Invasive Species

Ireland’s Changing Flora: A Vital Report

If you read nothing else right now, please read Ireland’s Changing Flora: A Summary of the Results of Plant Atlas 2020. All the quotes and charts in this post are from that report, while the photographs are my own. The report is written in English and as Gaeilge.

A publication of the Botanical Society of Britain and Ireland, and written in an accessible style, this vital report, a summary of a much longer book, charts what has been recorded of the changes in plant diversity in the last 20 years, based on the hard work of hundreds of recorders in the field. I’ve had the privilege to participate in a Rare Plant Monitoring Workshop (below, on Mizen Head) and every year I monitor three rare plants for the National Biodiversity Data Centre.

The results are, as you might expect, not happy. Here is a bar chart, for example, showing how Native Plants, Archaeophytes and Neophytes are trending. 

The chart shows that more than half of all natives have decreased, whereas the overwhelming majority of neophytes have increased. These figures are based on short term trends, i.e. since 1987.

Why does this matter?

The decline in awareness of plants has occurred when plants need our attention the most. Globally we know that 40% of plant species are threatened with extinction. Many insects and other forms of life depend on specific plants, so the extinction of plants leads in turn to the extinction of many other things. In the Ireland Red List, 18% of plant species are in one of the threat categories and a further 9% are on a waiting list because of insufficient data. Time is not on our side.

The report looks at examples of plants which have increased or decreased and our own experience in West Cork will readily confirm its findings. Sitka Spruce, of course is one of those that have increased enormously, but here are four other examples from my own files.

American Willowherb, first recorded in 1958 and now everywhere, including my own garden.

Butterfly Bush has spread rapidly since the 1960s. Butterfly Bush may seem benign but like many other introduced species there is a dark side. First of all, as Tony O’Mahony points out in his Wildflowers of Cork City and County, it’s quite invasive and can take over and crowd out native species. The roots can do significant structural damage to the very walls it depends on for survival. More serious is the charge that, while it provides nectar for butterflies it is not a butterfly host plant – that is, one that butterflies can use to deposit their larva, which will then feed on the leaves. According to a spokesperson concerned about the destruction of chalk grasslands at Folkestone Warren in Kent: If left uncontrolled, then buddleia and other shrubs would have engulfed the chalk grassland. Clouds of butterflies used to be seen there, but now only common species can be spotted and even these are in decline, with the rarest ones disappearing altogether. Buddleia was eliminating butterfly habitat by killing off everything else, and while the shrub provided food for adults and larger insects, other plants were needed for butterflies in their larval stages.

Himalayan Balsam, a beautiful but highly invasive species that can colonise waterways, choking out our native flowers.

Variegated Yellow Archangel – only here since the 70s, it can carpet woods in the spring, crowding out our native woodland species.

Examples are also given of plants that have decreased, and indeed most of these I have never seen, such as Agrimony, Corn Mint, Field Gentian, Heath Cudweed and Mugwort. Two that I have been fortunate to observe and photograph before they get even rarer are Corn Marigold and Marsh Lousewort.

Corn Marigold – just as it is supposed to grow, on the edges of arable fields. It is hanging on in West Cork here and there and it’s always a treat to see it.

Marsh Lousewort – I have only found this once, in the Derreennatra Bog I wrote about in my post “The Wildest and Richest Gardens” – West Cork Bog Soaks

A section of the report looks at Habitat Loss and another at Climate Change and its effects on our wild flora. Reading about the loss of species-rich native Grasslands is particularly sobering. 

It may seem ironic that grassland should be threatened in Ireland, but it is the loss of certain types of grassland – those on less fertile soils and rich in wild species – that is the issue. These ‘semi-natural’ grasslands supported a large number of our characteristic native species, including many orchids. They were maintained by extensive grazing, or by the cutting of hay in mid to late summer. Converting these habitats rich in species into more intensively managed grassland, or in some cases abandonment to scrub, has led to the loss of many species that could not compete in the altered environment. The underlying reason for the decline of many grassland plants lies in their response to nutrient concentrations, such as soil nitrogen levels and nitrogen deposition from the atmosphere. For the most part, native grassland species require low levels of fertility; they cannot compete successfully at higher levels. It may at first seem counterintuitive that high fertility levels could be inimical to plant diversity, but there is now a very large body of evidence pointing in this direction. We can conclude that grassland plants generally are in trouble, with the exception of those few species that thrive in highly fertile conditions.

