scholarly journals Desiccation plasticity and diapause in the Argentinian pearlfish Austrolebias bellottii

2017 ◽  
Author(s):  
Tom J M Van Dooren ◽  
Irma Varela-Lasheras
Keyword(s):  
Environmental Conditions ◽  
Variance Components ◽  
Life Histories ◽  
Survival Rates ◽  
Treatment Protocol ◽  
Life History Strategy ◽  
Annual Fish ◽  
Developmental Rates ◽  
Demographic Modelling ◽  
Annual Life History

AbstractBackgroundThe annual life history strategy with diapauses evolved repeatedly in killifish. To understand their and to characterize their variation between species, patterns of desiccation plasticity seem central. Plasticity might have played a role in the origin of these developmental arrests, when annual fish evolved from non-annual ones. The consequences of desiccation on survival and developmental rates of embryos of annual fish are poorly known. Using detailed demographic modelling of embryonal life histories, we investigate plasticity for desiccation in the Argentinian pearlfish Austrolebias bellottii. The treatment protocol contains changing environmental conditions with successive phases of mild desiccation and rewetting.ResultsWe observed no clear diapause II and thus no increased incidence caused by mild and prolonged desiccation. Embryos arrest development in the pre-hatching stage (DIII) or in the dispersed cell phase (DI) irrespective of environmental conditions. There are limited effects of desiccation on survival, limited developmental delays and an acceleration of development into the pre-hatching stage. We found significant parental variance components on developmental rates, but hardly any effect of parental age. Hatching probabilities increased with age, when embryos had been in air at 100% RH and increased further when embryos were rewetted a second time after a two month interval.ConclusionsMild desiccation and rewetting affect survival, rates of development and hatching probability, but not the fractions of embryos that arrest development in particular stages. We can conclude that the incidences of diapause have become relatively independent of the occurrence of mild desiccation, as if they have become assimilated. In contrast to the responses to mild desiccation observed in the non-annual rivulids, Austrolebias accelerates development into the pre-hatching stage.

Life history strategy of Lepraria borealis at an Antarctic inland site, Coal Nunatak

2010 ◽  
Vol 42 (3) ◽  
pp. 339-346 ◽  
Author(s):  
Andreas ENGELEN ◽  
Peter CONVEY ◽  
Sieglinde OTT
Keyword(s):  
Life History ◽  
Environmental Conditions ◽  
Life History Strategy ◽  
Sequence Polymorphism ◽  
Internal Transcribed Spacer Region ◽  
The West ◽  
Distinctive Features ◽  
Dna Sequence Polymorphism ◽  
Antarctic Continent ◽  
The Antarctic

AbstractCoal Nunatak is an ice-free inland nunatak located on southern Alexander Island, adjacent to the west coast of the Antarctic Peninsula. Situated close to the Antarctic continent, it is characterized by harsh environmental conditions. Macroscopic colonization is restricted to micro-niches offering suitable conditions for a small number of lichens and mosses. The extreme environmental conditions place particular pressures on colonizers. Lepraria borealis is the dominant crustose lichen species present on Coal Nunatak, and shows distinctive features in its life history strategy, in particular expressing unusually low selectivity of the mycobiont towards potential photobionts. To assess selectivity, we measured algal DNA sequence polymorphism in a region of 480–660 bp of the nuclear internal transcribed spacer region of ribosomal DNA. We identified three different photobiont species, belonging to two different genera. We interpret this strategy as being advantageous in facilitating the colonization and community dominance of L. borealis under the isolation and extreme environmental conditions of Coal Nunatak.

scholarly journals The effects of population synchrony, life history, and access constraints on benefits from fishing portfolios

2020 ◽  
Author(s):  
Kiva L. Oken ◽  
André E Punt ◽  
Daniel S. Holland
Keyword(s):  
Environmental Conditions ◽  
Life Histories ◽  
Oncorhynchus Tshawytscha ◽  
Environmental Drivers ◽  
Management Options ◽  
Population Synchrony ◽  
Natural Systems ◽  
Advantages And Disadvantages ◽  
Interannual Fluctuations ◽  
Short Time

