THE IMPACT OF FLOWER HARVESTING ON SEEDLING RECRUITMENT IN SEA LAVENDER (LIMONIUM CAROLINIANUM, PLUMBAGINACEAE)

Flowers of Limonium carolinianum are harvested for use in dried flower arrangements and various crafts. The increasing commercialization of this harvest has led to concerns regarding its sustainability. We quantified the extent of the harvest on four marshes on the Bay of Fundy coast of Nova Scotia, Canada. Over a four-year period from 1996 to 1999, flower stalk removal averaged 32% on easily accessible portions of these marshes (i.e., within 100 m of a road) compared to 5% on inaccessible portions (greater than 500 m from a road). In 5 × 5 m plots where flowers were experimentally removed, no seedlings emerged the following year, whereas seedlings always emerged in unpicked control plots. This rapid and dramatic impact of localized harvesting on seedling emergence is due to the limited dispersal and short life span of L. carolinianum seeds. Sampling in concentric circles around isolated adults revealed that 50% of seedlings emerged within 34 cm of the parent and 90% emerged within 61 cm. Tethered seed experiments revealed that seeds that did not germinate in the first spring after production did not survive to the next spring. Our results suggest that unregulated harvesting has the potential to dramatically impact recruitment into local populations. To reduce the likelihood of local extinction we recommend that harvesters do not reduce flower stalk densities below 1 per m2.