COLONISERS AND INNOVATORS PART II

Diarmuid Breatnach

(Reading time: 5 mins)

In Part I, we remarked that “Plants are pioneers, colonisers, innovators and builders at least comparable to the animal kingdom, to which they are related and …. with a superior record.” We followed their emergence from the waters and their colonising of land, along with various strategies they developed for their new environment. Now we watch them constructing their very own environments and adapting to some of the most challenging climes of the earth.

ENVIRONMENT-BUILDERS

          Most plants have leaves, which is where the photosynthesis takes place; they are in fact sunlight collectors and the plants deploy them to best effect to catch the available sun. Quite a late development, they were flanges on the stems first before becoming appendages further out of the plant’s main body. Most leaves are intricately veined and contain many different layers and parts and although it is within them that photosynthesis takes place, strangely they are mostly short-lived and in cold seasons, even in perennial plants, all but the conifers let them fall.

The greater the volume of material created by plants, the more there was to decompose with their deaths or seasonal decline. Bacteria, already long existent on the planet, evolved to feed on this detritus and break it down into soil, which the same plants or others could turn to their advantage as a medium in which to anchor but also from which to draw nutrients. Other organisms evolved to live on and break down cellulose too, the main building material of plants: fungi, gastropods like snails and slugs, woodlice, termites …..

The plants, with the help of bacteria and other organisms, were creating the environment below them!

But they were and are doing more than that: they are also creating an environment immediately around them. The most concentrated examples are perhaps rain forests, tropical, temperate or cold-climate, retaining a surrounding moisture-laden air, in which not only the local tree species thrive but also providing ideal environments for ferns, algae, orchids and epiphytes and, of course, mosses.

Inside a tropical rainforest.
(Photo source: Internet)
Temperate Rainforest — parts of the Wicklow hills and valleys would almost qualify.
(Photo source: Wikipeda)

Away from forests, sphagnum moss creates a mini-atmosphere around itself and as generations die, their bodies create a spongy moisture-laden medium. This bog is quite capable of existing on an incline, with much of the water being retained by the vegetation and ‘soil’, as may be seen in a number of examples in Ireland, such as parts of the Dublin and Wicklow Mountains.

Close-up of sphagnum moss, creator of its own environment and changer of landscape.
(Photo source: Internet)

 

Plants, especially trees, discharge oxygen into the air and consume carbon dioxide during the daytime, for which reason they are sometimes called “the lungs of the world”. They have not only created an environment for themselves, below, around and above but also for so many other life-forms – including ourselves.

LEARNING TO LIVE IN DIFFERENT CLIMES

          Creating one’s climate isn’t always possible and, when it’s not, adaptation is the other option. Plants that adapted to grow in arid areas developed fleshy ‘leaves’ and often stalks, in which to store water and also sometimes long tap roots to find that water. But extensive shallow root networks are good too, to collect the occasional rain water that is quickly absorbed into the soil or otherwise evaporates. The “pores” on leaves through which plants absorb carbon dioxide and allow the gas-exchange necessary for photosynthesis (stomates) also permit evaporation of water, hence many dry-condition plants have fewer of them. Some only open to collect carbon dioxide in the cool of the night and store it for use on the following day. Plants grow trichomes, tiny bristles, underneath their leaves but some arid-dwellers grow them also on top of their leaves; these ‘trap’ a layer of air that prevents or slows evaporation.

Arid-adapted plants, SW USA (Photo source: Internet)

In very wet areas, plants learned to remain active by a number of strategies. Of course they originally came from aquatic environments but for some of them, returning there again after adapting to dry land, produced challenges (think of the changes necessary for land mammals to evolve into seals, otters, dolphins and whales). Nevertheless we have lillies growing in shallow water with wide floating leaves, reeds with upright blade-like leaves growing inside the water margins, thin spears of rushes in damp and water-logged land. That too is the preferred environment of some other plants and grasses, including the rice plant. And of the willows, alders and hazels growing on the banks and stabilising them. In the tropics and semi-tropics, mangroves do a similar job to willows but on a much grander scale – and they tolerate seawater too.

Reeds and two different species of willow on the Royal Canal, Dublin. (Photo source: D.Breatnach)

The alder, a tree with a high toleration of water around its roots, is thought to have been the major post-glacial coloniser of Ireland, following the retreating ice across the land. It is the only native tree which though not an evergreen produces cones, an indication of its early adaptation to cold climate. Cones, when closed, protect the seeds inside against continual freezing and thawing and, when the cones begin to dry and automatically open in spring and summer, allow the seeds inside to drop out to the ground, to be carried by river or on the wind. A closed cone collected and brought home will open as it dries; shake it then and the seeds will fall out. Alder timber, incidentally, remains waterproof for centuries, witness the wooden piles in Venice.

Close view of alder cones and leaves from tree on the Royal Canal, Dublin north city centre. (Photo source: D.Breatnach)

Adapting to cold seasons required protective materials, structures and timing. The deciduous trees (and it is worth noting that many trees have both a deciduous and an evergreen version for different climes) shed their leaves and close down for the winter, the sap retreating down to the roots. Were the sap to remain in the exposed branches it would freeze, expand and destroy them. The leaves drop because they no longer receive anything from the tree; it is going into a kind of hibernation, in preparation for the coming winter.

