More Like this

1. Insights into the diet and feeding behavior of immature polar cod ( Boreogadus saida ) from the under‐ice habitat of the central Arctic Ocean

   https://doi.org/10.1111/jfb.15836  

   Schaafsma, Fokje L; Flores, Hauke; David, Carmen L; Castellani, Giulia; Sakinan, Serdar; Meijboom, André; Niehoff, Barbara; Cornils, Astrid; Hildebrandt, Nicole; Schmidt, Katrin; et al (September 2024, Journal of Fish Biology)

   Abstract Polar cod (Boreogadus saida) is an endemic key species of the Arctic Ocean ecosystem. The ecology of this forage fish is well studied in Arctic shelf habitats where a large part of its population lives. However, knowledge about its ecology in the central Arctic Ocean (CAO), including its use of the sea‐ice habitat, is hitherto very limited. To increase this knowledge, samples were collected at the under‐ice surface during several expeditions to the CAO between 2012 and 2020, including the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. The diet of immatureB. saidaand the taxonomic composition of their potential prey were analysed, showing that both sympagic and pelagic species were important prey items. Stomach contents included expected prey such as copepods and amphipods. Surprisingly, more rarely observed prey such as appendicularians, chaetognaths, and euphausiids were also found to be important. Comparisons of the fish stomach contents with prey distribution data suggests opportunistic feeding. However, relative prey density and catchability are important factors that determine which type of prey is ingested. Prey that ensures limited energy expenditure on hunting and feeding is often found in the stomach contents even though it is not the dominant species present in the environment. To investigate the importance of prey quality and quantity for the growth ofB. saidain this area, we measured energy content of dominant prey species and used a bioenergetic model to quantify the effect of variations in diet on growth rate potential. The modeling results suggest that diet variability was largely explained by stomach fullness and, to a lesser degree, the energetic content of the prey. Our results suggest that under climate change, immatureB. saidamay be at least equally sensitive to a loss in the number of efficiently hunted prey than to a reduction in the prey's energy content. Consequences for the growth and survival ofB. saidawill not depend on prey presence alone, but also on prey catchability, digestibility, and energy content. 

   more » « less
2. Herbaceous perennial plants with short generation time have stronger responses to climate anomalies than those with longer generation time

   https://doi.org/10.1038/s41467-021-21977-9  

   Compagnoni, Aldo; Levin, Sam; Childs, Dylan_Z; Harpole, Stan; Paniw, Maria; Römer, Gesa; Burns, Jean_H; Che-Castaldo, Judy; Rüger, Nadja; Kunstler, Georges; et al (March 2021, Nature Communications)

   Abstract There is an urgent need to synthesize the state of our knowledge on plant responses to climate. The availability of open-access data provide opportunities to examine quantitative generalizations regarding which biomes and species are most responsive to climate drivers. Here, we synthesize time series of structured population models from 162 populations of 62 plants, mostly herbaceous species from temperate biomes, to link plant population growth rates (λ) to precipitation and temperature drivers. We expect: (1) more pronounced demographic responses to precipitation than temperature, especially in arid biomes; and (2) a higher climate sensitivity in short-lived rather than long-lived species. We find that precipitation anomalies have a nearly three-fold larger effect onλthan temperature. Species with shorter generation time have much stronger absolute responses to climate anomalies. We conclude that key species-level traits can predict plant population responses to climate, and discuss the relevance of this generalization for conservation planning. 

   more » « less
3. Long‐term patterns in ecosystem phenology near Palmer Station, Antarctica, from the perspective of the Adélie penguin

   https://doi.org/10.1002/ecs2.4417  

   Cimino, Megan_A; Conroy, John_A; Connors, Elizabeth; Bowman, Jeff; Corso, Andrew; Ducklow, Hugh; Fraser, William; Friedlaender, Ari; Kim, Heather_Hyewon; Larsen, Gregory_D; et al (February 2023, Ecosphere)

   Abstract Climate change is leading to phenological shifts across a wide range of species globally. Polar oceans are hotspots of rapid climate change where sea ice dynamics structure ecosystems and organismal life cycles are attuned to ice seasonality. To anticipate climate change impacts on populations and ecosystem services, it is critical to understand ecosystem phenology to determine species activity patterns, optimal environmental windows for processes like reproduction, and the ramifications of ecological mismatches. Since 1991, the Palmer Antarctica Long‐Term Ecological Research (LTER) program has monitored seasonal dynamics near Palmer Station. Here, we review the species that occupy this region as year‐round residents, seasonal breeders, or periodic visitors. We show that sea ice retreat and increasing photoperiod in the spring trigger a sequence of events from mid‐November to mid‐February, including Adélie penguin clutch initiation, snow melt, calm conditions (low winds and warm air/sea temperature), phytoplankton blooms, shallow mixed layer depths, particulate organic carbon flux, peak humpback whale abundances, nutrient drawdown, and bacterial accumulation. Subsequently, from May to June, snow accumulates, zooplankton indicator species appear, and sea ice advances. The standard deviation in the timing of most events ranged from ~20 to 45 days, which was striking compared with Adélie penguin clutch initiation that varied <1 week. In general, during late sea ice retreat years, events happened later (~5 to >30 days) than mean dates and the variability in timing was low (<20%) compared with early ice retreat years. Statistical models showed the timing of some events were informative predictors (but not sole drivers) of other events. From an Adélie penguin perspective, earlier sea ice retreat and shifts in the timing of suitable conditions or prey characteristics could lead to mismatches, or asynchronies, that ultimately influence chick survival via their mass at fledging. However, more work is needed to understand how phenological shifts affect chick thermoregulatory costs and the abundance, availability, and energy content of key prey species, which support chick growth and survival. While we did not detect many long‐term phenological trends, we expect that when sea ice trends become significant within our LTER time series, phenological trends and negative effects from ecological mismatches will follow. 

