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1.
Zootaxa ; 4755(1): zootaxa.4755.1.7, 2020 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-32230198

RESUMO

A sponge collected along the Aleutian Islands of Alaska revealed an unusual combination of characters including ectosomal acantho - tornotes never before observed. Assignment to Poecilosclerida is without any doubt due to the presence of chelae but assignment to family is more problematic because 1) there is no family of Poecilosclerida (or any other demosponge) with ectosomal acantho-tornotes, and 2) the combination of occurring spicules and their arrangement does not conform completely to any Poecilosclerid family. Thus family assignment is only possible by amending the concept of an existing poecilosclerid family and allow for spined as well as smooth tornotes and a confusedly plumose choanosomal arrangement of megascleres. We suggest assignment to Hymedesmiidae as this requires relatively slight changes compared to other Poecilosclerid families. We suggest the erection of Acantorna n. gen. to accommodate Acantorna tahoma n. sp. The new genus and species differ from all other Hymedesmiid genera in the possession of the characters necessary for the suggested amendment. Additional differences to each Hymedesmiid genus are added.


Assuntos
Poríferos , Alaska , Animais
2.
Environ Monit Assess ; 191(Suppl 4): 813, 2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32185545

RESUMO

During a marine oil spill, injured birds often die on the water, some eventually washing ashore, but others becoming waterlogged and sinking or being scavenged before reaching the shoreline. Birds that disappear before they can be deposited on the shoreline are difficult to enumerate, but they commonly represent a large fraction of total oil spill-related mortality. As part of the process of quantifying the overall impact to seabirds resulting from the Deepwater Horizon oil spill, it was necessary to estimate the number of dead birds lost at sea. We conducted a study to estimate the beaching probability of birds that died at sea in the Gulf of Mexico in the areas most heavily used by seabirds and impacted by the spill. Using a mark-recapture analysis to derive the beaching probability from our field study data, we estimated that dead birds afloat at sea had about a 0.1414 probability of beaching in areas searched during the Deepwater Horizon oil spill. Sensitivity analyses of our model and requisite assumptions suggested that if our assumptions were violated, the "true" beaching probability could be anywhere between 0.11 and 0.16. These estimates are much lower than beaching probabilities estimated for seabirds killed during the Exxon Valdez oil spill in the waters of Alaska, for example, likely reflect higher rates of decomposition and scavenging in the warmer waters of the Gulf of Mexico. Our estimate suggests that bird carcasses that washed onshore during the Deepwater Horizon oil spill represented only 14% of those killed at sea during the spill.


Assuntos
Aves , Poluição por Petróleo , Poluentes Químicos da Água , Alaska , Animais , Monitoramento Ambiental , Golfo do México , Mortalidade , Dinâmica Populacional , Probabilidade , Poluentes Químicos da Água/toxicidade
3.
Dis Aquat Organ ; 137(3): 239-246, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32132276

RESUMO

Infectious disease is a major cause of mortality for sea otters Enhydra lutris, a keystone species of continued concern for conservationists. Parasitic infection has long been identified as a cause of mortality in otters in both Alaska and California, USA. Corynosoma enhydri (Acanthocephala) is the only parasite that uses sea otters as its primary definitive host and is highly prevalent in otter populations; however, it is generally considered unimportant both pathologically and ecologically, although this assumption is based on limited empirical knowledge. Research has instead focused on Profilicollis infections (P. major, P. kenti, P. altmani) as a significant source of otter mortality due to associated enteritis and peritonitis, which are threats to otter health. Here we describe acanthocephalan infections in sea otters by Profilicollis spp. and C. enhydri, from a survey comparing C. enhydri infections between northern sea otters E. lutris kenyoni (n = 12) and southern sea otters E. lutris nereis (n = 19). We report a novel infection of C. enhydri in a pup approximately 1 mo of age, which shows that the early introduction to solid food at around 3 wk by their mothers may lead to subsequent infection via infected prey items. We also document the first 2 known cases of Profilicollis infection in northern sea otters, which may present an unknown threat to the Alaskan population, or may be an interesting example of accidental infection.


