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Unformatted text preview: DensityIndependent Count Based PVA 16 January 2008 Stochastic exponential growth Most likely future population size: Probability distribution of future population size lognormally distributed, with variance increasing with time Want to know probability of falling below QE threshold by some time t t t G N N λ = Deterministic & Stochastic population growth Model assumptions No density dependence No demographic stochasticity No catastrophes or bonanzas No environmental autocorrelation No changes in mean or variance of growth rate No sampling error Parameters of the model 2 log Mean growth rate var( ) var(log ) Variance in growth rate Current population size QE thresh G i i C X r r N N μ λ σ λ = = = = old log log "Distance" to QE threshold C X d N N = Mean and variance of future population size Log population size Mean: Variance: Population size Mean: Variance: ( 29 ( 29 ( 29 2 2 2 2 /2 2 /2 log 1 C t C t t N t t N e e e μ σ μ σ σ μ σ + + + + Extinction statistics...
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This note was uploaded on 08/06/2008 for the course ESM 211 taught by Professor Kendall during the Winter '08 term at UCSB.
 Winter '08
 KENDALL

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