Analysis of variance comparing densities of adult Siphonaria concinna and S. serrata in 7 regions along the 1500 km of the limpets’ biogeographic range in 4 small and 4 large patches.

Region (Western Cape, South Western Cape, Southern Cape, Eastern Cape, Southern Transkei, Northern Transkei and Kwa-Zulu Natal) was a random factor, Species (S. concinna or S. serrata) was fixed and orthogonal, Size (small or large) was fixed and orthogonal, and Patch (4 small and 4 large) was a random factor and nested in Region and Size, and n = 6 replicate quadrats. Data were Sqrt(x+1) transformed to satisfy homogeneity of variances, Cochran’s Test C = 0.04. The Re x Sp x Si interaction term was non-significant (P>0.25) and was pooled with Sp x Pa(Re x Si) to allow a more powerful test of individual factors [26]. Post hoc Student-Newman-Keuls (SNK) tests were done for significant sources of variation to examine the direction of differences relevant to hypotheses of interest (highlighted in bold).xDenotes post hoc pooling when P>0.25. New F ratios are given for those tested against the pooled terms.