Natural resources often exhibit large interannual fluctuations in productivity driven by shifting environmental conditions, and this translates to high variability in the revenue resource users can earn. However, users can dampen this variability by harvesting a portfolio of resources. In the context of fisheries, this means targeting multiple populations, though the ability to actually build diverse fishing portfolios is often constrained by the costs and availability of fishing permits. These constraints are generally intended to prevent overcapitalization of the fleet and ensure populations are fished sustainably. As linked human-natural systems, both ecological and fishing dynamics influence the specific advantages and disadvantages of increasing the diversity of fishing portfolios. Specifically, a portfolio of synchronous populations with similar responses to environmental drivers should reduce revenue variability less than a portfolio of asynchronous populations with opposite responses. We built a bioeconomic model characterized by the Dungeness crab (Metacarcinus magister), Chinook salmon (Oncorhynchus tshawytscha), and groundfish fisheries in the California Current, and used it to explore the influence of population synchrony and permit access on revenue patterns. As expected, synchronous populations reduced revenue variability less than asynchronous populations, but only for portfolios including crab and salmon. Synchrony with longer-lived groundfish populations was not important because environmentally-driven changes in groundfish early life survival were mediated by growth and natural mortality over the full population age structure, and overall biomass was relatively stable across years. Thus, building a portfolio of diverse life histories can buffer against the impacts of extremely poor environmental conditions over short time scales, though not for long-term declines. Increasing access to all permits generally led to increased revenue stability and decreased inequality of the fleet, but also resulted in less revenue earned by an individual from a given portfolio because more vessels shared the available biomass. This means managers are faced with a tradeoff between the average revenue individuals earn and the risk those individuals accept. These results illustrate the importance of considering connections between social and ecological dynamics when evaluating management options that constrain or facilitate fishers’ ability to diversify their fishing.

scholarly journals Sympatric Atlantic puffins and razorbills show contrasting responses to adverse marine conditions during winter foraging within the North Sea

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Katie St. John Glew ◽  
Sarah Wanless ◽  
Michael P. Harris ◽  
Francis Daunt ◽  
Kjell Einar Erikstad ◽  
...  
Keyword(s):  
North Sea ◽  
Environmental Conditions ◽  
Trophic Position ◽  
Survival Rates ◽  
Sympatric Species ◽  
Ecological Niches ◽  
Overwinter Survival ◽  
The North ◽  
Winter Conditions ◽  
The North Sea

Abstract Background Natural environments are dynamic systems with conditions varying across years. Higher trophic level consumers may respond to changes in the distribution and quality of available prey by moving to locate new resources or by switching diets. In order to persist, sympatric species with similar ecological niches may show contrasting foraging responses to changes in environmental conditions. However, in marine environments this assertion remains largely untested for highly mobile predators outside the breeding season because of the challenges of quantifying foraging location and trophic position under contrasting conditions. Method Differences in overwinter survival rates of two populations of North Sea seabirds (Atlantic puffins (Fratercula arctica) and razorbills (Alca torda)) indicated that environmental conditions differed between 2007/08 (low survival and thus poor conditions) and 2014/15 (higher survival, favourable conditions). We used a combination of bird-borne data loggers and stable isotope analyses to test 1) whether these sympatric species showed consistent responses with respect to foraging location and trophic position to these contrasting winter conditions during periods when body and cheek feathers were being grown (moult) and 2) whether any observed changes in moult locations and diet could be related to the abundance and distribution of potential prey species of differing energetic quality. Results Puffins and razorbills showed divergent foraging responses to contrasting winter conditions. Puffins foraging in the North Sea used broadly similar foraging locations during moult in both winters. However, puffin diet significantly differed, with a lower average trophic position in the winter characterised by lower survival rates. By contrast, razorbills’ trophic position increased in the poor survival winter and the population foraged in more distant southerly waters of the North Sea. Conclusions Populations of North Sea puffins and razorbills showed contrasting foraging responses when environmental conditions, as indicated by overwinter survival differed. Conservation of mobile predators, many of which are in sharp decline, may benefit from dynamic spatial based management approaches focusing on behavioural changes in response to changing environmental conditions, particularly during life history stages associated with increased mortality.

What contributes to differences in phenotypic variation between generations?