Assuntos
Acantocéfalos , Infecções , Lontras , Alaska , Animais , California , Infecções/veterinária
5.
PLoS One ; 15(2): e0222744, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32106278

RESUMO

Denned polar bears (Ursus maritimus) are invisible under the snow, therefore winter-time petroleum exploration and development activities in northern Alaska have potential to disturb maternal polar bears and their cubs. Previous research determined forward looking infrared (FLIR) imagery could detect many polar bear maternal dens under the snow, but also identified limitations of FLIR imagery. We evaluated the efficacy of FLIR-surveys conducted by oil-field operators from 2004-2016. Aerial FLIR surveys detected 15 of 33 (45%) and missed 18 (55%) of the dens known to be within surveyed areas. While greater adherence to previously recommended protocols may improve FLIR detection rates, the physical characteristics of polar bear maternal dens, increasing frequencies of weather unsuitable for FLIR detections-caused by global warming, and competing false positives are likely to prevent FLIR surveys from detecting maternal dens reliably enough to afford protections consonant with increasing global threats to polar bear welfare.


Assuntos
Cavernas , Mapeamento Geográfico , Raios Infravermelhos , Ursidae , Alaska , Animais , Feminino , Aquecimento Global , Estações do Ano
6.
Oecologia ; 192(3): 671-685, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32052180

RESUMO

Warming-induced nutrient enrichment in the Arctic may lead to shifts in leaf-level physiological properties and processes with potential consequences for plant community dynamics and ecosystem function. To explore the physiological responses of Arctic tundra vegetation to increasing nutrient availability, we examined how a set of leaf nutrient and physiological characteristics of eight plant species (representing four plant functional groups) respond to a gradient of experimental nitrogen (N) and phosphorus (P) enrichment. Specifically, we examined a set of chlorophyll fluorescence measures related to photosynthetic efficiency, performance and stress, and two leaf nutrient traits (leaf %C and %N), across an experimental nutrient gradient at the Arctic Long Term Ecological Research site, located in the northern foothills of the Brooks Range, Alaska. In addition, we explicitly assessed the direct relationships between chlorophyll fluorescence and leaf %N. We found significant differences in physiological and nutrient traits between species and plant functional groups, and we found that species within one functional group (deciduous shrubs) have significantly greater leaf %N at high levels of nutrient addition. In addition, we found positive, saturating relationships between leaf %N and chlorophyll fluorescence measures across all species. Our results highlight species-specific differences in leaf nutrient traits and physiology in this ecosystem. In particular, the effects of a gradient of nutrient enrichment were most prominent in deciduous plant species, the plant functional group known to be increasing in relative abundance with warming in this ecosystem.


Assuntos
Ecossistema , Tundra , Alaska , Regiões Árticas , Nutrientes
7.
J Med Microbiol ; 69(2): 218-227, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32011229

RESUMO

Introduction. Gastric cancer is a health disparity in the Alaska Native people. The incidence of Helicobacter pylori infection, a risk factor for non-cardia gastric adenocarcinoma, is also high. Gastric cancer is partially associated with the virulence of the infecting strain.Aim. To genotype the vacA s, m and i and cag pathogenicity island (cagPAI) genes in H. pylori from Alaskans and investigate associations with gastropathy.Methodology. We enrolled patients with gastritis, peptic ulcer disease (PUD) and intestinal metaplasia (IM) in 1998-2005 and patients with gastric cancer in 2011-2013. Gastric biopsies were collected and cultured and PCR was performed to detect the presence of the right and left ends of the cagPAI, the cagA, cagE, cagT and virD4 genes and to genotype the vacA s, m and i regions.Results. We recruited 263 people; 22 (8 %) had no/mild gastritis, 121 (46 %) had moderate gastritis, 40 (15%) had severe gastritis, 38 (14 %) had PUD, 30 (11 %) had IM and 12 (5 %) had gastric cancer. H. pylori isolates from 150 (57%) people had an intact cagPAI; those were associated with a more severe gastropathy (P≤0.02 for all comparisons). H. pylori isolates from 77 % of people had either the vacA s1/i1/m1 (40 %; 94/234) or s2/i2/m2 (37 %; 86/234) genotype. vacA s1/i1/m1 was associated with a more severe gastropathy (P≤0.03 for all comparisons).Conclusions. In this population with high rates of gastric cancer, we found that just over half of the H. pylori contained an intact cagPAI and 40 % had the vacA s1/i1/m1 genotype. Infection with these strains was associated with a more severe gastropathy.


