General Impact
Kahili ginger can form dense growth in native forests, smothering young native seedlings and preventing them from establishing. This may result in the alteration of native forest habitats and ecosystems and in the degradation of native forest communities. In some instances forest regeneration may be completely prevented (Environment B.O.P).
First collected in 1954 at Hawaii Volcanoes National Park (HVNP) (Wester, 1992), populations are now found on all islands in Hawaii (Smith, 1985). It exhibits aggressive growth and shade-tolerance, and forms dense thickets on undisturbed sites in the understory of open and closed-canopy ohia-lehua (Metrosideros polymorpha Gaud.) rain forests as well as in open habitats and forest edges around the National Park. It threatens the viability of such natural forests by preventing their regeneration (Anderson and Gardner 1999).
Aircraft-based analysis has found that ginger reduces the amount of nitrogen in the Metrosideros forest canopy in Hawaii, a finding later corroborated by ground based sampling (Stanford Report March 9 2005). Such alteration in natural ecosystem processes could alter the type of fauna able to inhabit such a habitat.
Location Specific Impacts:New Zealand 
Competition: Dense rhizomes prevent growth of native flora. Coromandel (New Zealand)
Competition: Dense rhizomes prevent growth of native flora. Coromandel (New Zealand)
Modification of nutrient regime: Alters nutrient cycling.
Physical disturbance: Alters physical processes such as erosion and stream flow. Auckland Region (New Zealand)
Competition: Dense rhizomes prevent growth of native flora. Auckland Region (New Zealand)
Modification of nutrient regime: Alters nutrient cycling.
Physical disturbance: Alters physical processes such as erosion and stream flow. Bay of Plenty Region (New Zealand)
Competition: Forms dense colonies in native forests, smothering young native plants as well as preventing native seedling establishment. This leads to the alteration of both the function and structure of native forest and in some instances results in the total death of the forest. Northland Region (New Zealand)
Competition: Dense rhizomes prevent growth of native flora. Northland Region (New Zealand)
Modification of nutrient regime: Alters nutrient cycling.
Physical disturbance: Alters physical processes such as erosion and stream flow. Taranaki Region (New Zealand)
Modification of nutrient regime: Alters nutrient cycling.
Physical disturbance: Alters physical processes such as erosion and stream flow. Waikato Region (New Zealand)
Modification of nutrient regime: Alters nutrient cycling.
Physical disturbance: Alters physical processes such as erosion and stream flow. Wellington Region (New Zealand)
Modification of nutrient regime: Alters nutrient cycling.
Physical disturbance: Alters physical processes such as erosion and stream flow. Marlborough Region (New Zealand)
Modification of nutrient regime: Alters nutrient cycling.
Physical disturbance: Alters physical processes such as erosion and stream flow. Tauranga (New Zealand)
Modification of nutrient regime: Alters nutrient cycling.
Physical disturbance: Alters physical processes such as erosion and stream flow. Buller District (New Zealand)
Modification of nutrient regime: Alters nutrient cycling.
Physical disturbance: Alters physical processes such as erosion and stream flow. Azores (Portugal)
Economic/Livelihoods: Conteira (H. gardnerianum) causes problems for forestry operations due to the density levels.
Habitat alteration: The impacts of the native forest is almost complete replacement of the understory and interference with the recruitment of canopy species. Conteira (H. gardnerianum) is also invading higher altitude grassland communities. Reunion (La Réunion) 
Competition: In sites invaded by Hedychium gardnerianum, regeneration of native plants is significantly diminished (Lavergne, 2005). It has been established that H. gardnerianum cover absorbs up to 95% of available light (Lavergne et al., 2005).
|
