Table 3.

Parameter estimates for the best model predicting the total abundance (ind./site).

Explanatory variable	Coefficient	SE	95% CI
UDR	2.69	1.29	0.16–5.21
NUC_2 km	3.96	1.36	1.29–6.62
Proximity	−0.37	1.09	−2.51–1.78
Shear stress	−2.33	0.93	−4.16–−0.50
Habitat quality_PC1	0.69	0.62	−1.82–3.21
Habitat quality_PC2	2.31	0.85	−0.99–5.60
Stream order1	4.73	1.49	1.82–7.64

Coefficient, standardized partial regression coefficient; SE, standard error; 95% CI, 95% confidence interval; UDR, upstream distribution range of potential immigrants; NUC, the number of upstream tributaries; Proximity, proximity to downstream reproductive subpopulations.

Bold faces indicate variables whose 95% CI did not include zero.

¹Residuals of the fit linear relationship between Strahler stream order and UDR.