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British Lichens with April Windle
153 Plays8 days ago
I’m joined by lichenologist April Windle from The British Lichen Society to uncover the hidden world of lichens. What they are, how they grow, and why they’re vital for biodiversity, air quality, and ecosystem health. We explore lichen identification, their role as bioindicators, and how they can even signal ancient woodlands and environmental change. We also touch on their cultural history, uses in natural dyes and medicine, and why gardeners should embrace lichens in their outdoor spaces. Plus, in Ask Mykal, I answer a common question about moss lawns and how to work with, rather than against, your garden conditions.
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Transcript
Introduction to Gardener's Lodge Podcast
00:00:07
Speaker
Step into the gardener's lodge with me, Michael Haw. Let's explore the fascinating worlds of gardening, nature and ecology through conversations with experts, thought leaders, passionate enthusiasts, and of course, some real good friends.
00:00:23
Speaker
All from the cozy heart of the lodge. Come on in. Hi, and welcome to today's show.
New Segment: 'Ask Michael'
00:00:31
Speaker
i have an amazing guest lined up for us, but first I have our new segment, which is I guess called Ask Michael.
00:00:38
Speaker
And today i have a question, which I have somewhat kind of linked to today's episode.
Q&A: Managing Moss in Lawns
00:00:43
Speaker
Today's question comes from TJ and they ask, I have moss that consistently grows throughout my lawn. I really want just a nice, lush, grassy lawn, but I can't seem to manage it. No matter what I do, the moss comes back. Do you have any tips or advice to achieving just a lovely lawn?
00:01:02
Speaker
So TJ, I can infer some things about this space without actually seeing it. You've got moss growing in the lawn. So what that says to me is that you are trying to have a lawn in a shady position, which is never very easy.
00:01:16
Speaker
It also says to me that your ground is potentially compacted and that there is quite a lot of moisture in the environment. So three things that aren't conducive to a lovely lawn. Now, I would say,
00:01:32
Speaker
Give up. yeah If the moss is there and the moss is green, you can still mow it to keep it under control. It's green. It's soft underfoot. Yes, it's probably a little bit moist from time to time, but you're not going to have a particularly successful time growing grass or lawn in this area.
00:01:50
Speaker
You could try to include some other species in that area. So if you did get rid of the moss, ah you could put in some more ground covering things that don't mind a bit of the shade.
00:02:00
Speaker
I'm thinking like native ah Australian native violets are great. I believe you are. located in Australia or kidney weed, which does like a little bit of a sunnier spot, but it could take that kind of part shade. The two of those mixed together could make a nice ground cover, uh, lawn space that can still be mowed. You would be better suited to learning to love your mossy lawn, appreciate the environment that you do have, avoid using chemicals in the environment because you can get chemicals that will kill the moss.
00:02:29
Speaker
I would highly, highly recommend that you don't bother doing that. Love your moss, enjoy your moss, use your moss. Once you've, I mean, pushing a mower through moss can be challenging if you let it go too long, but once you get it down, it should stay nice and compact and look actually quite...
00:02:46
Speaker
Nice and cute and people do appreciate it. You could otherwise turn it into garden bed and mulch over it. The moss will still probably come back in time. You could try aerate your soil with a garden fork, just kind of going through, putting your fork in and giving it a wriggle and pulling it out without fully disturbing the soil, just getting a bit more aeration through it. That'll help a little bit as well. But really, I would truly just try and learn to love the mossy lawn you've got.
00:03:14
Speaker
actually wrote an article on my website on mongrel lawns, which you can check out. And I should yeah go back and edit this and include a section on mossy lawns. But it's sort of about embracing a mixed species lawn that might include things that aren't grass, but are green and...
00:03:32
Speaker
offer a lot to biodiversity and how to again, you change that mindset about like what the perfect lawn is. Cause to me, the perfect lawn is a monoculture and isn't a very healthy environment and needs a lot more work than it's worth.
00:03:48
Speaker
that was Ask Michael. If you'd like to ask me a question, head to the gardenerslodge.co.uk slash podcast. There's a form there and you can pop in a question and I will endeavor to answer it next time.
Introduction to Lichenology with April Wendell
00:04:00
Speaker
But on with the show. In today's episode, I speak with lichenologist April Wendell. She's the co-chair of the Education and Promotions Committee at the British Lichen Society. So that's right. Today's episode is all about lichens and April has a wealth of knowledge. She literally had my brain exploding the entire episode. Uh, I knew very little about this subject. I knew that they had a, that it was two organisms that had a symbiotic relationship, but I really didn't know much more than that. And I knew that they grew all over the place. But today's episode, we dive deep into
00:04:38
Speaker
into lichens, all the way from what they are, how they grow, through to their cultural and historical uses and their potential future uses in the pharmaceutical industry.
00:04:51
Speaker
And she tells us how
April's Journey into Lichenology
00:04:54
Speaker
lichens can be used to tell the health of an environment. But before we get into that, let's hear April's six rapid fire questions. Are you ready? I'm ready.
00:05:06
Speaker
Favourite plant? Favourite plant or favourite lichen? Well, I'll let you be the judge of that. It's got to be a lichen. It's definitely got be a lichen. So my favourite lichen, the first one that comes to mind is um it's called the rock tripe or lasalia postulata. Favourite way to connect with nature?
00:05:26
Speaker
getting up into the mountains. And the reason for that, I feel it's the only way my brain becomes quiet. Me too, just for the record. You like the mountains as well.
