Re-introduction of hammock shrubverbena into South Florida, USA

Summary

Hammock shrubverbena (Lantana canescens), a shrub restricted in Florida to disappearing pine rockland and hardwood ecotone habitat around Miami, dropped from 44 to 14 individuals at its single known wild site between 2004 and 2007. Fairchild Tropical Botanic Garden began an emergency rescue in 2004, propagating cuttings from 30 clonal lines on Miami-Dade County land. In July and December 2005, staff and volunteers planted 346 individuals across three Miami-Dade Natural Areas sites: two degraded historic pine/hardwood ecotones (270 and 40 plants) and one newly restored area cleared of invasive Brazilian pepper and replanted with 19 native species (36 plants). Ecotone sites needed repeated thinning of competing vegetation and eventual oak mulch to control weeds, while the restored site thrived with minimal intervention. At 15 to 18 months, survivorship was highest, 84 percent, at the largest ecotone planting, but the restored site alone produced significant natural recruitment, 267 seedlings, compared with fewer than six at each ecotone site. Overall, the wild population increased more than ten-fold. The project rated itself Successful, having achieved both recruitment and survivorship indicators at least at one site and substantially reduced extinction risk, while noting that historic ecotone habitat may no longer reliably sustain the species without intensive management.