Ricerc@Sapienza

The increasing use of phylogenetic methods in community ecology recognizes that accumulated evolutionary differences
among species mirror, to some extent, ecological processes. The scope of this work is thus to propose a new method for the
measurement of community-level phylogenetic redundancy, which takes into account the branching pattern of the underlying
phylogeny. Like for functional redundancy, a measure of phylogenetic redundancy can be described as a normalized
measure in the range (0–1) that relates the observed community-level phylogenetic diversity to the value of a hypothetical
assemblage with the same abundance distribution of the focal community in which all species had independent evolution.
Therefore, phylogenetic redundancy can be interpreted as the diversity decrease that is obtained by taking into account the
evolutionary relationships among species in the calculation of diversity. The behavior of the proposed method, for which
we provide a simple R function called ‘phyloredundancy’, was evaluated with published data on Alpine plant communities
along a primary succession on a glacier foreland in northern Italy. As shown by our results, the method accounts for the
length of shared branches in the phylogeny, producing a coherent framework for describing the evolutionary relationships
within a species assemblage. Being based on classical diversity measures, which have been used in ecology for decades, it
also has a great potential for future research in phylogenetic community ecology.