121 Figure 25. Results of the PCA relating the predicted seasonal number of nests per islet with the ‘islet’ variables. A: Correlation circle displaying how much the original ‘islet’ variables are correlated with the first two principal components of the associated PCA. B: Scatter diagram with representation of point classes addressing nesting intensities, ranging from green= ‘no nesting’ to red= ‘high nesting’. 4.2.2 Influence of habitat characteristics upon nesting site selection Then, we tested the influence of the islet geomorphology upon the predicted sector number of nests (Figure 26). The first dimension (27.5% of overall variance) of the corresponding PCA was strongly correlated with the nesting habitat’s attractiveness after loggerhead females have emerged on the beach. High nesting intensity were negatively influenced by erosion scarp, beach rock or woody debris indexes. The second dimension (15% of overall variance) was correlated with the nesting habitat’s accessibility to females looking for an opportunity to emerge from the sea. High nesting intensity were found on beaches sheltered from dominant winds (sector_exposition) and fringed by narrow reef-flats (reef_flat_wideness).
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