Eco Advocacy

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Invasive Species

Invasive Species are also know as 'invasive exotics' or 'alien invaders' and characterise flora and fauna, which after introduction have taken over a habitat and excluded native species. In other words, they could be described as a species that does not naturally occur in an area and whose introduction has caused or is likely to cause economic or environmental harm or in fact harm human health. Many of these species have been introduced to gardens and parkland over the last 200 or so years and subsequently escaped and became naturalised in the surrounding countryside.

Some species pose a serious health risk to humans while others pose a real and substantive economic threat by way of damage to property, health costs, control costs and of course other unquantifiable losses such as loss of biodiversity, species extinction, ecosystem services (pollination for example) and so on. Some estimates have put the cost to the US economy alone at some $138 billion dollars, with estimates of $1.4 trillion dollars a year to the world economy.

Some invasive species pose serious problems to the biodiversity of an area causing habitat destruction and may become ‘ecosystem engineers’ where they take over an area and exclude all other species, an example being Japanese Knotweed. Others are inherently dangerous with the potential to kill or cause serious injury to humans, an example being Giant Hogweed.

It is further estimated that the cost to the European economy is in excess of some €12 Billion per annum as a result of problems caused by invasive species. It will be noted that not all non-native species may be considered invasive. Some provide benefits to industry and society.


Having developed significant expertise in the area of Biodiversity generally, we offer in-house training and education, which can be tailored to reflect the particular species, threatening a specific part of the country.

Training can be on Biodiversity generally or it can be specific to Invasive Species only.

Regarding Invasive Species, training can be tailored to target a particular audience be it public or private sector staff or the schools and the education sector. We have designed a significant exhibition to support the bespoke training service we offer. In addition to the above, we have assembled a large variety of handout material, which can be reproduced as appropriate for distribution as part of this in-house training or indeed for education in schools, again being influenced by the species posing a threat to that area.

It is suggested that front line staff as well as senior management are aware of and competent to correctly identify species so that the alarm can be raised and corrective action including bio-security measures initiated to deal with the problem.

We should be happy to advise on the correct course of training to suit the needs of your organisation. Should you have any questions or would like to discuss your requirements, please do not hesitate to contact me.

Exhibits Designed by Kieran Cummins
Exhibits Designed by Kieran Cummins

Example Invasive Species

The Spanish Bluebell (Hyacinthoides hispanica)

The Spanish Bluebell is a spring-flowering bulbous perennial native to the Iberian Peninsula. It is distinguished from the Common Bluebell (Hyacinthoides non-scripta) by its paler, larger blue flowers, more erect flower stem (raceme), broader leaves, blue anthers (where the Common Bluebell has creamy-white ones) and little or no scent compared to the strong fragrant scent of the northern species. The Spanish Bluebell was introduced to the British Isles, where it has become an invasive species. The two species hybridise freely, and the resulting hybrid Hyacinthoides × massartiana and the Spanish Bluebell both produce highly fertile seed and can invade areas of the native Common Bluebell. This has caused the Common Bluebell to be viewed as a threatened species.

See also:

Spanish Bluebell
Spanish Bluebell


Japanese knotweed (Fallopia japonica)

Also know as Fallopia japonica, syn. Polygonum cuspidatum, Reynoutria japonica. Other common names are fleece flower, Mexican bamboo, Huzhang.

It is a large, herbatious perennial plant, native to eastern Asia in Japan, China and Korea. The species has flourished throughout much of Europe and North America and is classified as an Invasive species in many jurisdictions. Japanese knotweed has the capacity to grow through concrete and tarmac and is highly destructive to paving and walls and other architectural features. It is also problematic along roadsides and riparian ecosystems (interface between land and water). It takes over an area and crowds other species thereby excluding other species after a period of time. It is also problematic in that when it dies back in winder, riverbanks are subjected to erosion as other species have usually been pushed out by this weed. It is tolerant of a wide range of soils and climatic conditions with rhizomes (roots) surviving temperatures of 35 °C (31 °F). Moreover roots can extend to some 7-8 meters horizontally and can penetrate ground to a depth of 3 meters.

See also:

Japanese Knotweed
Japanese Knotweed


Giant Hogweed

Giant Hogweed (Heracleum mantegazzianum), and sometimes known as wild rhubarb, wild parsnip, cartwheel-flower, giant cow parsley. Typically grows to 2-4 meters in height. The stems are stout and a dark reddish-purple with mottled leaf stalks with hollow centers and with sturdy bristles.