Many of the conifers have downward-sloping branches, to allow most of the snow to slide off, rather than break the branches with its weight. People who live in areas with heavy snowfall also tend to live under sharply sloping roofs. The “leaves” of the conifers are small, narrow and hard so that most snow falls through them and are also covered in a waxy polymer to withstand freezing. The plant cells can be emptied of water to prevent freezing but a dense waxy residue keeps them open for refilling. So, of course, they have to be tolerant of dehydration. Concentration of sugars also lowers the freezing point and small flexible conduits for water resist the formation of large ice bubbles that can burst those “pipes”.

The “needles” on pine twigs. (Photo sourced: Internet)
The downward direction of the branches of many conifers ensures slide off by snow when it reaches a certain weight — but long before the branch might break. (Photo source: Internet)
Red and white spruce in snow. Though the branches incline slightly upward, they are very flexible and will bend and dislodge the snow overlaying them long before the branch is in danger of snapping.
(Photo source: Internet)

THE YOUNG TAKE TO THE WATER AND THE AIR

Diarmuid Breatnach

(Reading time: 3 minutes)

Some young take to the water, others to the air …..

          The last weeks of May and first half of June saw the young of many species take to air or water. On my walks in the Drumcondra area of Dublin where I live, although Glasnevin Cemetery and the Botanic Gardens were unreasonably closed (the Botanic is now open but on restricted hours, again unreasonably), the banks of the Tolka river in Griffith Park and the banks of the Royal Canal were open to the public.

A pair of mute swans (ealaí) nested on the stretch of Royal Canal east of Cross Guns Bridge but quite near to it. Well, the female, the pen, at least did, while the cob (male) was usually swimming nearby. So how did the pen feed during the long hatching period? Unlike some bird species, this male does not feed the broody female. Well, the male may take a turn, spelling her to go off and feed herself and difficult to know when that happens, as both genders look so much alike. Fumbling with my phone once I failed to catch a photo of the large grey eggs beneath the shifting body of the sitting bird – three, an East Asian woman told me, using her fingers. Later, I saw both parents with just one cygnet – whether some of the eggs were infertile or two of its siblings died I don’t know.

Mute Swan cygnet in ‘duvet’ on land
(Photo: D.Breatnach)
Mute Swan parents and lone cygnet, Royal Canal, Glasnevin.
(Photo: D.Breatnach)

Predators can take cygnets but the parents are very good at protecting them and eggs in the nest will not be left untended until the cygnets are hatched – and then it’s straight into the water. When not swimming itself, the cygnet climbs on to a swimming parent’s back and sits there surrounded by a natural feather duvet. From then on, the nest is not needed except perhaps in stormy weather.

A few days later I was fortunate to see another pair of mute swans on the Tolka in Griffith Park, these with no less than seven cygnets! Their parents took them upstream, the cygnets swimming easily, even under the branches of a fallen tree-trunk. Until they came to a mini-weir which the parents simply walked over but their offspring were too small to do that. However, they maintained position for quite a while swimming against the mini-waterfall, their parents seemingly unable to understand why their young could not follow them and, eventually, having to turn back to them. Many mammals, confronted with a similar problem, would simply pick its young in its mouth and carry them over the obstacle and then go back for the rest. A small crowd of Homo Sapiens mammals gathered to watch the proceedings with interest and delight.

Some of the mute swan brood following their parent upriver on the Tolka.
(Photo: D.Breatnach)
Can we go under this obstacle?
(Photo: D.Breatnach
Yes, we CAN go under that obstacle!
(Photo: D.Breatnach)
Why aren’t you coming?
(Photo: D.Breatnach)

Also out with their young were mallards (Lachain), the ducks and drakes (bardaill). Some had hatched their young as far back as April but most seemed to be doing so at this time period and then it’s straight into the water. I remember witnessing the unpleasant scene of a duck with a clutch of tiny ducklings on the Tolka being harassed by a couple of drakes, one in particular trying to mate with her, she quacking that she wanted no part of it. Contrary to comment by some writers, rape is not unknown in the animal world and though in most species it is rare, mallard drakes are known for it.

Delightful it was however on another day to see a newly-hatched clutch of ducklings zooming around on the water, in their fluffy chocolate brown-and-yellow down looking like aquatic bumblebees, both parents close by.

Duck and very young ducklings, Tolka, Griffith Park.
(Photo: D.Breatnach)

Walking past the high waterside vegetation of the canal one day I heard a kind of cheeping which I guessed to be the chicks of a moorhen (Cearc Uisce). These waterfowl are very shy and careful too not to reveal their nest locations which are constructed in waterside vegetation only inches above the water level and sometimes actually afloat on a kind of raft. Though egg-laying is in March-April and they will not fledge until about 50 days later, we should be seeing the chicks with their parents already. So where are they?