Assuntos
Proteínas de Bactérias/genética , Ilhas Genômicas , Infecções por Helicobacter/microbiologia , Helicobacter pylori/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Alaska , Nativos do Alasca/estatística & dados numéricos , Proteínas de Bactérias/metabolismo , Feminino , Helicobacter pylori/isolamento & purificação , Helicobacter pylori/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Úlcera Péptica/microbiologia , Neoplasias Gástricas/microbiologia , Fatores de Virulência/genética , Fatores de Virulência/metabolismo , Adulto Jovem
8.
Environ Sci Technol ; 54(5): 2951-2960, 2020 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-32023050

RESUMO

Permafrost contains a large (1700 Pg C) terrestrial pool of organic matter (OM) that is susceptible to degradation as global temperatures increase. Of particular importance is syngenetic Yedoma permafrost containing high OM content. Reactive iron phases promote stabilizing interactions between OM and soil minerals and this stabilization may be of increasing importance in permafrost as the thawed surface region ("active layer") deepens. However, there is limited understanding of Fe and other soil mineral phase associations with OM carbon (C) moieties in permafrost soils. To elucidate the elemental associations involved in organomineral complexation within permafrost systems, soil cores spanning a Pleistocene permafrost chronosequence (19,000, 27,000, and 36,000 years old) were collected from an underground tunnel near Fairbanks, Alaska. Subsamples were analyzed via scanning transmission X-ray microscopy-near edge X-ray absorption fine structure spectroscopy at the nano- to microscale. Amino acid-rich moieties decreased in abundance across the chronosequence. Strong correlations between C and Fe with discrete Fe(III) or Fe(II) regions selectively associated with specific OM moieties were observed. Additionally, Ca coassociated with C through potential cation bridging mechanisms. Results indicate Fe(III), Fe(II), and mixed valence phases associated with OM throughout diverse permafrost environments, suggesting that organomineral complexation is crucial to predict C stability as permafrost systems warm.


Assuntos
Pergelissolo , Alaska , Carbono , Compostos Férricos , Solo
9.
Mar Pollut Bull ; 151: 110857, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32056639

RESUMO

Blubber and muscle were collected from male bowhead whales (n = 71) landed near Utqiagvik (Barrow), Alaska, between 2006 and 2015 and analyzed for lipid content and concentrations of persistent organic pollutants (POPs) in order to determine levels and trends over the collection period. Collection year was a significant predictor of blubber concentrations for most classes of POPs, while for a few classes, animal length (proxy for age) was also a significant predictor. This is the first report on levels of PBDEs in bowhead whales; concentrations of these compounds are low (≤55 ng/g wet weight). Blubber concentrations were lower than those reported in samples collected between 1992 and 2000, and many POP classes in blubber declined significantly between 2006 and 2015. Concentrations of POPs in bowhead whale tissues, which are subsistence foods for Native Alaskan communities, appear to be declining at rates comparable with previously reported temporal trends in Arctic biota.


Assuntos
Tecido Adiposo/metabolismo , Baleia Franca/metabolismo , Poluentes Químicos da Água/metabolismo , Alaska , Animais , Regiões Árticas , Monitoramento Ambiental , Masculino
10.
Environ Pollut ; 259: 113872, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32069693

