Abstrakt
Patterns of phylogenetic relatedness of species within community types (phylogenetic structure; PS) are often used to infer processes of community assembly, yet the causes of these patterns remain poorly understood. Here we ask whether PS of extant plant species pools is related to availability of correspoding habitats in the geological history.
We characterized PS of recent species pools of 88 major vascular plant community types occurring in the country, comprising a total of 2306 species, using the mean phylogenetic distance (MPD) between all pairs of species found in each species pool, and compared the PS of these species pools with the relative ages of their habitats. Clustered PS was observed consistently in species pools of historically younger community types of grasslands and other open habitats, which were formed mainly during the late Tertiary as a consequence of climate aridization and cooling, and to which only a limited number of lineages had enough time to adapt.
Clustered PS was also typical of species pools of the recent human-made habitats, in which it probably resulted from environmental filtering of pre-adapted lineages. In contrast, overdispersed PS was observed in forests and other plant community types occurring in habitats that are assumed to have existed continuously since the Mesozoic.
Our analyses suggest that habitat age has a strong effect on PS of species pools of extant plant community types. Based on these results, we argue that history of the analysed species pools at a geological time scale should be considered whenever differences in PS are discussed and interpreted.