Understanding Lichens: Symbiosis and Ecology
00:05:40
Speaker
I'm a definitely ah a mountain goat. Yeah, amazing.
00:05:44
Speaker
What is the most beautiful garden or natural landscape that you've ever visited? Without a shadow of a doubt has to be the Borrowdale Valley in the Lake District.
00:05:55
Speaker
Okay, next question, and I'm going to alter it for you. um It's usually favorite garden tool, but favorite tool of the trade? The favorite tool of the trade, without a shadow of a doubt, has to be my hand lens.
00:06:08
Speaker
Yeah. If you could be one, a plant or an animal? I would be a lichen, so neither. Yeah. I would be a lichen. And finally, when you're stuck and looking for research on anything garden or nature related, where do you go for the most trusted advice?
00:06:27
Speaker
I actually go to the British Lichen Society and individuals who are part of the society. Perfect. As far back as I can remember, I've always had a real love for the natural world. And my parents have really shaped that, actually. And they used to, my earliest memories are where they used to take me and fossil hunting and fossil collecting on the Jurassic Coast. And for anyone that's familiar with that stretch, it's so so incredibly rich. And that's definitely shaped my love for nature.
00:07:01
Speaker
From a young age, it's always been a hobby. I've always gone out on walks and looked at invertebrates and looked at birds through my binoculars. But I'm fortunate enough now to have actually turned that hobby into a career where i work in the sector.
00:07:16
Speaker
And I'm currently a freelance lichenologist. I've had my own business now for the last five, six years. And I go across Britain and Ireland basically doing lichen surveys research. visiting some of the most remarkable habitats that we have in this country.
00:07:35
Speaker
And I have to pinch myself sometimes that this is actually my job. And I deeply believe that I've got the best career in the world where I get to work my hobby every day, basically.
April's Passion: Discovering Lichens
00:07:48
Speaker
Lichenologists. So i I presume there's not that many lichenologists around, particularly in Britain. um And it must be such a niche little kind of career that you've been able to dig out for yourself, pardon pun. um and Where did you first actually notice lichens and why did you kind of, why were you drawn to lichens beyond other sections of the natural world?
00:08:14
Speaker
I first got into Lycans when I'd just finished university and i was I had this amazing opportunity presented to me where I was involved in an internship working for Exmoor National Park for two years.
00:08:30
Speaker
My role was very, very desk based when I was based at the National Park and I was managing the environmental records and biological records um and doing a lot of GIS work. So i was at my computer pretty much every day.
00:08:44
Speaker
But where the office was situated Dalverton, there was this amazing stretch of riparian oak wood along the River Bale. a prime example of Atlantic woodland. And there was one day I went for my my daily lunchtime walk and it was just after a massive storm the night before.
00:09:07
Speaker
And this storm had brought the entire canopy down to the woodland floor. And there was a branch which was about a metre and a half long. And it was absolutely festooned in these weird little life forms, all different shapes, different sizes, different colours.
00:09:26
Speaker
And at the time, I had absolutely no idea what they were. but I just knew that I was absolutely besotted by what I was seeing. I didn't even realize species and life forms like this existed.
00:09:39
Speaker
So what i did is I dragged in the rain this huge branch back to the office, to the ecologist. And I said, allie this is the most beautiful thing I've ever seen. what What are all these things on this branch? And she said, oh, April, and these are called lichens and they're a really important component of Exmoor's natural heritage. But the problem is not very many people study them and not many people know about lichens. um
00:10:10
Speaker
So study them and enjoy them because they're absolutely beautiful. And that's exactly what I did. And with lichens, it was very much a case of, The more you read, the more it fuels your interest. And I started learning about them being a symbiotic life form. I read about their ability to indicate the quality of air.
00:10:31
Speaker
I read about the fact that they're jam packed full of these chemicals which have biomedical properties. And that was it. I was absolutely hooked. I went on this
Lichen Diversity and Ecological Roles
00:10:42
Speaker
day course by a lady called Pat Walsley, who was a bit of an inspiration of mine at the time and is now a really, really good friend and mentor. And I went on this day course and that was it. I was absolutely sold. You were hooked.
00:10:57
Speaker
I was. i was just absolutely fascinated by Lycans. And that was about eight or nine years ago Yeah. For people who are listening and don't know necessarily what a lichen is, is it a moss? is it How would you actually describe a lichen? There tends to be a little bit of confusion when it comes to lichens because most people actually think that lichens are plants.
00:11:23
Speaker
And I can see that. they They're very plant-like in appearance. They're green, they're shrubby, and they photosynthesize. However, lichens are not plants. They actually sit within the biological kingdom fungi.
00:11:39
Speaker
So they are a fungus. And recent genetic studies have shown that lichens are actually more closely related genetically to animals and humans than they are to plants, which I think is absolutely fascinating. Really?
00:11:55
Speaker
ah But these these fungi, they've adopted this really specific lifestyle or behavior where they partner up with either an algae or a photosynthetic bacteria, which we call a cyanobacteria.
00:12:11
Speaker
And only when you get all these different life forms come together, do you get this physical unit that we call a lichen. So when you have different species interacting and coexisting with one another, we call it a symbiotic relationship or a symbiosis.
00:12:32
Speaker
And all this basically means is you've got a life form which is comprised of multiple different species.
00:12:42
Speaker
and So lichens really fit the definition of an ecosystem more than they do a species or an organism because they are composite. They're made up of lots of different parts. And
Lichens: Public Awareness and Importance
00:12:55
Speaker
these different parts play a really important role for the survival of these lichens.
