Saltmarshes – unsung plant heroes holding back the rising tides

This spring a Green Shores project, lead by Dr Clare Maynard, is starting a regeneration of stalt marsh off the Tayport East Common. We are excited to join a volunteer planting session this Sunday, 23 April at 10am to give a hand with planting at the shore opposite Foodmek. All are welcome! You can find all details here.

Below is a transcript of an in-depth interview from February 2017 which gives more information on the project. Clare talks about the importance of salt marshes, their unfortunate history, clever salt marsh spiders and prettiest marsh plant flowers. We also discuss effects of climate change on sea levels, how it’s already affecting salt marshes and how a humble Sea Club Rush plant can help us fight the consequences of climate change at Tayport’s shore.

Kaska: Can you please introduce yourself to our readers.

Clare: Dr Clare Maynard, my official title is one of research fellow at the University of St Andrews but I tend to think of myself as more of a general salt marsh ecologist and conservationist. And I live in Tayport, outside Tayport.

Kaska: So you are a local! We’re talking today because you are just about to start a project aimed at regenerating a salt marsh at mudflats in Tayport. I thought our readers might enjoy finding out a little more about it.

Before we talk about the project I have to ask…Wading around in mud all day in weathers does not sound very appetising to me and probably most people. What attracted you to this project and why do you personally care about this issue so much?

Clare: Because I love looking after things. I take on rescue dogs, I like waifs and strays. I think I just saw the saltmarsh as a bit of a waif and stray and somebody needed to care for it! Because everybody is out there doing woodlands and sand dunes, nobody was out there doing salt marshes – I saw a niche!

Kaska: I have to say that mudflats, saltmarshes and such indeed do not sound too exciting to me, especially by comparison to sunny, sandy beaches we have around here. But I realised that I don’t know what salt marsh actually is and why it is important … can you tell us a little about that?

Clare: This new project we are starting this year represents a bit of a turning point for a habitat restoration strategy that’s been underway for years. I have been doing this for about 15 years now. But it’s such a hard sell. You are quite right. Most people would drive by an estuary and they won’t even think of what that estuary actually does for them.

When it comes to a sand dune system, we’ve been restoring sand dunes for decades, we know how to do them, we know we can do them. You can get communities involved. All the information is there largely because they are worth a lot of tourist money. People are really into sand dunes.

At the moment we are very up on woodland restoration, that’s largely because Scotland has these ancient Caledonian forests so there has been a real drive to look after our woodlands. We are also over the past decade have been pumping millions into restoring peatlands up in the North of Scotland and again it’s a big initiative from the RSPB and Scottish Natural Heritage because of the carbon content. It’s easy to see what the value of these peatlands are to us because of the sheer amount of carbon that they store in this day and age of climate change.

Rivers are another big thing and again it’s very easy. Rivers are liked by the public, people walk their dogs on rivers, more than anything here in Scotland we also have the rare pearl mussel. So there’s been a financial incentive to landowners to restore some of their rivers that were once straightened and channelized and polluted to get them restored. They can see little industries, little fledgling microbusinesses basically can come from that.

The one thing that we have been ignoring is saltmarshes. But ironically saltmarshes are one of the most highly productive ecosystems in the world. And they can beat tropical rainforests hands down in how much carbon they actually store.

Kaska: So what exactly is a saltmarsh?

Clare: Saltmarshes are ecosystems in the interface between the marine and the terrestrial world. They are the fringes of green scabby vegetation, and that’s how people think of them, they’re just scabby bits of vegetation form a bit of a ribbon around edges of estuaries. Now you’ve got to get your head back to 5,000 years ago. That long ago, all of our estuaries were ringed with vast acres of saltmarsh. We can prove that, we can look through the geological record and show that.

Kaska: So when you are looking at the mud flats in Tayport estuary, would that have been covered entirely in salt marsh vegetation?

Clare: Not the mud flats, the land! Things changed over time with human involvement, and the change started to increase in the age of enclosures about 200 years ago. Obviously humans like to live near estuaries, because they are at the bottom of a rivers which make for great transport systems. It’s also highly fertile land because it’s so often washed over by the sea. So we started to claim that land for our own use. The stage we’re at now is that all saltmarsh got whittled away.

Now, one of the biggest functions of a saltmarsh is that it reduces wave energy. So as the waves are coming in with the tide and they would normally, say, be hitting some houses. If you’ve got a saltmarsh in front of that you can reduce that wave energy by anything like 10, 20, even up to 50 or 60%, depending on big your salt marsh is. As we’ve been building our estuaries, we’ve basically taken our estuaries and squeezed them as much as we can on either side so there’re is nowhere for that energy to go, there is nowhere for that water to go. So all the water has been doing is eating away at the little toe of saltmarsh, or causing erosion.

