Fasting season length sets temporal limits for global polar bear persistence

Nature Climate Change, Journal Year: 2020, Volume and Issue: 10(8), P. 732 - 738

Published: July 20, 2020

Language: Английский

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Integrated Population Modeling Provides the First Empirical Estimates of Vital Rates and Abundance for Polar Bears in the Chukchi Sea

Scientific Reports, Journal Year: 2018, Volume and Issue: 8(1)

Published: Nov. 8, 2018

Large carnivores are imperiled globally, and characteristics making them vulnerable to extinction (e.g., low densities expansive ranges) also make it difficult estimate demographic parameters needed for management. Here we develop an integrated population model analyze capture-recapture, radiotelemetry, count data the Chukchi Sea subpopulation of polar bears (Ursus maritimus), 2008-2016. Our addressed several challenges in capture-recapture studies by including a multievent structure reflecting location life history states, while accommodating state uncertainty. Female breeding probability was 0.83 (95% credible interval [CRI] = 0.71-0.90), with litter sizes 2.18 CRI 1.71-2.82) age-zero 1.61 1.46-1.80) age-one cubs. Total adult survival 0.90 0.86-0.92) females 0.89 0.83-0.93) males. Spring on-ice west Alaska were 0.0030 bears/km2 0.0016-0.0060), similar 1980s-era density estimates although methodological differences complicate comparison. Abundance subpopulation, derived extrapolating from study area using spatially-explicit habitat metric, 2,937 1,552-5,944). findings consistent other lines evidence suggesting has been productive recent years, is uncertain how long this will continue given sea-ice loss due climate change.

Language: Английский

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The rapidly changing Arctic and its societal implications

Wiley Interdisciplinary Reviews Climate Change, Journal Year: 2021, Volume and Issue: 12(6)

Published: Sept. 7, 2021

Abstract The Arctic is undergoing rapid climate change and projected to experience the most warming this century of any world region. We review societal aspects these current changes. Indigenous knowledge local holders living in communities across have detected unprecedented increases temperature, altered precipitation regimes, changing weather patterns, documenting impacts on terrestrial marine environments. These observations situate as one multiple interacting stressors. societies exhibited resilience change, but vulnerabilities are emerging at nexus environmental conditions socioeconomic pressures. Infrastructure highly susceptible permafrost thaw, coastal erosion, sea level rise, compounded by age infrastructure, maintenance challenges, cost adapting. Livelihoods cultural activities linked subsistence harvesting been affected changes wildlife, with coping mechanisms undermined long‐term processes land dispossession landscape fragmentation. Reduced ice coverage dynamics creating opportunities for enhanced shipping, oil gas production, deep‐water fisheries. Legal, infrastructural, economic, climatic challenges expected constrain such developments, concerns over distribution potential benefits. Adaptation already taking place some sectors regions, efforts directly targeting also addressing underlying determinants vulnerability. Barriers limits adapting evident. Research that develops projections future advancing, studies examining implications or economies remain their infancy. This article categorized under: Trans‐Disciplinary Perspectives > Regional Reviews

Language: Английский

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Glacial ice supports a distinct and undocumented polar bear subpopulation persisting in late 21st-century sea-ice conditions

Science, Journal Year: 2022, Volume and Issue: 376(6599), P. 1333 - 1338

Published: June 16, 2022

Polar bears are susceptible to climate warming because of their dependence on sea ice, which is declining rapidly. We present the first evidence for a genetically distinct and functionally isolated group polar in Southeast Greenland. These occupy sea-ice conditions resembling those projected High Arctic late 21st century, with an annual ice-free period that >100 days longer than estimated fasting threshold species. Whereas most depend ice catch seals, Greenland have year-round hunting platform form freshwater glacial mélange. This suggests marine-terminating glaciers, although limited availability, may serve as previously unrecognized refugia. Conservation bears, meet criteria recognition world's 20th bear subpopulation, necessary preserve genetic diversity evolutionary potential

