Climate Change Winners: Receding Ice Fields Facilitate Colony Expansion and Altered Dynamics in an Adélie Penguin Metapopulation

There will be winners and losers as climate change alters the habitats of polar organisms. For an Adelie penguin (Pygoscelis adeliae) colony on Beaufort Island (Beaufort), part of a cluster of colonies in the southern Ross Sea, we report a recent population increase in response to increased nesting habitat as glaciers have receded. Emigration rates of birds banded as chicks on Beaufort to colonies on nearby Ross Island decreased after 2005 as available habitat on Beaufort increased, leading to altered dynamics of the metapopulation. Using aerial photography beginning in 1958 and modern satellite imagery, we measured change in area of available nesting habitat and population size of the Beaufort colony. Population size varied with available habitat, and both increased rapidly since the 1990s. In accord with glacial retreat, summer temperatures at nearby McMurdo Station increased by similar to 0.50 degrees C per decade since the mid-1980s. Although the Ross Sea is likely to be the last ocean with an intact ecosystem, the recent retreat of ice fields at Beaufort that resulted in increased breeding habitat exemplifies a process that has been underway in the Ross Sea during the entire Holocene. Furthermore, our results are in line with predictions that major ice shelves and glaciers will retreat rapidly elsewhere in the Antarctic, potentially leading to increased breeding habitat for Adelie penguins. Results further indicated that satellite imagery may be used to estimate large changes in Adelie penguin populations, facilitating our understanding of metapopulation dynamics and environmental factors that influence regional populations

Scientists' Warning to Humanity on Threats to Indigenous and Local Knowledge Systems

The knowledge systems and practices of Indigenous Peoples and local communities play critical roles in safeguarding the biological and cultural diversity of our planet. Globalization, government policies, capitalism, colonialism, and other rapid social-ecological changes threaten the relationships between Indigenous Peoples and local communities and their environments, thereby challenging the continuity and dynamism of Indigenous and Local Knowledge (ILK). In this article, we contribute to the “World Scientists' Warning to Humanity,” issued by the Alliance of World Scientists, by exploring opportunities for sustaining ILK systems on behalf of the future stewardship of our planet. Our warning raises the alarm about the pervasive and ubiquitous erosion of knowledge and practice and the social and ecological consequences of this erosion. While ILK systems can be adaptable and resilient, the foundations of these knowledge systems are compromised by ongoing suppression, misrepresentation, appropriation, assimilation, disconnection, and destruction of biocultural heritage. Three case studies illustrate these processes and how protecting ILK is central to biocultural conservation. We conclude with 15 recommendations that call for the recognition and support of Indigenous Peoples and local communities and their knowledge systems. Enacting these recommendations will entail a transformative and sustained shift in how ILK systems, their knowledge holders, and their multiple expressions in lands and waters are recognized, affirmed, and valued. We appeal for urgent action to support the efforts of Indigenous Peoples and local communities around the world to maintain their knowledge systems, languages, stewardship rights, ties to lands and waters, and the biocultural integrity of their territories—on which we all depend.Peer reviewe

Biocultural approaches to pollinator conservation

Pollinators underpin sustainable livelihoods that link ecosystems, spiritual and cultural values, and customary governance systems with indigenous peoples and local communities (IPLC) across the world. Biocultural diversity is a short-hand term for this great variety of people-nature interlinkages that have developed over time in specific ecosystems. Biocultural approaches to conservation explicitly build on the conservation practices inherent in sustaining these livelihoods. We used the Conceptual Framework of the Intergovernmental Platform on Biodiversity and Ecosystem Services to analyse the biocultural approaches to pollinator conservation by indigenous peoples and local communities globally. The analysis identified biocultural approaches to pollinators across all six elements of the Conceptual Framework, with conservation-related practices occurring in sixty countries, in all continents except Antarctica. Practices of IPLC that are significant for biocultural approaches to pollinator conservation can be grouped into three categories: the practice of valuing diversity and fostering biocultural diversity; landscape management practices; and diversified farming systems. Particular IPLCs may use some or all of these practices. Policies that recognise customary tenure over traditional lands, strengthen Indigenous and Community Conserved Areas, promote heritage listing and support diversified farming within a food sovereignty approach, are among several identified that strengthen biocultural approaches to pollinator conservation, and thereby deliver mutual benefits for pollinators and people

Adélie penguins coping with environmental change: results from a natural experiment at the edge of their breeding range.

