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Impacts of Gunnera tinctoria
Last updated: 17th November 2009

One of the definitions of an invasive species is that there must be a negative impact caused by it. Gunnera as mentioned can out compete native species, meaning it has a negative impact on the biodiversity. There are few plants that can live under the shade of Gunnera leaves, leaving large ares of muddy ground beneath, which is visible in winter when the leaves die down. When it grows on coastal cliffs it can cause erosion, as the large weight of the plant makes them frequently fall down to the bottom of the cliff and with it moving large quantities of soil and gravel.
There are also negative economic impacts. It is found largely along drainage ditches, which have to regularly cleared out, which in turn spreads the problem. There is also a large loss of land, as it invades the fields large valuable areas are being lost, land which could be used for cultivation, grazing or for amenity purposes. Other negative impacts include visual impact, Gunnera sticks out in an Irish landscape, it looks very alien with its immense leaves. During winter when the leaves die back a unsightly field of brown rhizomes is left behind and in most cases littered with rubbish that has got stuck between the plants. There is a potential health hazard associated with large fields as access into the field is difficult, with rhizomes crawling along the generally muddy ground. Although it is thought by many that it is poisonous, this is untrue, although it does have bristles along the leaf and leaf stem which can scratch the skin if walking through it.

Agricultural field completely lost to Gunnera

Gunnera invading a river

Loss of plant biodiversity growing underneath Gunnera