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. 2018 Feb 1;8:2177. doi: 10.1038/s41598-018-20675-9

Table 1.

Posterior summaries of parameters estimated from the SCR Poisson encounter model (null model, M0) to estimate wolf density.

Mean SD BCI
2.5% 50% 97.5%
Density (Dˆ) 2.55 0.42 1.87 2.50 3.51
alpha1 (αˆ0) −1.21 0.25 −1.38 −1.21 −0.74
alpha2 (αˆ2) 0.24 0.13 −0.01 0.24 0.50
psi (ψ) 0.38 0.07 0.27 0.38 0.53
sigma (σˆ) 0.33 0.03 0.27 0.32 0.40

Estimates were based on 3 chains of 50,000 iterations, and thin rate = 1, yielding 150,000 total samples from the joint posterior. BCI = Bayesian Credible Intervals. alpha1 (αˆ0) and alpha2 (αˆ2) are used to model the baseline encounter rate, being dependent on sampling effort (see main text for details): log(λ0[j])=α0+α1×L[j], where Lj is the density of transect in each cell; psi (ψ) is a parameter of the augmented data, and sigma (σ), or movement parameter, is the half-normal scale parameter that describes the rate at which detection probability declines as a function of distance.