is to preserve biological material in good shape so it can be used for scientific research for centuries to come, yet the technologies that can make use of such materials are advancing faster than collections can change their standardized practices. Thus, we also discuss current and potential new practices in biological collections that might bolster their usefulness for future biodiversity conservation research.
... For example, with continued lengthening thaw season and diminishing sea ice in the Arctic, polar bear distributions may shift away from prey dependent on sea ice such as ringed seal pups, and toward prey on solid ground, such as snow geese eggs (117), a shift that could reduce polar bear body condition and survival and increase competition with land-based brown bears (118). In Antarctica, receding glaciers have enabled more breeding habitat and increased abundances of Adélie penguins in some areas (119), whereas continued sea ice decline is detrimental to emperor penguin breeding habitat and populations (120). Multiple SAI scenarios predict diminished seasonality in high latitudes, with warmer winters and cooler summers, resulting in sea ice decreasing during winter and increasing during summer (32). ...
As the effects of anthropogenic climate change become more severe, several approaches for deliberate climate intervention to reduce or stabilize Earth’s surface temperature have been proposed. Solar radiation modification (SRM) is one potential approach to partially counteract anthropogenic warming by reflecting a small proportion of the incoming solar radiation to increase Earth’s albedo. While climate science research has focused on the predicted climate effects of SRM, almost no studies have investigated the impacts that SRM would have on ecological systems. The impacts and risks posed by SRM would vary by implementation scenario, anthropogenic climate effects, geographic region, and by ecosystem, community, population, and organism. Complex interactions among Earth’s climate system and living systems would further affect SRM impacts and risks. We focus here on stratospheric aerosol intervention (SAI), a well-studied and relatively feasible SRM scheme that is likely to have a large impact on Earth’s surface temperature. We outline current gaps in knowledge about both helpful and harmful predicted effects of SAI on ecological systems. Desired ecological outcomes might also inform development of future SAI implementation scenarios. In addition to filling these knowledge gaps, increased collaboration between ecologists and climate scientists would identify a common set of SAI research goals and improve the communication about potential SAI impacts and risks with the public. Without this collaboration, forecasts of SAI impacts will overlook potential effects on biodiversity and ecosystem services for humanity.
... To our knowledge, no studies of Antarctic vertebrate eDNA from snow samples have been published to date. This gap in the literature presents a potential for future eDNA studies on Antarctic wildlife (Box 1); importantly, eDNA could aid in monitoring of ice-dependent species that are likely to be negatively impacted by climate change in the near future (Siniff et al. 2008;Ainley et al. 2010;Jenouvrier et al. 2014;Trathan et al. 2020). Box 1. Weddell seals case study. ...
Antarctica is home to numerous species that are vulnerable to environmental change, and assessing species responses requires long-term monitoring. However, Antarctica’s extreme nature presents limitations to conducting the type of long-term or broad-scale studies necessary for understanding changes in community composition. In this paper, we evaluate the potential for the use of environmental DNA (eDNA) methods in expanding scientific research efforts for biodiversity monitoring and conservation genetics in Antarctica. Through a systematic literature review, we identify that most Antarctic eDNA studies have focused on microbial metabarcoding using samples from soil, sediment, snow, and water. Few eDNA studies in Antarctica have focused on vertebrate biodiversity or population genetics, but we highlight several examples that have effectively and creatively used eDNA to study vertebrates. We highlight the potential for the use of portable sequencing technologies in the future of Antarctic eDNA research. We conclude that eDNA could be a valuable tool for researchers in their efforts to assess, monitor, and conserve biodiversity in the Antarctic.
... Alternatively, certain species may be considered as "leading" sentinels, whereby population level responses in these species precede observable change in responses of other species or the ecosystem (Hazen et al., 2019). The penguin species that breed in Antarctica and forage in the Southern Ocean, feed extensively on krill or are ice-obligates, and are exemplar species for studying the potential links between system fluctuations and predator populations (e.g., fisheries pressures: Hinke et al., 2017;Trathan et al., 2018;Watters et al., 2020), or Antarctic marine ecosystem responses to environmental perturbations (e.g., climate change: Jenouvrier et al., 2014;Johnson et al., 2019;Emmerson et al., 2015;. Indeed, evidence already shows that penguin populations in particular are at risk from overexploitation of resources and climate change Dias et al., 2019;Ropert-Coudert et al., 2019). ...
Global targets for area-based conservation and management must move beyond threshold-based targets alone and must account for the quality of such areas. In the Southern Ocean around Antarctica, a region where key biodiversity faces unprecedented risks from climate change and where there is a growing demand to extract resources, a number of marine areas have been afforded enhanced conservation or management measures through two adopted marine protected areas (MPAs). However, evidence suggests that additional high quality areas could benefit from a proposed network of MPAs. Penguins offer a particular opportunity to identify high quality areas because these birds, as highly visible central-place foragers, are considered indicator species whose populations reflect the state of the surrounding marine environment. We compiled a comprehensive dataset of the location of penguin colonies and their associated abundance estimates in Antarctica. We then estimated the at-sea distribution of birds based on information derived from tracking data and through the application of a modified foraging radius approach with a density decay function to identify some of the most important marine areas for chick-rearing adult penguins throughout waters surrounding Antarctica following the Important Bird and Biodiversity Area (IBA) framework. Additionally, we assessed how marine IBAs overlapped with the currently adopted and proposed network of key management areas (primarily MPAs), and how the krill fishery likely overlapped with marine IBAs over the past five decades. We identified 63 marine IBAs throughout Antarctic waters and found that were the proposed MPAs to be adopted, the permanent conservation of high quality areas for penguin species would increase by between 49 and 100% depending on the species. Furthermore, our data show that, despite a generally contracting range of operation by the krill fishery in Antarctica over the past five decades, a consistently disproportionate amount of krill is being harvested within marine IBAs compared to the total area in which the fishery operates. Our results support the designation of the proposed MPA network and offer additional guidance as to where decision-makers should act before further perturbation occurs in the Antarctic marine ecosystem.