Even in West Cork, our fields are becoming larger and hedgerows are disappearing. Wetlands, woodlands and ‘Arable land and other disturbed habitats’ are also dealt with. The report notes that while the volume of ‘weeds’ in agricultural lands has reduced, what is mostly missing are the native plants, while the variety has increased with the advent of new species. The Common Poppy, for example, might be making a comeback since it is often included in wildflower mixes. I saw the ones below in a field in Wicklow.

The report concludes with some highly charged questions.

A botanical visitor to the present day from the 1950s would see vast changes in Ireland. Changes in the landscape would stand out, with large swathes of dark conifer forest in the uplands having replaced areas of blanket bog and hill pastures. There would be larger, more uniformly deep-green fields in the lowlands, less length of hedge, more fence, and many fewer areas of marsh and bogland. Roads would be larger and straighter with verges that were mown by machine once or twice a year rather than grazed or cut spasmodically by hand. There would be fewer small potato patches, and arable crops would be less widespread and more concentrated in favourable areas.

Looking more closely, they would see that the mature conifer plantations consisted mainly of one species, Sitka Spruce, in huge numbers of even-aged stands, and had very few plants growing within them. The green fields of the lowlands would have a few plants of familiar common species like Dandelions, Docks and Chickweed along with the ubiquitous Ryegrass, but the diverse flower-rich meadows would have disappeared. Road verges would be dominated by rank growth of grasses. Pockets of wetland would be far fewer except in the West. All these changes and many more have been documented, implicitly or explicitly, by the findings of Plant Atlas 2020 and comparisons with those of its predecessors.

Our visitor might raise a flurry of questions. Have scientists been looking the other way? Why were the best habitats not protected? Who should have prevented the pollution of water bodies by nutrients? How did the idea of planting vast uniform stands of one alien conifer on deep peat take root Whose job should it have been to develop a long-term vision for Irish land-use? Were the consequences of moving towards energy-intensive farming systems foreseeable?

These are questions closer to the realm of politics than of science. Plant Atlas 2020 itself cannot answer them, but the information within it provides an enormous wealth of data about the distributions of Irish plants and how they have changed.

Sea Kale, above, is a rare plant that seems to be more abundant now that it was 20 years ago. As the report points out, there are a few examples like this that may relate to how records are collected rather than the absolute abundance/rarity of the plant, and the report tries to provide a model that corrects for this.

Finally, there are a set of recommendations based on protecting and restoring habitats, and the last is this one:

Repair the cultural standing of plants. As generations of people become more distant from their origins on the land, they tend to overlook the vital roles of plants. Their place in formal education has dwindled, and most people can name very few of them. By omission, plants are misunderstood, downplayed, ignored, and dismissed, even though we still need them as much as ever. Plants require more of our attention and it is in our interest to give it to them.

So what can we- you and I – do about this? Here are my own actions – they are simple and doable by anyone.

First, I have educated myself about wildflowers. Buy a copy of Zoe Devlin’s Wildflowers of Ireland and take it with you as you walk (that’s Zoe, above, with a group of us hanging on her every word). Or take your phone and use her website or one of the new plant ID APPs. People swear by their own, but I have to say I have found the Picture This app to be reliable and easy to use.

Second, I have tried to spread the good word. I do this using this blog – see the Flora and Fauna of West Cork Page for many many posts on our wildflowers – including lots of slideshows for pure enjoyment. The one above, Wandering the Boreens, is one of my favourites and shows what can be seen along a typical West Cork road in summer. I have also developed a Wildflowers Brochure for use along the the Fastnet Trails, and occasionally lead wildflower walks (below) and give talks. Perhaps most importantly, I am now using my Instagram page for short (I aim for 30 seconds or less) videos on individual wildflowers. I’ll be starting that up again soon for 2023.

Third, I have set aside part of my own One Acre as a wildflower meadow. How I have done this is all laid out in my Rewilding My One Acre Posts and it has taken very little work on my part. If you have a garden or any bit of land around your residence, do consider whether you can do this too. The Pollinators will be very grateful.

Finally, I try to mow as little as possible and I have changed my mindset about ‘weeds’ and such concepts as ‘curb appeal’ and ‘tidiness.’ True gardeners would be horrified, but the insects don’t seem to mind. A tiny rare plant, Sharp-leaved Fluellen (below), showed up on my driveway, who knows how – but if the ‘weeds’ had been eliminated, I would never have found it.

PLEASE read the report, and see what you can do to protect our precious biodiversity.

Wild Wall

It’s a wall like hundreds of other such walls in the city, an old remnant of some enclosure long forgotten. It’s been heightened in a more recent period, although it’s not clear why.  ‘Round back’ of a plumbing supply place in Cork, people walk and drive by it every day without a second glance. But if you pause and take a close look it rewards with an astonishing variety of plant life.

