Distribution, Status, Phenology, Rate of Spread, and Management of Clidemia in Hawai`i

Clidemia (Clidemia hirta, Melastomataceae) is a significant disruptive weed in many ecosystems in Oceania and the Southeast Asian and Indian subcontinents. In Hawai`i, it forms dense monotypic stands in mesic to wet environments between 33 and 4,920 ft (10-1,500 m) elevation. First reported in the Hawai`ian Islands on O`ahu in 1941, it has since spread to Hawaì i Island (1972), Moloka`i (1973), Maui (1976), Kaua ì (1982) and Lana`i (1988). Humans are long-distance dispersal agents, whereas short-distance dispersal is effected by birds, feral pigs (Sus scrofa), mongooses (Herpestes auropunctatus), humans, and other organisms. Wildfires, landslides, and windstorms accelerate dominance of this weed. All efforts to eradicate newly established populations failed when they were not initiated before first fruit set. The impacts of this weed on native species and ecosystems are devastating. Clidemia has the potential of driving a number of species to extinction. However, impacts on the water balance of entire ecosystems may be more devastating in the long run.