We have two problems there. We have an ecological problem because it’s a very valuable habitat, the birds are clearly dependent on. We have plant life that is highly adapted to salt conditions and if that habitat isn’t there we lose all that biodiversity. So there is whole ecological wildlife side that we’ve lost. But there is also a social and economic side – without a salt marsh we get a lot more wave energy, a lot more tidal energy hitting our land.

Now, the other problem we’ve got is the two options we have at the moment. The engineer will say – ‘build higher seawalls, forget the salt marshes – build the high seawall. That’ll protect your land.’ Yes it will. For how long? And each seawall costs about £3-5 million per kilometre. It is not a cheap thing. It also displaces erosion, it has a whole baggage of problems quite apart from the money.

The nature conservationists would say: ‘ Just give up the land!’ And where this is relevant to Tayport is along at the project site at East Common. You could just flood that Common. You could just allow that seawall to get breached and have that back to saltmarsh. I have images a 100 years ago that show that that Common was an intertidal area.

We had nowhere to put our waste so it was a dumping ground – and that is how we treated our estuaries. Dump it at sea! Because sea just washes it all away. So we had that right up until the 1960s. This is the case around the Eden Estuary as well and the Tay Estuary and the Dornoch, every estuary right up until 1960s would just dump municipal waste. In that municipal waste is all sorts of nasty stuff. So we can’t reset the land there. We can’t give that back to the sea because to do that we’d actually have to dig up that waste and put it somewhere else that’s safe. This is cost-prohibitive. But the sea is still going to be acting on the front of that ground.

What my research has proven is that you can actually simply, and it is so simple, you can directly replant your salt marshes. But you have to get it right. It can’t be done ad hoc, you can’t just dig up anything and shove it in the ground there. Chances are it’ll wash away. This project is all about taking it to another level the amount that we actually do.

In America the approach is called the living shoreline approach. So I’m going for, it’s almost like new management, a new concept in managing your natural resources. We’re not giving them up, it’s not a conflict territory, nobody else wants that little bit of land. We’re not going out into the mud flats that would take away feeding areas for birds, we’re simply dealing with 10-20 meter stretch along appropriate area of coastline where we think it can be done and we’re replanting some saltmarsh habitat. And watching what happens. That’s it in a nutshell. That’s 15 years!

Kaska: That sounds pretty fantastic! So you said that salt marshes are found in estuaries, in between river and the sea. Do have lots of them around UK and Scotland?

Clare: Not at all – this is the problem. It’s also a rare habitat in its own right and in Britain you’re looking at about 5,000 ha. To put that into perspective – when you look at other rare habitat like ancient semi-natural woodland we actually have 50,000 ha. You don’t come across ancient woodland every day, do you? So imagine that’s only 5,000. It’s a very fragile, rare environment.

Kaska: Is there anywhere nearby where people can actually see a good example of a well preserved saltmarsh? Is there something around Tayport that they can see?

Clare: Yes. And this is why I know that the section of the shoreline that I want to restore is good to restore. It’s largely because the conditions are very similar to all the tests I’ve done in the Eden estuary. The best site in Tayport is at the edge of the Common just before you go into the entrance to Tentsmuir, opposite the Foodmek.

There you can see an eroding area of saltmarshes looking like it’s dying back. But you also have a different type of saltmarshes called a swamp saltmarsh. That’s very dependent on the wet oceanic climate and Scotland has that. The swamp saltmarsh been expanding slowly because the conditions are changing to favour it. What I am essentially doing, is I’m speeding up a process that we think is happening anyway and going to be spreading that swamp saltmarsh. So people can go and look at them for themselves.

Kaska: Is there a better example somewhere on the Fife coastline? Something that people can walk through?

Clare: There are pockets of saltmarsh all around but the largest are of saltmarsh we have is actually the Eden estuary’s Eden marsh. It represents Fife’s largest example. But you can think of the reed beds up the Tay at Invergowrie, that’s salt marsh to a certain extent – that’s a swamp salt marsh. But the biggest in the country – you would have to travel to places like the Solway Firth and Aberlady on the Forth estuary on the other side. These have got the vast areas that I was talking about earlier. But no – Fife doesn’t have any of those vast areas.

Kaska: Is there a favourite critter that you have which lives in the salt marsh?

Clare: I have seen absolutely everything! In my time on a saltmarsh I have seen a badger, I’ve seen roe deer use saltmarshes.

Kaska: Are these the typical inhabitants?

