scholarly journals Impacts of environmental variability on desiccation rate, plastic responses and population dynamics of Glossina pallidipes

2014 ◽  
Vol 27 (2) ◽  
pp. 337-348 ◽  
Author(s):  
E. Kleynhans ◽  
S. Clusella-Trullas ◽  
J. S. Terblanche
Keyword(s):  
Population Dynamics ◽  
Environmental Variability ◽  
Glossina Pallidipes ◽  
Desiccation Rate ◽  
Plastic Responses

scholarly journals Gradual plasticity alters population dynamics in variable environments: thermal acclimation in the green alga Chlamydomonas reinhartdii

2018 ◽  
Vol 285 (1870) ◽  
pp. 20171942 ◽  
Author(s):  
Colin T. Kremer ◽  
Samuel B. Fey ◽  
Aldo A. Arellano ◽  
David A. Vasseur
Keyword(s):  
Population Dynamics ◽  
Environmental Variability ◽  
Rapid Evolution ◽  
Ecological Dynamics ◽  
Lake Ecosystems ◽  
High Resolution Data ◽  
Temperature Changes ◽  
Variable Environments ◽  
The Impact ◽  
Plastic Responses

Environmental variability is ubiquitous, but its effects on populations are not fully understood or predictable. Recent attention has focused on how rapid evolution can impact ecological dynamics via adaptive trait change. However, the impact of trait change arising from plastic responses has received less attention, and is often assumed to optimize performance and unfold on a separate, faster timescale than ecological dynamics. Challenging these assumptions, we propose that gradual plasticity is important for ecological dynamics, and present a study of the plastic responses of the freshwater green algae Chlamydomonas reinhardtii as it acclimates to temperature changes. First, we show that C. reinhardtii 's gradual acclimation responses can both enhance and suppress its performance after a perturbation, depending on its prior thermal history. Second, we demonstrate that where conventional approaches fail to predict the population dynamics of C. reinhardtii exposed to temperature fluctuations, a new model of gradual acclimation succeeds. Finally, using high-resolution data, we show that phytoplankton in lake ecosystems can experience thermal variation sufficient to make acclimation relevant. These results challenge prevailing assumptions about plasticity's interactions with ecological dynamics. Amidst the current emphasis on rapid evolution, it is critical that we also develop predictive methods accounting for plasticity.

scholarly journals Climatic changes cause synchronous population dynamics and adaptive strategies among coastal hunter-gatherers in Holocene northern Europe

2020 ◽  
pp. 1-16 ◽  
Author(s):  
Erlend Kirkeng Jørgensen ◽  
Petro Pesonen ◽  
Miikka Tallavaara
Keyword(s):  
Population Dynamics ◽  
Environmental Changes ◽  
Environmental Variability ◽  
Temporal Frequency ◽  
Environmental Drivers ◽  
Natural Phenomenon ◽  
Northern Europe ◽  
Human Populations ◽  
Hunter Gatherers ◽  
Human Ecodynamics

Abstract Synchronized demographic and behavioral patterns among distinct populations is a well-known, natural phenomenon. Intriguingly, similar patterns of synchrony occur among prehistoric human populations. However, the drivers of synchronous human ecodynamics are not well understood. Addressing this issue, we review the role of environmental variability in causing human demographic and adaptive responses. As a case study, we explore human ecodynamics of coastal hunter-gatherers in Holocene northern Europe, comparing population, economic, and environmental dynamics in two separate areas (northern Norway and western Finland). Population trends are reconstructed using temporal frequency distributions of radiocarbon-dated and shoreline-dated archaeological sites. These are correlated to regional environmental proxies and proxies for maritime resource use. The results demonstrate remarkably synchronous patterns across population trajectories, marine resource exploitation, settlement pattern, and technological responses. Crucially, the population dynamics strongly correspond to significant environmental changes. We evaluate competing hypotheses and suggest that the synchrony stems from similar responses to shared environmental variability. We take this to be a prehistoric human example of the “Moran effect,” positing similar responses of geographically distinct populations to shared environmental drivers. The results imply that intensified economies and social interaction networks have limited impact on long-term hunter-gatherer population trajectories beyond what is already proscribed by environmental drivers.

Metrics and sampling designs for detecting trends in the distribution of spawning Pacific salmon (Oncorhynchus spp.)

2012 ◽  
Vol 69 (4) ◽  
pp. 681-694 ◽  
Author(s):  
Stephanie J. Peacock ◽  
Carrie A. Holt
Keyword(s):  
Population Dynamics ◽  
Environmental Variability ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Kisutch ◽  
Sensitivity Analyses ◽  
Observation Error ◽  
Simulated Population ◽  
Age At Maturity ◽  
Status Assessment

The distribution of individuals among populations and in space may contribute to their resilience under environmental variability. Changes in distribution may indicate the loss of genetically distinct subpopulations, the deterioration of habitat capacity, or both. The distribution of Pacific salmon ( Oncorhynchus  spp.) among spawning locations has recently been recognized as an important component of status assessment by USA and Canadian management agencies, but metrics of spawning distribution have not been rigorously evaluated. We evaluated three metrics of spawning distribution and four sampling designs for their ability to detect simulated contractions in the production of coho salmon ( Oncorhynchus kisutch ). We simulated population dynamics at 100 sites using a spawner–recruit model that incorporated natural variability in recruitment, age-at-maturity, dispersal, and measurement error in observations of abundance. Sensitivity analyses revealed that high observation error and straying of spawners from their natal streams may mask changes in distribution. Furthermore, monitoring only sites with high spawner abundance, as is often practiced, failed to capture the simulated contraction of production, emphasizing the importance of matching monitoring programs with assessment objectives.