Moorhen, Royal Canal, Phibsboro, not hanging around to be photographed.
(Photo: D.Breatnach)

Grey herons (Corr Ghlas) fish the Tolka and the Royal but their nests are nowhere there. They prefer to nest in trees, somewhat incongrously for birds with such long legs. I have never seen their nests in Ireland myself, though I read that a colony is to be found in St. Anne’s Park, in County Dublin. Grey herons take turns on the nest and also in feeding their young – which require a lot of fish and frogs. They would take a duckling or cygnet too, given the chance …. Which is why herons often get mobbed by other birds. In Drumcondra I watched one on house rooftop being dived at by seagulls, no angels themselves but they have nests of their own in higher rooftops nearby.

Grey Heron, Royal Canal, Glasnevin.
(Photo: D.Breatnach)

And one day, a Little Egret (Éigrit Beag) spent a little while looking for fish in the Tolka before departing. It’s a relatively new settler in Ireland but no longer rare along the east coast.

Not so much “taking to the water” as already in it are the tiny young of the three-spined stickleback (Garmachán), hatched out in underwater nests cared for only by the male. I have seen shoals of the fry of larger fish in the Tolka too, once heading downriver through the Botanic Gardens; what species they were I don’t know but a large stock of brown trout (Breac Donn/ Rua) lives in the river. Many sprats are at this moment concentrated in different parts of the Tolka.

However, on a number of occasions large numbers of fish have been killed by pollutants in the water. A few years ago it was reported that salmon (Bradán) had been seen making their way upriver and this year I saw some myself in the Tolka. These spawn in freshwater and after a few years their young make their way to the sea, the survivors returning years later to spawn in the river again. If the young are killed before making it into the sea obviously they won’t coming back to spawn in a few years’ time so a fishkill incident in one week can wipe out a species in the river for a number of years. I photographed the sprats of some species of fish a few weeks ago in the Tolka and again this week while walking through Griffith Park (I, not the fish).

Sprats, young of some fish species, Tolka, Griffith Park, 25 June 2020. Difficult to photograph with mobile phone even through not much more than a foot of water. (Photo: D.Breatnach)

Among the young taking to the air now are those of the magpie (Snag Breac) and the distinctive and irritating high-pitched calls of the juveniles can be heard just about everywhere, usually from above in the trees. The call is “feed me” and is designed to be difficult to ignore. However, they need to learn not only to fly but to find their own food, so the parents will feed them only on occasion. This corvid is apparently an invader recorded arriving in Wexford in 1676, over two decades after that other invader, Oliver Cromwell. It has settled in well but is recognised as a predator by songbirds and sometimes attacked by them; on the other hand the magpies themselves will gang up on seagulls, hooded crows and cats, when they will give a frequent rattling kind of call.

The juveniles who are calling to be fed were in the egg for 20 days and fledging for nearly a month, which means the eggs were laid in April. The nests are large, a mass of twigs and can be seen in trees all over Dublin.

Some of the cottonwood seed-carrying medium on the banks of the Tolka, Griffith Park, end of May.
(Photo: D.Breatnach)
Bullrushes, Royal Canal, Drumcondra, shedding some cotton but not where the main cotton fall is coming from.
(Photo: D.Breatnach)
Bedstraw, perhaps, flowers mostly gone to seed.
Royal Canal, Drumcondra; Yellow Flag Iris nearby.
(Photo: D.Breatnach)

The young of plants have taken to air too and along the banks of both the Royal Canal and the Tolka the flowers have died and are turning to see-capsules or to pods, while other species are bursting into flower.

Some days the ground was covered in drifts of a kind of cotton and I assumed this was seed-carrying material. But from what? Along the Royal I might suspect the bullrush or reed-mace, with tattered tufts of cotton around the mace “head” …. or perhaps the pussy willow … but surely not in these quantities? However, in Griffith Park clumps of it were drifting across my path and I remembered reading about “cottonwood trees” in stories set in the “Wild West”. Yes, three species of cottonwood are part of the larger poplar family and have been around for 55 million years in North America, Eurasia and Asia and although not native they do grow in Ireland. And poplar-type trees have been planted along stretches of the Royal but in particular in Griffith Park, recognisable by their somewhat rounded leaves and the compact upright growth of their branches, so perhaps they are the source of the cotton? Their name in Irish is Poibleog Mheiriceá Thuaidh, translating as “North American Poplar”; that’s a bit of a long one and if they become more popular (forgive the pun) we might have to start calling them ‘Crann Chadáis’ (Cotton Tree).

But it wasn’t them either.  The culprit was, after all, the willow (Sail) tree; but not the pussy or weeping willow, but the giant willows.

End (A Chríoch)

EXPLORERS, COLONISTS AND INNOVATORS Part 1

Part I: Expedition to the Unknown

Diarmuid Breatnach

(Reading time: 5 mins)

When plants first “crept” out of the sea and freshwater on to land, it was a perilous undertaking. The shore and in particular the sea shore is a very hostile environment, subject to battering and scouring action of wave, wind and wind-driven sand, alternating between inundation and desiccation and even both in the same day. Those early plants were not just explorers but colonisers and innovators; many died but those that survived changed the world, its very earth and atmosphere.

          There are about 320,000 known species of plants, a total that does not include most hybrids, sub-species or selectively-bred varieties. Botanists exclude from the term “plants” some of the green and all of the brown sea algae as well as the fungi and bacteria. The vast majority of plants are coloured some variety of green because of the action of photosynthesis inside them, which attracts the blue and red ends of the light spectrum but does not absorb green, which is why we see them in that colour. Some 260,000 to 290,000 species produce seeds but algae does not. Mosses and ferns, which are plants, produce spores instead, in common with fungi (which however are not plants).