Clare: No, no, no. They have both marine and terrestrial influences, and one of the things that I love about them is that if you start to dig down through the sediment, you’ve got all your typical marine shellfish types. So you’ve got cockles, and mussels, periwinkles and razor shells and clams. But you also get bumblebees, you also get spiders. Spiders actually live in the saltmarsh in the vegetation. Do you know what the clever things do when the tide comes in? The can bees fly away, but the spiders hang on in there. They’ll find themselves a little air pocket, and they’ll go into the little air pocket in a leaf sheath and wait for the tide to go away again. How clever is that?

Kaska: That’s amazing!

Clare: So really you do get marine and terrestrial animals in it. And I have seen everything. I don’t have a favourite because I do tend to just ignore animals…

Kaska: What about plants?

Clare: A salt marsh in summer when it’s blooming is a very beautiful thing, it really is. So you can almost look at it – it’s a bit like a field. It’s got a grassy base, but then because of that base, that’s risen it slightly higher than being inundated by the tide all the time. Every flower you can think of is represented – you have sea asters, you have sea scurvy grass…

Kaska: Sea asters are the lovely purple flowers, aren’t they?

Clare: Yes – they are just like a daisy, but they’re kind of bigger and very flexible. They have to be flexible because of the tides to make sure they do not snap when the tide comes in.

Kaska: That’s quite a surprise – when I think about marsh I don’t think about flowering plants – maybe algae and seaweed, and maybe some rushes.

Clare: Mainly you are looking at grass types but there are a lot of other forbs, your more traditional forb types. I wish I could say sea lavender – but here is a thing. Sea lavender very southerly. It’s a big wuss – it likes warm weather. But with climate change we are beginning to see its slow move north. So the flora is actually going to be changing. We might start to get Mediterranean type salt marshes here, similar to those in southern England. One of the wonderful things about the Eden and Tay Estuaries by the way is that it’s a meeting place for both Northern and Southern types which makes it very interesting. So we’re watching. This is what I said about the swamp saltmarsh spreading, we’re are watching a bit of a battle going on.

Kaska: So you already see the impact of climate change on vegetation?

Clare: Absolutely! Yeah. Swamp saltmarsh will respond to increased fresh water and that’s what we’re getting – the increasing rainfall on the East coast. Whereas the Mediterranean type saltmarsh, the one that’s eroding away, it might recover because it will respond to increasing temperatures. So scientists are still really trying to figure that one out.

Kaska: What’s going to happen with rising sea levels?

Clare: Ah – big problem! But it’s going to be even bigger problem if you don’t have a salt marsh. And that’s where the function, that buffering effect of a salt marsh comes into play. Sure, if you go far enough into the future we don’t know exactly how high the tides are going to be. We have good predictions but they’re very bound by local conditions. So it’s hard to say how fast, how deep the water’s going to be. In the worst case scenario, yes, your marshes are going to be drowned. So it might be considered a waste of time. But on the other hand you could say that bout every type of coastal flood defence there is. At what point do you stop building your seawalls, how high? At the moment they are building them based on 1 in 100 year flood.

Kaska: But you think that the salt marsh might be a much more dynamic coastal defence option?

Clare: It can respond to it.

Kaska: So it could be moving back and the seawall will not…

Clare: Exactly! The seawall is immovable and it costs a fortune, the saltmarsh can adapt if it’s healthy enough it can actually keep growing in height. It might not be able to go backwards if there is land that’s already developed, it might not be able to go forwards because it’s going to go into being drowned. It has got a limit on its tolerance but it can keep changing, it can keep adapting.

That’s why I would use the phrase that we’re learning to manage our natural resources. Not put them back and then walk away! It’s put them back and have local communities actually be as aware of them and what they’re doing for them as they would be a sand dune system.

Kaska: So we have some idea of what a saltmarsh actually looks like and the reasons for us to keep them. Let’s talk a bit more about your previous work on this. You said that Eden Estuary has fairly well preserved salt marshes for this area and that you have tested the regeneration methods there in the last 10-15 years. What did you do there?

Clare: Essentially it was my PhD study and I just tested a whole range of different species and methods in small plots. Over the course of two years I looked at what worked and what didn’t and I had it narrowed down to basically one plant being planted at very high density at springtime. And as vegetative transplant (a living plant) – the seeds didn’t work.

This is an area we are still looking into because restoration in general can be a lot cheaper and a lot faster via seeds. And you will also have the genetic diversity. If you keep doing it via vegetative transplants you are in danger of clonal disease burden. You are transferring on any problems you might have in your vegetative stock. You want that genetic diversity.

