scholarly journals Spatial Structure, Environmental Heterogeneity, and Population Dynamics: Analysis of the Coupled Logistic Map

1998 ◽  
Vol 54 (1) ◽  
pp. 11-37 ◽  
Author(s):  
Bruce E Kendall ◽  
Gordon A Fox
Keyword(s):  
Population Dynamics ◽  
Spatial Structure ◽  
Environmental Heterogeneity ◽  
Logistic Map ◽  
Dynamics Analysis

scholarly journals Population dynamics and spatial structure of human-biting mosquitoes, inside and outside of houses, in the Chockwe irrigation scheme, southern Mozambique

2013 ◽  
Vol 7 (2) ◽  
pp. 309 ◽  
Author(s):  
J. Derek Charlwood ◽  
Gracieta A. Macia ◽  
Maria Manhaca ◽  
Bruno Sousa ◽  
Nelson Cuamba ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Spatial Structure ◽  
Irrigation Scheme

scholarly journals Population dynamics with spatial structure and an Allee effect

2020 ◽  
Author(s):  
Anudeep Surendran ◽  
Michael Plank ◽  
Matthew Simpson
Keyword(s):  
Population Dynamics ◽  
Spatial Structure ◽  
Short Range ◽  
Allee Effect ◽  
Mean Field ◽  
Mean Field Approximation ◽  
Continuum Approximation ◽  
Spatial Moment ◽  
Mean Field Models ◽  
The Mean

AbstractAllee effects describe populations in which long-term survival is only possible if the population density is above some threshold level. A simple mathematical model of an Allee effect is one where initial densities below the threshold lead to population extinction, whereas initial densities above the threshold eventually asymptote to some positive carrying capacity density. Mean field models of population dynamics neglect spatial structure that can arise through short-range interactions, such as short-range competition and dispersal. The influence of such non mean-field effects has not been studied in the presence of an Allee effect. To address this we develop an individual-based model (IBM) that incorporates both short-range interactions and an Allee effect. To explore the role of spatial structure we derive a mathematically tractable continuum approximation of the IBM in terms of the dynamics of spatial moments. In the limit of long-range interactions where the mean-field approximation holds, our modelling framework accurately recovers the mean-field Allee threshold. We show that the Allee threshold is sensitive to spatial structure that mean-field models neglect. For example, we show that there are cases where the mean-field model predicts extinction but the population actually survives and vice versa. Through simulations we show that our new spatial moment dynamics model accurately captures the modified Allee threshold in the presence of spatial structure.

Dynamics analysis and cryptographic application of fractional logistic map

2019 ◽  
Vol 96 (1) ◽  
pp. 615-636 ◽  
Author(s):  
Liguo Yuan ◽  
Song Zheng ◽  
Zeeshan Alam
Keyword(s):  
Logistic Map ◽  
Dynamics Analysis

Population dynamics of the coconut caterpillar, Opisina arenosella Walker (Lepidoptera: Xyloryctidae), in Sri Lanka

1988 ◽  
Vol 78 (3) ◽  
pp. 479-492 ◽  
Author(s):  
P. A. C. R. Perera ◽  
M. P. Hassell ◽  
H. C. J. Godfray
Keyword(s):  
Population Dynamics ◽  
Sri Lanka ◽  
Dynamics Analysis ◽  
Triggering Mechanism ◽  
Working Hypothesis ◽  
Opisina Arenosella ◽  
Population Outbreaks ◽  
Pupal Parasitism ◽  
Generation Period

AbstractOpisina arenosella Walker is a defoliating pest of coconut in Sri Lanka. A first attempt was made to understand its population dynamics. Analysis of records of population outbreaks throughout the country from 1965 to 1985 revealed cycles in the population of approximately one generation period, giving the population the appearance of partially discrete generations. There was also evidence for longer cycles of six-month period. Outbreaks occurred throughout the coconut-growing regions of Sri Lanka, and the numbers of outbreaks per year in different provinces were sometimes correlated, indicating a common, probably climatic, triggering mechanism. Parasitism remained high throughout the outbreaks and there was some evidence that pupal parasitism increased towards the end of an outbreak. A working hypothesis that explains the population dynamics of O. arenosella and the origin of outbreaks is presented.

scholarly journals Multispecies coexistence of trees in tropical forests: spatial signals of topographic niche differentiation increase with environmental heterogeneity

2013 ◽  
Vol 280 (1764) ◽  
pp. 20130502 ◽  
Author(s):  
C. Brown ◽  
D. F. R. P. Burslem ◽  
J. B. Illian ◽  
L. Bao ◽  
W. Brockelman ◽  
...  
Keyword(s):  
Spatial Structure ◽  
Environmental Heterogeneity ◽  
Neutral Theory ◽  
Strong Support ◽  
Empirical Support ◽  
Niche Differentiation ◽  
Heterogeneous Environments ◽  
Strong Positive Relationship ◽  
Species Pairs ◽  
Topographic Heterogeneity

Neutral and niche theories give contrasting explanations for the maintenance of tropical tree species diversity. Both have some empirical support, but methods to disentangle their effects have not yet been developed. We applied a statistical measure of spatial structure to data from 14 large tropical forest plots to test a prediction of niche theory that is incompatible with neutral theory: that species in heterogeneous environments should separate out in space according to their niche preferences. We chose plots across a range of topographic heterogeneity, and tested whether pairwise spatial associations among species were more variable in more heterogeneous sites. We found strong support for this prediction, based on a strong positive relationship between variance in the spatial structure of species pairs and topographic heterogeneity across sites. We interpret this pattern as evidence of pervasive niche differentiation, which increases in importance with increasing environmental heterogeneity.

scholarly journals Recession of Tussilago farfara (L.) population from the agro coenose as a result of cultivation abandonment. I The effect of fallowing on population dynamics

2014 ◽  
Vol 57 (3) ◽  
pp. 371-386
Author(s):  
Anna Namura-Ochalska
Keyword(s):  
Population Dynamics ◽  
Spatial Structure ◽  
Interspecific Competition ◽  
Population Size ◽  
Dactylis Glomerata ◽  
Tussilago Farfara ◽  
Agropyron Repens

The paper evaluates the effect of fallowing on seasonal and multiyear dynamics, as well as on the spatial structure of <em>Tussilago farfara</em> population. In four years turfing and rapid increase in the size of grass populations - those of <em>Agropyron repens</em> (L.) PB. and <em>Dactylis glomerata</em> caused the elimination of <em>Tussilago farfara</em> population. The studies have showed that a decrease in the population size resulted from hampering of both vegetative and generative reproduction. The interspecific competition for available space seems to be a crucial factor limiting emergence of new shoots. In the agrocoenose big population size of <em>Tussilago farfara</em> remained throughout the studies.

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