In their magnificent book The Wild Flowers of Ireland:The Habitat Guide Declan Doogue and Carsten Krieger devote a chapter to Old Walls and Ruins. Here’s how they introduce that chapter: Walls, they say

. . .have over time been colonised by a number of plant species, some of which seldom live elsewhere in Ireland. . . . Buildings are completely artificial structures. Therefore the question arises as to where these colonising species lived before these walls were built. Some species were either deliberately or accidentally introduced by man into the country, usually for medicinal or ornamental reasons, within the past 1000 years and have become established or persist on walls. Another group of genuinely native Irish species made their own way, spreading from natural and usually rocky habitats within the Irish countryside onto the new buildings of the time. In both cases there were enough points of environmental similarity between the plants’ original natural habitats and the buildings of the Irish countryside to make it possible for them to extend their range and find new homes. In a sense an ongoing botanical battle between the native and newcomer was being fought on the fabric of these old buildings. This struggle comes complete with issues such as natural succession, colonisation, displacement, local extermination and sheer opportunism. The conflict continues to this day and can be observed in most older towns and cities.

Walls have other characteristics friendly to certain plants: the stones warm up in the sun and retain their heat into the evening, acting, as Doogue and Krieger put it, as a sort of storage heater. Lime-rich mortar allows lime-adapted plants to flourish even in non-lime areas. Microclimate and soil conditions on top of the wall can be different from those on the sides, or on south-facing versus north-facing walls.

This wall in Cork exemplifies everything Doogue and Krieger describe – native and non-native species growing side by side in an environment where it seems impossible that enough nourishment could be supplied.

Oxford Ragwort

Some of the plants have intriguing histories. Take the humble Oxford Ragwort, the one that looks like a yellow daisy. (This is not to be confused with Common Ragwort, or Buachaláns as they’re known in Ireland, which are on the Noxious Weeds list – although that’s another story.) It was introduced into an Oxford botanic garden in 1690 from Sicily, but soon escaped and was seen all over the walls of Oxford. The University of Bristol takes up the story from there:

During the Industrial Revolution, Oxford became a thriving railway centre and Oxford ragwort found a new habitat in the clinker beds of the railway lines that fanned out of Oxford to all parts of the country. These ‘furnished the plant with a replica of the lava-soils of its native home in Sicily’, said Druce in his Flora of Oxfordshire. Referring to the fruits (achenes) of Oxford ragwort, he said ‘I have seen them enter a railway-carriage window near Oxford and remain suspended in the air in the compartment until they found an exit at Tilehurst’ (near Reading).

Because this species hybridises readily with other Senecio species (other Ragworts and Groundsel), this site adds, the introduction and spread of the promiscuous Sicilian S. squalidus has resulted in a great deal of evolutionary novelty among British Senecio – an amazing example of evolution in action. I love the idea of a promiscuous plant.

Herb-Robert – surely one of our most-loved wildflowers

Herb-Robert is among our most commonly seen (and known) native wildflowers – a dependable spot of brilliant colour almost all year round in a huge variety of environments, with its frondy leaves turning a brilliant red as the season wears on. However, on this wall it was joined by a cousin – Shining-Crane’s-bill.

And this is Shining Crane’s-bill!

In fact, I had to do a double-take, as I had never seen this flower before and at first I thought I was looking at a miniature Herb-Robert. While it might be easy to confuse the flowers, the leaves are totally different, with the Shining Crane’s-bill leaves being smooth and hairless, almost waxy, with a distinctive shape. I wish all similar species were this easy to tell apart upon close inspection!

Shining Crane’s-bill – the flowers are smaller than Herb-Robert and the leaves are totally different

One of my favourite wall species has to be Ivy-leaved Toadflax – not a very pretty name for a truly spectacular flower. This is another Mediterranean plant, and we can blame Oxford for this one too, as it is thought to have hitched a ride on marble sculptures imported from Italy to Oxford in the seventeenth century. Once the flowers are finished, the seed heads bend away from the sun and towards the wall, dropping their seeds into the cracks – thus they are able to grow vertically up the wall.

Ivy-leaved Toadflax – every well-dressed wall should have some

At the bottom of the wall I thought I saw the ubiquitous dandelion, but once I looked closer I saw that the leaves were quite different. I think this is Smooth Sowthistle. Zoe Devlin of Wildflowers of Ireland tells me that the leaves can go this purplish colour in the absence of good soil. There are so many wildflowers that look, more or less, like dandelions – it has been a real journey of discovery to find out more about this large flower family.