00:13:01
Speaker
Does that make the term lichen a little bit redundant, being that they are multiple different beings that come together to form this? Lichens are basically a fungus, so I wouldn't so necessarily say it makes them redundant.
00:13:18
Speaker
However, it's just a group of fungi that have chosen So lichenisation, so partnering up with an algae as a mode of survival. So fungi are what we call heterotrophic organisms, which means they don't have the ability to make their own food. They can't produce their own carbohydrates. They have to tap into another source. And that's why you see fungi...
00:13:42
Speaker
growing you know in your gardens where they take carbohydrates and carbon from the soil. You see them growing on dead trees where they take carbon from the trees. From the rotting materials. yeah Rotting material, exactly. But these lichenised fungi...
00:13:57
Speaker
All they've done is they've said, hey, these algae and these cyanobacteria are producing carbohydrates for us. So let's tap into them and exploit these autotrophic organisms. So what I mean by autotrophic is is they have the ability to make their own food, make their own carbohydrates. They take energy from the sunshine. so through photosynthesis. Exactly, through photosynthesis. And that is what the fungi taps into.
00:14:27
Speaker
I always call these algae the sunshine eating life forms, yeah which is quite a nice way
Lichens as Bioindicators
00:14:33
Speaker
of looking at it because they do. They essentially take sun and produce the food that the carbohydrates need.
00:14:39
Speaker
And this actually brings into question, well, what is the relationship between the two? What form of symbiosis is this? Because there's lots of different types of symbiosis.
00:14:51
Speaker
So the most renowned one is parasitism, where one species is really benefiting to the detriment of the other. So and an argument for that is that these fungi are absolutely dependent on the algae or cyanobacteria for carbohydrates. And some people say that these fungi are actually farming the algae because what the algae cannot do is reproduce like it would in its free living state.
00:15:20
Speaker
And these algae can live, you know, outside of the lichen association, but the fungus is absolutely dependent because it needs those carbohydrates. And then to flip it on the other side, another form of symbiosis is um mutualism, where all of these different species in the relationship are benefiting. And I think that's a really lovely, cuddly, cute concept. And that's where I'd like to think that lichens sit, but it's probably not the case. But obviously fungi are benefiting because they
Traditional Uses of Lichens
00:15:51
Speaker
get their food.
00:15:52
Speaker
But some people say that the algae or the cyanobacteria are benefiting because they can actually expand and extend their geographic range and can occupy habitats that they wouldn't be able to in their free living state.
00:16:07
Speaker
Okay. With algae, if you think about them, they tend to live in quite damp, wet, shaded habitats. yeah But in the lichen association, they can occupy the summits of the mountains where they're exposed to sunlight the majority of the time.
00:16:24
Speaker
So it's quite a long and very unsolved debate. And actually, it is probably a spectrum across different species where different lichens take a different symbiotic approach.
00:16:36
Speaker
That is absolutely fascinating. I actually had no idea. So be honest. So there you go. I knew that it was a symbiotic relationship, but I i didn't quite understand yeah what the push and pull between the two species were. But yeah, I suppose that makes sense that they would be able to expand their geographic range while the fungi is kind of being able to feed. Very cool. Yeah.
00:16:57
Speaker
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00:17:09
Speaker
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00:17:29
Speaker
You can download your free perennial garden design as well as my free Australian native garden design at the link in the description. But what's really interesting is they've done studies in the past to see if these
Threats to Lichens and Conservation Efforts
00:17:45
Speaker
fungi can live independently without the algae.
00:17:48
Speaker
And they've actually germinated fungal spores in laboratory conditions. And when these spores germinate and the fungus develops... it just turns into this big lump of gloop.
00:18:02
Speaker
It's completely amorphous. It's got no shape whatsoever. And that just emphasizes the importance of this algae in creating this physical shape that we see, which is what we call the lichen.
00:18:16
Speaker
So they really are just dependent on each other. It's not as though they can really live independently. So generally speaking, most fungi within the lichen association have never been seen and in a free living state and growing independently. Interesting. that many species of algae and cyanobacteria, which you find in the symbiotic relationship,
00:18:41
Speaker
have been found growing in a free living state and independently. So the fungus is completely dependent on the algae, but the algae and the cyanobacteria is less dependent on the fungus, I think. But yeah the fungus does definitely provide shelter and protection for the algae.
00:18:58
Speaker
So let's go into then the life cycle of the lichens. Obviously, you've got this symbiotic relationship, but then does the fungi kind of put out a fruiting body like it would if it was like a ground dwelling or a wood dwelling fungi Lichen reproduction is very complex, but as a field lichenologist, and when you're looking at these lichens in your garden or in a woodland, they have very distinct reproductive features which we can use to aid the identification of these lichens. And they tend to take two different approaches in terms of reproducing.
00:19:36
Speaker
Lichens are a fungus, as I've already said, and they produce, some of them produce these fantastic fruiting bodies, which we refer to as apothecia or perothecia.
00:19:47
Speaker
And these fruiting bodies are absolutely jam packed with spores. And these spores are the single reproductive units of the lichen. So in most plants, the equivalent would be seeds.
00:20:03
Speaker
but fungi use spores to reproduce. And that's what contains all of the genetic material. However, not all lichens reproduce by fruits. Some of them reproduce asexually or vegetatively. And this is basically where small fragments of the lichen break off, blow off, get transported by animals and then colonize a new area.
00:20:28
Speaker
And these can be seen as what we call seredia which are these powdery propagules get they give the lichen a real powdery appearance across the surface but they can also be seen as acidia and these are tiny little finger like projections which are an extension of the upper cortex and they have to be physically broken off by a bird, for example, and they then get transported into the surrounding environment and colonise new area.