We study life to place it in an order, to simplify understanding but life diversifies into a huge array.

Plants are pioneers, colonisers, innovators and builders at least comparable to the animal kingdom, to which they are related and, I would argue, with a superior record.

LAND HO!  

          Plants first “crept” out of the sea and freshwater during the Ordovician period, around 470 million years ago; they were probably non-vascular (without “veins”) and without roots, like mosses and liverworts. It was a perilous undertaking. The shore and in particular the sea shore is a very hostile environment, subject to battering and scouring action of wave, wind and wind-driven sand, alternating between inundation and desiccation and even both in the same day. Plants on land carry the genes of the early explorers, pioneers, survivors – high in endurance, adaptability and innovation.

Rootless and low-growing, Irish liverworts and moss.
(Photo: irishwildflowers.ie)

But why abandon the seas, lakes and rivers in the first place? Presumably there is always a pressure in nature to explore niches and new territory, thereby escaping pressures of population, predation, competition and consumption of available nutrition … And while some life-forms specialise in particular environments and nature also pressures in that direction, ultimately that is a highly dangerous strategy, general adaptability to food sources and environments being the best bets for long-term survival and multiplying – as shown by homo sapiens, for example.

First ashore, establishing a literal (and littoral :-)) beachhead, might have been a kind of algal slime. Perhaps it survived only while wet, died, was replaced by other migrants …. but probably at some point some carried survival pockets within them, able to regenerate when moistened anew. Or it might have been some moss or liverwort, later a branched and trailing plant but dealing with the same problems and developing a similar strategy for survival.

We can imagine a conversation, in which one plant organism on the shore questions another:

It gets so dry here I feel I am going to wither and blow away.”

Just hang on there. We’ll get rain soon. And there’s always dew at night.”

I can hardly wait. Remind me why we didn’t stay where were were, with all that lovely moisture.”

Getting eaten by other life-forms. Competition for light.”

Oh, yeah. Sometimes I forget.”

Established seashore plants and lichen on the Saltee Islands, Co. Wexford.
(Photo: outsider.ie)

REACHING DOWN, STANDING UP

          In lakes, plants could simply float upright in the water reaching towards the light (and avoiding being covered in sand or silt) as many water plants do today, or on the surface, as algal mats and bloom do, or for example the various types of “duckweed” that not only float but multiply to cover the whole pond surface. In the sea and in fast-flowing rivers however, fixed plants needed to grasp surfaces and developed means of doing so; but these were not roots as such – more like anchors. Later, as they colonised the land, most plants did indeed develop roots not only to anchor themselves in the ground or to cling to difficult surfaces but also to bring up water, the tap roots for this purpose often going quite deep. Roots also brought up nutrients.

The roots also made it possible to cling to inhospitable surfaces, including even the perpendicular or overhanging and also to exploit cracks and fissures by tunneling into them. In the course of this activity, plants changed their immediate physical environment, by helping to break down stone and also by trapping material blowing in the wind.

But why set up home clinging to a cliff or today, a wall or a chimney stack? Well, plenty of sunshine, for one thing, no competition for another! Of course, not much soil there or even none at all for nutrition – but still, most things in life are a trade-off, right?

How did the seeds get up there in the first place? Wind … or birdshit.

Buddlieia bush clinging to a wall in Dublin (Photo source: D.Breatnach)

Of course, some of the colonisers developed other ways to cling to surfaces, as was the case with the mosses, lichens and liverworts. And they also trapped material and contributed their own to it as they died, regenerated, died …. But without roots that only works when you keep low and hug the ground. If you want to grow tall to reach for sunlight and if you want to exploit soil, you need roots.

Plants at first fed almost exclusively on sunlight it seems, broken down into sugars by chlorophyll in photosynthesis. But those that developed roots also, probably as anchors to prevent themselves being blown or washed away, or to help them grow tall and compete with other plants to catch the sun, learned to draw up water and to feed on nutrients in the soil – phosphates, nitrogen, potassium etc. Some, like the legumes, beans, peas and gorse for example, even learned to extract one of the gases that make up air, nitrogen and, with the help of a bacteria, to fix and store nodes of it around their roots.

Once you have roots, why not grow stems, branches, trunks, whereby you can reach higher and higher, for more unimpeded sunlight and outpacing the competition perhaps. Your building material will need to be tougher, especially for trees, bushes and shrubs, to bear the weight, withstand the winds …. but flexible enough to stretch as you grow and also bow to high wind. Having the ideal material already in cellulose, all that is necessary is some kind of hardening process. A plant might explain to puzzled humans: “Think of keratin and how the same basic substance has been used to make stuff as varied as feathers, fur, human hair and beetle carapaces.”

