scholarly journals Predictors of invertebrate biomass and rate of advancement of invertebrate phenology across eight sites in the North American Arctic

Polar Biology ◽  
2021 ◽  
Vol 44 (2) ◽  
pp. 237-257
Author(s):  
Rebecca Shaftel ◽  
Daniel J. Rinella ◽  
Eunbi Kwon ◽  
Stephen C. Brown ◽  
H. River Gates ◽  
...  
Keyword(s):  
Prey Availability ◽  
Population Level ◽  
The Arctic ◽  
Environmental Drivers ◽  
Chick Survival ◽  
The North ◽  
Phenological Mismatch ◽  
Nesting Sites ◽  
North American Arctic

AbstractAverage annual temperatures in the Arctic increased by 2–3 °C during the second half of the twentieth century. Because shorebirds initiate northward migration to Arctic nesting sites based on cues at distant wintering grounds, climate-driven changes in the phenology of Arctic invertebrates may lead to a mismatch between the nutritional demands of shorebirds and the invertebrate prey essential for egg formation and subsequent chick survival. To explore the environmental drivers affecting invertebrate availability, we modeled the biomass of invertebrates captured in modified Malaise-pitfall traps over three summers at eight Arctic Shorebird Demographics Network sites as a function of accumulated degree-days and other weather variables. To assess climate-driven changes in invertebrate phenology, we used data from the nearest long-term weather stations to hindcast invertebrate availability over 63 summers, 1950–2012. Our results confirmed the importance of both accumulated and daily temperatures as predictors of invertebrate availability while also showing that wind speed negatively affected invertebrate availability at the majority of sites. Additionally, our results suggest that seasonal prey availability for Arctic shorebirds is occurring earlier and that the potential for trophic mismatch is greatest at the northernmost sites, where hindcast invertebrate phenology advanced by approximately 1–2.5 days per decade. Phenological mismatch could have long-term population-level effects on shorebird species that are unable to adjust their breeding schedules to the increasingly earlier invertebrate phenologies.

scholarly journals Warming Arctic summers unlikely to increase productivity of shorebirds through renesting

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sarah T. Saalfeld ◽  
Brooke L. Hill ◽  
Christine M. Hunter ◽  
Charles J. Frost ◽  
Richard B. Lanctot
Keyword(s):  
Climate Change ◽  
Survival Rates ◽  
The Arctic ◽  
Adult Survival ◽  
Chick Survival ◽  
Ecological Processes ◽  
Bird Populations ◽  
Phenological Mismatch ◽  
Daily Survival ◽  
Adequate Food

AbstractClimate change in the Arctic is leading to earlier summers, creating a phenological mismatch between the hatching of insectivorous birds and the availability of their invertebrate prey. While phenological mismatch would presumably lower the survival of chicks, climate change is also leading to longer, warmer summers that may increase the annual productivity of birds by allowing adults to lay nests over a longer period of time, replace more nests that fail, and provide physiological relief to chicks (i.e., warmer temperatures that reduce thermoregulatory costs). However, there is little information on how these competing ecological processes will ultimately impact the demography of bird populations. In 2008 and 2009, we investigated the survival of chicks from initial and experimentally-induced replacement nests of arcticola Dunlin (Calidris alpina) breeding near Utqiaġvik, Alaska. We monitored survival of 66 broods from 41 initial and 25 replacement nests. Based on the average hatch date of each group, chick survival (up to age 15 days) from replacement nests (Ŝi = 0.10; 95% CI = 0.02–0.22) was substantially lower than initial nests (Ŝi = 0.67; 95% CI = 0.48–0.81). Daily survival rates were greater for older chicks, chicks from earlier-laid clutches, and during periods of greater invertebrate availability. As temperature was less important to daily survival rates of shorebird chicks than invertebrate availability, our results indicate that any physiological relief experienced by chicks will likely be overshadowed by the need for adequate food. Furthermore, the processes creating a phenological mismatch between hatching of shorebird young and invertebrate emergence ensures that warmer, longer breeding seasons will not translate into abundant food throughout the longer summers. Thus, despite having a greater opportunity to nest later (and potentially replace nests), young from these late-hatching broods will likely not have sufficient food to survive. Collectively, these results indicate that warmer, longer summers in the Arctic are unlikely to increase annual recruitment rates, and thus unable to compensate for low adult survival, which is typically limited by factors away from the Arctic-breeding grounds.

