Aquatic Weeds

The biggest threat to our country's ecology is aquatic weeds

Global warming, climate change, or merely cyclical temperature changes, the world is facing a warming climate leading to increased growing seasons for plants and an increased spread of suitable habitats for plants to develop.

Of all of the invasive plant species throughout the world the most concerning and potentially damaging are the aquatic invaders.

Watercourses, ponds and lakes are the veins of the world, travelling throughout the countryside and offering more ecological benefits than we could possibly imagine. These waterways are becoming increasingly choked and starved of life by invasive aquatic plant species.

The range of species causing problems seems to grow on a monthly basis. The actual species are of little concern - they all share the same traits, require similar control and can all affect massive damage to the environment.

I have recently been over in Holland and Belgium to discuss aquatic invasives with various governmental bodies and representatives. At last, people are realising the potential damage that these aquatic species can cause purely through lack of awareness.

To look at the Dutch and Belgian environment - vast areas of essentially flat landscape whose existence is solely based on the availability of effective drainage. This is also true for the Fens, Lincolnshire, Norfolk, Suffolk, The Somerset Levels etc. Without effective drainage and effective outlets for drainage we will all suffer the consequences of flooding and loss of habitat. Millions of pounds are spent on drainage schemes for Golf Courses, Parks and Open Spaces, Football Pitches and the like. Imagine the consequence of having nowhere to drain to!

Unlike the terrestrial plants, control and eradication of aquatic species is almost impossible. The range of controls available is limited severely, the use of chemicals in watercourses throughout Europe is heavily frowned upon. This, in itself, is an interesting point as to which is the worse of the two evils? Rivers dead through aquatic invasives or damaged through incorrect use of herbicides?

(Picture right Water Fern (Azola fillculoides)

Within the UK we basically have two herbicide options available for use on or adjacent to watercourses - RoundUp Pro Biactive and compounds of 2,4-D amine. With the authorisation of the Environment Agency we are permitted, in certain situations, to use these chemicals to assist with control. Belgium and Germany will not entertain any use of herbicides on or adjacent to watercourses and the Dutch are, as ever, slightly more relaxed and will accept proposals for herbicide use.

The governments throughout the world are starting to realise that the problems are significant. However, very little legislation has been put in place to prevent sales of invasive aquatics through Garden Centres, and there is seemingly no legal framework in place to prevent the wilful spread through members of the public cleaning their ponds and dumping the 'rubbish' into watercourses.

This problem is only in its infancy in the UK. America, Africa, Australia and Europe are further down the line and now have major problems. We, at least, have the opportunity to actually control the problem in the UK.

As ever, the sticking point is finance. Control is costly and needs to be coordinated throughout the UK starting with Government Legislation and working right through the system down to the members of the public who are actually causing the problem.

Australian Swamp Stonecrop (Crassula helmsii)	Floating Pennywort (Hydroculoidcs)

The species that we are currently concerned with here in the UK include; Parrots Feather, Creeping Water Primrose, Australian Swamp Stonecrop, Water Fern and Floating Pennywort. Identification of aquatic invasives is not always easy. However, they are obvious once they have taken hold!
Control strategies and management regimes are essential. If left alone the problem will spread and, once in a moving watercourse, control becomes almost impossible.

Action needs to be taken quickly and needs to be effective.

There is a vast amount of advice available on the internet, www.t-c-m-rd.co.uk contains detailed description and identification aides to the majority of problematic aquatic invaders, as does the DEFRA site and The Centre for Ecology and Hydrology www.ceh.ac.uk

Creeping Water Primrose ((Ludwigla hexapetala)	Parrots Feather (Myriophyllum)

Control methods need to combine both manual and chemical methodologies. Tiny fragments of these plants left untreated will rapidly form dense mat coverage of waterways. Biological control is being used in certain countries although to date not in the UK. Research undertaken in Holland has led to the development of biological control for Water Hyacinth and Water Lettuce using Mycoherbicides.

I intend to progress this work in Holland and investigate the possibility of large scale trials in a cross European project using various agencies from the UK and Holland in an attempt to try and not only stem the spread of these plants but to also raise public awareness in both countries.
Our old 'friend' Blanket Weed is an algael bloom that can cause problems very quickly in enclosed and slow flowing water bodies. Traditional manual methods have involved a lot of hard work, raking repeatedly throughout the season in order to keep the weed at bay.

However, new research has shown that there is a system of control and eradication available now on the market which uses Ultrasonic Sound Waves transmitted through the water. This appears to have no effect whatsoever on any other flora and fauna within the pond but completely destroys Blanket Weed, thus removing the need for any manual clearance.

These products are readily available through numerous outlets, even eBay!!! They require minimal maintenance and small power requirements and it really does appear to be the end for algae in our ponds - provided of course that there is an electrical supply nearby.
Maybe soon we will be able to undertake similar controls to the remaining aquatic invasives but, until then, there is a lot of hard manual work ahead of us.

tcm Philip Rusted Telephone 01440760170

Web site www.t-c-m-rd.co.uk