HYPERICUM CUMULICOLA DEMOGRAPHY IN UNOCCUPIED AND OCCUPIED FLORIDA SCRUB PATCHES WITH DIFFERENT TIME-SINCE-FIRE

1 Metapopulation models predict that unoccupied, but suitable, patches will exist for species subject to extinction and colonization dynamic s. We compared the demographic responses of Hypericum cumulicola, a ra re herbaceous species almost entirely restricted to Florida rosemary s crub, when transplanted to occupied or unoccupied patches. 2 Seedlings were transplanted and seeds buried into Florida rosemary scrub patche s differing in time since last lire, and in the presence or absence of H. cumulicola. We used a replicated, factorial design to place the tr ansplants and seeds in the field, and monitored their performance for 18 months. 3 Neither time-since-fire nor prior H. cumulicola site occu pancy affected survival of transplants. Only time-since-fire affected growth. Time-since-fire, H. cumulicola occupancy, and their interactio n affected reproductive effort, but these effects were not consistent between years. 4 Flowering and seed production led to subsequent seedl ing recruitment near transplants, mainly in recently burned sites. Gen etic screening of transplants and seedlings showed that transplants in occupied sites could have crossed with nearby resident plants, but th at offspring in sites previously unoccupied were likely to have been p arented only by nearby transplants. 5 Seeds buried, and later exhumed, germinated after 1 or 2 years of burial, demonstrating a persistent s oil seed bank from which populations could recover after fire. Neither time-since-fire nor H. cumulicola occupancy affected seed dormancy or germination. 6 Similar demography in unoccupied and occupied patches suggests that the patchy pattern of site occupancy by H. cumulicola is probably due to limited dispersal and periodic extinction, especially associated with long lire-free intervals. Conservation measures need to protect unoccupied patches to allow metapopulation dynamics and per sistence.