Northward ho! Obama, Diefenbaker and the North American Arctic

Polar Record ◽  
2015 ◽  
Vol 52 (2) ◽  
pp. 252-255
Author(s):  
Klaus J. Dodds
Keyword(s):  
Native American ◽  
Aleutian Islands ◽  
The Arctic ◽  
Arctic Circle ◽  
The North ◽  
American President ◽  
North American Arctic ◽  
To Come ◽  
Franklin Delano Roosevelt ◽  
Lying Down

President Barrack Obama became, in September 2015, the first US president to travel north of the Arctic Circle. Having started his Alaskan itinerary in Anchorage, attending and speaking at a conference involving Secretary of State John Kerry and invited guests, the president travelled north to the small town of Kotzebue, a community of some 3000 people with the majority of inhabitants identifying as native American. Delivered to an audience in the local high school numbering around 1000, the 41st US president placed his visit within a longer presidential tradition of northern visitation: I did have my team look into what other Presidents have done when they visited Alaska. I’m not the first President to come to Alaska.Warren Harding spent more than two weeks here – which I would love to do. But I can't leave Congress alone that long. (Laughter.) Something might happen. When FDR visited – Franklin Delano Roosevelt – his opponents started a rumor that he left his dog, Fala, on the Aleutian Islands – and spent 20 million taxpayer dollars to send a destroyer to pick him up. Now, I’m astonished that anybody would make something up about a President. (Laughter.) But FDR did not take it lying down. He said, “I don't resent attacks, and my family doesn't resent attacks – but Fala does resent attacks. He's not been the same dog since.” (Laughter.) President Carter did some fishing when he visited. And I wouldn't mind coming back to Alaska to do some fly-fishing someday. You cannot see Alaska in three days. It's too big. It's too vast. It's too diverse. (Applause.) So I’m going to have to come back. I may not be President anymore, but hopefully I’d still get a pretty good reception. (Applause.) And just in case, I’ll bring Michelle, who I know will get a good reception. (Applause.) . . .. But there's one thing no American President has done before – and that's travel above the Arctic Circle. (Applause.) So I couldn't be prouder to be the first, and to spend some time with all of you (Obama 2015a).

scholarly journals Bayesian inference reveals positive but subtle effects of experimental fishery closures on marine predator demographics

2018 ◽  
Vol 285 (1871) ◽  
pp. 20172443 ◽  
Author(s):  
Richard B. Sherley ◽  
Barbara J. Barham ◽  
Peter J. Barham ◽  
Kate J. Campbell ◽  
Robert J. M. Crawford ◽  
...  
Keyword(s):  
South Africa ◽  
Bayesian Inference ◽  
Population Growth ◽  
Prey Availability ◽  
Population Level ◽  
Marine Ecosystems ◽  
Forage Fish ◽  
Chick Survival ◽  
Marine Predator ◽  
Management Interventions

Global forage-fish landings are increasing, with potentially grave consequences for marine ecosystems. Predators of forage fish may be influenced by this harvest, but the nature of these effects is contentious. Experimental fishery manipulations offer the best solution to quantify population-level impacts, but are rare. We used Bayesian inference to examine changes in chick survival, body condition and population growth rate of endangered African penguins Spheniscus demersus in response to 8 years of alternating time–area closures around two pairs of colonies. Our results demonstrate that fishing closures improved chick survival and condition, after controlling for changing prey availability. However, this effect was inconsistent across sites and years, highlighting the difficultly of assessing management interventions in marine ecosystems. Nevertheless, modelled increases in population growth rates exceeded 1% at one colony; i.e. the threshold considered biologically meaningful by fisheries management in South Africa. Fishing closures evidently can improve the population trend of a forage-fish-dependent predator—we therefore recommend they continue in South Africa and support their application elsewhere. However, detecting demographic gains for mobile marine predators from small no-take zones requires experimental time frames and scales that will often exceed those desired by decision makers.

