Clonal vs leaf-height-seed (LHS) traits: which are filtered more strongly across habitats?

Plant functional traits are now frequently used instead of species identity to identify how plant species co-exist in assemblages. One notion is that species inhabiting the same environment have more characteristics in common than species from different habitats, leading to different prevailing dominant traits along environmental gradients, and also to a lesser diversity of traits in habitats that impose a stronger filter on these traits. Though such patterns have been demonstrated for different environmental drivers and different traits, studies using easily available traits connected to above ground processes (i.e. traits of the leaf-height-seed, or LHS, strategy scheme) are largely overrepresented in these analyses. Here we combined data on clonal and bud bank traits, representing the ability to reproduce and spread vegetatively, with LHS trait data and examined how these traits varied in relation to the vegetational composition of 29 Central-European habitat types. Our analysis focused on determining whether clonal/bud bank or LHS traits play an important role for environmental filtering along gradients approximated by Ellenberg indicator values (EIV) across these habitats. Our results show that clonal and bud bank traits are at least as – if not more – important for the differentiation of the 29 habitat types. Overall, diversity and dominance of clonal and bud bank traits was more strongly correlated with gradients of light availability, temperature, moisture, soil reaction, and nutrient availability across these habitats than it was the case for traits of the leaf-height-seed scheme. Our results call for a stronger integration of belowground traits into the functional traits approach in plant ecology and for an extension of efforts to collect such data.