Specific Niche Characteristics Facilitate the Invasion of an Alien Fish Invader in Boreal Streams

Table 6

Results of logistic regression with forward selection for the occurrence of brown trout, brook trout, and bullhead in relation to environmental factors in 2004. Separate analyses were performed for 0+ and 1+ fish.

Variable	𝑏	S.E.	Wald	𝑃	Nagelkerke 𝑅^2
Brown trout 0+					0.082
Macrophytes	−0.029	0.014	4.283	0.039
Constant	0.576	0.720	0.640	0.424
Brown trout 1+					0.136
Particle size	0.556	0.226	6.043	0.014
Constant	−0.774	0.926	0.699	0.403
Brook trout 0+					0.219
pH	−1.802	0.676	7.100	0.008
Velocity	3.260	1.586	4.223	0.040
Constant	9.193	4.570	4.047	0.044
Brook trout 1+					0.189
pH	−2.137	0.723	8.733	0.003
Constant	13.688	4.838	8.006	0.005
Bullhead					0.383
pH	2.994	1.092	7.513	0.006
Depth	0.136	0.062	4.772	0.029
Constant	−21.717	8.127	7.140	0.008