If you were a plant that had learned to spread fast over distances to catch the sun, covering ground and clambering over obstacles, you might find one day that there is another way to reach towards the sun – climb up the plants that are already up there! Don’t invest in slow build-up and hardening of cellulose – go for fast growth and gripping or winding ability instead, or turn some of your leaves into grasping tendrils. Some climbers such as lianas in the tropics and ivy and honeysuckle in Ireland, are perpetual climbers, remaining in position throughout the year (although the honeysuckle will lose most of its leaves in the Autumn) and extending during the growing seasons. Others climb only in the Spring and Summer and die afterwards, for example bindweed and runner-beans.

Cultivated climbing plants, runner beans, winding around canes in a “teepee” frame.
(Photo source: Internet)

end.

Ivy making its way up a tree trunk.
(Photo source: Internet)

COMPLAINT TO DAVID ATTENBOROUGH

Dear Mr. Attenborough,

We wish to draw your attention to what we perceive as a serious bias in your series The Natural World, a bias which is as unjust as it is unproffessional and, indeed, unscientific.

In your otherwise excellent film documentary series The Natural World you depict the wonders of our world and the many levels of interaction and responses to different environments within it, of plant and animal, of eater and eaten, prey and predator.

However, when any of us appear upon the scene, your narrative voice drops in volume as if to indicate the arrival of something sinister, the evil presence in this otherwise natural world. We are neither sinister nor evil, Mr. Attenborough – we are an integral part of this natural world, the same as all the rest.

You seem to delight to show footage of us pursuing the young calves and fawns of grazers, thereby seeking the sympathy of your human audiences for their plight and, in turn, hostility towards us. No doubt the omnivores among your human audience are able to disassociate themselves mentally from the relative immaturity states of lamb, veal, piglet, pullet, egg and sprat in their diet. But much more to the point – do we not have young too? And how do you – or your sympathetic audiences – imagine that our young get fed? Or what do you or they imagine stands between our cubs and dying of starvation?

We note also that it is not all higher predators that you depict in this way – not of course humans but not the great cats either. We laugh when we see you depict the lion, “the king of the jungle” as some kind of majestic monarch. Those of us in the African veldt know well that most of what he eats is what our brethren have chased and brought down before he has bullied us off what is ours. And the rest of his food is killed only by the females in his group. Among us, on the contrary, males and females all take part in the planning, the chase and the kill.

As a naturalist you know that all predators play a part in the balance of nature and generally cull the weak and unwary, strengthening the overall health of the prey species. As a naturalist, we would not expect you to have this bias against us and can only wonder whether perhaps as a child you had an unpleasant experience with a domesticated canid. If so we hope that you can put it behind you.

We trust you will consider what we have to say and hope that you will change your depiction of us in any future series.

Sincerely,

Wolves, Dingoes, Wild Dogs, Jackals and Hyenas

on behalf of Canids of the Wild (CaW)

A Grey Wolf adult ‘cuddles’ a pup (Source: Internet).

 

 

Three Dingo pups — one of them camera shy. (Source photo: Internet)
“Parents have to work hard to feed a big family.  We hope you’ll think about that, Mr. Attenborough.  Goodbye for now ….. C’mon, kids.”
(Photo source: Internet)

EXPLORERS, COLONISTS AND INNOVATORS

Diarmuid Breatnach

(Reading time: 15 mins.)

When plants first “crept” out of the sea and freshwater on to land, it was a perilous undertaking. The shore and in particular the sea shore is a very hostile environment, subject to battering and scouring action of wave, wind and wind-driven sand, alternating between inundation and desiccation and even both in the same day. Those early plants were not just explorers but colonisers and innovators; many died but those that survived changed the world, its very earth and atmosphere.

          There are about 320,000 known species of plants, a total that does not include most hybrids, sub-species or selectively-bred varieties. Botanists exclude from the term “plants” some of the green and all of the brown sea algae as well as the fungi and bacteria. The vast majority of plants are coloured some variety of green because of the action of photosynthesis inside them, which attracts the blue and red ends of the light spectrum but does not absorb green, which is why we see them in that colour. Some 260,000 to 290,000 species produce seeds but algae does not. Mosses and ferns, which are plants, produce spores instead, in common with fungi (which however are not plants).

We study life to place it in an order, to simplify understanding but life diversifies into a huge array.

Plants are pioneers, colonisers, innovators and builders at least comparable to the animal kingdom, to which they are related and, I would argue, with a superior record.

LAND HO!

          Plants first “crept” out of the sea and freshwater during the Ordovician period, around 470 million years ago; they were non-vascular (without “veins”) and without roots, like mosses and liverworts. It was a perilous undertaking. The shore and in particular the sea shore is a very hostile environment, subject to battering and scouring action of wave, wind and wind-driven sand, alternating between inundation and desiccation and even both in the same day. Plants on land carry the genes of the early explorers, pioneers, survivors – high in endurance, adaptability and innovation.

Brown & Green Algaes in shallow seawater (the brown uses floats to stay upright but the green doesn’t need it. Just almost out of view is a yellow lichen colonising the stone sea-wall. (Photo source: D.Breatnach)

But why abandon the seas, lakes and rivers in the first place? Presumably there is always a pressure in nature to explore niches and new territory, thereby escaping pressures of population, predation, competition and consumption of available nutrition … And while some life-forms specialise in particular environments and nature also pressures in that direction, ultimately that is a highly dangerous strategy, general adaptability to food sources and environments being the best bets for long-term survival and multiplying – as shown by homo sapiens, for example.