Language: Английский

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Spring fasting behavior in a marine apex predator provides an index of ecosystem productivity

Global Change Biology, Journal Year: 2017, Volume and Issue: 24(1), P. 410 - 423

Published: Oct. 10, 2017

The effects of declining Arctic sea ice on local ecosystem productivity are not well understood but have been shown to vary inter-specifically, spatially, and temporally. Because marine mammals occupy upper trophic levels in food webs, they may be useful indicators for understanding variation productivity. Polar bears (Ursus maritimus) apex predators that primarily consume benthic pelagic-feeding ice-associated seals. As such, their integrates conditions the supporting them. Declining availability has linked negative population polar does fully explain observed changes. We examined relationships between spring foraging success conditions, prey productivity, general patterns Beaufort Chukchi Seas (CSs). Fasting status (≥7 days) was estimated using serum urea creatinine 1,448 samples collected from 1,177 adult subadult across three subpopulations. increased Sea 1983-1999 2000-2016 related an index ringed seal body condition. This change concurrent with declines condition changes diet, and/or reproduction four other vertebrate consumers within chain. In contrast, fasting declined CS periods less common than two subpopulations consistent studies demonstrating higher primary maintenance or improved bears, seals, bearded seals despite recent loss this region. Consistency regional temporal bear web suggests a indicator species. Furthermore, our results suggest spatial ecological is important affecting trophic-level these ecosystems.

Language: Английский

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Interrelated ecological impacts of climate change on an apex predator

Ecological Applications, Journal Year: 2020, Volume and Issue: 30(4)

Published: Jan. 11, 2020

Climate change has broad ecological implications for species that rely on sensitive habitats. For some top predators, loss of habitat is expected to lead cascading behavioral, nutritional, and reproductive changes ultimately accelerate population declines. In the case polar bear (Ursus maritimus), declining Arctic sea ice reduces access prey lengthens seasonal fasting periods. We used a novel combination physical capture, biopsy darting, visual aerial observation data project performance bears by linking in use, body condition (i.e., fatness), cub production. Satellite telemetry from 43 (1991-1997) 38 (2009-2015) adult female Baffin Bay subpopulation showed now spend an additional 30 d land (90 total) 2000s compared 1990s, closely correlated with spring breakup fall formation. Body declined all sex, age, classes was positively availability current previous year. Furthermore, litter size maternal date later leading larger litters), negatively duration ice-free period longer periods smaller litters). Based these relationships, we projected three generations into future (approximately 35 yr). Results indicate two-cub litters, previously norm, could largely disappear as continues. Our findings demonstrate how concurrent analysis multiple types collected over long can provide mechanistic understanding climate change. This information needed long-term conservation planning, which includes quantitative harvest risk assessments incorporate estimated or assumed trends environmental carrying capacity.

Language: Английский

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Incorporating citizen science data in spatially explicit integrated population models

Ecology, Journal Year: 2019, Volume and Issue: 100(9)

Published: June 6, 2019

Information about population abundance, distribution, and demographic rates is critical for understanding a species' ecology effective conservation management. To collect data over large spatial temporal extents such inferences, especially species with low densities or wide distributions, citizen science can be an efficient approach. Integrated models have also emerged as important methodology to estimate parameters by combining multiple types of data, including data. We developed spatially explicit integrated model that combines opportunistically collected presence-absence (PA) commonly in efforts, systematically capture-recapture (SCR) which are often limited small extents. conducted single multi-season simulations informed North American black bear (Ursus americanus) populations, evaluate the influence varying amounts opportunistic PA at larger on estimation population-level parameters. Integrating increased precision accuracy posterior estimates survival recruitment rates. In some cases, adding locations improved abundance more than increasing detection probability. Posterior were precise unbiased when higher quality, but sparse, SCR available. applied bears New York, results consistent our simulations. Our findings indicate cost-efficient way improve increase spatiotemporal extent inference. Continued developments will offer additional ways structure demographics.