2009 ◽  
Vol 2009 ◽  
pp. 200-200
Author(s):  
A Wolc ◽  
I White ◽  
M Lisowski ◽  
W G Hill
Keyword(s):  
Animal Model ◽  
Environmental Effects ◽  
Environmental Conditions ◽  
Phenotypic Variation ◽  
Variance Components ◽  
Genetic Variance ◽  
Phenotypic Variance ◽  
Base Population ◽  
Substantial Heterogeneity ◽  
Over Time

Under the animal model genetic variance is estimated in the base population taking into account inbreeding and is otherwise assumed to remain unchanged over generations. In practice, phenotypic variation differs randomly or systematically over time. Intuitively, such changes would be attributed mostly to environmental effects, and so lower heritability would be expected when variation is inflated. Studies in dairy cattle show contradictory results (e.g. Boldman and Freeman, 1990). Laying hens are kept under environmental conditions intended to be constant, but show substantial heterogeneity in phenotypic variance (VP) over generations. The aim was to investigate how variance components change.

scholarly journals Cost of Treating Pediatric Cancer at the Butaro Cancer Center of Excellence in Rwanda

2018 ◽  
pp. 1-7
Author(s):  
Claire Neal ◽  
Christian Rusangwa ◽  
Ryan Borg ◽  
Jean Claude Mugunga ◽  
Stephanie Kennell-Heiling ◽  
...  
Keyword(s):  
Social Support ◽  
Hodgkin Lymphoma ◽  
Survival Rates ◽  
Treatment Protocol ◽  
Fiscal Year ◽  
Cancer Center ◽  
Labor Costs ◽  
Center Of Excellence ◽  
The Cost

Purpose Improvements in childhood survival rates have been achieved in low- and middle- income countries that have made a commitment to improve access to cancer care. Accurate data on the costs of delivering cancer treatment in these settings will allow ministries of health and donors to accurately assess and plan for expansions of access to care. This study assessed the financial cost of treating two common pediatric cancers, nephroblastoma and Hodgkin lymphoma, at the Butaro Cancer Center of Excellence in rural Rwanda. Methods A microcosting approach was used to calculate the per-patient cost for Hodgkin lymphoma and nephroblastoma diagnosis and treatment. Costs were analyzed retrospectively from the provider perspective for the 2014 fiscal year. The cost per patient was determined using an idealized patient receiving a full course of treatment, follow-up, and recommended social support in accordance with the national treatment protocol for each cancer. Results The cost for a full course of treatment, follow-up, and social support was determined to be between $1,490 and $2,093 for a patient with nephroblastoma and between $1,140 and $1,793 for a pediatric patient with Hodgkin lymphoma. Conclusion Task shifting, reduced labor costs, and locally adapted protocols contributed to significantly lower costs than those seen in middle- or high-income countries.

scholarly journals Extreme climatic events in relation to global change and their impact on life histories

2011 ◽  
Vol 57 (3) ◽  
pp. 375-389 ◽  
Author(s):  
Juan Moreno ◽  
Anders Pape Møller
Keyword(s):  
Environmental Conditions ◽  
Life Histories ◽  
Reproductive Effort ◽  
Weather Conditions ◽  
Extreme Weather ◽  
Reproductive Failure ◽  
Adult Survival ◽  
Extreme Climatic Events ◽  
Empirical Tests ◽  
Living Organisms

Abstract Extreme weather conditions occur at an increasing rate as evidenced by higher frequency of hurricanes and more extreme precipitation and temperature anomalies. Such extreme environmental conditions will have important implications for all living organisms through greater frequency of reproductive failure and reduced adult survival. We review examples of reproductive failure and reduced survival related to extreme weather conditions. Phenotypic plasticity may not be sufficient to allow adaptation to extreme weather for many animals. Theory predicts reduced reproductive effort as a response to increased stochasticity. We predict that patterns of natural selection will change towards truncation selection as environmental conditions become more extreme. Such changes in patterns of selection may facilitate adaptation to extreme events. However, effects of selection on reproductive effort are difficult to detect. We present a number of predictions for the effects of extreme weather conditions in need of empirical tests. Finally, we suggest a number of empirical reviews that could improve our ability to judge the effects of extreme environmental conditions on life history.

scholarly journals Hibernation is associated with increased survival and the evolution of slow life histories among mammals

