Family: Cyatheaceae
Sphaeropteris cooperi (Australian tree fern, straw tree fern) is a tree fern native to Australia. It is commonly cultivated as an ornamental plant. It is reported to be naturalized in New Zealand, parts of Australia and the islands of Kauaʻi, Hawaiʻi, Oʻahu, Lanaʻi, Maui and potentially Molokai. This plant of high concern to Hawaiʻis forests as it invades and threatens biodiversity, outcompeting native vegetation. It creates dense stands, and can produce thousands of spores spread by wind and water, traveling quickly. It grows and matures rapidly, outpacing the growth of nearby native plants. Due to the way it threatens native ecosystems, planting Australian tree fern is highly discouraged.
High Risk Traits:
- Thrives in tropical climates
- Elevation range exceeds 1000 m
- Naturalized in the Hawaiian Islands, New Zealand, parts of Australia outside its native range, and possibly elsewhere
- An environmental weed (threatens biodiversity)
- Unpalatable to feral pigs (giving it a competitive advantage over Hawaiian tree ferns in the genus Cibotium)
- Alternate host of the Australian fern weevil, a pest of native ferns
- Small spines on scales can be a skin and eye irritant
- Shade-tolerant
- Tolerates many soil types
- Can from dense monocultures that exclude other vegetation
- Produces 1000s of wind-dispersed and water-dispersed spores
- Prolific spore production may result in inadvertent dispersal through soil contamination or through attachment to animals, clothing, or machinery
- Rapid growth rate and can reach maturity after 1 year
- Can regrow if cut down without damage to the apical meristem
Low Risk Traits:
- Not known to spread vegetatively
- Valued as an ornamental
- Herbicides have provided effective control