We investigated life history responses to extreme variation in physical environmental conditions during a long-term demographic study of Adélie penguins at 3 colonies representing 9% of the world population and the full range of breeding colony sizes. Five years into the 14-year study (1997-2010) two very large icebergs (spanning 1.5 latitude degrees in length) grounded in waters adjacent to breeding colonies, dramatically altering environmental conditions during 2001 - 2005. This natural experiment allowed us to evaluate the relative impacts of expected long-term, but also extreme, short-term climate perturbations on important natural history parameters that can regulate populations. The icebergs presented physical barriers, not just to the penguins but to polynya formation, which profoundly increased foraging effort and movement rates, while reducing breeding propensity and productivity, especially at the smallest colony. We evaluated the effect of a variety of environmental parameters during breeding, molt, migration and wintering periods during years with and without icebergs on penguin breeding productivity, chick mass, and nesting chronology. The icebergs had far more influence on the natural history parameters of penguins than any of the other environmental variables measured, resulting in population level changes to metrics of reproductive performance, including delays in nesting chronology, depressed breeding productivity, and lower chick mass. These effects were strongest at the smallest, southern-most colony, which was most affected by alteration of the Ross Sea Polynya during years the iceberg was present. Additionally, chick mass was negatively correlated with colony size, supporting previous findings indicating density-dependent energetic constraints at the largest colony. Understanding the negative effects of the icebergs on the short-term natural history of Adélie penguins, as well as their response to long-term environmental variation, are importan

Climate change winners: receding ice fields facilitate colony expansion and altered dynamics in an Adélie penguin metapopulation.

There will be winners and losers as climate change alters the habitats of polar organisms. For an Adélie penguin (Pygoscelis adeliae) colony on Beaufort Island (Beaufort), part of a cluster of colonies in the southern Ross Sea, we report a recent population increase in response to increased nesting habitat as glaciers have receded. Emigration rates of birds banded as chicks on Beaufort to colonies on nearby Ross Island decreased after 2005 as available habitat on Beaufort increased, leading to altered dynamics of the metapopulation. Using aerial photography beginning in 1958 and modern satellite imagery, we measured change in area of available nesting habitat and population size of the Beaufort colony. Population size varied with available habitat, and both increased rapidly since the 1990s. In accord with glacial retreat, summer temperatures at nearby McMurdo Station increased by ~0.50 °C per decade since the mid-1980s. Although the Ross Sea is likely to be the last ocean with an intact ecosystem, the recent retreat of ice fields at Beaufort that resulted in increased breeding habitat exemplifies a process that has been underway in the Ross Sea during the entire Holocene. Furthermore, our results are in line with predictions that major ice shelves and glaciers will retreat rapidly elsewhere in the Antarctic, potentially leading to increased breeding habitat for Adélie penguins. Results further indicated that satellite imagery may be used to estimate large changes in Adélie penguin populations, facilitating our understanding of metapopulation dynamics and environmental factors that influence regional populations

Sex‐specific recruitment rates contribute to male‐biased sex ratio in Adélie penguins