First ashore, establishing a literal (and littoral :-)) beachhead, might have been a kind of algal slime. Perhaps it survived only while wet, died, was replaced by other migrants …. but probably at some point some carried survival pockets within them, able to regenerate when moistened anew. Or it might have been some moss or liverwort, later a branched and trailing plant but dealing with the same problems and developing a similar strategy for survival.

We can imagine a conversation, in which one plant organism on the shore questions another:

It gets so dry here I feel I am going to wither and blow away.”

Just hang on there. We’ll get rain soon. And there’s always dew at night.”

I can hardly wait. Remind me why we didn’t stay where were were, with all that lovely moisture.”

Getting eaten by other life-forms. Competition for light.”

Oh, yeah. Sometimes I forget.”

REACHING DOWN, STANDING UP

          In lakes, plants could simply float upright in the water reaching towards the light (and avoiding being covered in sand or silt) as many water plants do today, or on the surface, as algal mats and bloom do, or for example the various types of “duckweed” that not only float but multiply to cover the whole pond surface. In the sea and in fast-flowing rivers however, fixed plants needed to grasp surfaces and developed means of doing so; but these were not roots as such – more like anchors. Later, as they colonised the land, most plants did indeed develop roots not only to anchor themselves in the ground or to cling to difficult surfaces but also to bring up water, the tap roots for this purpose often going quite deep. Roots also brought up nutrients.

The roots also made it possible to cling to inhospitable surfaces, including even the perpendicular or overhanging and also to exploit cracks and fissures by tunneling into them. In the course of this activity, plants changed their immediate physical environment, by helping to break down stone and also by trapping material blowing in the wind.

Buddleia bush clinging to a wall in Dublin (Photo source: D.Breatnach)

But why set up home clinging to a cliff or today, a wall or a chimney stack? Well, plenty of sunshine, for one thing, no competition for another! Of course, not much soil there or even none at all for nutrition – but still, most things in life are a trade-off, right? How did the seeds get up there in the first place? Wind … or birdshit.

Ivy making its way up a tree trunk.
(Photo source: Internet)

Of course, some of the colonisers developed other ways to cling to surfaces, as was the case with the mosses, lichens and liverworts. And they also trapped material and contributed their own to it as they died, regenerated, died …. But without roots that only works when you keep low and hug the ground. If you want to grow tall to reach for sunlight and if you want to exploit soil, you need roots.

Plants at first fed almost exclusively on sunlight it seems, broken down into sugars by chlorophyll in photosynthesis. But those that developed roots also, probably as anchors to prevent themselves being blown or washed away, or to help them grow tall and compete with other plants to catch the sun, learned to draw up water and to feed on nutrients in the soil – phosphates, nitrogen, potassium etc. Some, like the legumes, beans, peas and gorse for example, even learned to extract one of the gases that make up air, nitrogen and, with the help of a bacteria, to fix and store nodes of it around their roots.

Once you have roots, why not grow stems, branches, trunks, whereby you can reach higher and higher, for more unimpeded sunlight and outpacing the competition perhaps. Your building material will need to be tougher, especially for trees, bushes and shrubs, to bear the weight, withstand the winds …. but flexible enough to stretch as you grow. Having the ideal material already in cellulose, all that is necessary is some kind of hardening process. A plant might explain to puzzled humans: “Think of keratin and how the same basic substance has been used to make stuff as varied as feathers, fur, human hair and beetle carapaces.”

If you were a plant that had learned to spread fast over distances to catch the sun, covering ground and clambering over obstacles, you might find one day that there is another way to reach towards the sun – climb up the plants that are reaching up there! Don’t invest in slow build-up and hardening of cellulose – go for fast growth and gripping or winding ability instead, or turn some of your leaves into grasping tendrils. Some climbers such as lianas in the tropics and ivy and honeysuckle in Ireland, are perpetual climbers, remaining in position throughout the year (although the honeysuckle will lose most of its leaves in the Autumn) and extending during the growing seasons. Others climb only in the Spring and Summer and die afterwards, for example bindweed and runner-beans.

Runner Bean plants climbing a support structure (‘tower’) in a garden. (Photo source: Internet)

ENVIRONMENT-BUILDERS

          Most plants have leaves, which is where the photosynthesis takes place; they are in fact sunlight collectors and the plants deploy them to best effect to catch the available sun. Quite a late development, they were flanges on the stems first before becoming appendages further out of the plant’s main body. Most leaves are intricately veined and contain many different layers and parts and it is within them that photosynthesis takes place but strangely, they are mostly short-lived and in cold seasons even in perennial plants, with a few exception, all but the conifers let them fall.

The greater the volume of material created by plants, the more there was to decompose with their deaths or seasonal decline. Bacteria, already long existent on the planet, evolved to feed on this detritus and break it down into soil, which the same plants or others could turn to their advantage as a medium in which to anchor but also from which to draw nutrients. Other organisms evolved to live on and break down cellulose too, the main building material of plants: fungi, gastropods like snails and slugs, woodlice, termites …..

The plants, with the help of bacteria and other organisms, were creating the environment below them!

