Flora
Christmas Island's flora assemblage has developed largely due to the influences of warm temperatures, high rainfall, isolation, fauna, and geological history. There are approximately 411 plant species on Christmas Island and approximately 18 of these are endemic.
The natural vegetation on the island can be categorised into three main community types:
- Primary rainforest
- Marginal Rainforest
- Scrub Forest (also referred to as open forest and vine forest)
There are also some other types of natural vegetation that are restricted to smaller areas on Christmas Island. These include the Coastal Fringe Forest (also referred to as Shore Cliff and Spray Zone Vegetation), and areas with surface water (Hosnies Springs, the Dales, and parts of the Eastern Terraces). Christmas Island's vegetation is like no other on earth due to its endemic plants and animals and the presence of a large population of land crabs and seabirds.
| Endemic Plants | Habit | General Location |
|---|---|---|
Abutilon listeri |
shrub |
coastal fringe and terraces |
Arenga listeri |
tree palm |
plateau and terraces |
Asplenium listeri |
fern |
terraces |
Asystasia alba |
herb |
coastal fringe and terraces |
Brachypeza archytas |
orchid |
terraces |
Colubrina pedunculata |
shrub |
terraces |
Dicliptera maclearii |
herb |
coastal fringe and terraces |
Dendrocnide peltata var. murrayana |
tree |
terraces |
Flickeringia nativitatis |
orchid |
plateau |
Grewia insularis |
shrub/tree |
terraces |
Hoya aldrichii |
vine |
plateau |
Ischaemum nativitatis |
grass |
coastal fringe |
Pandanus christmatensis |
shrub/tree |
terraces |
Pandanus elatus |
tree |
plateau and terraces |
Phreatia listeri |
orchid |
plateau |
Peperromia rossii |
herb |
plateau |
Zehneria alba |
vine |
coastal fringe and terraces |
Zeuxine exilis |
orchid |
plateau |
Exotic plants
Over 230 Christmas Island plant species are exotic having been introduced by humans over the last century. About 80 of these exotic species are now categorised as noxious weeds, threatening species, or common alien invaders of natural areas on mainland Australia, Pacific Islands and tropical America.
Several exotic trees, shrubs and vines have established in the settled areas and disturbed areas throughout the island. A number of species have begun to spread into undisturbed forest areas including coffee bush, (Clausena excavata), black sage (Cordia curassavica), African tulip tree (Spathodea campanulata), royal poinciana (Delonix regia) and candlenut (Aleurites moluccana). The threats posed by these plants are attrition of the forest edges or the interruption of natural succession. Some exotic species, such as poinciana and candlenut which were widely planted in previous rehabilitation operations, require control to prevent them spreading in forest areas.
