scholarly journals Individual-based modelling of resource competition to predict density-dependent population dynamics: a case study with white storks

Oikos ◽  
2014 ◽  
Vol 124 (3) ◽  
pp. 319-330 ◽  
Author(s):  
Damaris Zurell ◽  
Ute Eggers ◽  
Michael Kaatz ◽  
Shay Rotics ◽  
Nir Sapir ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Resource Competition ◽  
Density Dependent ◽  
White Storks

scholarly journals Harvesting can stabilize population fluctuations and buffer the impacts of extreme climatic events

2021 ◽  
Author(s):  
Bart Peeters ◽  
Vidar Grøtan ◽  
Marlène Gamelon ◽  
Vebjørn Veiberg ◽  
Aline Magdalena Lee ◽  
...  
Keyword(s):  
Resource Competition ◽  
Growth Models ◽  
Extinction Risk ◽  
Environmental Stochasticity ◽  
Environmental Drivers ◽  
Population Fluctuations ◽  
Vital Rates ◽  
Density Dependent ◽  
Environmental Perturbations

Harvesting can magnify the destabilizing effects of environmental perturbations on population dynamics and, thereby, increase extinction risk. However, population-dynamic theory predicts that impacts of harvesting depend on the type and strength of density-dependent regulation. Here, we used logistic population growth models and an empirical reindeer case study to show that low to moderate harvesting can actually buffer populations against environmental perturbations. This occurs because of density-dependent environmental stochasticity, where negative environmental impacts on vital rates are amplified at high population density due to intraspecific resource competition. Simulations from our population models show that even low levels of harvesting may prevent overabundance, thereby dampening population fluctuations and reducing the risk of population collapse and quasi-extinction following environmental perturbations. Thus, depending on the species’ life history and the strength of density-dependent environmental drivers, low to moderate harvesting can improve population resistance to increased climate variability and extreme weather expected under global warming.

China and the Geopolitics of Rare Earths

2017 ◽  
Author(s):  
Sophia Kalantzakos
Keyword(s):  
Rare Earth ◽  
Rare Earths ◽  
Resource Competition ◽  
Renewable Energy Sources ◽  
High Tech ◽  
Trade Dispute ◽  
Policy Responses ◽  
Economic Statecraft ◽  
The Rare Earth

In 2010, because of a geopolitical incident between China and Japan, seventeen elements of the periodic table known as rare earths became notorious overnight. An “unofficial” and temporary embargo of rare-earth shipments to Japan alerted the world to China’s near monopoly position on the production and export of these indispensable elements for high-tech, defense, and renewable energy sources. A few months before the geopolitical confrontation, China had chosen to substantially cut export quotas of rare earths. Both events sent shockwaves across the markets, and rare-earth prices skyrocketed, prompting reactions from industrial nations and industry itself. The rare-earth crisis is not a simple trade dispute, however. It also raises questions about China’s use of economic statecraft and the impacts of growing resource competition. A detailed and nuanced examination of the rare-earth crisis provides a significant and distinctive case study of resource competition and its spill-over geopolitical effects. It sheds light on the formulation, deployment, longevity, effectiveness, and, perhaps, shortsightedness of policy responses by other industrial nations, while also providing an example of how China might choose to employ instruments of economic statecraft in its rise to superpower status.

scholarly journals Decentralized Control for Urban Drainage Systems via population dynamics: Bogotá case study

2015 ◽  
Author(s):  
J. Barreiro-Gomez ◽  
G. Obando ◽  
G. Riano-Briceno ◽  
N. Quijano ◽  
C. Ocampo-Martinez
Keyword(s):  
Population Dynamics ◽  
Decentralized Control ◽  
Urban Drainage ◽  
Drainage Systems ◽  
Urban Drainage Systems

scholarly journals Population dynamics of the species Plantago major L. and Poa annua L. in a replacement series experiment

2009 ◽  
Vol 61 (4) ◽  
pp. 819-825
Author(s):  
A. Mijovic ◽  
N. Stavretovic ◽  
Zorica Popovic
Keyword(s):  
Population Dynamics ◽  
Specific Interaction ◽  
Growth Dynamics ◽  
Bare Soil ◽  
Poa Annua ◽  
Plantago Major ◽  
Ontogenetic Changes ◽  
Replacement Series ◽  
Density Dependent ◽  
Study Results

Population dynamics of the species Plantago major L. and Poa annua L., typical representatives of ruderal vegetation, was analyzed in a replacement series experiment. The analyzed species were sown in an area with meadow vegetation, where the vegetation present had been previously removed by a total herbicide and additionally by hoeing. The objective of the experiment was to monitor growth dynamics and the effect of intra- and inter-specific interaction of the species Plantago major and Poa annua in conditions of different sowing densities and proportions. The effects of intra- and inter-specific interference and the density-dependent responses were assessed on the basis of several parameters (natality, mortality, age structure, and measures of ontogenetic changes). Based on the study results, it can be concluded that the responses of the species in the experiment were different, which is explained by different adaptive mechanisms, i.e., strategies, in the specific environmental conditions. An effect of the density dependent response was present in both species in the replacement series experiment. The response was amplified by water deficit caused by intensive evapora?tion of the bare soil. No effect of inter-specific interference was observed at the given densities of the study species on the sample plots. An effect of intra-specific interference of the species Plantago major and Poa annua was observed in the guise of a density-negative response of the rate of ontogenetic changes and fecundity.

Population dynamics in echinococcosis and cysticercosis: regulation ofTaenia hydatigenaandT. ovisin lambs through passively transferred immunity

Parasitology ◽  
1990 ◽  
Vol 101 (1) ◽  
pp. 145-151 ◽  
Author(s):  
M. A. Gemmell ◽  
J. R. Lawson ◽  
M. G. Roberts ◽  
J. F. T. Griffin
Keyword(s):  
Population Dynamics ◽  
Natural Environment ◽  
Population Regulation ◽  
Acquired Immunity ◽  
Taenia Hydatigena ◽  
Density Dependent ◽  
Active Immunity ◽  
Infection Pressure ◽  
High Infection

SUMMARYA comparison has been made of the interactions between passively transferred and actively acquired immunity in regulating populations ofTaenia hydatigenaandT. ovis.When ewes were grazed prior to parturition under a high infection pressure, immunity was transferred to their offspring for up to 8 weeks. A qualititative difference between the species was the destruction of larvalT. ovisprior to their establishment (‘pre-encystment immunity’) and that ofT. hydatigenaafter they had become established (‘post-encystment immunity’) in the challenged lambs. The major difference in terms of population regulation between the two parasites was that infection occurred withT. hydatigenabut not withT. ovisin those lambs reared from birth for 16 weeks under high infection pressure. Passive, like active immunity, is a density-dependent constraint. It plays an important role in the population regulation ofT. ovis, but not ofT. hydatigena. This is discussed in terms of transmission in the natural environment, an hypothesis on humoral protection and the need to elucidate pathways of protection when immunization schedules are being evaluated for controlling the taeniid zoonoses.

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