RESUMO

The Arctic is subject to long-range atmospheric deposition of globally-distilled semi-volatile organic compounds (SVOCs) that bioaccumulate and biomagnify in lipid-rich food webs. In addition, locally contaminated sites may also contribute SVOCs to the arctic environment. Specifically, Alaska has hundreds of formerly used defense (FUD) sites, many of which are co-located with Alaska Native villages in remote parts of the state. The purpose of this study was to investigate the extent of SVOC contamination on Alaska's St. Lawrence Island through the analysis of sentinel fish, the ninespine stickleback (Pungitius pungitius), collected from Troutman Lake located within the watershed of an FUD site and adjacent to the Yupik community of Gambell. We measured the concentrations of legacy and emerging SVOCs in 303 fish samples (81 composites), including polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), organophosphate esters (OPEs) and their diester metabolites, and per- and poly-fluoroalkyl substances (PFAS). PBDEs and PCBs were the most abundant SVOC groups found in stickleback with ΣPBDE and ΣPCB median concentrations of 25.8 and 10.9 ng/g ww, respectively, followed by PFAS (median ΣPFAS 7.22 ng/g ww). ΣOPE and ΣOPE metabolite concentrations were lower with median concentrations of 4.97 and 1.18 ng/g ww, respectively. Chemical patterns and distributions based on correlations and comparison with SVOC concentrations in stickleback from other parts of the island suggest strong local sources of PCBs, PBDEs, and PFAS on St. Lawrence Island.


Assuntos
Monitoramento Ambiental , Peixes , Compostos Orgânicos Voláteis , Poluentes Químicos da Água , Alaska , Animais , Regiões Árticas , Ilhas , Militares , Compostos Orgânicos Voláteis/análise , Poluentes Químicos da Água/análise
11.
Dis Aquat Organ ; 137(2): 159-165, 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31942861

RESUMO

Tracking and understanding variation in pathogens such as Batrachochytrium dendrobatidis (Bd), the agent of amphibian chytridiomycosis which has caused population declines globally, is a priority for many land managers. However, relatively little sampling of amphibian communities has occurred at high latitudes. We used skin swabs collected during 2005-2017 from boreal toads Anaxyrus boreas (n = 248), in southeast Alaska (USA; primarily in and near Klondike Gold Rush National Historical Park [KLGO]) and northwest British Columbia (Canada) to determine how Bd prevalence varied across life stages, habitat characteristics, local species richness, and time. Across all years, Bd prevalence peaked in June and was >3 times greater for adult toads (37.5%) vs. juveniles and metamorphs (11.2%). Bd prevalence for toads in the KLGO area, where other amphibian species are rare or absent, was highest from river habitats (55.0%), followed by human-modified upland wetlands (32.3%) and natural upland wetlands (12.7%)-the same rank-order these habitats are used for toad breeding. None of the 12 Columbia spotted frogs Rana luteiventris or 2 wood frogs R. sylvatica from the study area tested Bd-positive, although all were from an area of low host density where Bd has not been detected. Prevalence of Bd on toads in the KLGO area decreased during 2005-2015. This trend from a largely single-species system may be encouraging or concerning, depending on how Bd is affecting vital rates, and emphasizes the need to understand effects of pathogens before translating disease prevalence into management actions.


Assuntos
Quitridiomicetos , Alaska , Animais , Colúmbia Britânica , Ecossistema , Prevalência
12.
Biol Lett ; 16(1): 20190725, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31937217

RESUMO

Individual condition at one stage of the annual cycle is expected to influence behaviour during subsequent stages, yet experimental evidence of food-mediated carry-over effects is scarce. We used a food supplementation experiment to test the effects of food supply during the breeding season on migration phenology and non-breeding behaviour. We provided an unlimited supply of fish to black-legged kittiwakes (Rissa tridactyla) during their breeding season on Middleton Island, Alaska, monitored reproductive phenology and breeding success, and used light-level geolocation to observe non-breeding behaviour. Among successful breeders, fed kittiwakes departed the colony earlier than unfed controls. Fed kittiwakes travelled less than controls during the breeding season, contracting their non-breeding range. Our results demonstrate that food supply during the breeding season affects non-breeding phenology, movement and distribution, providing a potential behavioural mechanism underlying observed survival costs of reproduction.