... This 'capital' breeding strategy contrasts with 'income' breeding, in which individuals rely directly on exogenous food sources consumed concomitantly with breeding to build offspring (Drent & Daan, 1980). Understanding such nutrient allocations during reproduction is valuable because it illuminates the evolution of life-history strategies and the relative importance of different habitats and food sources at different points during the annual cycle, a key factor in organismal responses to environmental shifts (Jenouvrier et al., 2014). However, tracing allocation of endogenous and exogenous nutrients to reproduction in wild animals is challenging. ...
Capital breeders accumulate nutrients prior to egg development, then use these stores to support offspring development. In contrast, income breeders rely on local nutrients consumed contemporaneously with offspring development. Understanding such nutrient allocations is critical to assessing life‐history strategies and habitat use.
Despite the contrast between these strategies, it remains challenging to trace nutrients from endogenous stores or exogenous food intake into offspring. Here, we tested a new solution to this problem.
Using tissue samples collected opportunistically from wild emperor penguins Aptenodytes forsteri, which exemplify capital breeding, we hypothesized that the stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope values of individual amino acids (AAs) in endogenous stores (e.g. muscle) and in egg yolk and albumen reflect the nutrient sourcing that distinguishes capital versus income breeding. Unlike other methods, this approach does not require untested assumptions or diet sampling.
We found that over half of essential AAs had δ¹³C values that did not differ between muscle and yolk or albumen, suggesting that most of these AAs were directly routed from muscle into eggs. In contrast, almost all non‐essential AAs differed in δ¹³C values between muscle and yolk or between muscle and albumen, suggesting de novo synthesis. Over half of AAs that have labile nitrogen atoms (i.e. ‘trophic’ AA) had higher δ¹⁵N values in yolk and albumen than in muscle, suggesting that they were transaminated during their routing into egg tissue. This effect was smaller for AAs with less labile nitrogen atoms (i.e. ‘source’ AA).
Our results indicate that the δ¹⁵N offset between trophic‐source AAs (Δ¹⁵Ntrophic‐source) may provide an index of the extent of capital breeding. The value of emperor penguin Δ¹⁵NPro‐Phe was higher in yolk and albumen than in muscle, reflecting the mobilization of endogenous stores; in comparison, the value of Δ¹⁵NPro‐Phe was similar across muscle and egg tissue in previously published data for income‐breeding herring gulls Larus argentatus smithsonianus. Our results provide a quantitative basis for using AA δ¹³C and δ¹⁵N, and isotopic offsets among AAs (e.g. Δ¹⁵NPro‐Phe), to explore the allocation of endogenous versus exogenous nutrients across the capital versus income spectrum of avian reproduction.
Emperor penguins (Aptenodytes forsteri) are under increasing environmental pressure. Monitoring colony size and population trends of this Antarctic seabird relies primarily on satellite imagery recorded near the end of the breeding season, when light conditions levels are sufficient to capture images, but colony occupancy is highly variable. To correct population estimates for this variability, we develop a phenological model that can predict the number of breeding pairs and fledging chicks, as well as key phenological events such as arrival, hatching and foraging times, from as few as six data points from a single season. The ability to extrapolate occupancy from sparse data makes the model particularly useful for monitoring remotely sensed animal colonies where ground-based population estimates are rare or unavailable.
Ecological predictions are necessary for testing whether processes hypothesized to regulate species population dynamics are generalizable across time and space. In order to demonstrate generalizability, model predictions should be transferable in one or more dimensions, where transferability is the successful prediction of responses outside of the model data bounds. While much is known as to what makes spatially-oriented models transferable, there is no general consensus as to the spatio-temporal transferability of ecological time series models. Here, we examine whether the intrinsic predictability of a time series, as measured by its complexity, could limit such transferability using an exceptional long-term dataset of Adélie penguin breeding abundance time series collected at 24 colonies around Antarctica. For each colony, we select a suite of environmental variables from the Community Earth System Model, version 2 to predict population growth rates, before assessing how well these environmentally-dependent population models transfer temporally and how reliably temporal signals replicate through space. We show that weighted permutation entropy (WPE), a model-free measure of intrinsic predictability recently introduced to ecology, varies spatially across Adélie penguin populations, perhaps in response to stochastic environmental events. We demonstrate that WPE can strongly limit temporal predictive performance, although this relationship could be weakened if intrinsic predictability is not constant over time. Lastly, we show that WPE can also limit spatial forecast horizon, which we define as the decay in spatial predictive performance with respect to the physical distance between focal colony and predicted colony. Irrespective of intrinsic predictability, spatial forecast horizons for all Adélie penguin breeding colonies included in this study are surprisingly short and our population models often have similar temporal and spatial predictive performance compared to null models based on long-term average growth rates. For cases where time series are complex, as measured by WPE, and the transferability of biologically-motivated mechanistic models are poor, we advise that null models should instead be used for prediction. These models are likely better at capturing more generalizable relationships between average growth rates and long-term environmental conditions. Lastly, we recommend that WPE can provide valuable insights when evaluating model performance, designing sampling or monitoring programs, or assessing the appropriateness of preexisting datasets for making conservation management decisions in response to environmental change.
