Table 2.

Results of generalized linear models aimed at testing the effects of fragmentation (fragmented of continuous) and of the distance of each site from the source on allelic richness and observed heterozygosity

		Allelic richness			Observed heterozygosity
Fish species	d.f.	Deviance	F-value	P-value	Deviance	F-value	P-value
(A) Leuciscus cephalus
Null model		4.764			0.054
Fragmented status	1,14	1.907	32.086	<0.001	0.031	12.637	0.004
Distance to the source	1,13	1.645	2.944	0.111	0.029	0.391	0.543
Distance × status	1,12	1.068	6.489	0.026	0.022	3.928	0.070
(B) Leuciscus leuciscus
Null model		9.168			0.011
Fragmented status	1,14	1.244	207.306	<0.001	0.007	10.546	0.006
Distance to the source	1,13	0.483	19.894	<0.001	0.006	1.806	0.203
Distance × status	1,12	0.458	0.649	0.435	0.005	0.094	0.763
(C) Gobio gobio
Null model		28.820			0.032
Fragmented status	1,19	5.073	99.614	<0.001	0.024	7.019	0.017
Distance to the source	1,18	4.256	3.423	0.081	0.023	0.003	0.958
Distance × status	1,17	4.052	0.85	0.367	0.022	0.762	0.394
(D) Phoxinus phoxinus
Null model		13.190			0.053
Fragmented status	1,19	12.779	1.075	0.314	0.047	5.232	0.035
Distance to the source	1,18	7.681	13.332	0.002	0.031	14.170	0.001
Distance × status	1,17	6.500	3.087	0.096	0.019	10.997	0.004

Results are shown for each of the four species independently [from (A) to (D), in decreasing order of body length, see Table 1)]. Bold P-values are significant (P < 0.05).