Understanding the response of plant biodiversity to environmental perturbation using Grime’s CSR theory

Recent large-scale analyses of plant trait variation have identified two principal spectra of functional variability: 1). an ‘economics’ spectrum ranging from acquisitive species with rapid growth and thin leaves to conservative species with tough, carbon-rich leaves and, 2). for species of intermediate economics, a size spectrum characterized in part by leaf size variation (Wright et al. 2004; Díaz et al. 2004; Cerabolini et al. 2010; Pierce et al. 2012). Indeed, a triangle of viable leaf trait combinations is evident for the Italian flora, and has been used to produce a methodology (Pierce et al. 2013) for the classification of woody and herbaceous angiosperms, gymnosperms and pteridophytes according to CSR (competitor, stress-tolerator, ruderal) theory (Grime 2001; see also Grime & Pierce 2012). Here we review the application of CSR classification for the interpretation of the functional characteristics and assembly of a range of plant communities in Italy and worldwide. We show how CSR classification can be applied to investigate species coexistence at the centimeter scale (e.g. Pierce et al. 2014) and, by allowing a functional interpretation of macro-scale phenomena such as the relationship between biomass production and potential species richness (e.g. Cerabolini et al. 2014), how CSR strategies can allow the prediction of ecosystem and plant community responses to environmental change.