00:20:58
Speaker
And where where they reproduce vegetatively is obviously an extremely effective means of
Call to Action: Research and Public Interest in Lichenology
00:21:04
Speaker
reproduction because you're working with a pre-made package of lichen These pre-made propagules contain both the fungus and the algal component. So it's essentially a clone of its parent and they will just blow off and colonize where they need to.
00:21:22
Speaker
like But with the spores, when they get released from the fungal fruits, the spore contains the fungal component only. So the fungus has, well, the spore has to blow off in the surrounding environment, land on a suitable surface, find an algal partner in the vicinity. So when that spore germinates, it can actually incorporate the algae and then it can start to grow.
00:21:48
Speaker
Wow. Therefore, with this, the chances are much lower for a successful, and to successfully reproduce. So this is why you find millions of sports jam-packed in these fruiting bodies, because it it really is all down to chance as to whether they find an algal partner or not.
00:22:08
Speaker
There are some species that actually it's been shown that when the spore is released from the fruit, they take a little algal cell with it, which is is quite a neat approach.
00:22:19
Speaker
But for the majority, it's the spores get released and then they've got to find their own. Exactly. Yeah. Wow. My brain's whirling right now. If you wanted something to compare them to in the natural world, the closest resemblance in terms of the symbiosis is coral.
00:22:39
Speaker
So when you're working with coral, you're working with a polyp, which is an animal and that polyp partners up with an algae and that algae photosynthesizes, produces carbohydrates, which then the polytaps into. and And for me, both lichens and coral are the textbook example of of symbiosis. There are so many parallels between the two, even though they obviously occupy completely contrasting habitats and ecosystems. That yes that would be the closest resemblance, I would say.
00:23:16
Speaker
That's cool. Obviously, there's a symbiotic relationship between the two organisms, but what role does the you know tree log that they grow on or the stone that they grow on play in this process? Do they have any relationship other than just it's a nice place to sit with those substrates in that context?
00:23:37
Speaker
Lychans are a self-sustained unit. Yeah. Yeah. they The algae has the ability to photosynthesize and the fungus can then tap into that algae.
00:23:50
Speaker
So when we're talking about the rocks and the trees, the only reason the lichen needs those substrates is for attachment. It just needs somewhere to live.
00:24:03
Speaker
Lichens don't have a vascular system like bacteria. Lots of plants do. They don't have phloem or xylem and they don't have roots which actively uptake water and nutrients.
00:24:16
Speaker
Lichens are a sponge, essentially, and they absorb absolutely everything from their surrounding environment, from what they need to survive, so water, nutrients and minmals minerals.
00:24:29
Speaker
But what they then can't do is differentiate between those necessities and things like toxins and pollutants. And that's what makes lichens such excellent indicators of air quality because they are a sponge.
00:24:44
Speaker
We call them bioaccumulators. So they just accumulate everything that's going on in their environment. So the stones and the trees are absolutely essential for lichens inform in in terms of attachment. but they don't necessarily take anything from the surface in which they're growing. And what's really cool as well is that they will literally grow on anything. You can guarantee that if you've got a surface, a lichen will eventually grow on it.
00:25:14
Speaker
I've done this little experiment on my car where I haven't washed it for a couple of years. and it's covered in lichens. It's it's growing on the the rubber seals around the windows. It's growing on the textured cracks where I've reversed my car into a bollard. It's growing in all of the nooks and crannies where there's there's moisture retained.
00:25:36
Speaker
So if it was dependent on the surface, it was growing on for nutrients and water and minerals, then you wouldn't necessarily get them growing on a car, for example.
00:25:47
Speaker
That's true. Yeah. I, um, i actually grew up in far North Queensland, which is a tropical region. And you're right. I mean, yeah, people definitely, we had them growing on your house, on your ah car, they were kind of everywhere. In fact, I kind of didn't realize what trees looked like until I kind of grew up and left and went down South and i was like, oh, there's like, there's not kind of like mottling all over them, you know, whereas in, in the rainforest, it's just, they're absolutely everywhere. yeah And they do these these lichens, they add so much colour and texture and beauty to the world around us.
00:26:23
Speaker
For me, obviously, they are on the radar and they've been on the radar for such a long period of time. But if you were to leave your front door now, you can more or less guarantee you stand immediately on a lichen where they're growing on the pavements.
00:26:36
Speaker
As you're walking down the street, they're growing on the trees, they're growing on people's cars, they're growing on fence posts, they're growing on rock. They're absolutely everywhere. And all of these wonderful habitats that we've got across Britain and Ireland, lichens are a really characteristic component of these places.
00:26:57
Speaker
You know, if we went to the west coast of Scotland and the amazing rainforest up there, you could easily get over 250, 300 species of lichen in one tiny little woodland. where They contribute so significantly to the overarching biodiversity of any site and any habitat in which you explore.
00:27:17
Speaker
And for me, that all starts on your doorstep. Yeah, well exactly. I think I was just thinking then, like in the gardening community or in the kind of nature community, we talk about plant blindness, right?
00:27:29
Speaker
But I think probably even people who are interested in nature and gardens have almost like lichen blindness. If they're everywhere, we just don't notice them and see them and appreciate them for what they are.