But they were and are doing more than that: they are also creating an environment immediately around them. The most concentrated examples are perhaps rain forests, tropical, temperate and cold-climate, retaining a surrounding moisture-laden air, in which not only the local tree species thrive but also providing ideal environments for ferns, algae, orchids and epiphytes and, of course, mosses.

Away from forests, sphagnum moss creates a mini-atmosphere around itself and as generations die, their bodies create a spongy moisture-laden medium. This bog is quite capable of existing on an incline, with much of the water being retained by the vegetation and ‘soil’, as may be seen in a number of examples in Ireland, such as parts of the Dublin and Wicklow Mountains.

Close-up of sphagnum moss, creator of its own environment and changer of landscape.
(Photo source: Internet)

 

Temperate Rainforest, Fraga do Eume park, Galicia, Spanish state. Despite the deforestation of Ireland during centuries of British occupation, areas such as parts of Wicklow arguably qualify for the description “rainforest”.
(Photo source: Wikipedia)

 

Plants, especially trees, discharge oxygen into the air and consume carbon dioxide during the daytime, for which reason they are sometimes called “the lungs of the world”. They have not only created an environment for themselves, below, around and above but also for so many other life-forms – including ourselves.

LEARNING TO LIVE IN DIFFERENT CLIMES

          Plants that adapted to grow in arid areas developed fleshy ‘leaves’ and often stalks, in which to store water and sometimes long tap roots to find that water. But extensive shallow root networks are good too, to collect the occasional rain water that is quickly absorbed into the soil or otherwise evaporates. The “pores” on leaves through which plants absorb carbon dioxide and allow the gas-exchange necessary for photosynthesis (stomates) also permit evaporation of water, hence many dry-condition plants have fewer of them. Some only open to collect carbon dioxide in the cool of the night and store it for use on the following day. Plants grow trichomes, tiny bristles, underneath their leaves but some arid-dwellers grow them also on top of their leaves; these ‘trap’ a layer of air that prevents or slows evaporation.

In very wet areas, plants learned to remain active by a number of strategies. Of course they originally came from aquatic environments but for some of them, returning there again after adapting to dry land, produced challenges (think of the changes necessary for land mammals to evolve into seals, otters, dolphins and whales). Nevertheless we have lilies growing in shallow water with wide floating leaves, rushes with upright blade-like leaves growing inside the water margins, thin spears of rushes in damp and water-logged land. That too is the preferred environment of some other plants and grasses, including the rice plant. And of the willows, alders and hazels growing on the banks and stabilising them. In the tropics and semi-tropics, mangroves do a similar job to willows but on a much grander scale – and they tolerate seawater too.

Selection of waterside plants, reeds and different types of willow tree, growing along the Royal Canal, Dublin, yesterday. (Photo source: D.Breatnach)
Immature cones of the alder showing among leaves of the tree.
(Photo source: Internet)

The alder, a tree with a high toleration of water around its roots, is thought to have been the major post-glacial coloniser of Ireland, following the retreating ice across the land. It is the only native tree which though not an evergreen produces cones, an indication of its early adaptation to cold climate. Cones, when closed, protect the seeds inside against continual freezing and thawing and, when the cones begin to dry and automatically open in spring and summer, allow the seeds inside to drop out to the ground, to be carried by river or on the wind. A closed cone collected and brought home will open as it dries; shake it then and the seeds will fall out. Alder timber, incidentally, remains waterproof for centuries, witness the wooden piles in Venice.

Adapting to cold seasons required protective materials, structures and timing. The deciduous trees (and it is worth noting that many trees have both a deciduous and an evergreen version for different climes) shed their leaves and close down for the winter, the sap retreating down to the roots. Were the sap to remain in the exposed branches it would freeze, expand and destroy them. The leaves drop because they no longer receive anything from the tree; it is going into a kind of hibernation, in preparation for the coming winter.

Many of the conifers have downward-sloping branches, to allow most of the snow to slide off, rather than break the branches with its weight. People who live in areas with heavy snowfall also tend to live under sharply sloping roofs. The “leaves” of the conifers are small, narrow and hard so that most snow falls through them and are also covered in a waxy polymer to withstand freezing. The plant cells can be emptied of water to prevent freezing but a dense waxy residue keeps them open for refilling. So, of course, they have to be tolerant of dehydration. Concentration of sugars also lowers the freezing point and small flexible conduits for water resist the formation of large ice bubbles that can burst those “pipes”.

AWARENESS

          Seeds know which way is “up” and which is “down”, which is quite an amazing thing; the tap root of a seed, germinating in the dark, goes downwards while its shoot grows upward.

In fact, the plant seed also knows the right time to germinate – too early in many climes and it will be killed by frost, too late and it will have insufficient time to develop before the next cold period or will be unable to compete with other seeds that sprouted earlier, depriving the late-comer of sunlight and possibly nutrients. The decision is made by a number of factors feeding into a small cluster in the seed tip, consisting of preventative and initiator command centres. When the initiator section’s hormones exceed that of the preventative, it is time to germinate. Not very different from our brains’ decision-making process, is it?