After the initial trials I ended up focusing on a single species the Sea Club Rush (Bolboschoenus maritimus). Club rush is a bit of a wonder plant. It’s endemic around the temperate world. Most of your lakes in North America are surrounded by thousands of acres of a club rush variety. It’s a very common plant. It’s a bit of a wonder plant as it can tolerate no oxygen and high salinity. So that’s when I linked it to climate change and increasing rainfall and realised that it’s this species that was going to gain the upper hand naturally.

But I also did not want to ignore other species just because it did not work in my initial trials. So I have been trying them again with a lot of success. In Tayport I am also going to be testing a whole range of species.

Kaska: So it’s not going to be just a monoculture – we will be able to see regeneration of a diverse habitat.

Clare: Big time. We know that because of the results from my Eden Estuary experiments. We had about 10 sites, 8 have been successful. And out those 8 sites more half of them have had 3000 percent expansion. The expansion has been incredible. This is the main reason that this new project got funded.

In the successful plots, the erosion features are going and it’s a very healthy marsh. And now other species are coming in. We even have sea grass, Zostera marina, coming in. People who go cockle picking would know sea grasses. It’s a key species – it’s the lowest flowering plant on the tidal frame and it’s an ecosystem builder. But it is very rare and it’s on the endangered list. I have got it now coming in as well as lots of other different plants. And eroded mash behind this newly planted sacrificial buffer has recovered and land behind has been protected. It’s been a win-win for everybody.

Kaska: It sounds really promising. Can people in Tayport get involved in this?

Clare: Yes, please. I need people to get involved. This would have never had happened without communities. So far I have had over 200 volunteers on board that have come from about 30 different organisations. Anyone can come – we provide training and equipment as well as close supervision.

Kaska: You will be planting the area along the common nearest to Tenstmuir. What can we expect to see when we walk out to that spot say in the next 10-20 years’ time.

Clare: It’s a slow process. I am not Alan Titchmarsh so it’s not going to happen overnight! At first you would expect to see straggly looking plants looking like you feel really sorry for them. But over time that slowly starts to build and I am hoping that we will turn the existing natural marsh into a linear belt of marsh at least a 100 m along that wall. And it’ll be a flourishing marsh. We will expect build-up of sediment and that starts the whole process of beginning to protect that land. You will also begin to see, and that’s what I have seen in my research, wherever there is no salt marsh the embankment is really loose and eroded. The minute you have a salt marsh in front of that embankment, it solidifies. It allows terrestrial plants to establish themselves on it. Where you’ve got some leaching coming out I would expect that to fill up with sediment and terrestrial plants.

Kaska: What about 100 years’ time?

Clare: Wow! That’s a question for scientists working on sea level rise. In 100 years’ time we might all be under sea. I don’t know. I really don’t know.

Kaska: It’s a bit scary…

Clare: It’s a very real thing. Scientists are measuring increasing tides of 2 mm per year at Aberdeen tide gage. It’s happening. It is happening. But the best models we have find it hard to predict how high the sea will rise. The only thing that we can say for sure is that it will rise.

So some of the arguments I have had from my own colleagues is that salt marsh restoration a waste of time. Maybe in the long run but then so is the Thames barrier…that’s a waste of time. And that was a waste of £50 million worth of time by the way. Ok – it’s protecting a lot more valuable land but do we know it’s fail-safe? Because the tide just came around the River Hull barrier which was was build for this very purpose!

But society will put more faith into models and engineers and hard defences. It’s something they can see. And nature is seen as not being able to protect you…it’s whimsical.

I don’t dismiss the need for engineering, there is always going to be need for that. Tayport harbour for example, we can’t have a salt marsh in front. That harbour needs to be sea-walled. But just as you said that you did not know what saltmarsh was …it’s just this forgotten habitat…it’s just completely overlooked. And because it’s overlooked nobody wants to visit it much – other than wild fowlers and me. And that also means that the society is undervaluing it– and it is undervaluing it’s ability to buffer the impact of sea level rise as well.

Kaska: Seeing that climate change is such a serious issue – what else do you think people can do about it?

Claire: Cut down on their consumerist habits! But that’s hard because we all love our creature comforts, and I like them too. I would say get out and about doing good conservation work. Because that’s where you really learn about nature and that’s where you get most health benefits as well. And you can be part of groups that range in diversity of people so you meet a lot of interesting people. This is really where it all started for me.

Kaska: Thanks for talking to me about your project – I hope this will inspire some of the Tayportians to get involved! I will certainly be out there with my wellies on!

For more about the Eden Estuary project and how saltmarshes are important in the world of climate change see this blog on Scottish Natural Heritage website.

Leave a Reply