The invasion of Chiswick Eyot

Image above: Withy bundling on Chiswick Eyot; photograph by Alanna McCrumb

Every year the Old Chiswick Protection Society puts out a call for volunteers to come and bundle withies to shore up Chiswick Eyot. This year they’re doing it earlier than usual, and they need people to come and help in early December.

Chiswickians are mostly familiar with the terminology of withies and eyots, but for the benefit of those unfamiliar with the particuliarities of Thames-side living, who may be thinking this sounds positively Mediaeval, they’d be right. New readers start here. 

An eyot (or ait) is a small river island, typically in the Thames, formed by sediment in the water which accumulates over time to form characteristically long and narrow islands, which often are vibrant green spaces home to many different kinds of wildlife. The Thames has around 180 of them.

Chiswick Eyot is a nature reserve and ancient withy bed. Swans nest there and willow trees have been grown and cut for centuries. The cut branches, known as withies, were once used to make baskets to take produce from Chiswick’s market gardens into London. Now, they serve a different purpose: defending against invasion.

Invasion, that is, by the Chinese Mitten Crab, a species of crab thought to have been introduced to the Thames estuary in roughly 1935, arriving in this country as a by-product of intercontinental shipping, by clinging  onto the hulls of ships.

The crabs burrow into muddy banks and create complex, interconnected burrows. The consequences for Chiswick Eyot are potentially disastrous, as the crabs’ burrowing loosens the mud around the eyot, and when the tide flows in and out, the earth is washed away, steadily eroding the island over time.

The Old Chiswick Protection Society, who aim to preserve and protect Chiswick’s natural and open spaces, use withy branches to build defences against the erosion of the eyot. 

The Chiswick Calendar interviewed a member of the Old Chiswick Protection Society, Therese Bennett, who has been gathering withies and looking after the eyot for years.

Image above: Withies shoring up Chiswick Eyot; photograph by Alanna McCrumb

Shoring up defences

“The eyot belongs to Hounslow, but they do nothing for it really. We pay for the pollarding of the trees; some chaps come along to cut all the branches and leave them in piles for us to gather. That’s done over three or four days, you don’t really get much time with the tides coming in and out” Therese told me.

The removal of the willows’ upper branches, to promote the growth of a dense head of foliage, is done in winter while the trees are dormant. 

“Normally what we do is just have the local community come to gather, the Old Chiswick Protection society and some other locals too. Normally we would get 30 or 40 people over there but of course this year we couldn’t do that, so I’ve had to arrange lots of smaller sessions” said Therese.

“We gather all of the withies up into bundles and store them in the corral on the eyot which then are used throughout the year. We bang stakes into the riverbed and then weave the willows in-between those stakes to provide a defence and then we throw bundles and old coffee sacks full of stuff behind those fences and then the mud builds up. 

“We’re trying to a do a bit of planting as well to make it all firm up. If you go at low tide, with your wellies, you’ll see the work we have done on the Chiswick Mall side but also you can see the work we have done on the back of the island on the reed beds, because they’re also disintegrating in the same way because of the Chinese Mitten Crab.”

Know your enemy

Images above: the Chinese Mitten Crab has distinctive furry claws

The Natural History Museum is asking members of the public to report sightings of the Chinese Mitten Crab, a species which is listed as one of the world’s worse invasive species. 

Other than damaging river banks, they cause numerous other problems to areas that they occupy such as damaging fishing gear, blocking intake streams from rivers and reservoirs, modifying natural habitats and competing with native species.

The crabs can grow to the size of a dinner plate. They have distinctive claws that make them appear furry and they have a squarish body with four spines.

“There’s big research project being done on the Chinese Mitten Crab by the Natural History Museum and Royal Holloway College, so we’ll know more about all that at some point in the future” said Therese. 

If you’ve seen a Chinese Mitten Crab, or thought you might have, you can report it by clicking here.

Images above: Withy bundling on Chiswick Eyot; photographs by Alanna McCrumb

Volunteer to help with bundling

The Old Chiswick Protection Society are running several withy bundling sessions from 3 – 8 December.

You don’t have to be an experienced gardener to take part and “any random person” can take part according to Therese. 

“Last week we had an eight-year-old and we had an 82-year-old, so anybody is welcome. You don’t need any experience, we show people what to do and it’s very simple”.

I asked if there was any recommendations Therese had for someone who had never withy gathered before, to which she replied:

“Gloves and wellies! You don’t need any tools, if you do need tools then we have some. Really it’s all bending down, picking up branches, using the tripods which we have built to lay the withies across and if they’re too heavy as a bundle then there’s always someone else who will volunteer to carry them.

“We’ve also been very careful about social distancing, it’s a big space so there’s plenty of space for people to work on their own.

“I’m slightly worried at the moment at having too many people will turn up and if that does happen, I will have to turn people away as people won’t be able to work at a distance but so far, I think the most we have had on one day last week is 16.”

The event poster says you take part at your own risk, so watch out for crabs!

If you’d like to take part in withy bundling and would like more information, you can follow the link below to the Old Chiswick Protection Society’s website:

Read more stories on The Chiswick Calendar

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