Population viability and spatial fish reproductive strategies in constant and changing environments: an individual-based modelling approach

1997 ◽  
Vol 54 (10) ◽  
pp. 2235-2246 ◽  
Author(s):  
C LePage ◽  
P Cury
Keyword(s):  
Reproductive Strategies ◽  
Environmental Changes ◽  
Environmental Variability ◽  
Reproductive Function ◽  
Population Level ◽  
Population Viability ◽  
Natural Systems ◽  
The Individual ◽  
Modelling Approach

A spatially explicit individual-based model (IBM) helps to explain how two reproductive strategies, described as obstinate and opportunist, may be acting at the population level. Factors such as the spatial structure and the dynamics of the environment, the shape of the reproductive function, and spawning season duration are considered. Five simulations are presented to explore the importance of these factors in the success of two reproductive strategies experiencing in a first step, a constant, and in a second step, a changing environment. Simulations show that the obstinate strategy is characterized by high inertia and mainly selects optimal environmental conditions in the long term, whereas the opportunist strategy maintains diversity in site choice and allows the individual to explore environmental variability. Under drastic environmental changes, only a population combining both strategies avoids extinction. A low percentage of opportunists (about 1%) coupled with a high proportion of obstinates (about 99%) ensure population viability. Similar percentages have been observed in nature for philopatric species. The respective percentages of inertia and innovation that are needed in the functioning of natural systems are discussed.

scholarly journals The crucial role of genome-wide genetic variation in conservation

2021 ◽  
Vol 118 (48) ◽  
pp. e2104642118
Author(s):  
Marty Kardos ◽  
Ellie E. Armstrong ◽  
Sarah W. Fitzpatrick ◽  
Samantha Hauser ◽  
Philip W. Hedrick ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Environmental Changes ◽  
Population Viability ◽  
Adaptive Potential ◽  
Biodiversity Crisis ◽  
Genome Wide ◽  
Simulation Based ◽  
Functional Genetic Variation

The unprecedented rate of extinction calls for efficient use of genetics to help conserve biodiversity. Several recent genomic and simulation-based studies have argued that the field of conservation biology has placed too much focus on conserving genome-wide genetic variation, and that the field should instead focus on managing the subset of functional genetic variation that is thought to affect fitness. Here, we critically evaluate the feasibility and likely benefits of this approach in conservation. We find that population genetics theory and empirical results show that conserving genome-wide genetic variation is generally the best approach to prevent inbreeding depression and loss of adaptive potential from driving populations toward extinction. Focusing conservation efforts on presumably functional genetic variation will only be feasible occasionally, often misleading, and counterproductive when prioritized over genome-wide genetic variation. Given the increasing rate of habitat loss and other environmental changes, failure to recognize the detrimental effects of lost genome-wide genetic variation on long-term population viability will only worsen the biodiversity crisis.

Changes in wild red squirrel personality across ontogeny: activity and aggression regress towards the mean

Behaviour ◽  
2015 ◽  
Vol 152 (10) ◽  
pp. 1291-1306 ◽  
Author(s):  
A.D. Kelley ◽  
M.M. Humphries ◽  
A.G. McAdam ◽  
Stan Boutin
Keyword(s):  
Structural Stability ◽  
Environmental Changes ◽  
Population Level ◽  
Behavioural Syndrome ◽  
Red Squirrels ◽  
Individual Level ◽  
Personality Changes ◽  
The Mean ◽  
Differential Stability ◽  
The Individual

Both juvenile and adult animals display stable behavioural differences (personality), but lifestyles and niches may change as animals mature, raising the question of whether personality changes across ontogeny. Here, we use a wild population of red squirrels to examine changes in activity and aggression from juvenile to yearling life stages. Personality may change at the individual level (individual stability), population level (mean level stability), and relative to other individuals (differential stability). We calculated all three types of stability, as well as the structural stability of the activity–aggression behavioural syndrome. Within individuals, both activity and aggression scores regressed towards the mean. Differential stability was maintained for activity, but not aggression. Structural stability was maintained; however, the activity–aggression correlation increased in squirrels that gained territories later in the season. These results suggest that personality undergoes some changes as animals mature, and that the ontogeny of personality can be linked to environmental changes.

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.