Assuntos
Charadriiformes , Alaska , Animais , Cruzamento , Abastecimento de Alimentos , Ilhas , Reprodução , Estações do Ano
13.
Int J Phytoremediation ; 22(3): 259-266, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31478391

RESUMO

Permafrost thawing could increase soil contaminant mobilization in the environment. Our objective was to quantify metal accumulation capacities for plant species and functional groups common to Alaskan military training ranges where elevated soil metal concentrations were likely to occur. Plant species across multiple military training range sites were collected. Metal content in shoots and roots was compared to soil metal concentrations to calculate bioconcentration and translocation factors. On average, grasses accumulated greater concentrations of Cr, Cu, Ni, Pb, Sb, and Zn relative to forbs or shrubs, and bioconcentrated greater concentrations of Ni and Pb. Shrubs bioconcentrated greater concentrations of Sb. Translocation to shoots was greatest among the forbs. Three native plants were identified as candidate species for use in metal phytostabilization applications. Elymus macrourus, a grass, bioconcentrated substantial concentrations of Cu, Pb, and Zn in roots with low translocation to shoots. Elaeagnus commutata, a shrub, bioconcentrated the greatest amounts of Sb, Ni, and Cr, with a low translocation factor. Solidago decumbens bioconcentrated the greatest amount of Sb among the forbs and translocated the least amount of metals. A combination of forb, shrub, and grass will likely enhance phytostabilization of heavy metals in interior Alaska soils through increased functional group diversity.


Assuntos
Metais Pesados , Militares , Poluentes do Solo , Alaska , Biodegradação Ambiental , Humanos , Solo
14.
Ambio ; 49(3): 749-761, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31073984

RESUMO

Rock ptarmigan (Lagopus muta) and willow ptarmigan (L. lagopus) are Arctic birds with a circumpolar distribution but there is limited knowledge about their status and trends across their circumpolar distribution. Here, we compiled information from 90 ptarmigan study sites from 7 Arctic countries, where almost half of the sites are still monitored. Rock ptarmigan showed an overall negative trend on Iceland and Greenland, while Svalbard and Newfoundland had positive trends, and no significant trends in Alaska. For willow ptarmigan, there was a negative trend in mid-Sweden and eastern Russia, while northern Fennoscandia, North America and Newfoundland had no significant trends. Both species displayed some periods with population cycles (short 3-6 years and long 9-12 years), but cyclicity changed through time for both species. We propose that simple, cost-efficient systematic surveys that capture the main feature of ptarmigan population dynamics can form the basis for citizen science efforts in order to fill knowledge gaps for the many regions that lack systematic ptarmigan monitoring programs.


Assuntos
Galliformes , Alaska , Animais , Regiões Árticas , Groenlândia , América do Norte , Dinâmica Populacional , Federação Russa , Svalbard , Suécia
15.
Ambio ; 49(1): 271-280, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30905056

RESUMO

Wood bison (Bison bison athabascae) were reintroduced into Alaska after a 170-year absence in the state. Wildlife reintroductions may cause problems by damaging property, spreading disease, increasing fear levels, and human injury and death. We examined the influence of urban Alaskan's wildife value orientations (WVO; domination and mutualism), fear, and attitudes toward wood bison on their behavioral intention to support lethal management under specific situations. We hypothesized that: (a) domination, mutualism and fear would influence public attitudes toward wood bison, and (b) attitudes would predict an individual's behavioral intention to support lethal management of the newly restored bison population. We collected data through a self-administered questionnaire randomly distributed to residents in Anchorage (n = 243) and Fairbanks (n = 272). Regression analyses indicated that both mutualism and domination positively correlated with attitudes, and fear negatively correlated with attitudes. Attitudes did not predict behavioral intention to support lethal management practices. Both WVOs and fear predicted behavioral intentions. The model helps to illustrate how cognitive and emotional components can influence acceptance of newly restored herbivore species. Our findings also suggested that for situations where an attitude may not exist, people may use more basic value orientations and emotions when thinking about how they would react in specific situations.


