LRA and PCA to Determine Contribution of Species to Fruit Diet
The total logratio variance in the frugivory dataset was 0.53, which is based on the total possible combinations of 120 ratios formed by the 16 endozoochorous plant species. These 16 species are listed in Table 4 as a summary table of the LRA, quantifying the chi squared distance, inertia, and LRA dimension values for each of the species, in descending order by inertia. These inertia values suggest that individually, saw palmetto, sabal palm, prickly pear, and locustberry are among the most variance-explaining fruits consumed by the tortoises.
To identify which logratios in the dataset best explain the majority of total logratio variance, we followed the stepwise approach of Graeve and Greenacre (2020). The subsequent series of four steps identified five logratios comprised of six fleshy-fruited species that explained 96.96% of the total logratio variance. After these four steps, the addition of more logratios had minimal statistical and practical relevance (Supp. Table 1).
In the LRA, we consecutively accounted for more of the total logratio variance until we described > 95% of the variance, proceeding with each step as follows: