Ecological Archives E095-114-A1

Marie-Andrée Giroux, Jean-Pierre Tremblay, Marie Anouk Simard, Nigel G. Yoccoz, Steeve D. Côté. 2014. Forage-mediated density and climate effects on body mass in a temperate herbivore: a mechanistic approach. Ecology 95:1332–1340. http://dx.doi.org/10.1890/13-0956.1

Appendix A. Detailed results of the principal component analysis used to estimate the index of forage abundance.

The first axis of the principal component analysis (PCA) used to summarize the two variables describing forage abundance (i.e., biomass of field-layer plants and number of saplings of browsed species) explained 77% of the variation and discriminated sampling units (experimental unit per year) with high vs. low abundance of preferred species (PCA loadings: biomass of field-layer plants = 0.7, number of saplings of browsed species = 0.7; see Fig. A1). The second axis of the PCA explained 23% of the variation.

FigA1

Fig. A1. Results of the principal component analysis used to summarize the variables describing forage abundance (i.e., biomass of field-layer plants and number of saplings of browsed species).


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