Climate change and climate variability have been shown to affect a broad range of species worldwide. As seabirds are likely to be affected by changing climate while breeding on-land and foraging at-sea, their population status and ecological changes are monitored as indicators of ecosystem change. This paper reviews the ecological processes and population consequences of climate impacts on penguins. The review shows that climate change and climate variability are important factors driving the changes in the population size and breeding success of various penguin species (up to 13 of 18 extant species) via changes in their breeding and foraging environments. However, these factors affect penguins in a complex way. For example, the effects of a warming climate can vary from negative to positive in different parts of the distribution range of a single species, or in different life-history parameters within a single population (e.g., breeding success vs. adult survival rates). Some simulation studies have produced future population projections for Antarctic and subantarctic penguins based on multiple climate change scenarios, emphasizing the importance of climate mitigation. The results of these simulations should still be interpreted with caution, while appreciating the uncertainties associated with climate projections and penguin responses to future climate. More research on penguin foraging ecology is needed, especially during data-poor non-breeding or juvenile periods, to elucidate fully the processes of climate impacts on penguins. Finally, mitigating existing human impacts is essential to safeguard penguin species, and will help penguin populations become more resilient to existing and future climate impacts.
Habitat loss and degradation are currently the main anthropogenic causes of species extinctions. The root cause is human overpopulation. This unique volume provides, for the very first time, a comprehensive overview of all threatened and recently extinct mammals, birds, reptiles, amphibians, and fishes within the context of their locations and habitats. The approach takes a systematic examination of each biogeographic realm and region of the world, both terrestrial and marine, but with a particular emphasis on geographic features such as mountains, islands, and coral reefs. It reveals patterns useful in biodiversity conservation, helps to put it all into perspective, and ultimately serves as both a baseline from which to compare subsequent developments as well as a standardization of the way threatened species are studied.
This chapter assesses climate information relevant to regional impact and risk assessment. It complements other WG1 chapters which focus on the physical processes determining changes in the climate system and on methods for estimating regional changes.
This chapter is new in the IPCC WGI assessment reports, in that it represents a contribution to the “IPCC Risk Framework”. Within this framework, climate-related impacts and risks are determined through an interplay between the occurrence of climate hazards and their consequences depending on the exposure of the affected human or natural system and its vulnerability to the hazardous conditions. In Chapter 12, we are assessing climatic impact-drivers that could lead to hazards or to opportunities, from the literature and model results since AR5. This will particularly support the assessment of key risks related to climate change by WGII (Chapter 16). Despite the fact that impacts may also be induced by climate adaptation and mitigation policies themselves, as well as by socioeconomic trends, changes in vulnerability or exposure, and external geophysical hazards such as volcanoes, the focus here is only on ‘climatic’ impacts and risks induced by shifts in physical climate phenomena that directly influence human and ecological systems.
Range shift is the primary short-term response of species to rapid climate change but it is hampered by natural or anthropogenic habitat fragmentation. Fragmented habitats expose different critical areas of a species niche to heterogeneous environmental changes resulting in uncoupled effects. Modelling species distribution under complex real-life scenarios and incorporating such uncoupled effects has not been achieved yet. Here we identify the most vulnerable areas and the potential cold refugia of a top-predator with fragmented niche range in the Southern ocean by integrating genomic, ecological and behavioural data with atmospheric and oceanographic models. Our integrative approach constitutes an indispensable example for predicting the effect of global warming on species relying on spatially and ecologically distinct areas to complete their life-cycle (e.g., migratory animals, marine pelagic organisms, central-place foragers) and, in general, on species constrained in fragmented landscapes due to continuously-growing anthropogenic pressure.
Large ensemble climate modelling experiments demonstrate the large role natural variability plays in local climate on a multi-decadal timescale. Variability in local weather and climate influences individual beliefs about climate change. To the extent that support for climate mitigation policies is determined by citizens' local experiences, natural variability will strongly influence the timescale for implementation of such policies. Under a number of illustrative threshold criteria for both national and international climate action, we show that variability-driven uncertainty about local change, even in the face of a well-constrained estimate of global change, can potentially delay the time to policy implementation by decades. Because several decades of greenhouse gas emissions can have a large impact on long-term climate outcomes, there is substantial risk associated with climate policies driven by consensus among individuals who are strongly influenced by local weather conditions.