00:27:41
Speaker
But how many lichen species are there within the UK? Yeah. a lot yeah within Britain and Ireland alone there are well over 2,000 species of lichen wow which is phenomenal if you take into account the lichenicholus fungi which are fungi that parasitize lichens which are you know separate from the lichen symbiosis you're looking at 2,700 species around that number which is absolutely phenomenal and Like I said, they're just such an important component of every habitat that you go to. Lichens are everywhere and they contribute so much to the biodiversity within this country.
00:28:27
Speaker
What about the world then? How many, do you know how many lichens there are on earth? How long is a piece of string? I think is the the answer to that question. But the rough number that gets thrown around is between 20,000 to 30,000 species of lichen.
00:28:44
Speaker
wow But the problem is with that number is a lot of the taxonomy of lichens, so the lichen... how how we go about naming lichens and describing new species. A lot of that was based on morphology.
00:28:59
Speaker
So the different shapes and features that lichens have and how they look basically. But what we're now discovering with this molecular revolution is as we're doing more and more DNA sequencing, species of lichens, which we thought belonged to one genus, for example, or one group, now actually belong to 10 different genera or groups.
00:29:24
Speaker
Good old DNA testing just blowing everything up for us. old DNA testing, exactly. And we're at the point where like under 20% species within this country have been ah DNA sequenced. So if you think of that on a global scale, there's still so much work that needs to be done. yeah But alongside that, we're making new discoveries all the time.
00:29:47
Speaker
I have a colleague, yeah going back to Pat, my friend and mentor, she's based at the Natural History Museum and she's just sat on hundreds of undescribed species where she's conducted so much fieldwork in the tropics.
00:30:02
Speaker
So there's so many new species to be described and added to our scientific knowledge. um I think the number is just going to continue to increase over the years as as DNA sequencing advances and we spend a lot more time and money getting lichen sequenced.
00:30:19
Speaker
Probably too much work and too few people doing it at the moment, I'd imagine. Absolutely right, Michael. So... Within, you know, we have a really strong biological recording community in Britain and Ireland, and we have done for a long time. And we're in a very fortunate position, but numbers of lichenologists, unfortunately, are dwindling. And with lichens, they really are a slow burn. They're such ah a lifelong commitment. And even the experts in this country are still learning and making new discoveries all the time.
00:30:56
Speaker
And a problem that we are facing is that we're not getting people into lichens at a young enough age so they can commit a life to to studying them and understanding them.
00:31:09
Speaker
Because they are complex, as I'm sure you you're coming to grips with from this conversation. but Definitely. It's that complexity which makes them so exciting. And I know that I'm going to spend a life of learning and feeling constantly perplexed by these wonderful little life forms. And they continue to amaze and fascinate me all the time. And if we can get them on the radar,
00:31:36
Speaker
so um in the public. And if we can get children and teenagers studying these species, I think it gives us a lot of hope in the future. Where do lichens actually sit in the food chain then?
00:31:50
Speaker
Lichens play a really important role in ecosystems and within the food chain. It's probably quite a small contribution, but I would still say it's very significant.
00:32:00
Speaker
Okay. Lichens like plants, are producers because they have the ability to make their own food and they have the ability to photosynthesize. And you get lots of beautiful animal-lichen interactions where animals are seen feeding directly on lichens or they live amongst these lichens.
00:32:23
Speaker
In this country, they're a really important food source for slugs and snails, so are mollusks, and a lot of moth larvae and caddis fly larvae as well feed directly on lichens. They're very lichen specific in terms of their their food source. And then also lots of orobated mites as well feed directly on lichens too.
00:32:48
Speaker
but if you go further afield into Arctic and subarctic regions, a lot of people are aware that reindeers or depending where you are, caribou feed directly on lichens, especially when the snow is up and it covers all of the the vascular vegetation, which they would normally eat.
00:33:06
Speaker
Lichens then become a real staple lichens. in the in the diet of of reindeer and caribou which is not only important to these like little tiny creatures but they're important to quite large animals as well absolutely um and they are a really important part of of of their diet and then obviously you have these herbivores which which uh graze and eat these lichens and then you've got predators which will then feed on these herbivores and
00:33:38
Speaker
The same with the the small invertebrates in this country. These inverts are a really important food source for birds. Yeah. and Which is, which is, yeah. So it all contributes to the the food chain, basically. The chain just runs up, doesn't it? Yeah. And also you've got these decomposers, which break lichens down as well.
00:33:57
Speaker
The fungi and the bacteria are, and as I said earlier, you know, you have these lichen italous fungi, which are absolute obligates on a lot of these lichen species. And without the lichens there, you wouldn't necessarily get these these fungi. So they they it's really a suite of cascading benefits in the food chain, think.
00:34:16
Speaker
But just coming back to the fact how lichens are an ecosystem within their own right. So you have these lichens, and you have different species feeding on these lichens as just discussed.
00:34:30
Speaker
You have invertebrates which live among these lichens, birds which feed on these invertebrates. And then all of these species are interacting with their surrounding habitat.
00:34:41
Speaker
And that is the definition of an ecosystem, which is wonderful. That is, it's a really cool way to think of it. And I suppose it's very similar in that respect to the coral, ah to the reefs, as you were mentioning before, like they kind of almost form the basis of of, a little ecosystem in themselves. They really do. And that's why I love studying lichens as well, because when you get into lichens, your walks will never be the same again. Don't think you can walk fast and cover 10 kilometers in a couple of hours. You're spending a couple of hours on a single tree. That's how detailed and intricate these lichens are on the surface.
00:35:19
Speaker
Wow. And even on like a single tree like that, is there a massive diversity of different species? Yeah. Such a diversity. I think the highest number of species that I've ever had on a single tree is over 60. Because lichens are extremely specific as to where they grow. They all have their very own ecological niche.
