Intra-population variation in physical dormancy

Many studies investigate variation in initial seed dormancy, but this is a measure of little value in fire-prone ecosystems where initial dormancy levels are uniformly high. Liyanage and Ooi use heat treatments and germination trials to assess intra-population variation in dormancy-breaking thresholds for five physically dormant shrub species (Fabaceae) from fire-prone vegetation. They find that instead of variation in initial dormancy, the species maintain different dormancy-breaking temperature thresholds among individuals growing in close proximity to each other. They conclude that differences found at the individual plant level could contribute to subsequent variation within the seed bank and provide a bet-hedging strategy, and represent a mechanism for increasing the probability of population persistence in the face of variability in the fire regime.