Smooth Sowthistle and Ivy-leaved Toadflax in the act of climbing up the wall

Smooth Sowthistle is edible when young and has been used as fodder for animals. According to one authority I read, In Greek mythology Theseus is said to have eaten smooth sow-thistle to gain power before leaving to slay the Minotaur in its Cretan labyrinth, where it dined on human bodies, bull’s heads and young Atheneans.

Rue-leaved Saxifrage. It’s also pictured in the lead photograph at the head of the post, where you can see the basal rosette

Growing from the mossy ridges in the wall was a delicate little white flower with a reddish basal rosette, and this turned out to be Rue-leaved Saxifrage. Although it was new to me, this little native beauty is common in many parts of Ireland. As the season progresses the stem, leaves and rosette become redder – hence ‘rue-leaved.’

Red Valerian sprouting from the wall, with Oxford Ragwort and Ivy-leaved Toadflax. The tiny fern growing in the cracks glories in the name Maidenhair Spleenwort

We all know the plant known as Red Valerian, yet another Mediterranean import. I saw it growing in huge masses in the Burren a couple of years ago, meaning it’s one of those plants that enjoys the lime-rich environment provided by the mortar in the wall.

This is not, by the way, the Valerian that the sleep-aid tea is made from, the one that makes cats go loopy. It can also come in shades of pink and white, all growing side-by-side.

Keel-fruited Cornsalad (above) is also known as Lamb’s Lettuce, although it doesn’t look like the supermarket variety known by the same name. It is, in fact, very edible, with a kind of parsley after-taste and packed with vitamins (although you probably shouldn’t pick it anywhere near dog-height). The tiny blue/purple flowers reward examination through a hand-lens if you have one.

It took me a while to identify one little plant growing close to the pavement (above). It turned out to be Petty Spurge and, although it is not native to Ireland it’s been here a long time and has spread widely. It’s not usually as red-tinged as this when you see it in ID sources. It’s of huge interest to scientists at the moment because of the potential of its sap (a toxic latex substance) to treat common forms of skin cancer. Several rigorous double-blind studies have come to the same conclusion that it is an effective treatment for non-melanoma lesions. It’s a hardy little thing too – seeds found in excavations, dormant for a hundred years, can still germinate.

Finally, up on top of the wall is sprouting a Butterfly-bush (above); many of us know it as Buddleia. It’s well named, as butterflies love it. It was introduced into Europe by missionaries returning from China and it spread quickly as it will grow just about anywhere. What you see on this specimen are the remains of last year’s flowers: by June it will be hosting butterflies. Butterfly Bush may seem benign but like many other introduced species there is a dark side. First of all, as Tony O’Mahony points out in his Wildflowers of Cork City and County, it’s quite invasive and can take over and crowd out native species. The roots can do significant structural damage to the very walls it depends on for survival. More serious is the charge that, while it provides nectar for butterflies it is not a butterfly host plant – that is, one that butterflies can use to deposit their larva, which will then feed on the leaves. According to a spokesperson concerned about the destruction of chalk grasslands at Folkestone Warren in Kent: If left uncontrolled, then buddleia and other shrubs would have engulfed the chalk grassland. Clouds of butterflies used to be seen there, but now only common species can be spotted and even these are in decline, with the rarest ones disappearing altogether. Buddleia was eliminating butterfly habitat by killing off everything else, and while the shrub provided food for adults and larger insects, other plants were needed for butterflies in their larval stages.

So there you have it – it’s just like the human history of Ireland, full of invasions, adaptations, displacements and resurgence. All in a Wild Wall.

Late Bloomers: Invasive, Naturalised and Native

Creeper on white cottage wall

This is my last wildflower post! You must be getting tired of my wildflower obsession by now. So, no more after this one. (Well, at least not in 2016.) The thing is, I had assumed that there was nothing left to see at this point. We are in October after all, and autumn is coming early this year after a cool and misty summer. But a walk today put flight to that notion.

Bee on Ivy Flower

Bracken undergrowthThe ivy flowers are alive with bees right now (above) and the bracken is putting on its winter coat

The predominant colour of the countryside is changing now as the brackens take on their winter amber-brown. The ivy is in full flower. Stand near a patch and you will be instantly aware of the hum. Our little black Irish bees are gathering while they still can and depend on this late flowering and ubiquitous plant for the last remaining nectar. Ivy honey is darker in colour and can smell a little rank, but it has a great reputation as a soothing cure for coughs and colds (especially if mixed with a little whiskey).