00:35:43
Speaker
And on a single tree, there are so many niches and so many of these little micro habitats which the lichens occupy. Because all of these micro habitats are subject to different environmental conditions.
00:35:56
Speaker
The north face of the tree will have different species to the south face of the tree. The dry crevices of the bark will have different species to the more exposed m trunk.
00:36:08
Speaker
The branches, the twigs, which are obviously younger, they're subject to higher light levels, will have completely different communities on than the trunk. And Pat, my mentor, she always says, looking at a tree is like looking back in time.
00:36:26
Speaker
You start off on the twigs, which are the youngest part of the tree. You work your way along the branches and down to the trunk, which is the oldest part. And it tells you such an important story about the history of that area, particularly with regards to air pollution.
00:36:42
Speaker
So whenever you're looking for lichens, these micro habitats are absolutely essential. And the more micro habitats that you have in a habitat, you will get an increased lichen diversity. And that's where management advice comes in when we do these do these surveys.
00:37:02
Speaker
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00:38:05
Speaker
You just dropped a little nugget there about um air quality. What do lichens tell us about air quality? Lichens are...
00:38:16
Speaker
the textbook example of bioindication. And what I mean by that is we use different species to make inferences about the quality of the environment in which they're found.
00:38:29
Speaker
And lichens are fantastic at doing that because going back to what I said earlier, they are essentially a sponge. They cannot differentiate between toxins and pollutants and the necessities that they need for survival. So everything from their environment gets absorbed. And because that's the approach they ah take, if the quality of the environment in which they're found is poor, that's reflected in the lichens. And vice versa, if the quality of the environment in which they're found is high, again, that completely dictates what species and communities that you find.
00:39:09
Speaker
There's a bit of a misconception with lichens and air pollution. And a lot of people think that in polluted environments, you don't get lichens and you only find lichens in really clean air okay situations. And there's a little bit of merit to that, but it's also slightly more complicated.
00:39:28
Speaker
You actually find lichen species and communities occupying both polluted and non-polluted situations. But what happens is you just get different species and communities.
00:39:40
Speaker
So in an area where you have high nitrogen pollution, for example, you will have a collection of species that are well adapted to that environment. Whereas in areas where you've got extremely clean air, you will have a collection of species that are extremely sensitive, and which occupy that sort of habitat.
00:40:04
Speaker
So when it comes to air pollution, it's more the presence or absence of certain species allows us to make inferences about the quality of the air. But it's not just air pollution either. We can use lichens to indicate the quality of water, And we can use them to indicate the quality of woodlands. They're fantastic ancient woodland indicators because they're so slow at growing and they're really poor at colonising.
00:40:32
Speaker
And there's this amazing index which we use called um the Indices of Ecological Continuity. And it's basically using certain species of lichen to try and work out if a woodland is of ancient origin or not.
00:40:51
Speaker
Again, I'm mind blown.
00:40:54
Speaker
That is fascinating. it They sound like such important indicators that can tell us so much about the world around us that we just ignore. i think that kind of brings us to my next point.
00:41:09
Speaker
In garden spaces, when I've gone into clients' gardens or not as much anymore, but I would say a few years ago, people used to come and say, what is this on my tree? It's hurting it or it's a disease or it's a fungus or like we need to chop it down or something like that. What can I do And I think it come kind that would kind of come back to education and not understanding what they are, not an understanding their importance of it of of them. How can we change people's minds about lichens and get them thinking about them as a object of beauty? You're absolutely right with what you said, Michael.
00:41:43
Speaker
a lot of this boils down to education. And there is a bit of a misconception with gardeners, and it's understandably so that lichens actually change harm the trees or harm the surfaces in which they're growing on. And yeah if if your gardening community can take one thing from this podcast, it's that lichens absolutely don't do that.
00:42:05
Speaker
And what people tend to see in their gardens is they might see a tree that is dying, which is absolutely covered in lichens and straight away they attribute it to the lichens as to why the tree has died.
00:42:18
Speaker
But what happens is that the tree dies, it drops its leaves, which increases the light levels to the bark. And then the lichens just grow in luxuriance because they're so light dependent. And, you know, light is such a driving force within these ecosystems.
00:42:37
Speaker
um And lichens respond so positively that it's actually the other way around, that the tree dies first and then the lichens move in. But coming back to what I said a second ago, lichens are such poor colonizers and they grow so slowly. So if you have lichens in your garden or lichens in the environment, it's really reflective of very positive management, low disturbance, long continuity and it's definitely something that should be appreciated on your local patch, in your lawn, in your back garden. the protected. So protected, absolutely, because these lichens, they play such an important role within the ecosystem. And again, they just add to the beauty and of these places. that're They're absolutely stunning. And I feel with lichens, obviously you can appreciate them from a distance,
00:43:34
Speaker
But it's not until you get up really close to them that you realize just how beautiful they are. And as lichenologists, we go around with a times 10 magnification hand lens. So this hand lens allows you to see 10 times bigger than what you see with the naked eye. And you just delve into a completely different world when you have access to one of these hand lenses and you can pick them up for about £2.50 off of the internet. They're such a bargain. And I encourage all of your community to to go out and buy one and just take a step out into their gardens and to try and understand what they've got.
00:44:13
Speaker
They might have, i don't know, 50 to 100 different plant species, which rightly so people should really pride. But on top of that, you've probably got 20 to 30 to 40 different lichen species as well. So it just adds to the the biodiversity of the garden, in my opinion.