We describe a new breeding behaviour discovered in emperor penguins; utilizing satellite and aerial-survey observations four emperor penguin breeding colonies have been recorded as existing on ice-shelves. Emperors have previously been considered as a sea-ice obligate species, with 44 of the 46 colonies located on sea-ice (the other two small colonies are on land). Of the colonies found on ice-shelves, two are newly discovered, and these have been recorded on shelves every season that they have been observed, the other two have been recorded both on ice-shelves and sea-ice in different breeding seasons. We conduct two analyses; the first using synthetic aperture radar data to assess why the largest of the four colonies, for which we have most data, locates sometimes on the shelf and sometimes on the sea-ice, and find that in years where the sea-ice forms late, the colony relocates onto the ice-shelf. The second analysis uses a number of environmental variables to test the habitat marginality of all emperor penguin breeding sites. We find that three of the four colonies reported in this study are in the most northerly, warmest conditions where sea-ice is often sub-optimal. The emperor penguin's reliance on sea-ice as a breeding platform coupled with recent concerns over changed sea-ice patterns consequent on regional warming, has led to their designation as "near threatened" in the IUCN red list. Current climate models predict that future loss of sea-ice around the Antarctic coastline will negatively impact emperor numbers; recent estimates suggest a halving of the population by 2052. The discovery of this new breeding behaviour at marginal sites could mitigate some of the consequences of sea-ice loss; potential benefits and whether these are permanent or temporary need to be considered and understood before further attempts are made to predict the population trajectory of this iconic species.
Estimates of impacts from anthropogenic climate change rely on
projections from climate models. Uncertainties in those have often been
a limiting factor, in particular on local scales. A new generation of
more complex models running scenarios for the upcoming Intergovernmental
Panel on Climate Change Fifth Assessment Report (IPCC AR5) is widely,
and perhaps naively, expected to provide more detailed and more certain
projections. Here we show that projected global temperature change from
the new models is remarkably similar to that from those used in IPCC AR4
after accounting for the different underlying scenarios. The spatial
patterns of temperature and precipitation change are also very
consistent. Interestingly, the local model spread has not changed much
despite substantial model development and a massive increase in
computational capacity. Part of this model spread is irreducible owing
to internal variability in the climate system, yet there is also
uncertainty from model differences that can potentially be eliminated.
We argue that defining progress in climate modelling in terms of
narrowing uncertainties is too limited. Models improve, representing
more processes in greater detail. This implies greater confidence in
their projections, but convergence may remain slow. The uncertainties
should not stop decisions being made.
Krill (Euphausia superba) provide a direct link between primary producers and higher trophic levels in the Antarctic marine food web. The pelagic tunicate Salpa thompsoni can also be important during spring and summer through the formation of extensive and dense blooms. Although salps are not a major dietary item for Antarctic vertebrate predators,, their blooms can affect adult krill reproduction and survival of krill larvae. Here we provide data from 1995 and 1996 that support hypothesized relationships between krill, salps and region-wide sea-ice conditions,. We have assessed salp consumption as a proportion of net primary production, and found correlations between herbivore densities and integrated chlorophyll-a that indicate that there is a degree of competition between krill and salps. Our analysis of the relationship between annual sea-ice cover and a longer time series of air temperature measurements, indicates a decreased frequency of winters with extensive sea-ice development over the last five decades. Our data suggest that decreased krill availability may affect the levels of their vertebrate predators. Regional warming and reduced krill abundance therefore affect the marine food web and krill resource management.
The arrival in January 2001 in the south-west Ross Sea of two giant icebergs, C16 and B15A, subsequently had dramatic affects on two emperor penguin colonies. B15A collided with the north-west tongue of the Ross Ice Shelf at Cape Crozier, Ross Island, in the following months and destroyed the penguins' nesting habitat. The colony totally failed in 2001, and years after, with the icebergs still in place, exhibited reduced production that ranged from 0 to 40% of the 1201 chicks produced in 2000. At Beaufort Island, 70 km NW of Crozier, chick production declined to 6% of the 2000 count by 2004. Collisions with the Ross Ice Shelf at Cape Crozier caused incubating adults to be crushed, trapped in ravines, or to abandon the colony and, since 2001, to occupy poorer habitat. The icebergs separated Beaufort Island from the Ross Sea Polynya, formerly an easy route to feeding and wintering areas. This episode has provided a glimpse of events which have probably occurred infrequently since the West Antarctic Ice Sheet began to retreat 12 000 years ago. The results allow assessment of recovery rates for one colony decimated by both adult and chick mortality, and the other colony by adult abandonment and chick mortality.
Our aim was to estimate the population of emperor penguins (Aptenodytes fosteri) using a single synoptic survey. We 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.
We found four new colonies and confirmed the location of three previously suspected sites giving a total number of emperor penguin breeding colonies of 46. We estimated the breeding population of emperor penguins at each colony during 2009 and provide a population estimate of ∼238,000 breeding pairs (compared with the last previously published count of 135,000–175,000 pairs). Based on published values of the relationship between breeders and non-breeders, this translates to a total population of ∼595,000 adult birds.
There is a growing consensus in the literature that global and regional emperor penguin populations will be affected by changing climate, a driver thought to be critical to their future survival. However, a complete understanding is severely limited by the lack of detailed knowledge about much of their ecology, and importantly a poor understanding of their total breeding population. To address the second of these issues, our 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.
