Is the positive response of seed germination to plant-derived smoke associated with plant traits?

• Smoke response of species was compared in a semiarid temperate region of Europe.
• Species displaying smoke-enhanced germination were typical of disturbed habitats.
• Smoke-responsive species were frequent on soils rich or moderately rich in nitrogen.
• Annuals or biennials were dominant among the smoke-responsive species.
• Germination response to smoke was not associated with seed mass or shape.

Relationships between seed germination response to plant-derived smoke and various plant traits (habitat requirements, life form, seed morphology, seed bank type) were analysed for 97 species of the Hungarian flora using published data. It was hypothesized that smoke-responsive species – those displaying enhanced germination in response to smoke – differ from non-responsive species – smoke having an indifferent or inhibitory effect on germination – in habitat requirements and/or certain life history traits. To our knowledge, no such comparison has previously been reported for a European flora. We found that species indicating disturbance and those preferring soils rich or moderately rich in nitrogen were more frequent in the smoke-responsive group (80% and 41%, respectively) than in the non-responsive group, while the non-responsive group contained a high percentage of natural species (i.e. species dominant or characteristic in natural plant communities; 47%) and species indicative of nutrient poor (38%) or (sub)mesotrophic (38%) soils. Annuals or biennials (67%) dominated the smoke-responsive group, whereas in the non-responsive group these short-lived species and perennial herbs were equally abundant (43% each). There was a tendency for higher frequency of long-term persistent seed bank among smoke-responsive species (78%) than in the non-responsive group (54%). These findings suggest that smoke-stimulated germination is associated with only a few specific plant traits for species from a semiarid temperate region of Europe, but highlight the frequent occurrence of smoke-enhanced germination among short-lived, nitrophilous or disturbance tolerant species. These results can contribute to a better understanding of post-fire regeneration of plant communities, and could also be considered during vegetation restoration or weed management.