Krill (Euphausiacea) demography and variability in abundance and distribution

2000 ◽  
Vol 57 (S3) ◽  
pp. 151-167 ◽  
Author(s):  
Volker Siegel
Keyword(s):  
Energy Flow ◽  
Environmental Changes ◽  
Population Level ◽  
Survival Strategies ◽  
Detailed Knowledge ◽  
Species Survival ◽  
Flow Through ◽  
Abundance And Distribution ◽  
Geographical Locations

Among euphausiids, there are many species that are represented by enormous numbers of individuals and are of considerable importance to various ecosystems, as well as to human exploitation. Considerable progress has been made regarding quantitative aspects of krill biology. This detailed knowledge about krill population parameters is necessary to answer questions about the importance of euphausiids to energy flow through certain ecosystems. This information also helps in assessing the importance of seasonal or long-term climate effects on variation in euphausiid populations because variability is not simply noise. Hypotheses have been developed as to how large seasonal or latitudinal environmental changes affect species survival strategies in poor conditions and maintenance of a stable population level. This paper discusses aspects of the spatial distribution with regard to seasonal and interannual changes, developments to define genetically distinct populations, and results of long-term variability in krill abundance and biomass for various species in different geographical locations.

scholarly journals The crucial role of genome-wide genetic variation in conservation

2021 ◽  
Author(s):  
Martin Kardos ◽  
Ellie Armstrong ◽  
Sarah W Fitzpatrick ◽  
Samantha Hauser ◽  
Philip Hedrick ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Environmental Changes ◽  
Population Viability ◽  
Adaptive Potential ◽  
Biodiversity Crisis ◽  
Genome Wide ◽  
Simulation Based ◽  
Functional Genetic Variation

The unprecedented rate of extinction calls for efficient use of genetics to help conserve biodiversity. Several recent genomic and simulation-based studies have argued that the field of conservation biology has placed too much focus on the conservation of genome-wide genetic variation, and that this approach should be replaced with another that focuses instead on managing the subset of functional genetic variation that is thought to affect fitness. Here, we critically evaluate the feasibility and likely benefits of this approach in conservation. We find that population genetics theory and empirical results show that the conserving genome-wide genetic variation is generally the best approach to prevent inbreeding depression and loss of adaptive potential from driving populations towards extinction. Focusing conservation efforts on presumably functional genetic variation will only be feasible occasionally, often misleading, and counterproductive when prioritized over genome-wide genetic variation. Given the increasing rate of habitat loss and other environmental changes, failure to recognize the detrimental effects of lost genome-wide variation on long-term population viability will only worsen the biodiversity crisis.

Sleep and pain

2018 ◽  
Author(s):  
Nicole K. Y. Tang ◽  
Esther F. Afolalu ◽  
Fatanah Ramlee
Keyword(s):  
Public Health ◽  
Primary Care ◽  
Population Level ◽  
Population Based ◽  
Future Research ◽  
Long Term Conditions ◽  
Treatment Development ◽  
The Individual ◽  
The Relationship

Pain and sleeplessness are two of the commonest reasons for primary care appointments. The prevalence of each problem alone is high, and to add to the complexity, pain and insomnia frequently co-occur, with pain interrupting sleep and pain being further aggravated following a poor night’s sleep. Sleep and pain management are increasingly recognized as important to public health. In particular, insomnia and chronic pain are long-term conditions that actively contribute to morbidity, disability, economic burden to society, and suffering to the individual and immediate family. This chapter examines the interrelationship between the two at the population level. Specifically, evidence from population-based studies regarding the co-occurrence and temporal link of pain and sleep is reviewed, with moderators and mediators of the relationship highlighted. Possible directions for future research and treatment development are also outlined.

scholarly journals The impact of antiretroviral therapy on population-level virulence evolution of HIV-1

2015 ◽  
Vol 12 (113) ◽  
pp. 20150888 ◽  
Author(s):  
Hannah E. Roberts ◽  
Philip J. R. Goulder ◽  
Angela R. McLean
Keyword(s):  
Antiretroviral Therapy ◽  
Deterministic Model ◽  
Population Level ◽  
Threshold Condition ◽  
Virulence Evolution ◽  
Downward Pressure ◽  
The Individual ◽  
The Impact ◽  
Hiv 1

