Table 1. Summary analysis of the 13 microsatellite loci used in this study.

Island	Year of sampling	Heterozygosity±SD	Number of alleles±SD	FST between time samplings	Locus specific heterozygosity (p values)
Fernandina	1993	0.766±0.022	9.77±3.00	0.000	0.094
	2004	0.815±0.016	11.69±4.15
San Cristóbal	1993	0.707±0.023	6.15±1.57	0.000	0.278
	2004	0.708±0.018	6.54±1.90
Floreana	1993	0.810±0.025	7.85±2.97	0.008	0.787
	2004	0.755±0.022	9.62±4.09
Genovesa	1991	0.701±0.018	6.92±1.85	0.000	0.588
	2004	0.705±0.021	6.46±2.26
Marchena	1993	0.756±0.022	7.77±2.20	0.008*	0.032*
	2004	0.786±0.016	7.69±2.56
Pinta	1993	0.647±0.021	5.85±1.07	0.003	0.305
	2004	0.637±0.018	6.31±1.49
Santiago	1993	0.765±0.025	7.23±2.55	0.001	0.893
	2004	0.762±0.022	8.23±2.65
Santa Cruz	1991	0.801±0.019	9.00±3.29	0.000	0.04*
	2004	0.814±0.020	9.08±3.59
Española	1993	0.794±0.018	8.77±3.17	0.000	0.893
	2004	0.801±0.020	8.92±3.84
Isabela	1993	0.762±0.022	9.38±2.96	0.000	0.893
	2004	0.769±0.021	9.38±2.75
Santa Fé	1991/93	0.733±0.020	8.31±2.72	0.000	0.893
	2004	0.762±0.017	8.77±2.98

Average heterozygosity and standard deviation (SD) and number of alleles with SD are shown for the pre- and post-El Niño time samplings of specific populations. Values of F_ST and locus specific heterozygosity values were calculated between time point samplings. In the last column, only the p values of the corresponding Wilcoxon signed-ranks test are provided for the locus specific differences in heterozygosity between time samplings of a specific population. The actual locus specific heterozygosity values can be found in Table S2. Significant differentiation (p<0.05) of F_ST values and locus specific heterozygosity values are marked with an asterisk (*).