Alien flora-The aliens have landed.

Aliens have landed, literally, they have parachuted in to many parts of the country.They have jumped over walls, they have drifted along our waterways, they have followed trains along their tracks, they have attached themselves to animals and to the clothes of humans.

They aliens are so established in many parts of the country, and the use of the ordinary tools of man to eradicate them have proved futile. They continue to dominate places where natives once tenanted, but now are gone. They are not little green men from Mars but they are akin to the trifids, these alien plants that have invaded Britain over the last decades, it is claimed that they are a threat to our biodiversity. they have produced head line grabbing stories such as " Japanese knotweed takes over the country."

How real is the threat? In many areas where the aliens have been removed, their place has been taken over by native invasive plants such as nettle and bramble. It is argued by some conservationists that alien species need to be eradicated to protect our countryside. They complain about Japanese knotweed, Fallopia japonica, while ignoring a large bramble thicket situated close by. { Brambles are, to those that oppose spending large amounts of money eradicating alien species,thugs of the British flora}. The same argument has been forwarded in respect of the Himalayan balsam Impatiens glandulifera, yet ignoring a bed of nettles close by {another so called thug of the British flora.}

My own personal opinion of these four examples are as follows. The Japanese knotweed and Himalayan balsam need to be controlled especially where they occur at nature reserves and local beauty spots. For these locations are havens specially when they are situated among urban localities.

 The Japanese knotweed was introduced by the Victorians as a garden ornamental plant, that escaped over the wall to get established in many areas of the countryside.It has no natural predators and expensive chemical sprays do little to halt its progress.  The root stock runs deep below the surface and if but a tiny fragment of the root is left in the ground after cultivation it is all most certain to produce a new plant. It has got so prolific in places that talks have taken place about introducing a beetle from Japan that is known to eat the plant. The trouble with this theory is that -are we not introducing another alien species to keep in check another?

Below-Japanese Knotweed. 

Photograph by Dal.

Bramble  -a thug?

To the best of my knowledge the Japanese knotweed is not used for medicinal or culinary purposes in this country. {although I have heard that a restaurant in the south of England was trying out Japanese knotweed in some of its dishes}. On the other hand  the bramble "thug" is a vital habitat for many species for protection and food, it provides pollen and nectar, fruit and aromatic leaves. They are utilised in medicinal and culinary preparations which are beneficial to man. I rest my case!

The Himalayan balsam is not only invasive {see link HIDDEN GEMS 2} . They produce lots of nectar that attract bees and other pollinators to their large prominent flowers, leaving smaller native flora less pollinated in that particular region, thus producing less seeds. The nettle on the other hand is a vital part of the food chain. Insects eat the leaves and lay their eggs on them. When larvae hatch they also use  the foliage as a food plant. The nettle is beneficial to man's health and is employed for culinary purposes. {see link NETTLES FOR FOOD AND MED}. Once again I rest my case!.

Below- the flowers give easy access to bees, this is to the detriment of native species in the locality. below top the flowers of Indian balsam visited by a bee. Below--- The balsam quickly takes over a locality.

Photographs by Dal

Are we going overboard ?

Are we in danger of going over board in this dislike displayed in many quarters, for non-native flora? In Britain the vast majority of plants  that have arrived  here by one means or another are fairly benign, examples are the evening primrose,Onethers erythrosepala and Oxford ragwort,Senecio squalidus.

The alien species can be placed into two groups. High impact plants {as far as the environment is concerned} and low impact plants .Many of the plants have been with us for centuries and are now established as being part of the British flora. For instance the Victorians introduced the Rosebay willowherb into their gardens  from which they parachuted over the walls and into the general countryside. There are now few locations where they do not occur.

However, gout weed or ground elder Aegopodium podagaria has been with us since Medieval times when it was utilized as medicinal and culinary purposes. This species id listed on the D.E.F.R.A. list of invasive alien plants. It is known that at least 140 non native species have been here with us for over 500 years. Another 2,000 + have arrived during the last 500 years.

There are a large numbers of aliens that have established themselves in urban situations Rosebay willowherb, Oxford ragwort,and Pineapple weed are examples, but with the exception of the Rosebay willowherb, not many get established in the wider countryside. If all the species of flora were as rampant as the headlines suggests the countryside would look much different than it does today I feel we need to keep a prespective about these invaders and enjoy the countryside with all its diverse flora. We must of course keep a watchful eye on species that come into the country in the future and monitor any environmental impact. Some species are already causing an ecological  imbalance both fauna and flora species. The American mink is a prime example and there will be a page on this site about the American mink in the near future.

Below- the Rosebay willowherb is well established in the British Flora.

photograph by Dal

Plants with High or low impact.

BELOW is a small sample of common high and low impact plants.

                                           HIGH IMPACT PLANTS




                                         LOW IMPACT PLANTS





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