A Daphnia population model that considers pesticide exposure and demographic stochasticity

2014 ◽  
Vol 275 ◽  
pp. 37-47 ◽  
Author(s):  
Richard A. Erickson ◽  
Stephen B. Cox ◽  
Jessica L. Oates ◽  
Todd A. Anderson ◽  
Christopher J. Salice ◽  
...  
Keyword(s):  
Population Model ◽  
Pesticide Exposure ◽  
Demographic Stochasticity ◽  
Daphnia Population

Demography and viability analyses of a diamondback terrapin population

2003 ◽  
Vol 81 (4) ◽  
pp. 716-726 ◽  
Author(s):  
Matthew G Mitro
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Rhode Island ◽  
Population Model ◽  
Population Growth Rate ◽  
Diamondback Terrapin ◽  
Matrix Population Model ◽  
Demographic Stochasticity ◽  
Mark Recapture ◽  
Declining Populations

The diamondback terrapin, Malaclemys terrapin, is a long-lived species with special management requirements but quantitative analyses to support management are lacking. I analyzed mark–recapture data and constructed an age-classified matrix population model to determine the status and viability of the only known diamondback terrapin population in Rhode Island. Female diamondback terrapins were captured, marked, and recaptured while nesting during 1990–2001. Population growth rate (λ) was 1.034 (95% confidence interval = 1.012–1.056). For the preceding 5 years, however, abundance had been stable at about 188 breeding females. Adult apparent survival was high but declined slightly by 0.14% per year from 0.959 in 1990 to 0.944 in 2000. Recruitment of breeding females also decreased during the study period; therefore, survival was increasingly a greater component of population growth rate. Juvenile survival was 0.565 at λ = 1.034 and 0.446 at λ = 1. Both retrospective (mark–recapture) and prospective (matrix population model) analyses showed a greater influence of survival versus reproduction on population growth. Population- model projections showed that capping nests to improve reproductive success could increase population growth rate, but the magnitude of increase was positively related to pre-reproductive survival, therefore negating nest capping as a remedy for declining populations or poor survival. Extinction attributable to demographic stochasticity is unlikely.

Numerical Analysis of the Age-Sex-Structured Population Dynamics Taking into Account Spatial Diffusion

2005 ◽  
Vol 10 (4) ◽  
pp. 365-381 ◽  
Author(s):  
Š. Repšys ◽  
V. Skakauskas
Keyword(s):  
Population Dynamics ◽  
Numerical Analysis ◽  
Population Model ◽  
Local Stability ◽  
Deterministic Model ◽  
Random Mating ◽  
Spatial Diffusion ◽  
Neumann Problems ◽  
Structured Population ◽  
Structured Population Dynamics

We present results of the numerical investigation of the homogenous Dirichlet and Neumann problems to an age-sex-structured population dynamics deterministic model taking into account random mating, female’s pregnancy, and spatial diffusion. We prove the existence of separable solutions to the non-dispersing population model and, by using the numerical experiment, corroborate their local stability.

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