The Theory of Population Dynamics: Back to First Principles

The theory of population dynamics: I. Back to first principles

Journal of Theoretical Biology ◽

10.1016/s0022-5193(86)80180-1 ◽

1986 ◽

Vol 122 (4) ◽

pp. 385-399 ◽

Cited By ~ 56

Author(s):

Lev R. Ginzburg

Keyword(s):

Population Dynamics ◽

First Principles

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A generic target for species recovery

Canadian Journal of Zoology ◽

10.1139/cjz-2013-0276 ◽

2014 ◽

Vol 92 (5) ◽

pp. 371-376 ◽

Cited By ~ 4

Author(s):

Jeffrey A. Hutchings ◽

Anna Kuparinen

Keyword(s):

Population Dynamics ◽

Population Growth ◽

Threatened Species ◽

Carrying Capacity ◽

First Principles ◽

Conservation Status ◽

Basic Density ◽

Species Recovery ◽

Density Dependent

Recovery targets for threatened species are typically developed on a species- or population-specific basis. Such narrow taxonomic specificity stands in contrast with widely applied species-independent metrics of conservation status. Here, we propose a generic protocol that can be used to specify broadly applicable targets intended to recover the ecological and evolutionary functionality of threatened species. The method is based on basic density-dependent population dynamics, draws on first principles related to population growth, and explicitly incorporates habitat by accounting for changes in carrying capacity. It offers a consistently applied, methodologically transparent, and predictable biological benchmark for recovery purposes. The benefits of a generic method for articulating recovery targets, particularly from a policy- and statute-implementation perspective, are substantive.

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Inequality in resource allocation and population dynamics models

Royal Society Open Science ◽

10.1098/rsos.182178 ◽

2019 ◽

Vol 6 (7) ◽

pp. 182178 ◽

Cited By ~ 3

Author(s):

Masahiro Anazawa

Keyword(s):

Resource Allocation ◽

Population Dynamics ◽

First Principles ◽

Dynamics Model ◽

Fixed Amount ◽

Resource Unit ◽

Population Dynamics Model ◽

Population Dynamics Models ◽

Dynamics Models ◽

Competition For Resources

The Hassell model has been widely used as a general discrete-time population dynamics model that describes both contest and scramble intraspecific competition through a tunable exponent. Since the two types of competition generally lead to different degrees of inequality in the resource distribution among individuals, the exponent is expected to be related to this inequality. However, among various first-principles derivations of this model, none is consistent with this expectation. This paper explores whether a Hassell model with an exponent related to inequality in resource allocation can be derived from first principles. Indeed, such a Hassell model can be derived by assuming random competition for resources among the individuals wherein each individual can obtain only a fixed amount of resources at a time. Changing the size of the resource unit alters the degree of inequality, and the exponent changes accordingly. As expected, the Beverton–Holt and Ricker models can be regarded as the highest and lowest inequality cases of the derived Hassell model, respectively. Two additional Hassell models are derived under some modified assumptions.

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