Nest-site selection and its influence on breeding success in a poorly-known and declining seabird: The Tahiti petrel Pseudobulweria rostrata
Fig 2
Classification of habitat groups based on Principal Component Analysis (PCA) and Hierarchical Clustering on Principal Components (HCPC) (i.e., dimensions) applied to substrate and vegetation data in (a) the 102 quadrats characterized for the analysis of Tahiti petrel nest-site selection and (b) the 87 1-m radius plots around burrows used to identify factors influencing Tahiti petrel breeding success.
Axes represent scores for every 102 quadrats and 87 1-m radius plots from variables included in the PCA. The percentage in brackets is the variation of the variables explained by each dimension. Plots were classified into three groups for both the Tahiti petrel nest-site selection and breeding success. Each group represented a specific habitat type, as described in the results section. For nesting habitat selection (a): G1 = open habitats, G2 = closed habitats and G3 = rocky habitats. For breeding success (b): GA = habitat mainly with tree and scree, GB = habitat mainly with rocky substrate and GC = habitat with low vegetation.