Data from: Decomposing changes in phylogenetic and functional diversity over space and time

1. The α, β, γ diversity decomposition methodology is commonly used to
investigate changes in diversity over space or time but rarely conjointly.
However, with the ever-increasing availability of large-scale biodiversity
monitoring data, there is a need for a sound methodology capable of
simultaneously accounting for spatial and temporal changes in diversity.
2. Using the properties of Chao's index, we adapted Rao's
framework of diversity decomposition between orthogonal dimensions to a
multiplicative α, β, γ decomposition of functional or phylogenetic
diversity over space and time, thereby combining their respective
properties. We also developed guidelines for interpreting both temporal
and spatial β-diversities and their interaction. 3. We characterised the
range of β-diversity estimates and their relationship to the nested
decomposition of diversity. Using simulations, we empirically demonstrated
that temporal and spatial β-diversities are independent from each other
and from α and γ-diversities when the study design is balanced, but not
otherwise. Furthermore, we showed that the interaction term between the
temporal and the spatial β-diversities lacked such properties. 4. We
illustrated our methodology with a case study of the spatio-temporal
dynamics of functional diversity in bird assemblages in four regions of
France. Based on these data, our method makes it possible to discriminate
between regions experiencing different diversity changes in time. Our
methodology may therefore be valuable for comparing diversity changes over
space and time using large-scale datasets of repeated surveys.