Large-scale climate and local weather drive interannual variability in Adélie penguin chick fledging mass

Abstract

The fledging mass of penguin chicks can be an indicator of food availability and environmental conditions at a penguin colony. For the period 1989 to 2011, we analyzed predictor variables of environmental and food resource factors acting on multiple spatial scales near Palmer Station, Antarctica, that may influence the interannual variability in Adélie penguin chick fledging mass (CFM). To understand the influence of parental Adélie penguin diet on CFM, we modeled the energy density and krill demographics of penguin diet samples. We found a weak but significant positive relationship between the proportion of immature krill in adult penguin diets and CFM, which may indicate that krill recruitment and prey availability to adults influences CFM. However, the impact of large-scale climate and local weather outweighed the impact of parental diet characteristics on CFM. CFM was negatively associated with a positive Antarctic Oscillation (or Southern Annular Mode) and increased westerly winds and was positively associated with increased air temperature. The mechanistic relationship between climate, local weather, and CFM could include direct and indirect impacts, such as increased thermo-regulative costs for unattended chicks, decreased chick feeding frequency, and smaller meal mass for chicks driven by the geophysical transport of krill by climate and wind events.

Spatial niche partitioning may promote coexistence of Pygoscelis penguins as climate‐induced sympatry occurs

“…Our results indicate that during the breeding season, Adélie and gentoo penguins in this area rely heavily on a single prey species that is projected to decline as a result of sea ice loss, though, the results of our tracking study show that adequate spatial separation between foraging areas may buffer against interspecific competition in a resource-limited scenario. Our results support recent research that has shown other physical mechanisms (e.g., sea ice loss and increased precipitation) and postbreeding season factors (e.g., reduced prey availability) may have a greater influence on the overall success of these two Pygoscelis species given future climate projections (Cimino, Lynch, Saba, & Oliver, 2016;Cimino et al, 2014;Fraser et al, 2013;Hinke, Salwicka, Trivelpiece, Watters, & Trivelpiece, 2007).…”

“…Because gentoo penguins rely on krill as a primary prey resource in the Palmer area, declining krill stocks would contradict the rapid increase in gentoo penguin populations. Furthermore, a study of long‐term trends (1989–2011) of Adélie penguin chick fledgling mass (CFM) in the Palmer area determined that Adélie penguin diet characteristics had a minimal influence on CFM, suggesting that penguins had adequate prey resources during the breeding season (Cimino et al., ). Despite long‐term population trends indicating that prey resources are not currently limited in the Palmer area, we did not directly measure the distribution and density of prey within our study area.…”

“…Because breeding phenology affects penguin foraging behavior (e.g., Clarke, Emmerson, & Otahal, 2006;Clarke et al, 1998), the extent of foraging niche overlap that we observed in our study may have differed slightly had data collection overlapped completely between species. Allochrony of Pygoscelis penguins may act as an additional dimension of niche partitioning (Trivelpiece et al, 1987) and has been shown to be an important factor driving differences in Adélie and gentoo penguin nesting success under variable weather and climate scenarios (Cimino, Fraser, Patterson-Fraser, Saba, & Oliver, 2014;Fraser et al, 2013;Hinke et al, 2015). A more detailed investigation into the effects of breeding chronology on Adélie and gentoo penguin foraging niches in this region is warranted and would help to elucidate population-level responses to rapid environmental change on the WAP.…”

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

“…Variations in the environment (here indexed by the ONI) and LKB may affect penguin performance in myriad, complex ways. For example, precipitation has been negatively correlated with both chick survival and fledgling mass 40,41 . Also, when the standing stock of krill is large, small krill are proportionally more abundant 22 , and, when small krill are more abundant, chinstrap penguins take longer foraging trips 20 .…”

The interaction between island geomorphology and environmental parameters drives Adélie penguin breeding phenology on neighboring islands near Palmer Station, Antarctica

“…In bird populations, the theoretical and empirical relationships between breeding phenology, resource availability and population dynamics has long been recognized (Lack, ), and with Adélie penguins these relationships have provided important insights into the probable mechanisms driving demography in the rapidly warming climate of the WAP related to changing precipitation patterns (Chapman, Hofmann, Patterson, Ribic, & Fraser, ; Cimino, Fraser, Patterson‐Fraser, Saba, & Oliver, ; Fraser & Patterson, ; Fraser et al, ; Patterson et al, ; Salihoglu, Fraser, & Hofmann, ). For example, it has been suggested that severe snowstorms and cold spring air temperature that prevent snowmelt can delay reproductive timing in Adélie penguins (Hinke, Polito, Reiss, Trivelpiece, & Trivelpiece, ; Lynch, Fagan, Naveen, Trivelpiece, & Trivelpiece, ; Lynch, Naveen, Trathan, & Fagan, ), and delayed breeding is often associated with lower breeding success (Youngflesh et al, ).…”