2011 ◽  
Vol 278 (1723) ◽  
pp. 3355-3363 ◽  
Author(s):  
Christopher Turbill ◽  
Claudia Bieber ◽  
Thomas Ruf
Keyword(s):  
Life Histories ◽  
Survival Rates ◽  
Diverse Range ◽  
Annual Survival ◽  
Active Season ◽  
Evolutionary Theories ◽  
Generation Times ◽  
Evolution Of Life ◽  
Reproductive Rates ◽  
Similar Survival

Survival probability is predicted to underlie the evolution of life histories along a slow–fast continuum. Hibernation allows a diverse range of small mammals to exhibit seasonal dormancy, which might increase survival and consequently be associated with relatively slow life histories. We used phylogenetically informed GLS models to test for an effect of hibernation on seasonal and annual survival, and on key attributes of life histories among mammals. Monthly survival was in most cases higher during hibernation compared with the active season, probably because inactivity minimizes predation. Hibernators also have approximately 15 per cent higher annual survival than similar sized non-hibernating species. As predicted, we found an effect of hibernation on the relationships between life history attributes and body mass: small hibernating mammals generally have longer maximum life spans (50% greater for a 50 g species), reproduce at slower rates, mature at older ages and have longer generation times compared with similar-sized non-hibernators. In accordance with evolutionary theories, however, hibernating species do not have longer life spans than non-hibernators with similar survival rates, nor do they have lower reproductive rates than non-hibernators with similar maximum life spans. Thus, our combined results suggest that (i) hibernation is associated with high rates of overwinter and annual survival, and (ii) an increase in survival in hibernating species is linked with the coevolution of traits indicative of relatively slow life histories.

The size-structure of corals with contrasting life-histories: A multi-scale analysis across environmental conditions

2015 ◽  
Vol 112 ◽  
pp. 131-139 ◽  
Author(s):  
Mehdi Adjeroud ◽  
Quentin Mauguit ◽  
Lucie Penin
Keyword(s):  
Environmental Conditions ◽  
Life Histories ◽  
Size Structure ◽  
Scale Analysis ◽  
Multi Scale ◽  
Multi Scale Analysis

scholarly journals Living slow and dying young? Life-history strategy and age-specific survival rates in a precocial small mammal

2004 ◽  
Vol 74 (1) ◽  
pp. 171-180 ◽  
Author(s):  
CORNELIA KRAUS ◽  
DAVID L. THOMSON ◽  
JOACHIM KÜNKELE ◽  
FRITZ TRILLMICH
Keyword(s):  
Life History ◽  
Small Mammal ◽  
Survival Rates ◽  
Life History Strategy ◽  
Young Life

scholarly journals The influence of weather conditions during gestation on life histories in a wild Arctic ungulate

2016 ◽  
Vol 283 (1841) ◽  
pp. 20161760 ◽  
Author(s):  
Mathieu Douhard ◽  
Leif Egil Loe ◽  
Audun Stien ◽  
Christophe Bonenfant ◽  
R. Justin Irvine ◽  
...  
Keyword(s):  
Life History ◽  
Reproductive Success ◽  
Environmental Conditions ◽  
Early Life ◽  
Life Histories ◽  
Weather Conditions ◽  
Later Life ◽  
Svalbard Reindeer ◽  
Long Term Study ◽  
Age Related

The internal predictive adaptive response (internal PAR) hypothesis predicts that individuals born in poor conditions should start to reproduce earlier if they are likely to have reduced performance in later life. However, whether this is the case remains unexplored in wild populations. Here, we use longitudinal data from a long-term study of Svalbard reindeer to examine age-related changes in adult female life-history responses to environmental conditions experienced in utero as indexed by rain-on-snow (ROS utero ). We show that females experiencing high ROS utero had reduced reproductive success only from 7 years of age, independent of early reproduction. These individuals were able to maintain the same annual reproductive success between 2 and 6 years as phenotypically superior conspecifics that experienced low ROS utero . Young females born after high ROS utero engage in reproductive events at lower body mass (about 2.5 kg less) than those born after low ROS utero . The mean fitness of females that experienced poor environmental conditions in early life was comparable with that of females exposed to good environmental conditions in early life. These results are consistent with the idea of internal PAR and suggest that the life-history responses to early-life conditions can buffer the delayed effects of weather on population dynamics.

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