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Dicksonia antarctica

Tree fern that can reach 15 m tall and 25 cm in diameter with the stem covered by brown fibrous roots; it has very jagged “leaves” including fertile and sterile “leaves” in alternating layers.

Scientific name: Dicksonia antarctica Labill.

Common name: Australian tree fern

Family: Dicksoniaceae

Status in Portugal: Invasive species in the Azores and on Madeira but no records outside cultivation in maniland Portugal.

Risk Assessment Score: [in development].

Synonymy: Balantium antarcticum (Labill.) C. Presl

Last update: 28/11/2016 ! Profile prepared by the LIFE+ Terras do Priolo project team.

Help us map this species on our citizen-science platform

Avistamentos actuais da espécie: 
Family: 
Dicksoniaceae
Appearence: 
Fern

How to recognize it

Perennial tree fern that can reach 15 m in height and 25 cm in diameter. The stem is thick, erect, unbranched (although it may have shoots at the base) and covered by fibrous, brownish aerial roots and by the base of persistent stems closer to the crown. The base of the stipes and the apex of the stem are covered with dense reddish-brown hairs that can be up to 4.5 cm. It has slow growth (2.5 cm per year).

“Leaves”:  fronds gathered in a large crown, alternating layers of fertile and sterile fronds. Fronds 2-4m, 3-fold, narrow, tapering at each end; hair-covered upper surface covered, margins with curved (sterile) teeth or lobes; midrib covered by brown hairs; short, brownish stipes with dense hairiness.

“Flowers”: sori arranged one in each lobe of the fronds with an indusium composed of two tissues of similar size.

Similar species

It is similar to the Australian tree fern (Cyathea cooperi (Hook. Ex F. Muell) Domin). It is distinguished by having fronds with curved tooth margins whose surface is covered with hairs; stipes dark brown, short and voluminous and with hairs along the base.

Dicksonia antarctica (right) has more curved frond margins than Cyathea cooperi (left).

Characteristics that facilitate invasion

The spores disperse easily and originate new plants.

 

Native distribution area

Australia and Tasmania.

Distribution in Portugal

Present in the Azores (São Miguel Island) and on Madeira (Madeira Island). Invader in the Azores.

For more detailed locations of this species, check the online interactive map. This map is still incomplete – we need your help! Contribute by submitting records of the location of the species where you can find it.

Geographic areas where there are records of Dicksonia antarctica Labill.

Other places where the species is invasive

It is considered naturalized in Sri Lanka.

Introduction reasons

The introduction was intentional for ornamental purposes in gardens and parks.

Preferential invasion environments

Laurisilva forest, creek banks, ravines, clearings, and incense woods and cryptomeria forests.

 

Although legally not considered invasive in Portugal, it shows invasive behaviour in some locations do archipelago dos Açores.

Impacts on ecosystems

The species forms dense patches that disrupt the structure, abundance and succession of the ecosystems it invades. It prevents the development of native vegetation and reduces species diversity through competition and recruitment.

Economic impacts

Potentially high costs in applying control measures.

Natura 2000 Network habitats more prone to impacts

– Mediterranean Sclerophyllous Forests (Macaronesian laurel forests) (9360);

– Endemic Forests with Juniperus spp. (9560).

Controlling an invasive species demands a well-planned management, which includes the determination of the invaded area, identifying the causes of invasion, assessing the impacts, defining the intervention priorities, selecting the adequate control methodologies and their application. Afterwards it is fundamental to monitor the efficiency of the methodologies and recuperation of the intervened area as to perform, whenever necessary, the follow-up control.

The control methodologies used for Dicksonia antarctica include:

Physical control

Hand pulling: is the most effective form of control for small plants. The total extraction of the root and the plant requires labor and work time, however, it is feasible and advisable in easy-access places, with low erosion risk or in small patches occurring close to populations of rare and endangered species. Plant residues and plant fragments must be transported to landfill to prevent their regeneration.

Cutting: most recommended, with the use of backhoe loaders, for large plants in easy-access places. Plants must be cut or pulled out with the complete and intact root, but special care must be taken not to damage the frond, which could burst again. Plant residues/fragments must be conveyed to landfill to prevent their regeneration.

Visit the webpage How to Control for additional and more detailed information about the correct application of these methodologies.

Borges PAV, Abreu C, Aguiar AMF, Carvalho P, Jardim R, Melo I, Oliveira P, Sérgio C, Serrano ARM, Vieira P (eds.) (2008) A list of the terrestrial fungi, flora and fauna of Madeira and Selvagens archipelagos. Direção Regional do Ambiente da Madeira e Universidade dos Açores, Funchal e Angra do Heroísmo, 440 pp.

Borges PAV, Costa A, Cunha R, Gabriel R, Gonçalves V, Martins AF, Melo I, Parente M, Raposeiro P, Rodrigues P, Santos RS, Silva L, Vieira P, Vieira V (Eds.) (2010) A list of terrestrial and marine biota from the Azores. Princípia, Cascais, 432 pp.

Jeménez S, Coelho R, López Y, Silva C (2013) Guia de Controlo de Espécies Exóticas invasoras">Invasoras. Sociedade Portuguesa para o Estudo das Aves, Lisboa.

Ranil RHG, Pushpakumara DKNG, Premakantha KT, Bostock PD, Ebihara A (2014) Naturalization of Dicksonia antarctica Labill. in Pidurutalagala Mountain Forest Reserve and Adjacent Eucalyptus Plantation in Sri Lanka. Bull. Natl. Mus. Nat. Sci., Ser. B, 40(3), pp. 107–112.

Schäfer H (2005) Flora of the Azores. A Field Guide. Second Enlarged edition. Margraf Publishers, Weikersheim.