A coordinated set of global coupled climate model [atmosphere-ocean general circulation model (AOGCM)] experiments for twentieth- and twenty-first-century climate, as well as several climate change commitment and other experiments, was run by 16 modeling groups from 11 countries with 23 models for assessment in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). Since the assessment was completed, output from another model has been added to the dataset, so the participation is now 17 groups from 12 countries with 24 models. This effort, as well as the subsequent analysis phase, was organized by the World Climate Research Programme (WCRP) Climate Variability and Predictability (CLIVAR) Working Group on Coupled Models (WGCM) Climate Simulation Panel, and constitutes the third phase of the Coupled Model Intercomparison Project (CMIP3). The dataset is called the WCRP CMIP3 multimodel dataset, and represents the largest and most comprehensive international global coupled climate model experiment and multimodel analysis effort ever attempted. As of March 2007, the Program for Climate Model Diagnostics and Intercomparison (PCMDI) has collected, archived, and served roughly 32 TB of model data. With oversight from the panel, the multimodel data were made openly available from PCMDI for analysis and academic applications. Over 171 TB of data had been downloaded among the more than 1000 registered users to date. Over 200 journal articles, based in part on the dataset, have been published so far. Though initially aimed at the IPCC AR4, this unique and valuable resource will continue to be maintained for at least the next several years. Never before has such an extensive set of climate model simulations been made available to the international climate science community for study. The ready access to the multimodel dataset opens up these types of model analyses to researchers, including students, who previously could not obtain state-of-the-art climate model output, and thus represents a new era in climate change research. As a direct consequence, these ongoing studies are increasing the body of knowledge regarding the understanding of how the climate system currently works, and how it may change in the future.
In 1948, a small colony of emperor penguins Aptenodytes forsteri was discovered breeding on Emperor Island (67° 51' 52″ S, 68° 42' 20″ W), in the Dion Islands, close to the West Antarctic Peninsula (Stonehouse 1952). When discovered, the colony comprised approximately 150 breeding pairs; these numbers were maintained until 1970, after which time the colony showed a continuous decline. By 1999 there were fewer than 20 pairs, and in 2009 high-resolution aerial photography revealed no remaining trace of the colony. Here we relate the decline and loss of the Emperor Island colony to a well-documented rise in local mean annual air temperature and coincident decline in seasonal sea ice duration. The loss of this colony provides empirical support for recent studies (Barbraud & Weimerskirch 2001; Jenouvrier et al 2005, 2009; Ainley et al 2010; Barber-Meyer et al 2005) that have highlighted the vulnerability of emperor penguins to changes in sea ice duration and distribution. These studies suggest that continued climate change is likely to impact upon future breeding success and colony viability for this species. Furthermore, a recent circumpolar study by Fretwell & Trathan (2009) highlighted those Antarctic coastal regions where colonies appear most vulnerable to such changes. Here we examine which other colonies might be at risk, discussing various ecological factors, some previously unexplored, that may also contribute to future declines. The implications of this are important for future modelling work and for understanding which colonies actually are most vulnerable.
The polar bear (Ursus maritimus) depends on sea ice for feeding, breeding, and movement. Significant reductions in Arctic sea ice are forecast to continue because of climate warming. We evaluated the impacts of climate change on polar bears in the southern Beaufort Sea by means of a demographic analysis, combining deterministic, stochastic, environment-dependent matrix population models with forecasts of future sea ice conditions from IPCC general circulation models (GCMs). The matrix population models classified individuals by age and breeding status; mothers and dependent cubs were treated as units. Parameter estimates were obtained from a capture-recapture study conducted from 2001 to 2006. Candidate statistical models allowed vital rates to vary with time and as functions of a sea ice covariate. Model averaging was used to produce the vital rate estimates, and a parametric bootstrap procedure was used to quantify model selection and parameter estimation uncertainty. Deterministic models projected population growth in years with more extensive ice coverage (2001-2003) and population decline in years with less ice coverage (2004-2005). LTRE (life table response experiment) analysis showed that the reduction in lambda in years with low sea ice was due primarily to reduced adult female survival, and secondarily to reduced breeding. A stochastic model with two environmental states, good and poor sea ice conditions, projected a declining stochastic growth rate, log lambdas, as the frequency of poor ice years increased. The observed frequency of poor ice years since 1979 would imply log lambdas approximately - 0.01, which agrees with available (albeit crude) observations of population size. The stochastic model was linked to a set of 10 GCMs compiled by the IPCC; the models were chosen for their ability to reproduce historical observations of sea ice and were forced with "business as usual" (A1B) greenhouse gas emissions. The resulting stochastic population projections showed drastic declines in the polar bear population by the end of the 21st century. These projections were instrumental in the decision to list the polar bear as a threatened species under the U.S. Endangered Species Act.
We present a new approach to modeling two-sex populations, using periodic, nonlinear two-sex matrix models. The models project the population growth rate, the population structure, and any ratio of interest (e.g., operational sex ratio). The periodic formulation permits inclusion of highly seasonal behavioral events. A periodic product of the seasonal matrices describes annual population dynamics. The model is nonlinear because mating probability depends on the structure of the population. To study how the vital rates influence population growth rate, population structure, and operational sex ratio, we used sensitivity analysis of frequency-dependent nonlinear models. In nonlinear two-sex models the vital rates affect growth rate directly and also indirectly through effects on the population structure. The indirect effects can sometimes overwhelm the direct effects and are revealed only by nonlinear analysis. We find that the sensitivity of the population growth rate to female survival is negative for the emperor penguin, a species with highly seasonal breeding behavior. This result could not occur in linear models because changes in population structure have no effect on per capita reproduction. Our approach is applicable to ecological and evolutionary studies of any species in which males and females interact in a seasonal environment.
