Evolutionary Ecology

, Volume 17, Issue 3, pp 277–292

Are seed set and speciation rates always low among species that resprout after fire, and why?

Authors

    • Environmental BiologyCurtin University
  • Delbert Wiens
    • Rancho Santa Ana Botanic Garden
Article

DOI: 10.1023/A:1025535223021

Cite this article as:
Lamont, B.B. & Wiens, D. Evolutionary Ecology (2003) 17: 277. doi:10.1023/A:1025535223021

Abstract

A general dichotomy in response to catching alight during fire is for perennial plants to die (nonsprouters, N) or to regrow via dormant buds (resprouters, R). Contrasting effects on other life-history traits, especially those relating to sexual reproduction, can be expected. We hypothesized that fecundity should be lower in R. Our meta-analysis of 33 case studies of co-occurring generic pairs of N and R showed that viable seed and fruit set relative to inflorescence, flower and ovule production were lower for R than N in 30 cases. Three mechanisms have been invoked to explain these trends: resource competition between vegetative and reproductive growth, an outbreeding (R)/inbreeding (N) dichotomy, and higher genetic load among R due to their accumulation of deleterious somatic mutations over many fire cycles. Though poorly researched, we conclude that the high genetic load of R in association with strong self-incompatibility (xenogamy) can best explain the dichotomy in lifeform-fecundity as well as the exceptions. Over the long-term, we suggest that marked xenogamy-longevity in association with frequent axillary branching (induced by recurrent fire, herbivory and drought) via copious stored buds within R might favour expression among their genets and ramets of beneficial somatic mutations present in their meristematic tissues. These conditions would favour ecotypic differentiation and speciation among R that has contributed, along with N, to the exceptional species richness of several fire-prone mediterranean regions.

breeding systemdisturbancefire responsegenetic loadresource allocationspeciation

Copyright information

© Kluwer Academic Publishers 2003