Aspecto geral da planta (Foto: Direção Regional dos Recursos Florestais).

Gunnera tinctoria

Perennial herb up to 2 m, rhizomatous, with rough leaves of large dimensions and green, very small flowers arranged in conic spikes.

Scientific name: Gunnera tinctoria (Molina) Mirbel

Common names: Chilean gunnera, Chilean rhubarb, giant rhubarb

Family: Gunneraceae

Status in Portugal: invasive species (listed in the Plano regional de erradicação e controlo de espécies de flora invasora em áreas sensíveis)

Risk Assessment score: (in development)

Synonymy: Gunnera chilensis Lam., Gunnera scabra (Ruiz.&Pav.), Panke tinctoria Molina

Last update: 11/07/2014

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How to recognise it

Perennial herb up to 2 m, with bulky rhizomes; stems with reddish spines, lobate, rough and large leaves  and green tiny flowers.

Leaves: alternate, dark green, with 0,8 x 1,5 m, with 5 to 7 lobes, rough and pubescent on both surfaces. Long petioles (up to 1,5 m) covered by prickles, succulent and edible in springtime.

Flowers: unisexual and hermaphrodite, green and very small (up to 1 mm), sessile,  apetalous and with 2 tepals, arranged in spikes up to 1 m long, normally 3 or 4 per plant.

Fruits: reddish-orange drupes, oblong, with 1,5-2 mm diameter.

Flowering: March to June.

 

Characteristics that aid invasion

It propagates by seed, producing a large amount of seeds (each plant may produce between 80000 and 250000 seeds) that are easily dispersed by birds or water.

It also propagates vegetatively, by rhizome fragments, presenting very high growth rates. The rhizomes normally grow near the ground surface, being able to reach 2 m in length.

Native distribution area

South America (Colombia-Chile).

 

Distribution in Portugal

Azores archipelago (São Miguel island).

Geographic areas where there are records of Gunnera tinctoria

Other places where the species is invasive

Europe (France, Ireland, United Kingdom), Australia, New Zealand, west USA (California).

 

Introduction reasons

Ornamental reasons.

 

Preferential invasion environments

Roadsides and watercourses. It also invades disturbed areas.

 

 

Impacts on ecossystems

It forms dense impenetrable thickets that inhibit the development of native vegetation.

 

Economic impacts

High costs in the application of control methodologies.

In watercourses, it may obstruct the drainage channels, consequently enhancing flood risk.

 

 

 

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 Gunnera tinctoria include:

 

Physical control

Hand pulling: preferential methodology for seedlings and young plants and in small invaded areas. In more compacted substrates, hand pulling must be made during the rainy as to facilitate the removal of the root system. As much as possible, it should be guaranteed that there are no rhizomes and/or large rhizome fragments left in the ground because they regenerate very vigorously, diminishing the efficacy of this methodology.

 

Physical + chemical control

Cut stump method. The stems should be cut as close to the ground as possible and applied herbicide (active substance: triclopyr, 2,4-D) to the cut surface.

 

Chemical control

Foliar application of herbicide: methodology applied to invaded areas of larger dimensions. Spray with herbicide (active substance: triclopyr, 2,4-D) limiting as much as possible its application to the target species. It should be made on the time of the plants’ greater growth.

 

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

 

Armstrong C, Osborne B, Kelly J, Maguire CM (2009) Giant Rhubarb (Gunnera tinctoria) Invasive Species Action Plan. Prepared for NIEA and NPWS as part of Invasive Species Ireland, 18 pp.

CABI (2013) Gunnera tinctoria. In: Invasive Species Compendium. CAB International, Wallingford, UK. Available: http://www.cabi.org/isc/ [Retrieved 04/01/2013].

DAISIE European Invasive Alien Species Gateway (2013) Gunnera tinctoria. Available: http://www.europe-aliens.org/speciesFactsheet.do?speciesId=6193 [Retrieved 04/01/2013].

Global Invasive Species Database (2005) Gunnera tinctoria. Available: http://www.issg.org/database/species/ecology.asp?si=836 [Retrieved 04/01/2013].

Penacho ML, Amaral RS, Malveiro A, Machado CAS, Aranha JTM (2009) Controlo de invasoras Hedychium gardnerianum e Gunnera tinctoria em áreas florestais na ilha de S. Miguel – Açores. In: SPCF (ed) 6º Congresso Florestal Nacional: A floresta num mundo globalizado, Ponta Delgada, Açores, pp. 802-806.

Penacho ML, Amaral RS, Malveiro A, Machado CAS (2011) Controlo da invasora Gunnera tinctoria em áreas florestais na ilha da São Miguel – Açores. In: Gabriel R, Elias RB (eds) Workshop Prevenção e controlo de espécies invasoras. Universidade dos Açores, Angra do Heroísmo, Açores, pp. 51-52.

Silva L, Corvelo R, Moura M (2008) Gunnera tinctoria (Molina) Mirbel. In: Silva L, Land EO, Luengo JLR (eds) Flora e fauna terrestre invasora na Macaronésia. Top 100 nos Açores, Madeira e Canárias. Arena, Ponta Delgada, pp. 403-405.

 

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