The severity of damaging human-induced climate change depends not only on the magnitude of the change but also on the potential for irreversibility. This paper shows that the climate change that takes place due to increases in carbon dioxide concentration is largely irreversible for 1,000 years after emissions stop. Following cessation of emissions, removal of atmospheric carbon dioxide decreases radiative forcing, but is largely compensated by slower loss of heat to the ocean, so that atmospheric temperatures do not drop significantly for at least 1,000 years. Among illustrative irreversible impacts that should be expected if atmospheric carbon dioxide concentrations increase from current levels near 385 parts per million by volume (ppmv) to a peak of 450-600 ppmv over the coming century are irreversible dry-season rainfall reductions in several regions comparable to those of the "dust bowl" era and inexorable sea level rise. Thermal expansion of the warming ocean provides a conservative lower limit to irreversible global average sea level rise of at least 0.4-1.0 m if 21st century CO(2) concentrations exceed 600 ppmv and 0.6-1.9 m for peak CO(2) concentrations exceeding approximately 1,000 ppmv. Additional contributions from glaciers and ice sheet contributions to future sea level rise are uncertain but may equal or exceed several meters over the next millennium or longer.
Studies have reported important effects of recent climate change on Antarctic species, but there has been to our knowledge no attempt to explicitly link those results to forecasted population responses to climate change. Antarctic sea ice extent (SIE) is projected to shrink as concentrations of atmospheric greenhouse gases (GHGs) increase, and emperor penguins (Aptenodytes forsteri) are extremely sensitive to these changes because they use sea ice as a breeding, foraging and molting habitat. We project emperor penguin population responses to future sea ice changes, using a stochastic population model that combines a unique long-term demographic dataset (1962-2005) from a colony in Terre Adélie, Antarctica and projections of SIE from General Circulation Models (GCM) of Earth's climate included in the most recent Intergovernmental Panel on Climate Change (IPCC) assessment report. We show that the increased frequency of warm events associated with projected decreases in SIE will reduce the population viability. The probability of quasi-extinction (a decline of 95% or more) is at least 36% by 2100. The median population size is projected to decline from approximately 6,000 to approximately 400 breeding pairs over this period. To avoid extinction, emperor penguins will have to adapt, migrate or change the timing of their growth stages. However, given the future projected increases in GHGs and its effect on Antarctic climate, evolution or migration seem unlikely for such long lived species at the remote southern end of the Earth.
The North Atlantic northern right whale (Eubalaena glacialis) is considered the most endangered large whale species. Its population has recovered only slowly since the cessation of commercial whaling and numbers about 300 individuals. We applied mark-recapture statistics to a catalog of photographically identified individuals to obtain the first statistically rigorous estimates of survival probability for this population. Crude survival decreased from about 0.99 per year in 1980 to about 0.94 in 1994. We combined this survival trend with a reported decrease in reproductive rate into a branching process model to compute population growth rate and extinction probability. Population growth rate declined from about 1. 053 in 1980 to about 0.976 in 1994. Under current conditions the population is doomed to extinction; an upper bound on the expected time to extinction is 191 years. The most effective way to improve the prospects of the population is to reduce mortality. The right whale is at risk from entanglement in fishing gear and from collisions with ships. Reducing this human-caused mortality is essential to the viability of this population.
Planning and decision-making can be improved by access to reliable forecasts of ecosystem state, ecosystem services, and natural
capital. Availability of new data sets, together with progress in computation and statistics, will increase our ability to
forecast ecosystem change. An agenda that would lead toward a capacity to produce, evaluate, and communicate forecasts of
critical ecosystem services requires a process that engages scientists and decision-makers. Interdisciplinary linkages are
necessary because of the climate and societal controls on ecosystems, the feedbacks involving social change, and the decision-making
relevance of forecasts.
Climate change over the past approximately 30 years has produced numerous shifts in the distributions and abundances of species and has been implicated in one species-level extinction. Using projections of species' distributions for future climate scenarios, we assess extinction risks for sample regions that cover some 20% of the Earth's terrestrial surface. Exploring three approaches in which the estimated probability of extinction shows a power-law relationship with geographical range size, we predict, on the basis of mid-range climate-warming scenarios for 2050, that 15-37% of species in our sample of regions and taxa will be 'committed to extinction'. When the average of the three methods and two dispersal scenarios is taken, minimal climate-warming scenarios produce lower projections of species committed to extinction ( approximately 18%) than mid-range ( approximately 24%) and maximum-change ( approximately 35%) scenarios. These estimates show the importance of rapid implementation of technologies to decrease greenhouse gas emissions and strategies for carbon sequestration.
Open access to an unprecedented, comprehensive coordinated set of global coupled climate model experiments for twentieth and twenty-first century climate and other experiments is changing the way researchers and students analyze and learn about climate. The history of climate change modeling was first characterized in the 1980s by a number of distinct groups developing, running, and analyzing model output from their own models with little opportunity for anyone outside of those groups to have access to the model data. This was partly a consequence of relatively primitive computer networking and data transfer capabilities, along with the daunting task of collecting and storing such large amounts
Sea ice conditions in the Antarctic affect the life cycle of the emperor penguin (Aptenodytes forsteri). We present a population projection for the emperor penguin population of Terre Adélie, Antarctica, by linking demographic models (stage-structured, seasonal, nonlinear, two-sex matrix population models) to sea ice forecasts from an ensemble of IPCC climate models. Based on maximum likelihood capture-mark-recapture analysis, we find that seasonal sea ice concentration anomalies (SICa ) affect adult survival and breeding success. Demographic models show that both deterministic and stochastic population growth rates are maximized at intermediate values of annual SICa , because neither the complete absence of sea ice, nor heavy and persistent sea ice, would provide satisfactory conditions for the emperor penguin. We show that under some conditions the stochastic growth rate is positively affected by the variance in SICa . We identify an ensemble of five general circulation climate models whose output closely matches the historical record of sea ice concentration in Terre Adélie. The output of this ensemble is used to produce stochastic forecasts of SICa , which in turn drive the population model. Uncertainty is included by incorporating multiple climate models and by a parametric bootstrap procedure that includes parameter uncertainty due to both model selection and estimation error. The median of these simulations predicts a decline of the Terre Adélie emperor penguin population of 81% by the year 2100. We find a 43% chance of an even greater decline, of 90% or more. The uncertainty in population projections reflects large differences among climate models in their forecasts of future sea ice conditions. One such model predicts population increases over much of the century, but overall, the ensemble of models predicts that population declines are far more likely than population increases. We conclude that climate change is a significant risk for the emperor penguin. Our analytical approach, in which demographic models are linked to IPCC climate models, is powerful and generally applicable to other species and systems.