In HIV-infected patients, an individual's set point viral load (SPVL) strongly predicts disease progression. Some think that SPVL is evolving, indicating that the virulence of the virus may be changing, but the data are not consistent. In addition, the widespread use of antiretroviral therapy (ART) has the potential to drive virulence evolution. We develop a simple deterministic model designed to answer the following questions: what are the expected patterns of virulence change in the initial decades of an epidemic? Could administration of ART drive changes in virulence evolution and, what is the potential size and direction of this effect? We find that even without ART we would not expect monotonic changes in average virulence. Transient decreases in virulence following the peak of an epidemic are not necessarily indicative of eventual evolution to avirulence. In the short term, we would expect widespread ART to cause limited downward pressure on virulence. In the long term, the direction of the effect is determined by a threshold condition, which we define. We conclude that, given the surpassing benefits of ART to the individual and in reducing onward transmission, virulence evolution considerations need have little bearing on how we treat.

scholarly journals Multi-Level Resources to Support Health Behavior Maintenance

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 827-827
Author(s):  
Susan Hughes ◽  
Janet Bettger ◽  
Mina Raj ◽  
Jaime Hughes
Keyword(s):  
Health Behaviors ◽  
Local Community ◽  
Population Level ◽  
Individual Level ◽  
Safe Environment ◽  
Multi Level ◽  
The Individual ◽  
Behavior Maintenance ◽  
Term Maintenance

Abstract Although behavior change is largely thought to occur on the individual level, maintenance of health behaviors also depends upon factors at the community and population levels. As discussed in earlier presentations, health behaviors can be influenced by social support, environmental context, and population-level policies. For example, maintaining a physical activity regimen is made easier when an older adult has access to a safe environment, support of family and friends, and/or ongoing access to a program that is continuously offered, or sustained, at a local community center. This presentation will focus on the importance of discussing sustainability when considering long-term maintenance of health behaviors. Specifically, this presentation will use examples from the evidence-based Fit & Strong! program, now being offered in 32 states, to explore sustainability of programs at the participant and community level and will provide an overview of barriers and facilitators faced by community organizations.

Aspects of Psychological Aging and Technology

1985 ◽  
Vol 1 (1) ◽  
pp. 117-121
Author(s):  
Stig Berg
Keyword(s):  
Genetic Factors ◽  
Environmental Changes ◽  
Eating Habits ◽  
Social Resources ◽  
Psychological Resources ◽  
Age Changes ◽  
Short Term ◽  
Technological Factors ◽  
The Individual

Aging is generally regarded as a reduction of physical, psychological, and social resources. This reduction is due to two processes that operate simultaneously during the life of an individual. One of these processes is the basic biological changes which take place within the individual and are probably programmed by genetic factors. The other is change due to environmental factors, such as air pollution, noise, poor working conditions, and eating habits, social and psychological factors such as attitudes and norms, and technological factors which can enhance adaptation or cause a decline in social or psychological resources. According to present knowledge, biological age changes are irreversible. However, it should be possible to reverse the environmental changes either through short-term interventions among individuals and the community, or by long-term interventions in the society.

scholarly journals A modular hierarchical array camera

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Xiaoyun Yuan ◽  
Mengqi Ji ◽  
Jiamin Wu ◽  
David J. Brady ◽  
Qionghai Dai ◽  
...  
Keyword(s):  
High Performance ◽  
Modular Design ◽  
Population Level ◽  
Real World Data ◽  
Camera System ◽  
Individual Level ◽  
The Individual ◽  
Term Monitoring ◽  
Array Camera

AbstractArray cameras removed the optical limitations of a single camera and paved the way for high-performance imaging via the combination of micro-cameras and computation to fuse multiple aperture images. However, existing solutions use dense arrays of cameras that require laborious calibration and lack flexibility and practicality. Inspired by the cognition function principle of the human brain, we develop an unstructured array camera system that adopts a hierarchical modular design with multiscale hybrid cameras composing different modules. Intelligent computations are designed to collaboratively operate along both intra- and intermodule pathways. This system can adaptively allocate imagery resources to dramatically reduce the hardware cost and possesses unprecedented flexibility, robustness, and versatility. Large scenes of real-world data were acquired to perform human-centric studies for the assessment of human behaviours at the individual level and crowd behaviours at the population level requiring high-resolution long-term monitoring of dynamic wide-area scenes.

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