TABLE 1.
Posterior summaries of fixed effects estimated from a Bayesian hierarchical shared frailty model of greater sage‐grouse nest survival in California and Nevada, United States, fit to data from 2009 to 2017. Negative coefficients indicate reduced hazard (i.e., increased survival probability) a , while positive values indicate increased hazard (reduced survival probability). Effects are sorted by relative influence (|mean[β]|/SD[β])
Variable | Mean | 2.5th | Median | 97.5th | |Mean|/SD | Influence on survival |
---|---|---|---|---|---|---|
% Total shrub cover (scale 2) | −0.185 | −0.310 | −0.184 | −0.061 | 2.898 | + |
Roughness (scale 4) a | 0.600 | 0.195 | 0.597 | 1.023 | 2.852 | + a |
Initiation date | −0.149 | −0.259 | −0.149 | −0.040 | 2.691 | + |
Cumulative burned area (scale 2) | 0.138 | 0.016 | 0.138 | 0.261 | 2.212 | − |
% Litter (scale 3) | 0.115 | 0.006 | 0.114 | 0.226 | 2.040 | − |
Proximity to wet meadow | −0.924 | −1.950 | −0.903 | 0.003 | 1.852 | + |
Scale 1: radius = 75 m (area = 1.8 ha).
Scale 2: radius = 167.9 m (area = 8.7 ha).
Scale 3: radius = 439.5 m (area = 61.5 ha).
Scale 4: radius = 1,451.7 m (area = 661.4 ha).
RR = Index of resistance and resilience, regional scale = 21,584 m (area = 146,574 ha).
Roughness was fit as an exponential decay function to allow its effect to subside at high values, rather than increase linearly. The coefficient of this effect is thereby reversed, indicating reduced hazard (increased survival) with increasing roughness.