The sap from Giant Hogweed is phototoxic and considered to be a noxious weed in many jurisdictions. (Phototoxicity is a chemically induced skin irritation requiring light (photoirritation or photosensitivity). The skin may resemble a very sever sunburn). This may result in blisters, long-lasting scars, and—should it come in contact with eyes—blindness. These serious reactions are due to the furocoumarin derivatives in the leaves, roots, stems, flowers, and seeds of the plant. By forming dense stands, they displace native plants and reduce wildlife and biodiversity in general terms.

Giant hogweed is native to the Caucasus Region and Central Asia. It was introduced to the Britain Isles as an ornamental in the 19th century, and it has also spread to most other European countries and to the United States and Canada. Giant hogweed closely resembles common hogweed (Heracleum sphondylium), and Heracleum sosnowskyi or garden angelica (Angelica archangelica). Common hogweed will also cause burns and contact with skin should be avoided. Burns from common hogweed are not as sever as from its relative 'Giant Hogweed' (pictured).

See also:


Giant Hogweed
Giant Hogweed


Gunnera manicata, native to the Serra do Mar mountains of southeastern Brazil and is one of the largest species. Leaf size is from 1.5-2 m (5-6 ft) wide and up to 3.4 m (11 ft), borne on thick, succulent leaf stalks (petioles) up to 2.5 m (8 ft) long.

Gunnera tinctoria, the Chilean rhubarb, is a plant species native to southern Chile and neighboring zones in Argentina. It is a large-leaved perennial plant that grows up to two meters tall.

Gunnera species have taken over whole swathes of mountainside along Irelands western seaboard, where the authorities are grappling with its eradication which is a very difficult task given its inaccessibility in terms of size and location. The reader is referred to the following useful extract from ‘The Global Invasive Species Database’: -

Gunnera manicata can reduce natural biodiversity and compete with native species. The large leaves of G. manicata can prevent native species from growing underneath them and it may also form dense stands. Gunnera are the only known angiosperms to have a symbiosis with nitrogen-fixing cyanobacteria (Johansson & Bergman 1994). Unlike most symbioses between plants and cyanobacteria, in the case of the Gunneraceae the cyanobacteria are located intercellularly (Bergman 2002). The nitrogen fixing ability the cyanobacteria impart Gunnera species, makes the dicot nitrogen-independent (Osborne & Sprent 2002). This may contribute to the invasiveness of the Gunneraceae G. manicata and G. tinctoria since the symbiosis can fulfil the plants' nitrogen needs in nitrogen-deficient soils, especially during early stages of growth (Osborne et al. 1991). This could also give these Gunneraceae an advantage over native species

See also:


Grey Squirrel

In Ireland, the Grey Squirrel (Sciurus carolinensis) originated from a single introduction in 1911 at Castle Forbes in County Longford, reputedly at a wedding party. Since then their population has grown exponentially, colonising most of Ireland, with devastating results for the native Irish Red Squirrell (Sciurus vulgaris). In England, Grey Squirrels were first introduced by the Victorians at Henbury park, Cheshire, in 1876 and within a timeframe of 25 years had apparently colinised an area of 300 miles between Argyll and Stirlingshire in Scotland.

Grey squirrels are larger, more aggressive and very adaptable. They can digest foods like acorns and beech nuts before they are ripe enough for red squirrels. Grey squirrels are also carriers of the parapox virus, which is detrimental to red squirrels. This is an example of the dangers of invasive species.


Invasive Species and the The Law

The Law in England and Wales

The Wildlife and Countryside Act 1981

Schedule 9 of the Wildlife and Countryside Act in England and Wales

The Wildlife and Countryside Act 1981 (Variation of Schedule 9) (England and Wales) Order

which lists a number of species, the planting in the wild of which constitutes an offence


The Law in Ireland

Statutory Instrument 477 of 2011



Section 49: Prohibition on introduction and dispersal of certain species

Section 50: Prohibition on dealing in and keeping certain species



PART 1: All species listed in Annex IV of the Habitats Directive

PART 2: All species listed in Annex V of the Habitats Directive



Non-native species subject to restrictions under Regulations 49 and 50


Recommended Links

Invasive Species Ireland:

Irish National Invasive Species Database:

Introduced species in the British Isles:

The Global Invasive Species Database:

Invasive Species Specilist Group:

Great Britain Non-native species secretariat:

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