TABLE 5.

Associations between measures of genetic diversity and single explanatory variables

		Allelic richness			Genotypic richness
Explanatory variable	Type of data	Slope	Statistics	N	Slope	Statistics	N
D. longispina
Age of population	Continuous	0.08	t = 5.23****	49	0.21	t = 4.70****	49
Volume	Continuous	0.81	t = 4.61****	49	2.45	t = 5.29****	49
Distance to neighbor	Continuous	−0.84	t = −2.46*	49	−1.84	t = −1.93	49
Relative distance to sea	Continuous	1.33	t = 2.86**	49	2.94	t = 2.23*	49
Presence of competitor	Class	—	t = 0.63	49	—	t = 1.15	49
Island	Class	—	F = 1.56	48	—	F = 1.46	48
D. magna
Age of population	Continuous	0.04	t = 2.39*	29	0.11	t = 3.92***	29
Volume	Continuous	−0.05	t = −0.34	29	0.22	t = 0.72	29
Distance to neighbor	Continuous	0.28	t = 1.28	29	0.50	t = 1.12	29
Relative distance to sea	Continuous	0.20	t = 1.03	29	0.64	t = 1.73	29
Presence of competitor	Nominal	—	t = 0.579	29	—	t = 0.087	29
Island	Nominal	—	F = 8.70***	25	—	F = 3.39*	25

Reported statistics are either F-values (island) or t-values (all other variables). The regression slope is given only for continuous variables. N, the number of pools for which a given statistic was calculated. Significant values after correction for multiple testing (sequential Bonferroni correction) are underlined. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.