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

Table 2

The number of sites occupied by the native species and the alien brook trout (Salvelinus fontinalis). Total number of sites was 78 in both years.

Species	Number of sites (1994)	Number of sites (2004)	Difference
Salmo trutta 1+	56	64	8
Salmo trutta 0+	32	23	−9
Salvelinus fontinalis 1+	21	28	7
Salvelinus fontinalis 0+	15	27	12
Lampetra planeri	32	22	−10
Phoxinus phoxinus	37	54	17
Lota lota	32	7	−25
Cottus gobio	69	70	1
Thymallus thymallus	8	12	4
Pungitius pungitius	16	20	4