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Identifying the trait syndromes of conservation indicator species: how distinct are British ancient woodland indicator plants from other woodland species?


corresponding author,



Ancient woodland indicator species (AWIs) are plant species which are thought to be restricted to areas of long-continuity woodland habitat. In many cases, however, these species have been identified on the basis of personal, to some extent, subjective experience. Do the species proposed as AWIs according to these lists have traits in common, and how distinct is their trait profile from that of other woodland plant species?


United Kingdom.


We applied classification tree analysis to a plant trait database to assess the extent to which proposed AWI species can be clearly separated from other woodland plants based upon their traits. We contrasted AWI species with an objectively defined list of plants that are not considered to be AWIs but that have been commonly recorded in woodlands. We also investigate the effects of phylogeny and region specificity on species' proposed AWI status.


The results provide support for the distinctiveness of plant species thought to be associated with ancient woodland; they were found to be almost exclusively short, perennial species, usually with a high seed weight. Results also indicate that rarer AWIs have a more distinguishable trait profile than more common species. No link was found between phylogeny and AWI status.


AWI species do have a distinguishable trait profile, despite their often partially subjective selection. The results of the classification tree analysis suggest that traits reflecting poor dispersal ability may be partly responsible for confining these species to ancient woodlands. This confirms other studies that emphasize their low ability to colonize secondary woodland sites and hence vulnerability to habitat conversion.