Knotweed News

Are invasive species actually useful?

Author: Mike Clough

Date Posted: Wednesday 1st February 2017

I’ve been having a bit of a mid-life crisis recently where I begin to question everything that I do? I’ve been dealing with invasive species for the last twenty years or so and have been pretty clear in my mind what it is that I’ve been doing.

We have ‘native’ plants and we have ‘non-native’ plants. ‘Native’ ones ‘should’ be here …’non-native’ ones ‘shouldn’t’…easy. One can look at a river frontage and see Himalayan balsam, Japanese knotweed, Giant hogweed all surrounded by sycamore trees. You can look at this and say that …’really none of these plants should be here’…we have native species that have been bullied out of this picture by the aggressive ‘alien’ species.

But – having been involved in a significant number of invasive species clearance projects – I am beginning to see something else going on.

Let’s be honest here – human beings are a pretty recent phenomenon. A recent phenomenon that has had a massive global impact ….but…in the scheme of things still a pretty recent feature. I look at my life and look at changes in the impact of ‘invasive species’ and really I’m looking at a ‘speck’ in time. Literally a mere micro dot, on a micro dot, on a micro dot…..on a spot in time.

Completely insignificant….yet I’m expecting to….’see changes …’

These ‘changes’ that I’m expecting will probably take hundreds, thousands maybe millions of years…yet in my sad little world I’m expecting Mike Clough to have an impact – not gonna happen.

What I am beginning to see though is that the ‘random’ spread of invasive non-native species is perhaps not as random as I first thought. Perhaps ‘invasions’ are natures ‘salve’…? …nature’s way of covering a wound?

The spread of Japanese knotweed is often described as… ‘covering the entire UK’. This is a bit misleading although it is based on scientific evidence. The ‘spread’ is shown by use of a ten kilometer grid and states that JK is present in each of these squares – the squares cover the entire UK …hence jk covers the whole of the UK.

However, if the grid is split down to a 2.5km grid, a slightly different picture emerges where the super weed is shown to be concentrated in our urban areas – our major cities being the hot spots of reported growth and identified problems.

So ….NOT our farmland, NOT our National Parks, NOT our woodlands or our coastal areas.

Our urban areas have at various times all been through massive change as the industrial revolution took hold, flourished… then declined.

We have seen changes in housing and the way we live from terraced houses to flats …with various models being tried ….then cast away to become derelict.

Changes in the way we heat and power our homes and the loss of the coal mining industry have all has massive impact on our land use.

We have been through two world wars which have had massive impact – plus the bombing of central Manchester by the IRA.

Global warming – flooding – river management.

All of the above have created patches of dead land – patches of land that have been ignored, fenced off and left untouched.

It is these areas that have begun to cause me concern.

We are often employed to survey such areas and to mitigate against invasive species – going in heavy handed with chemicals and machinery …yet much of the vegetation that we perceive as ‘invasive’ has in fact grown in areas where no native plant would grow?

Heavy metals and toxic ground conditions mean that our typical native flora just has not got the ability to withstand the conditions …so without the invasive non-native species …nothing would be growing in these areas.

Hand in hand with the invasive species we see insects and wildlife responding to the new vegetation and adapting to the new environment.

Bees love Himalayan balsam….

Otters find cover within Japanese knotweed…

So…my big question is…should we be so dismissive of invasive non-nationwide species??

Should we be so vigorous in their eradication or should we be taking a step back and asking a few more pertinent questions before hitting them with glyphosate?

It’s all to do with money and development and house building…but …maybe one or two people should be asking about the ‘environment’ and what the bigger picture is??…maybe we should look at nature’s master plan???

Hmmm a lot to think about here??

Watch this space.


Mike C

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Mike Clough

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