   more » « less
4. Patterns in avian reproduction in the Prudhoe Bay Oilfield, Alaska, 2003–2019

   https://doi.org/10.1111/jav.03075  

   McGuire, Rebecca L.; Robards, Martin; Liebezeit, Joseph R. (July 2023, Journal of Avian Biology)

   The Arctic Coastal Plain is one of the most important avian breeding grounds in the world; however, many species are in decline. Arctic‐breeding birds contend with short breeding seasons, harsh climatic conditions, and now, rapidly changing, variable, and unpredictable environmental conditions caused by climate change. Additionally, those breeding in industrial areas may be impacted by human activities. It is difficult to separate the impacts of industrial development and climate change; however, long‐term datasets can help show patterns over time. We evaluated factors influencing reproductive parameters of breeding birds at Prudhoe Bay, Alaska, 2003–2019, by monitoring 1265 shorebird nests, 378 passerine nests, and 231 waterfowl nests. We found that nest survival decreased significantly nearer high‐use infrastructure for all guilds. Temporally, passerine nest survival declined across the 17 years of the study, while there was no significant evidence of change in their nest density. Shorebird nest survival did not vary significantly across years, nor did nest density. Waterfowl nest density increased over the course of the study, but we could not estimate nest survival in all years. Egg predator populations varied across time; numbers of gulls and ravens increased in the oilfields 2003–2019, while Arctic fox decreased, and jaeger numbers did not vary significantly. Long‐term datasets are rare in the Arctic, but they are crucial for understanding impacts to breeding birds from both climate change and increasing anthropogenic activities. We show that nest survival was lower for birds nesting closer to high‐use infrastructure in Arctic Alaska, which was not detected in earlier, shorter‐term studies. Additionally, we show that Lapland longspur nest survival decreased across time, in concert with continent‐wide declines in many passerine species. The urgency to understand these relationships cannot be expressed strongly enough, given change is continuing to happen and the potential impacts are large. 

   more » « less
5. Demographic responses of hybridizing cinquefoils to changing climate in the Colorado Rocky Mountains

   https://doi.org/10.1002/ece3.10097  

   Carscadden, Kelly_A; Doak, Daniel_F; Oldfather, Meagan_F; Emery, Nancy_C (July 2023, Ecology and Evolution)

   Abstract Hybridization between taxa generates new pools of genetic variation that can lead to different environmental responses and demographic trajectories over time than seen in parental lineages. The potential for hybrids to have novel environmental tolerances may be increasingly important in mountainous regions, which are rapidly warming and drying due to climate change. Demographic analysis makes it possible to quantify within‐ and among‐species responses to variation in climate and to predict population growth rates as those conditions change. We estimated vital rates and population growth in 13 natural populations of two cinquefoil taxa (Potentilla hippianaandP. pulcherrima) and their hybrid across elevation gradients in the Southern Rockies. Using three consecutive years of environmental and demographic data, we compared the demographic responses of hybrid and parental taxa to environmental variation across space and time. All three taxa had lower predicted population growth rates under warm, dry conditions. However, the magnitude of these responses varied among taxa and populations. Hybrids had consistently lower predicted population growth rates thanP. hippiana. In contrast, hybrid performance relative toP. pulcherrimavaried with population and climate, with the hybrid maintaining relatively stable growth rates while populations ofP. pulcherrimashrank under warm, dry conditions. Our findings demonstrate that hybrids in this system are neither intrinsically unfit nor universally more vigorous than parents, suggesting that the demographic consequences of hybridization are context‐dependent. Our results also imply that shifts to warmer and drier conditions could have particularly negative repercussions forP. pulcherrima, which is currently the most abundant taxon in the study area, possibly as a legacy of more favorable historical climates. More broadly, the distributions of these long‐lived taxa are lagging behind their demographic trajectories, such that the currently less commonP. hippianacould become the most abundant of thePotentillataxa as this region continues to warm and dry. 

   more » « less