Climate change commitment in the 21st -century due to human activity in
the 20th century is quantified using output from 16 global coupled
general circulation models. With the atmospheric composition held
constant at year 2000 values, the global annual mean surface temperature
anomaly stabilizes with an additional warming over and above what
already occurred in the 20th century of +0.5° +/- 0.2°C by the
end of the 21st century. The magnitude is about 0.1°C warmer in the
models with the 20th century volcanic aerosol than those models without.
The multi-model ensemble (from 6 models) globally averaged sea level
rises +10 +/- 3cm by 2100 and does not show signs of leveling off. The
committed winter warming pattern is characterized by polar amplification
due in part to ice albedo feedback, with a further committed warming of
above 1.0°C and 0.6°C in the Arctic and Antarctic regions,
respectively. The tropical surface temperature pattern shows an El
Nino-like response, with consequent changes in precipitation over the
tropics. Thus, even after GHGs are stabilized, the multi-model results
show that the climate continues to change with similar patterns to those
when GHGs are continuously increasing, but these changes are due to the
thermal inertia of the climate system reacting to the radiative forcing
from the atmospheric composition changes applied during the 20th
century.
This review focuses on the impacts of climate change on population dynamics. I introduce the MUP (Measuring, Understanding, and Predicting) approach, which provides a general framework where an enhanced understanding of climate‐population processes, along with improved long‐term data, are merged into coherent projections of future population responses to climate change. This approach can be applied to any species, but this review illustrates its benefit using birds as examples.
Birds are one of the best‐studied groups and a large number of studies have detected climate impacts on vital rates (i.e., life history traits, such as survival, maturation, or breeding, affecting changes in population size and composition) and population abundance. These studies reveal multifaceted effects of climate with direct, indirect, time‐lagged, and nonlinear effects. However, few studies integrate these effects into a climate‐dependent population model to understand the respective role of climate variables and their components (mean state, variability, extreme) on population dynamics. To quantify how populations cope with climate change impacts, I introduce a new universal variable: the ‘population robustness to climate change.’ The comparison of such robustness, along with prospective and retrospective analysis may help to identify the major climate threats and characteristics of threatened avian species.
Finally, studies projecting avian population responses to future climate change predicted by IPCC ‐class climate models are rare. Population projections hinge on selecting a multiclimate model ensemble at the appropriate temporal and spatial scales and integrating both radiative forcing and internal variability in climate with fully specified uncertainties in both demographic and climate processes.
We examined the population dynamics of two Antarctic seabirds and the influence of environmental variability over a 40-year period by coupling the estimation of demographic parameters, based on capture–recapture data, and modeling, using Leslie ma-trix population models. We demonstrated that the demographic parameters showing the greatest contribution to the variance of population growth rate were adult survival for both species. Breeding success showed the same contribution as adult survival for Emperor Penguins, whereas the proportion of breeders had the next stronger contribution for Snow Petrels. The sensitivity of population growth rate to adult survival was very high and the adult survival variability was weak for both species. Snow Petrel males survived better than females, whereas Emperor Penguin males had lower survival than females. These differ-ences may be explained by the different investment in breeding. Emperor Penguin adult survival was negatively affected by air temperature during summer and winter for both sexes; male survival was negatively affected by sea ice concentration during summer, autumn, and winter. On the other hand, there was no effect of environmental covariates on Snow Petrel adult survival. The Emperor Penguin population has declined by 50% because of a decrease in adult survival related to a warming event during a regime shift in the late 1970s, whereas Snow Petrels showed their lowest numbers in 1976, but were able to skip reproduction. Indeed, the retrospective analysis of projection population matrix entries indicated that breeding abstention played a critical role in the population dynamics of Snow Petrels but not Emperor Penguins. Snow Petrels did not breed either when air temperature decreased during spring (probably reducing nest attendance and laying) or when sea ice decreased during autumn (reducing food availability). Emperor Penguin and Snow Petrel breeding population sizes were positively influenced by sea ice through its effect on adult survival for Emperor Penguins and on the proportion of breeders for Snow Petrels. Therefore, we hypothesize that the population sizes of the two species could be negatively affected by reduced sea ice in the context of global warming.
In 1902, the first breeding colony of emperor penguins was discovered. Over the following decades, the number of known emperor
penguin colonies increased steadily and new ones are still being discovered. However, rigorous census work has been carried
out at only a few colonies and accurate information on trends in breeding populations is limited to a small number of locations.
