Fire, Invertebrate Damage, and Reproductive Output in the Endemic Forb Liatris ohlingerae (Asteraceae)

ABSTRACT In pyrogenic ecosystems, fire often plays an integral part in plant population dynamics. For a subset of plant species in such ecosystems, fire is connected to seed set and/or germination, resulting in postfire recruitment episodes. We investigated the relationship between fire and seed set in the perennial forb Liatris ohlingerae (Asteraceae), one of many species endemic to the pyrogenic Lake Wales Ridge ecosystem of central Florida. Our study focused on comparisons of seed production and invertebrate damage to flowers across L. ohlingerae populations in locations encompassing a range of intervals since fire, between 1 mo and 9 yr prior to the study. We found that the estimated seed set was significantly higher in populations burned less than 1 yr prior to the study than in all other populations. Both low invertebrate damage and high seed production rates contributed to this trend in the populations burned < 1 yr prior to the study. Previous research has demonstrated that germination of L. ohlingerae seeds is higher and seed predation is lower in more recently burned patches, so it is likely that the pulse of seed production observed in recently burned populations would carry through to the seedling stage. The processes behind the observed increase in fecundity remain unknown, and their characterization will likely be valuable for continued efforts to conserve L. ohlingerae. Because invertebrate damage did not significantly influence seed production, it need not be prioritized for conservation management.