Language: Английский

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Identifying drivers of demographic rates in an at‐risk population of marine mammals using integrated population models

Ecosphere, Journal Year: 2024, Volume and Issue: 15(2)

Published: Feb. 1, 2024

Abstract Effective conservation of threatened populations requires identification the processes limiting recovery. When multiple population are potentially limiting, they sometimes analyzed independently, often using different datasets. Analytically, this is suboptimal, as correlated, which can lead to biased estimates parameters and quantities interest. Integrated models (IPMs) synthesize several data streams in same probabilistic framework circumvent these issues. Lack prey was identified one primary threats recovery critically endangered southern resident killer whales (SRKWs), Orcinus orca . Previous studies have correlated SRKW demographic rates with indices Chinook salmon Oncorhynchus tshawytscha abundance, but approaches modeled reproduction survival independently. We developed an IPM for SRKWs that both simultaneously, a function abundance along west coast North America. used model evaluate relationship between SRKWs, goal updating our understanding potential causal availability dynamics, how relationships may changed over time. Results suggest mortality more strongly associated than birth rates. Our analysis also suggests northern whale could be affecting carrying capacity, possibly through competition shared resources. The fit observed total well predicted temporal changes demographics reasonable accuracy, small sample size opacified selection. approach offers valuable tool predicting response alternative management strategies involving stocks eastern Pacific.

Language: Английский

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Seal body condition and atmospheric circulation patterns influence polar bear body condition, recruitment, and feeding ecology in the Chukchi Sea

Global Change Biology, Journal Year: 2021, Volume and Issue: 27(12), P. 2684 - 2701

Published: March 1, 2021

Abstract Polar bears ( Ursus maritimus ) are experiencing loss of sea ice habitats used to access their marine mammal prey. Simultaneously, ocean warming is changing ecosystems that support populations. The interactive effects and prey not well understood yet may explain spatial–temporal variation in the response polar loss. Here, we examined potential combined ice, seal body condition, atmospheric circulation patterns on recruitment, diet, feeding probability 469 captured Chukchi Sea, 2008–2017. condition ringed seals Pusa hispida ), primary females subadults, was related dietary proportions seal, probability, cubs. In contrast, adult males consumed more bearded Erignathus barbatus exhibited better when higher. litter size, number yearlings per female, dependent young were higher following winters characterized by low Arctic Oscillation conditions, consistent with a growing studies. Body either associated or negatively suggesting that, unlike some subpopulations, Sea currently limited availability. However, spring cover declined 2% year during our study reaching levels previously observed satellite record resulting bear hunting pupping habitat. Our suggests status populations likely an important factor can compound mitigate over short term. long term, neither nor robust limitless

Language: Английский

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Partial and complete dependency among data sets has minimal consequence on estimates from integrated population models

Ecological Applications, Journal Year: 2020, Volume and Issue: 31(3)

Published: Nov. 11, 2020

Integrated population models (IPMs) are widely used to combine disparate data sets in joint analysis better understand dynamics and provide guidance for conservation activities. An often-cited assumption of IPMs is independence among component within the combined likelihood. Dependency should lead underestimation variance bias because individuals contribute more than one set. In practice, studied often occur multiple (i.e., overlap), which way be violated. Such cases have potential dissuade practitioners limit application solve emerging ecological problems. We assessed precision demographic rates estimated from using a complete gradient (0-100%) overlap sets, wide ranges (e.g., survival 0.1-0.8) sample sizes (100-1,200 individuals) variable sources. compared results our simulations with those constructed empirical on tree swallows (Tachycineta bicolor) where either had or included different individuals. Contrary previous investigators, we found no substantive uncertainty any rate derived overlap. While variability was greater at low capture, recapture, survey probabilities), there were negligible differences posterior mean root square error strong dependence vs. sets. Our suggest can designed only capture-recapture harvest capture-recovery estimates obtained same as productivity data. encourage researchers carefully consider modeling approach best suited their that does not generally compromise IPM estimates. Thus, violation research.

Language: Английский

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