00:44:31
Speaker
Completely. And as you're saying, they're part of the food web. So they're promoting beneficials coming into the space and building that biodiversity that I think everyone's trying to move towards in the gardening space at the moment. Another way to look at it as well, I think, is that when all the flowers finish in the summer and you know you you just have your garden of green leaves, which is often the case in the autumn and wintertime,
00:44:58
Speaker
these lichens are there all year round. They're not necessarily seasonal in the slightest. So you can still have splashes of colour in your garden, even in the wintertime. And I think that's another really nice way of looking at them.
00:45:11
Speaker
That is actually really cool too, because you're right, there are so many different colors. You can get these quite bright colored lichens kind kind of in that reddy, yellowy, orangey tones, as well as, you know, kind of standard greeny colors. But that's the perfect way to look at it. Yeah. And just while we're on color. So the reason lichens are such different colors is due to a variety of different reasons.
00:45:33
Speaker
A lot of lichens that we have are green and obviously that is because of the algal component in the lichen. But when these lichens start partnering up with cyanobacteria, you can get these really vibrant purple colours and and brown colours, and some of them are very bluish in colour.
00:45:50
Speaker
But alongside the photobion, so the algae or the cyanobacteria, lichens are also jam-packed with chemicals. And we call these chemicals secondary metabolites. And across lichens, there's I think there's over 700 different chemicals that have been formally described from lichens. And these chemicals give lichens fantastic colours. You know, there's a really common one called the sunburst lichen, which you find in towns and cities. It's all over the twigs. And that bright yellow colour is due to a chemical pigment, which we call parietin.
00:46:29
Speaker
And that yellow colour actually protects the lichen from the sunshine. So if you look at a twig, the top of it will be bright, bright yellow because it's protecting the lichen body from the sun. But then if you look on the underside of the twig, it's actually a greeny colour because it doesn't need that chemical pigment there to protect it from the sun because it's already shaded. And producing these chemicals is very energetically expensive. So these lichens distribute it as to where they need it.
00:46:59
Speaker
But if you were then to put that twig upside down and leave it out in the sunshine, the chemicals would redistribute and what was once a green-grey color would then turn to yellow because it's now exposed to the sunshine, which is insane. That is really cool. Really cool. And these chemicals are really something that particularly interested and excited me when I first got into lichens is that these chemicals, which we call secondary metabolites, they have a suite of biomedical properties.
00:47:33
Speaker
They've been shown have... to have and antimicrobial properties, antifungal properties, antibacterial qualities as well. And going back to that sunburst lichen, that parietin, which is produced, has actually been shown to inhibit and halt and slow down the growth of tumour cells in laboratory conditions. So the pharmaceutical potential of these lichens is absolutely huge. And it's so under explored as well.
00:48:06
Speaker
These chemists know way more about lichen chemicals than what us lichenologists do. And yeah it's a field of science that I would love people to get into because, you know, if you think about fungi, so many chemicals have been extracted for them, which we use in the pharmaceutical industry. Think of penicillin, for example.
00:48:26
Speaker
But with lichens, it's so underexplored. And I just feel there's so many discoveries yet to be made with lichen chemistry. Absolutely. Well, that's interesting. I mean, of course, when Big Pharma wants to get involved into something, discoveries will be made and and probably made quite quickly with these types of things. Definitely. i just hope it goes down a you know sustainable route where environments are protected while that's happening at the same time.
00:48:55
Speaker
Absolutely. And we're just, I think as technology advances, lichens will become more and more to the forefront, but you can't plant lichens in a monoculture like you could with a plant.
00:49:08
Speaker
So it's actually really hard to extract and synthe synthesize these chemicals on a large enough scale to apply for human testing. But in the future, when this technology advances, I think there's going to be some really exciting movements in that sector.
00:49:24
Speaker
Absolutely. What about cultural and historical uses of lichens? You know, we've evolved with them and they've evolved with us. How have we in the past used them?
00:49:39
Speaker
There is a really long and beautiful cultural history of um humans interacting with lichens and The most renowned one is lichens as a food source. And I just want to cover my back and that of the British Lichen Societies. and I'm not advocating for people to eat lichens and I would actually discourage it because like some lichens are safe to eat.
00:50:06
Speaker
But what i must stress is that other lichens are actually poisonous. So it's really outside my area of expertise and probably forager would know more about it than what I do. But there are quite a few examples of lichens being used as food.
00:50:23
Speaker
um And there's this species that we have in this country, which belongs to the family Umbilicaraceae, or the Latin is Lysalia postulata, which is the rock tripe.
00:50:34
Speaker
And this is a species which is characteristic of and acid rock in upland situations. And it's been documented in the past that it's been eaten by mountaineers in times of food shortage. where they've actually boiled up this rock tripe and eaten it.
00:50:51
Speaker
I can't imagine it being very nice though. Yeah, I was going to say. And this this family, the Umbilicariaece, it's actually eaten across all across the globe, particularly in and Asian food culture, where it's it's seen as a real delicacy and it's harvested off these rocks and and eaten.
00:51:11
Speaker
And when you go to... and Asian markets in London I really encourage you to go actually as you're based in that neck of the woods yeah you get these lichen spice packets where these lichens are used as flavor enhancers and spices and used in cooking which is is quite nice i have you had any have you tried them Do you know what I've never tried any. No, oh okay um I haven't. that's it would be I'd be really interested to know if anyone has and what they they thought about it and how it changed the food that they eat.