Suitability of a young deciduous-dominated forest for American marten and the effects of forest removal

2004 ◽  
Vol 82 (3) ◽  
pp. 423-435 ◽  
Author(s):  
Kim G Poole ◽  
Aswea D Porter ◽  
Andrew de Vries ◽  
Chris Maundrell ◽  
Scott D Grindal ◽  
...  
Keyword(s):  
Populus Tremuloides ◽  
Forest Cover ◽  
Agricultural Land ◽  
Prey Availability ◽  
Population Level ◽  
Home Ranges ◽  
American Marten ◽  
Individual Level ◽  
The Individual

American marten (Martes americana (Turton, 1806)) are generally considered to be reliant upon and most successful in continuous late-successional coniferous forests. By contrast, young seral forests and deciduous-dominated forests are assumed to provide low-quality marten habitat, primarily as a result of insufficient structure, overhead cover, and prey. This study examined a moderate-density population of marten in northeastern British Columbia in what appeared to be comparatively low-quality, deciduous-dominated habitat, overgrown agricultural land primarily consisting of 30- to 40-year-old stands of regenerating trembling aspen (Populus tremuloides Michx.). Over 4 years, we monitored 52 radio-collared marten. The population appeared to be stable, as indicated by large numbers of adults, relatively constant densities, long-term residency of many individuals, low mortality rates, and older age structure. Relatively small home ranges (males, 3.3 km2; females, 2.0 km2) implied good habitat quality and prey availability. Shearing (removal of immature forest cover) of 17% of the study area resulted in home range shifts at the individual level but no detectable impact at the population level. Categorically, marten avoided nonforested cover types and preferred mature coniferous (>25% conifer) stands (7% of the study area) but otherwise appeared to use all forested stands relative to their availability, including extensive use of deciduous-dominated stands and deciduous stands <40 years of age. Thus, these young deciduous forests appeared to have sufficient structure, overhead cover, and prey to maintain moderate densities of resident marten on a long-term basis.

The Arctic Institute of North America

Polar Record ◽  
1956 ◽  
Vol 8 (52) ◽  
pp. 22-23 ◽  
Author(s):  
P. D. Baird
Keyword(s):  
North America ◽  
North American ◽  
Scientific Research ◽  
The Arctic ◽  
The North ◽  
Reference Information ◽  
North American Arctic ◽  
Mcgill University

The Arctic Institute of North America was established in 1945 in two small rooms in McGill University, with a staff consisting of Dr Lincoln Washburn and a secretary, who made up for the lack of equipment and facilities by abundant energy and enthusiasm. Since then the Institute's growth has been considerable, always in the direction of its three main objectives—to form a centre for reference information and study on the North American Arctic, to encourage arctic scientific research in any field, and to disseminate arctic information by means of a journal, other publications, and lectures.

scholarly journals The Oxford Handbook of the Prehistoric Arctic

2016 ◽  
Keyword(s):  
North American ◽  
Full Range ◽  
Limited Range ◽  
Great Accuracy ◽  
The Arctic ◽  
Stone Tool ◽  
Cultural Tradition ◽  
Cold Temperatures ◽  
The North ◽  
North American Arctic

The North American Arctic was one of the last regions on Earth to be settled by humans, due to its extreme climate, limited range of resources, and remoteness from populated areas. Despite these factors, it holds a rich and complex history relating to Inuit, Iñupiat, Inuvialuit, Yupik, and Aleut peoples and their ancestors. The artifacts, dwellings, and food remains of these ancient peoples are remarkably well preserved due to cold temperatures and permafrost, allowing archaeologists to reconstruct their lifeways with great accuracy. Furthermore, the combination of modern Elders’ traditional knowledge with the region’s high-resolution ethnographic record allows past peoples’ lives to be reconstructed to a level simply not possible elsewhere. Combined, these factors yield an archaeological record of global significance—the Arctic provides ideal case studies relating to issues as diverse as the impacts of climate change on human societies, the complex process of interaction between indigenous peoples and Europeans, and the dynamic relationships between environment, economy, social organization, and ideology in hunter-gatherer societies. In this book, each Arctic cultural tradition is described in detail, with up-to-date coverage of recent interpretations of all aspects of their lifeways. Additional chapters cover broad themes applicable to the full range of arctic cultures, such as trade, stone tool technology, ancient DNA research, and the relationship between archaeology and modern arctic communities. The resulting volume, written by the region’s leading researchers, is by far the most comprehensive coverage of North American arctic archaeology ever assembled.

scholarly journals Approaching Freshet beneath Landfast Ice in Kugmallit Bay on the Canadian Arctic Shelf: Evidence from Sensor and Ground Truth Data