Assuntos
Bison , Alaska , Animais , Animais Selvagens , Humanos
16.
Chemosphere ; 239: 124783, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31726517

RESUMO

This research concerned radioactivity of lichens and mosses from coastal zones of the Canadian Arctic and Alaska. Over 50 samples were collected from 7 positions during two scientific expeditions in 2012 and 2013. The tundra contamination caused by anthropogenic radionuclides was relatively low, reaching mean values with SD's of: 17.4 ±â€¯3.5 Bq/kg for 90Sr, 14.0 ±â€¯2.9 Bq/kg for 134Cs, 38.4 ±â€¯7.5 Bq/kg for 137Cs, 0.86 ±â€¯0.24 Bq/kg for 239+240Pu, 0.065 ±â€¯0.017 Bq/kg for 238Pu and 0.50 ±â€¯0.13 Bq/kg for 241Am. The increase of activity concentration with increasing latitudes was noticed mostly in regard to 90Sr, Pu isotopes and 241Am. The analysis of isotopic ratios exhibited dominant contribution of the global fallout (+SNAP 9A satellite re-entry fallout) for the presence of plutonium isotopes and 241Am. The Fukushima fallout signature was identified in a few lichens from Alaska. However, the influence of additional unknown factor on the occurrence of 90Sr and 137Cs has been detected in western part of Canadian Arctic. Natural radioisotopes of thorium and uranium were found throughout the entire investigated region and the average values of activity concentration with SD's were as follows: 2.92 ±â€¯0.47 Bq/kg for 230Th, 2.61 ±â€¯0.48 Bq/kg for 232Th, 4.32 ±â€¯0.80 Bq/kg for 234U and 3.97 ±â€¯0.71 Bq/kg for 238U. Examined Western Arctic tundra was not affected with any technically enhanced natural radioactivity.


Assuntos
Poluentes Radioativos do Ar/análise , Briófitas/química , Líquens/química , Cinza Radioativa/análise , Poluentes Radioativos do Solo/análise , Poluentes Radioativos da Água/análise , Alaska , Regiões Árticas , Canadá , Radioisótopos de Césio/análise , Acidente Nuclear de Fukushima , Plutônio/análise , Monitoramento de Radiação/métodos , Tório/análise , Urânio/análise
17.
Sci Total Environ ; 698: 134183, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31494417

RESUMO

Contaminant exposure is particularly important for species and populations of conservation concern, such as the Steller sea lion (Eumetopias jubatus). We used blubber samples (n = 120) to determine organochlorine concentrations, including polychlorinated biphenyls (PCBs) and dichloro-diphenyl-trichloroethane (DDTs), and blood samples (n = 107) to estimate total body lipids based on the hydrogen isotope dilution method. We assessed the influence of age, sex, condition, and geographic area on contaminant concentrations in blubber and contaminant body load. The concentration of ΣPCBs was highest in pups (<6 months) from the Aleutian Islands, and the concentrations in males were higher than females in all regions. The ΣPCBs and ΣDDTs concentrations and loads decreased with increasing mass in pups, however, there were no regional or sex differences in contaminant load. Within each of the five age classes, the concentrations of ΣPCBs and ΣDDTs decreased with increasing mass, but overall these OCs increased with age. Further, accounting for the lipid content, a potential proxy for energy balance, in the animal load reduced or removed the regional and sex effects present in age models for contaminants. We propose, that adjusting OCs concentration by the lipid content of the blubber sample alone may not fully account for the variability in OC concentrations associated with differences in condition or energy states between young Steller sea lions.


Assuntos
Monitoramento Ambiental , Hidrocarbonetos Clorados/metabolismo , Leões-Marinhos/metabolismo , Poluentes Químicos da Água/metabolismo , Tecido Adiposo , Alaska , Animais , Feminino , Masculino
18.
Oecologia ; 192(2): 391-401, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31858230