00:51:46
Speaker
um and Another species we have in this country is called um the Icelandic moss, even though it's not a moss, it's a lichen, called Citrary Icelandica. And ah this is famously known for being drunk as Icelandic tea. So the lichen's put in hot water and then it's it's drank as tea, which is um quite a nice concept. But lichens, he they've long been used in traditional medicine.
00:52:16
Speaker
And there's this wonderful concept called the doctrine of signatures. The doctrine of signatures is this concept which herbalists use where parts of the natural world, such as plants, fungi, lichens, they are used in and medicine, in herbal medicine. If they resemble different parts of the body, they can be used to treat minor ailments.
00:52:40
Speaker
And there's this lovely lichen called Liberia pulmonaria or the lungwort lichen. And that species is meant to resemble lung tissue. And again, it was boiled up and it was drunk to treat respiratory problems, which is really interesting. and That is interesting. um What about perfumes? Are they scented at all? Yeah, so, um yeah, another really good point. So ah these secondary metabolites, these chemicals that are found in lichens, and are also used in the perfume industry. Oh, they are? They are used in perfume industry, yep. And they're also used, lichens are also used and as dyes as well, to dye materials, to dye walls, for example.
00:53:21
Speaker
And... the actual color of the lichen when you first see it they produce completely different colors as dyes and there's this wonderful lichen um which we get all over the uk uh it's called ocralechia tartarea it's best developed in the west and up in scotland this species was harvested um on quite a large scale and it's white in appearance with these little orange fruits but it produces this bright purple dye and it was actually used to dye kilts in Scotland to get that that purple color for certain for the certain clams up there, which is nice.
00:54:02
Speaker
but What kind of threats are lichens under today? Unfortunately, lichens are subject to a wide range of threats. Some of them are very large scale threats and other others are much more site specific.
00:54:17
Speaker
So in terms of the large scale threats that they face, climate change is always going to be a big one, as it is with other taxonomic groups. Air pollution is particularly pertinent with lichens as well.
00:54:31
Speaker
And also in terms of woodland lichens, these tree pests and diseases that are coming in all of the time have the ability to really significantly influence and shape where lichens are found in this country.
00:54:47
Speaker
I suppose habitat destruction as well for farmlands. and That's it. Habitat destruction, habitat loss, habitat degradation. Lichens are so sensitive to change in their environment. And unfortunately, with a lot of these anthropogenic changes, these lichens simply cannot cope with how rapidly they're happening.
00:55:12
Speaker
um And what happens with that if they cannot cope and they cannot adapt quick enough, then they are simply lost. And we are seeing more and more lichens creep onto our British and Irish red lists where they are now high conservation concern due to these habitat changes.
00:55:31
Speaker
And then at this the site scale, so the biggest one that we face, be working in a woodland or up on a mountain or in in a nice grassland, for example, is to do with the light levels and the loss of light And many of these habitats are becoming increasingly shaded and outcompeted.
00:55:55
Speaker
So if you have lots of bramble moving into a habitat or holly encroachment or increased levels of ivy, this vascular vegetation just completely overshades lichens because they they can't compete against something that's so much bigger than them.
00:56:14
Speaker
yeah So light is a ah real driving force in these habitats and unfortunately they're becoming increasingly shaded. So with these larger scale issues, been it's they're really hard to address because but a real landscape scale approach is is needed to conserve habitats across the countryside. But, you know, these these site level issues can certainly be addressed by land managers or land owners. And that's where we really encourage and try to promote these bespoke conditions that lichens love.
00:56:52
Speaker
So does the British Lichen Society help landowners promote the health of their lichens? We at the British Lichen Society do everything we can do to meet our main aims and objectives. And that is to promote the enjoyment of lichens, and but also their conservation as well.
00:57:10
Speaker
um Across the society, we have about 700 members, both within Britain and Ireland, but also overseas as well. And I always think we're like this quirky camaraderie of folks that are just completely besotted by lichens. And it's absolutely wonderful when we all come together. Our website is contains a wealth of information from habitat management, on how to identify lichens, on how to get involved with the society. So I really encourage your community to explore our website because there's so many fantastic opportunities and so much amazing information there which which people can learn from. And that's the BritishLichenSociety.org.uk. Correct. Yeah.
00:57:58
Speaker
Thank you for sharing that. ah But just to say, I actually chair the Education and Promotions Committee for the British Lichen Society. And this committee, which I'm so fortunate enough to chair, ah we're all really dedicated to raising the profile and awareness of lichens. So again, just thank you so much for having me on your podcast. No, of course. And if if you go on the learning tab on the British Lichen Society's website,
00:58:29
Speaker
There's lots of really useful information that people could read to learn more about lichens because, ah you know, we only have an hour together today I've only scratched the surface with how wonderful lichens are. So there's lots lots more information to be found on our website. Various social media platforms. So we're on Twitter, we're on YouTube. and So if people want to hear more or want to get involved, then please, please follow us on those platforms as well.
00:58:57
Speaker
April, thank you so, so much for your time. I really appreciate it. And I really appreciate the work of the British Lichen Society. Thank you so much for educating me. I've said it probably three times now, but my mind has been blown. it's so full of information. um And I can't wait to dive even deeper into the world of lichen. Michael, it's been a pleasure. Thank you so much for having me on your podcast and also the British Lichen Society. And just thank you for everything that you're doing with your podcast. It's really amazing. me Thank you so much for joining me today. If you like the show, don't forget to hit the follow or subscribe button, tell a friend or two, or maybe even give the show five-star rating and a review.
00:59:38
Speaker
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