ARCTIC ◽  
2009 ◽  
Vol 61 (1) ◽  
pp. 76 ◽  
Author(s):  
Tony R. Walker ◽  
Jon Grant ◽  
Peter Jarvis
Keyword(s):  
Arctic Ocean ◽  
Ground Truth ◽  
Open Water ◽  
Early Spring ◽  
The Arctic ◽  
Ground Truth Data ◽  
The North ◽  
Landfast Ice ◽  
North American Arctic ◽  
Mackenzie River

The Mackenzie River is the largest river in the North American Arctic. Its huge freshwater and sediment load impacts the Canadian Beaufort Shelf, transporting large quantities of sediment and associated organic carbon into the Arctic Ocean. The majority of this sediment transport occurs during the freshet peak flow season (May to June). Mackenzie River-Arctic Ocean coupling has been widely studied during open water seasons, but has rarely been investigated in shallow water under landfast ice in Kugmallit Bay with field-based surveys, except for those using remote sensing. We observed and measured sedimentation rates (51 g m-2 d-1) and the concentrations of chlorophyll a (mean 2.2 ?g L-1) and suspended particulate matter (8.5 mg L-1) and determined the sediment characteristics during early spring, before the breakup of landfast ice in Kugmallit Bay. We then compared these results with comparable data collected from the same site the previous summer. Comparison of organic quality in seston and trapped material demonstrated substantial seasonal differences. The subtle changes in biological and oceanographic variables beneath landfast ice that we measured using sensors and field sampling techniques suggest the onset of a spring melt occurring hundreds of kilometres farther south in the Mackenzie Basin.

scholarly journals Timing of Breeding Site Availability Across the North-American Arctic Partly Determines Spring Migration Schedule in a Long-Distance Neotropical Migrant

2021 ◽  
Vol 9 ◽  
Author(s):  
Jean-François Lamarre ◽  
Gilles Gauthier ◽  
Richard B. Lanctot ◽  
Sarah T. Saalfeld ◽  
Oliver P. Love ◽  
...  
Keyword(s):  
North American ◽  
Breeding Site ◽  
The Arctic ◽  
Timing Of Breeding ◽  
Long Distance ◽  
Breeding Sites ◽  
The North ◽  
North American Arctic ◽  
Departure Date ◽  
Breeding Location

Long-distance migrants are under strong selection to arrive on their breeding grounds at a time that maximizes fitness. Many arctic birds start nesting shortly after snow recedes from their breeding sites and timing of snowmelt can vary substantially over the breeding range of widespread species. We tested the hypothesis that migration schedules of individuals co-occurring at the same non-breeding areas are adapted to average local environmental conditions encountered at their specific and distant Arctic breeding locations. We predicted that timing of breeding site availability (measured here as the average snow-free date) should explain individual variation in departure time from shared non-breeding areas. We tested our prediction by tracking American Golden-Plovers (Pluvialis dominica) nesting across the North-American Arctic. These plovers use a non-breeding (wintering) area in South America and share a spring stopover area in the nearctic temperate grasslands, located &gt;1,800 km away from their nesting locations. As plovers co-occur at the same non-breeding areas but use breeding sites segregated by latitude and longitude, we could disentangle the potential confounding effects of migration distance and timing of breeding site availability on individual migration schedule. As predicted, departure date of individuals stopping-over in sympatry was positively related to the average snow-free date at their respective breeding location, which was also related to individual onset of incubation. Departure date from the shared stopover area was not explained by the distance between the stopover and the breeding location, nor by the stopover duration of individuals. This strongly suggests that plover migration schedule is adapted to and driven by the timing of breeding site availability per se. The proximate mechanism underlying the variable migration schedule of individuals is unknown and may result from genetic differences or individual learning. Temperatures are currently changing at different speeds across the Arctic and this likely generates substantial heterogeneity in the strength of selection pressure on migratory schedule of arctic birds migrating sympatrically.

scholarly journals A Benchmark for Trace Greenhouse Gases in the Arctic Ocean

Eos ◽  
2017 ◽  
Author(s):  
Terri Cook
Keyword(s):  
Nitrous Oxide ◽  
Greenhouse Gases ◽  
Arctic Ocean ◽  
North American ◽  
The Arctic ◽  
The North ◽  
The Arctic Ocean ◽  
North American Arctic

Samples of seawater from the North American Arctic show that the region is neither a major source nor sink of methane and nitrous oxide to the overlying atmosphere.

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