Choosing Fagus sylvatica L. matrix model dimension by sensitivity analysis of the population growth rate with respect to the width of the diameter classes

2008 ◽  
Vol 218 (3-4) ◽  
pp. 307-314 ◽  
Author(s):  
I. López Torres ◽  
C. Fullana Belda ◽  
S.F. Ortuño Pérez ◽  
A.J. Martín Fernández
Keyword(s):  
Growth Rate ◽  
Sensitivity Analysis ◽  
Population Growth ◽  
Fagus Sylvatica ◽  
Matrix Model ◽  
Population Growth Rate ◽  
Fagus Sylvatica L ◽  
Model Dimension ◽  
Diameter Classes

Structured Population Models

2021 ◽  
pp. 47-60
Author(s):  
Timothy E. Essington
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Matrix Model ◽  
Age Structure ◽  
Population Growth Rate ◽  
Population Models ◽  
State Variables ◽  
Elasticity Analysis ◽  
Structured Population Models ◽  
Structured Population

The chapter “Structured Population Models” illustrates how one adds more detail to a model, first through density-independent models, then by showing common matrix-model formulations and how those are used to reveal properties of structured models (e.g. population growth rate, stage/age structure). Structured population models have more detail than their nonstructured counterparts. They account for the differences among individuals within a population, usually by explicitly modeling them as distinct state variables. Elasticity analysis is introduced as a way to identify life stages that have a disproportionately large influence on population growth rate. Structured density-dependent models are briefly introduced as extensions on these models.

scholarly journals Demographic analysis of the shortfin mako shark, Isurus oxyrinchus, in the Northwest Pacific using a two-sex stage-based matrix model

2014 ◽  
Vol 71 (7) ◽  
pp. 1604-1618 ◽  
Author(s):  
Wen-Pei Tsai ◽  
Chi-Lu Sun ◽  
André E. Punt ◽  
Kwang-Ming Liu
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Matrix Model ◽  
Population Growth Rate ◽  
Future Research ◽  
Northwest Pacific ◽  
Vital Rates ◽  
Mako Shark ◽  
Shortfin Mako ◽  
The Impact

Most demographic models are single sex, and assume both sexes have the same vital rates. However, many species, including the shortfin mako shark, are sexually dimorphic in vital rates, which suggests the need for two-sex models. In this study, a two-sex stage-structured matrix model was constructed to estimate shortfin mako shark demography and population dynamics. Monte Carlo simulations were used to evaluate the impact of uncertainties on the estimate of population growth rate. The number of shortfin mako sharks is found to be dropping under current conditions, but will stabilize if size-limit management is implemented. The simulations indicated that population growth rate estimates are mainly influenced by the uncertainty related to survival rate and fecundity. The effects of uncertainty regarding the age at maturity and longevity were found to be relatively minor. Future research should focus on obtaining estimates of natural mortality and reproductive traits for this species to improve the accuracy of demographic estimates.

scholarly journals Biological scaling in green algae: the role of cell size and geometry

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Helena Bestová ◽  
Jules Segrestin ◽  
Klaus von Schwartzenberg ◽  
Pavel Škaloud ◽  
Thomas Lenormand ◽  
...  
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Population Growth Rate ◽  
Internal Diffusion ◽  
Scaling Exponent ◽  
Power Scaling ◽  
Nutrient Distribution ◽  
Metabolic Scaling ◽  
Key Factor ◽  
Size And Morphology

AbstractThe Metabolic Scaling Theory (MST), hypothesizes limitations of resource-transport networks in organisms and predicts their optimization into fractal-like structures. As a result, the relationship between population growth rate and body size should follow a cross-species universal quarter-power scaling. However, the universality of metabolic scaling has been challenged, particularly across transitions from bacteria to protists to multicellulars. The population growth rate of unicellulars should be constrained by external diffusion, ruling nutrient uptake, and internal diffusion, operating nutrient distribution. Both constraints intensify with increasing size possibly leading to shifting in the scaling exponent. We focused on unicellular algae Micrasterias. Large size and fractal-like morphology make this species a transitional group between unicellular and multicellular organisms in the evolution of allometry. We tested MST predictions using measurements of growth rate, size, and morphology-related traits. We showed that growth scaling of Micrasterias follows MST predictions, reflecting constraints by internal diffusion transport. Cell fractality and density decrease led to a proportional increase in surface area with body mass relaxing external constraints. Complex allometric optimization enables to maintain quarter-power scaling of population growth rate even with a large unicellular plan. Overall, our findings support fractality as a key factor in the evolution of biological scaling.

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