Bee on Ivy 2

Red Admiral on IvyThe bees and the Red Admiral Butterflies depend on this late flowering ivy

The trees haven’t quite started to turn yet, but brambles and creepers are in brilliant autumn reds. On our walk today this white cottage wall with its scarlet creeper caught my eye.

Creeper on cottage wall

A couple of surprises awaited us today. The first one was to come across a stand of Indian Balsam. This alas, is an invasive species, introduced as far back at 200 years ago from the Himalayas. The distribution map at the Botanical Society of Britain and Ireland does not show it in West Cork, but I guess I can now say it’s here. In fact, I submitted a report to Invasive Species Ireland – anyone can do this via their Alien Watch Program. Although it is certainly beautiful, it’s a divil – read all about its negative impacts on the Invasive Species Ireland website. Among its other attributes, it has a explosive seedpod that can throw seed up to six metres!

Indian Balsam

Indian Balsam – Invasive Species Ireland lists it with Rhododendron, Japanese Knotweed and Giant Hogweed as the most damaging invasive species

So  what’s the difference between non-native plants that are labelled invasive versus this that are called simply naturalised? Although it can be a matter of debate and perception, in the main we use the term invasive for those non-native plants that spread to such a degree as to exclude native species from the habitat they favour, or cause damage to the environment or the economy. Happily, the only invasive species we encountered on our walk was the Indian Balsam. However, we did come across lots of non-native, naturalised flowers too.

Greater Periwinkle

The Greater Periwinkle – seen a few days ago on The Mizen

The first one (actually seen a few days ago) is this beautiful Greater Periwinkle. It’s not a native plant but has been here a long time. It’s supposed to have great medicinal properties, especially as a laxative and, in an ointment it’s good for, er, piles. According to Zoe Devlin’s Wildflowers of Ireland (my go-to guide) The 17th century herbalist, Nicholas Culpeper wrote ‘that the leaves eaten by man and wife together, cause love between them. Ooh – think I might head back to where I saw it…

Ivy-leaved Toadflax

Ivy-leaved Toadflax

Another non-native species is the Ivy-Leaved Toadflax – not an attractive name for a very pretty little creeper found commonly on rock walls. During the 1600s, wealthy Brits started to import Italian marble into England in the form of building material and statuary. The Toadflax came along for the ride and is now so completely naturalised that few people realise it’s not a native plant. They look wonderful on rock walls but it’s not usually necessary to plant them yourself. According to one source I read, seeds, complete with a starter-pack of organic growing medium, are usually delivered by birds.

Pink Sorrel

Pink Sorrel

The final non-native flower we saw today was the pink sorrel. I thought at first it was Herb Robert, which is a native plant that grows everywhere and is still blooming, but closer examination revealed  a deeper pink, a more massed growth pattern and very different foliage. It’s a garden escape, now naturalised across the south and south east of Ireland.

Fuchsia on bare branches

Actually, I suppose I also have to add the fuchsia to the naturalised non-native list, even though we think of it as the quintessential West Cork flowering shrub. It’s still hanging in there, even though most of the leaves have dropped already.

Creeping Buttercup

Tormentil

The native plants still bravely blooming to delight us tended to be tiny, but bright enough among the grasses, brambles and bracken to immediately catch the eye. We saw Herb Robert, Prickly Sowthistle, Tormentil and patches of what might be Sea Radish (or perhaps not). 

Prickly Sowthistle

Prickly Sowthistle

Herb Robert is such a hardy little flower – it seems to peep out and last longer than almost everything else in the hedgerows. Birds love the seeds of the Prickly Sowthistle – it has guaranteed its survival by appealing to them and providing food when other sources are fading.

Herb Robert

Sea Radish

Herb Robert (top) and possibly Sea Radish

As  a member of the cabbage family, the leaves of the Sea Radish are edible, if a little peppery. Interestingly, it normally finishes flowering in July, so the ones we found today must be in a particularly sheltered spot. But this also raises the possibility that this is a different plant. Can anyone help identify it?

Tormentil Patch

And finally the strangely named Tormentil – it sounds like it may cause pain but in fact it’s the opposite. There are all kinds of medicinal uses for this little flower and its parts, some of which relieve the ‘torment’ of pain. It also, according to this website,  imparts nourishment and support to the bowels and the fresh root, bruised, and applied to the throat and jaws was held to heal the King’s Evil. You heard it here first!

Ballycummisk Coppermine and Gabrial

Our walk today, along one of the Fastnet Trails, took us past the old Ballycummisk mine site and gave us distant views of Mount Gabriel