Abstract Sex‐related differences in vital rates that drive population change reflect the basic life history of a species. However, for visually monomorphic bird species, determining the effect of sex on demographics can be a challenge. In this study, we investigated the effect of sex on apparent survival, recruitment, and breeding propensity in the Adélie penguin (Pygoscelis adeliae), a monochromatic, slightly size dimorphic species with known age, known sex, and known breeding history data collected during 1996–2019 (n = 2127 birds) from three breeding colonies on Ross Island, Antarctica. Using a multistate capture–mark–recapture maximum‐likelihood model, we estimated apparent survival (Ŝ), recapture (resighting) probability (p^), and the probability of transitioning among breeding states and moving between colonies (ψ̂; colony‐specific non‐juvenile pre‐breeders, breeders, and non‐breeders). Survival rate varied by breeding status and colony, but not sex, and pre‐breeders had higher survival rates than breeders and non‐breeders. Females had a higher probability of recruiting into the breeding population each year and may enter the breeding pool at younger ages. In contrast, both sexes had the same probability of breeding from year to year once they had recruited. Although we detected no direct sex effects on survival, the variation in recruitment probability and age‐at‐first reproduction, along with lower survival rates of breeders compared to pre‐breeders, likely leads to shorter lifespans for females. This is supported by our findings of a male‐biased mean adult sex ratio (ASR) of 1.4 males for every female (x̂ proportion of males = 0.57, SD = 0.07) across all colonies and years in this metapopulation. Our study illustrates how important it can be to disentangle sex‐related variation in population vital rates, particularly for species with complex life histories and demographic dynamics

Trends in the breeding population of Adélie penguins in the Ross Sea, 1981-2012: a coincidence of climate and resource extraction effects.

Measurements of the size of Adélie penguin (Pygoscelis adeliae) colonies of the southern Ross Sea are among the longest biologic time series in the Antarctic. We present an assessment of recent annual variation and trends in abundance and growth rates of these colonies, adding to the published record not updated for more than two decades. High angle oblique aerial photographic surveys of colonies were acquired and penguins counted for the breeding seasons 1981-2012. In the last four years the numbers of Adélie penguins in the Ross and Beaufort Island colonies (southern Ross Sea metapopulation) reached their highest levels since aerial counts began in 1981. Results indicated that 855,625 pairs of Adélie penguins established breeding territories in the western Ross Sea, with just over a quarter (28%) of those in the southern portion, constituting a semi-isolated metapopulation (three colonies on Ross Island, one on nearby Beaufort Island). The southern population had a negative per capita growth rate of -0.019 during 1981-2000, followed by a positive per capita growth rate of 0.067 for 2001-2012. Colony growth rates for this metapopulation showed striking synchrony through time, indicating that large-scale factors influenced their annual growth. In contrast to the increased colony sizes in the southern population, the patterns of change among colonies of the northern Ross Sea were difficult to characterize. Trends were similar to southern colonies until the mid-1990s, after which the signal was lost owing to significantly reduced frequency of surveys. Both climate factors and recovery of whale populations likely played roles in the trends among southern colonies until 2000, after which depletion of another trophic competitor, the Antarctic toothfish (Dissostichus mawsoni), may explain the sharp increasing trend evident since then

Factors driving Adélie penguin chick size, mass and condition at colonies of different sizes in the Southern Ross Sea

Body size, mass and condition can affect an organism’s ability to cope with variation in resource availability or metabolic demand, particularly as juveniles reach independence. It follows that changes to parental provisioning efficiency (size and frequency of meals) through intraspecific competition or environmental conditions that affect prey availability may affect chick size, mass and condition and ultimately post-fledging survival. We examined how Adélie penguin chick size, mass and condition varied among colonies of different sizes on Ross Island during a 15 yr period of high environmental variability and varying intraspecific competition. Aiding the study was a natural experiment in which the presence of 2 giant icebergs midway through the study abnormally increased sea ice concentration (SIC), altering adults’ access to food. Concurrently, the colonies were rapidly increasing in size; based on previous work, this indicated increased trophic competition near colonies, a trend likely indicating a changing food web in the greater region. Results showed that increased amounts of sea ice, which reduced the ability of adults to access food, had a negative effect on the size and mass of chicks. However, a greater proportion of fish (vs. krill) in the diet had a positive effect on chick size. Moreover, in some cases, increased intraspecific competition may be a more important driver of provisioning rate and chick size than abiotic factors, with chicks showing the effects of reduced food delivery at larger colonies. Understanding these patterns will allow better understanding of how factors such as climate change and altered food webs may affect Adélie penguin populations.Keywords: Intraspecific competition, Chick growth, Diet variability, Adélie penguin, Provisioning efficiencyKeywords: Intraspecific competition, Chick growth, Diet variability, Adélie penguin, Provisioning efficienc