scholarly journals A model-based approach to incorporate environmental variability into assessment of a commercial fishery: a case study with the American lobster fishery in the Gulf of Maine and Georges Bank

2019 ◽  
Vol 76 (4) ◽  
pp. 884-896 ◽  
Author(s):  
Kisei R Tanaka ◽  
Jie Cao ◽  
Burton V Shank ◽  
Samuel B Truesdell ◽  
Mackenzie D Mazur ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Habitat Suitability ◽  
Environmental Variability ◽  
Homarus Americanus ◽  
Assessment Model ◽  
American Lobster ◽  
Fishing Mortality ◽  
Model Based ◽  
Stock Assessments ◽  
Envelope Model

Abstract Changes in bottom-up forcing are fundamental drivers of fish population dynamics. Recent literature has highlighted the need to incorporate the role of dynamic environmental conditions in stock assessments as a key step towards adaptive fishery management. Combining a bioclimate envelope model and a population dynamic model, we propose a model-based approach that can incorporate ecosystem products into single-species stock assessments. The framework was applied to a commercially important American lobster (Homarus americanus) stock in the Northwest Atlantic. The bioclimate envelope model was used to hindcast temporal variability in a lobster recruitment habitat suitability index (HSI) using bottom temperature and salinity. The climate-driven HSI was used to inform the lobster recruitment dynamics within the size-structured population dynamics model. The performance of the assessment model with an environment-explicit recruitment function is evaluated by comparing relevant assessment outputs such as recruitment, annual fishing mortality, and magnitude of retrospective biases. The environmentally-informed assessment model estimated (i) higher recruitment and lower fishing mortality and (ii) reduced retrospective patterns. This analysis indicates that climate-driven changes in lobster habitat suitability contributed to increased lobster recruitment and present potential improvement to population assessment. Our approach is extendable to other stocks that are impacted by similar environmental variability.

scholarly journals Extinction Risk from Human Impacts on Small Populations of Marine Mammals

2020 ◽  
Author(s):  
Paul R. Wade ◽  
Elisabeth Slooten
Keyword(s):  
Population Dynamics ◽  
Marine Mammals ◽  
Environmental Variability ◽  
Human Impacts ◽  
Extinction Risk ◽  
Small Populations ◽  
Allee Effects ◽  
Structured Population Model ◽  
Increased Risk ◽  
Low Levels

ABSTRACTPopulation models used to set limits for whaling, fisheries bycatch and other human-caused mortality (HCM) usually focus on relatively large populations and do not include Allee effects (declines in population growth rate at small population sizes). These models are not suitable for managing small and endangered populations of marine mammals. We use a stochastic age-structured population model to investigate the effect of HCM on extinction risk. Compared to environmental variability and catastrophes, Allee effects had a strong influence on risk. Depending on the scenario, HCM (1) delayed the rate of population recovery (with no increased risk), (2) increased extinction risk because populations lingered at low levels, (3) increased extinction risk because the population was pushed below an Allee threshold, or (4) increased extinction risk over 100 years because the rate of extinction for a doomed population was accelerated. Population dynamics in small populations are poorly known for most marine mammals. Therefore, we recommend that managers consider the range of potential population dynamics for the species under consideration and make precautionary decisions on allowable levels of HCM. For critically depleted populations (e.g., small populations, well below historic levels) even low levels of HCM have the potential to substantially increase extinction risk.

Lagged response of Adélie penguin population dynamics to environmental variability in the Ross Sea, Antarctica

2020 ◽  
Author(s):  
Xintong Chen ◽  
Xianglan Li
Keyword(s):  
Population Dynamics ◽  
Environmental Factors ◽  
Sea Ice ◽  
Environmental Changes ◽  
Environmental Variability ◽  
Ross Sea ◽  
Chlorophyll Concentration ◽  
Pygoscelis Adeliae ◽  
Sea Ice Concentration ◽  
Ice Concentration

<p>Adélie penguin (Pygoscelis adeliae) are known as an eco-indicator species of the Southern Ocean marine ecosystem. Environmental variability drives penguin population dynamics through its effects on vital rates (e.g., survival, dispersal, or breeding success). Recent studies suggested that inter-annual variation strongly affected Adélie penguin abundance in individual colonies, and aggregating abundance across space provided more reliable trends of population dynamics. By considering the similarity of the regional sea-ice concentration, we divided the Ross Sea region into six areas to investigate the effects of environmental changes on penguin population dynamics from 1982–2013. Time lagged analysis of 0–6 years between penguin abundance and environmental factors were conducted in our study. We found that penguin abundance was significantly correlated with environmental factors at different lag times (p <0.05). In the western Ross Sea region, penguin abundance was positively correlated with temperature over the past 5 years (p <0.05), and positively correlated with sea-ice concentration at a lag of 4–6 years (p <0.05). In the northernmost region of the Ross Sea, penguin abundance was significantly correlated with chlorophyll concentration 4 years earlier (p <0.01). Generalized additive model (GAM) results showed that in mid-Victoria Land, the relationship between sea-ice concentration and penguin abundance was quadratic. Penguin abundance peaked when sea-ice concentration was approximately 40%. On Franklin Island, temperature positively affected penguin abundance when temperature was lower than -3°C, and the contribution decreased considerably when temperature was higher than -2.5°C. Optimal ranges of environmental factors for Adélie penguin population might exist and differ spatially in the Ross Sea. Our study highlighted the lagged response of penguin population to environmental factors to further understand the effects of climate changes on the Antarctic biosphere.</p>

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