RESUMO

Understanding the mechanisms by which populations are regulated is critical for predicting the effects of large-scale perturbations. While discrete mortality events provide clear evidence of direct impacts, indirect pathways are more difficult to assess but may play important roles in population and ecosystem dynamics. Here, we use multi-state occupancy models to analyze a long-term dataset on nesting bald eagles in south-central Alaska with the goal of identifying both direct and indirect mechanisms influencing reproductive output in this apex predator. We found that the probabilities of both nest occupancy and success were higher in the portion of the study area where water turbidity was low, supporting the hypothesis that access to aquatic prey is a critical factor limiting the reproductive output of eagles in this system. As expected, nest success was also positively related to salmon abundance; however, the negative effect of spring warmth suggested that access to salmon resources is indirectly diminished in warm springs as a consequence of increased glacial melt. Together, these findings reveal complex interrelationships between a critical prey resource and large-scale weather and climate processes which likely alter the accessibility of resources rather than directly affecting resource abundance. While important for understanding bald eagle reproductive dynamics in this system specifically, our results have broader implications that suggest complex interrelationships among system components.


Assuntos
Águias , Alaska , Animais , Ecossistema , Dinâmica Populacional , Temperatura
19.
Dis Aquat Organ ; 137(2): 131-144, 2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31854331

RESUMO

Steller sea lions (SSLs) Eumetopias jubatus experienced a population decline in the 1960s, leading to the listing of the western stock as endangered and the eastern stock as threatened under the US Endangered Species Act. A decrease of births in the western stock beginning in the late 1960s indicates that reproductive failure may have contributed to the decline. We evaluated the role pathogens play in spontaneous abortions, premature births and neonatal deaths in SSLs. Archived tissues from carcasses (n = 19) collected in Alaska from 2002 to 2015 were tested by PCR for Coxiella burnetii, Brucella spp., Chlamydia and morbilliviruses. Animals examined included 47% premature pups, 32% aborted fetuses, 11% neonates and 11% intrauterine fetuses. Gross necropsy and histology findings were summarized in the context of the PCR findings. Tissues were negative for Chlamydia and C. burnetii. Brucella spp. were detected in the lung tissues of 3 animals, including 1 positive for the ST27 strain, the first detection of Brucella spp. DNA in SSLs. Phocine distemper virus was detected in 3 animals in 2 skin lesions and 1 placenta by hemi-nested diagnostic qRT-PCR. Both skin and the placental lesions had vesiculoulcerative changes, and 1 skin lesion contained inclusion bodies in syncytia and upon histologic examination, suggesting that the lesions may be associated with an infection reminiscent of phocine distemper virus, the first in SSLs. We highlight the continuing need for disease surveillance programs to improve our understanding of the prevalence and potential population impacts of these infectious disease agents for pinnipeds in Alaskan waters.


Assuntos
Coxiella burnetii , Leões-Marinhos , Alaska , Animais , Espécies em Perigo de Extinção , Feminino , Gravidez , Inquéritos e Questionários
20.
Zootaxa ; 4561(1): zootaxa.4561.1.1, 2019 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-31716563

RESUMO

The description of a new representative of the species-poor genus Condyloderes Higgins, 1969 from the Northeast Pacific (Alaska) is reported. The analyzed specimens of Condyloderes shirleyi sp. nov. showed a significant variation of numerous morphological characters, along with female-specific traits known also from other congeneric species. These findings stimulated the re-investigation of the type material of the six species of Condyloderes described so far, i.e., C. kurilensis Adrianov Maiorova, 2016, C. megastigma Sørensen, Rho Kim, 2010b, C. multispinosus (McIntyre, 1962) Higgins, 1969, C. paradoxus Higgins, 1969, C. setoensis Adrianov, Murakami Shirayama, 2002, and C. storchi Higgins, 2004 in Martorelli Higgins, 2004. Our study allowed to reveal various morphological novelties and to emend the diagnosis of these species and of the genus Condyloderes. Furthermore, our analysis led to synonymize C. megastigma with C. setoensis. The results of our investigation about the significant variation in C. shirleyi sp. nov. raise a wider question on species identity within Kinorhyncha, underscoring the necessity, if possible, to describe new species from a higher number of specimens and to concentrate on the morphological variation of the going-to-be-described species.


Assuntos
Invertebrados , Alaska , Animais , Feminino
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