Thus, the total number of breeding pairs is still unknown as is the size of the global population (breeders, non-breeders,
juveniles). The International Union for the Conservation of Nature (IUCN) lists the species’ status as ‘least concern’ and
states that although the population trend for emperor penguins has not been quantified, the global population appears to be
stable. This review summarises the currently available information on the populations of emperor penguins at known colonies
in terms of survey methods, count units used and survey frequency. It examines what is known about the state of various colonies
and demonstrates that currently available data are inadequate for a trend assessment of the global population.
KeywordsEmperor penguins–Population data–Historical information–Monitoring
We assess the response of pack ice penguins, Emperor (Aptenodytes forsteri) and Ade´ lie (Pygoscelis adeliae), to habitat variability and, then, by modeling habitat alterations, the qualitative changes to their populations, size and distribution, as Earth's average tropospheric temperature reaches 28C above preindustrial levels (ca. 1860), the benchmark set by the European Union in efforts to reduce greenhouse gases. First, we assessed models used in the Intergovernmental Panel on Climate Change Fourth Assessment Report (AR4) on penguin performance duplicating existing conditions in the Southern Ocean. We chose four models appropriate for gauging changes to penguin habitat: GFDL-CM2.1, GFDL-CM2.0, MIROC3.2(hi-res), and MRI-CGCM2.3.2a. Second, we analyzed the composited model ENSEMBLE to estimate the point of 28C warming (2025–2052) and the projected changes to sea ice coverage (extent, persistence, and concentration), sea ice thickness, wind speeds, precipitation, and air temperatures. Third, we considered studies of ancient colonies and sediment cores and some recent modeling, which indicate the (space/time) large/centennialscale penguin response to habitat limits of all ice or no ice. Then we considered results of statistical modeling at the temporal interannual-decadal scale in regard to penguin response over a continuum of rather complex, meso- to large-scale habitat conditions, some of which have opposing and others interacting effects. The ENSEMBLE meso/decadal-scale output projects a marked narrowing of penguins' zoogeographic range at the 28C point. Colonies north of 708 S are projected to decrease or disappear: ;50% of Emperor colonies (40% of breeding population) and ;75% of Ade´ lie colonies (70% of breeding population), but limited growth might occur south of 738 S. Net change would result largely from positive responses to increase in polynya persistence at high latitudes, overcome by decreases in pack ice cover at lower latitudes and, particularly for Emperors, ice thickness. Ade´ lie Penguins might colonize new breeding habitat where concentrated pack ice diverges and/or disintegrating ice shelves expose coastline. Limiting increase will be decreased persistence of pack ice north of the Antarctic Circle, as this species requires daylight in its wintering areas. Ade´ lies would be affected negatively by increasing snowfall, predicted to increase in certain areas owing to intrusions of warm, moist marine air due to changes in the Polar Jet Stream.
Climate change has created the need for a new strategic framework for conservation. This framework needs to include new protected areas that account for species range shifts and management that addresses large-scale change across international borders. Actions within the framework must be effective in international waters and across political frontiers and have the ability to accommodate large income and ability-to-pay discrepancies between countries. A global protected-area system responds to these needs. A fully implemented global system of protected areas will help in the transition to a new conservation paradigm robust to climate change and will ensure the integrity of the climate services provided by carbon sequestration from the world's natural habitats. The internationally coordinated response to climate change afforded by such a system could have significant cost savings relative to a system of climate adaptation that unfolds solely at a country level. Implementation of a global system is needed very soon because the effects of climate change on species and ecosystems are already well underway.
Variations in ocean-atmosphere coupling over time in the Southern Ocean have dominant effects on sea-ice extent and ecosystem structure, but the ultimate consequences of such environmental changes for large marine predators cannot be accurately predicted because of the absence of long-term data series on key demographic parameters. Here, we use the longest time series available on demographic parameters of an Antarctic large predator breeding on fast ice and relying on food resources from the Southern Ocean. We show that over the past 50 years, the population of emperor penguins (Aptenodytes forsteri) in Terre Adélie has declined by 50% because of a decrease in adult survival during the late 1970s. At this time there was a prolonged abnormally warm period with reduced sea-ice extent. Mortality rates increased when warm sea-surface temperatures occurred in the foraging area and when annual sea-ice extent was reduced, and were higher for males than for females. In contrast with survival, emperor penguins hatched fewer eggs when winter sea-ice was extended. These results indicate strong and contrasting effects of large-scale oceanographic processes and sea-ice extent on the demography of emperor penguins, and their potential high susceptibility to climate change.
Recent changes in Antarctic seabird populations may reflect direct and indirect responses to regional climate change. The best long-term data for high-latitude Antarctic seabirds (Adélie and Emperor penguins and snow petrels) indicate that winter sea-ice has a profound influence. However, some effects are inconsistent between species and areas, some in opposite directions at different stages of breeding and life cycles, and others remain paradoxical. The combination of recent harvest driven changes and those caused by global warming may produce rapid shifts rather than gradual changes.
IPCC Climate Change 2007: The Physical Science Basis
- G Meehl
Meehl, G. et al. in IPCC Climate Change 2007: The Physical Science Basis
(eds Solomon, S. et al.) (Cambridge Univ. Press, 2010).
- H Caswell
Caswell, H. Matrix Population Models (Sinauer, 2001).
IUCN Red List Categories and Criteria (International Union for Conservation of
IUCN Red List Categories and Criteria (International Union for Conservation
of Nature, 2012).