Also, cut a living branch and often the plant will mobilise to produce one or more shoots at the cut-site. But should that cut be enclosed within soil, the tree or bush will produce roots instead – it ‘knows’ the difference. This knowledge the gardener takes advantage of when she “air-layers” a shrub or tree by nicking a branch, then covers the cut with soil wrapped in a plastic bag, waiting for a root to develop and then cutting the cloned sapling free, ready to plant.

Air-layering a branch, possibly from a a peach tree. The branch inside the wrapping has been cut, packed around with soil, to fool the plant into sending out a root.
(Photo source: Internet)

Without eyes, plants are also capable of detecting where the light is; if one places a climbing plant seedling in a dark cellar with a small window high above, the plant will climb towards the window, striving to reach the light. The sunflower and the flowers of some other plants turn towards the sun, following its progress across the sky. Many flowers, including those of the dandelions and daisies all around us at this time of year, close when the day ends. A “Swiss Cheese Plant” I once had managed to slip one of its suckers — like a long surface root — down the back out of sight and when I eventually discovered it, the sucker had gone under the carpet and had extended around six feet towards the window.

Of course, it may have been searching for moisture.

Plants can sense moisture and do go looking for it, something at which eucalypts are particularly adept. Unfortunately, this can cause problems for other trees and shrubs growing in the same area, as the eucalypts suck up the water from greater depths (the eucalypt doesn’t care however nor do some of its planters). During the severe drought in parts of the USA last year, it was reported that trees were breaking open water pipes with their roots to get at the precious liquid. It appears that the reports were mistaken but instead the roots were extending towards the detected moisture from leaks in the pipework. Of course, then the roots might widen the gap ….

Some plants at least are also ‘aware’ of being attacked, for example by an infestation of caterpillars. Those that have reserves of a defensive poison at their disposal are not only able to deploy it but also to communicate to other nearby trees of the same species, so that they too deploy the poison – before the caterpillars have even reached them! It is thought that the trees communicate underground, through their roots.

Plants also know when their offspring have reached enough numbers and a sufficiently advanced stage so as to put their energy into maturing them, rather than producing more growth or even more seeds. Presumably they receive a chemical signal when enough roses have bloomed, been fertilised and the rose hips, the fruit containing the seeds, are swelling. Likewise when the beans inside a runner-bean pod have swollen and will shortly be ready to burst the pod and drop to earth. Gardeners know how to fool the plants into continuing to produce for a longer period by “dead-heading” dying flowers and picking runner-bean pods when they are still very young.

THORNS, SPINES, POISONS, GAS – AND HELPERS

           Among the many features that plants have developed are an impressive array of defences. Filamentous algae, with low mass investment and constantly renewing, probably did not need defences nor perhaps did the plants that first came ashore. Defence against what, after all? But later, as soon as animal life began to develop on land …..

Here in the north-west of Europe we are familiar with thorns and spines on the trunks and branches of the rose and briar, blackberry, gooseberry, gorse, blackthorn and hawthorn. It is not always on the trunks and branches that the sharp spikes are to be found, as we are reminded by the prickly leaves of the thistles and holly. Thorny and spiny defences are repeated around the world on other plants from acacias to cacti and many others. Thorns stab, rip and tear but spines lodge in the skin and continue to irritate, some forming sites of infection.

Well at least you’re safe among grass, right? Not necessarily, for example the dune builder grasses, marram or beach grass, can cut the skin of mammals moving through it. In other parts of the world they have aptly-named ‘sword’ and ‘saw’ grasses. Some of these cut with a thin edge but many with tiny hair-like spines growing on the underside of grass blades, called trichomes, defend against herbivorous invertebrates but may also cause “grass itch” in some people.

Mostly, these are a defence against grazing animals or protection against the theft of the plants’ fruits. Other plants have developed poisons, which they employ not only against mammal and bird grazers but also against insects such as caterpillars (as commented earlier) and locusts; examples in Ireland are the foxglove and the deadly nightshade or belladonna, a relative of the tomato and potato. Another is the hemlock, a relative of the carrot, parsley and angelica plants – even its sap can burn your skin. An invasive shrub or small tree, the cherry laurel, carries arsenic within its wood, leaves and berries and can be seen in many gardens, parks and growing wild around much of Wicklow.

Belladonna or Deadly Nightshade plant in flower with some immature berries (ultimately rich purple colour).
(Photo source: Internet)

But trees have also been observed to emit chemical compounds that attract the enemies of parasites or grazers feeding on the trees.

Poisons can be employed against competing plants too, as does the hydrangea, a shrub with lovely luxuriant flowers in your garden (or indeed in a public park in Howth) but a seriously invasive plant in the wild as it eliminates its competition and grows unchecked. It does this by a relationship with a bacteria around its roots that produces a poison to kill competing vegetation. However, the native pine also produces an allelopathy in its discarded needles, inhibiting the germination of other plant seeds and growth – it is not only the blocking of sunlight that keeps pine forests so free of undergrowth.

The onion carries an aroma warning that rough handling of the bulb will produce a gas attack on eyes and nasal passages, as known to any who have handled them in food preparation.

Plants employ some poisons continually but others selectively, as in ripening seeds (for example in the seed pods of the laburnum) or in sensitive growing tips (for example the fiddleheads or curled growing tips of bracken, toxic to grazers). The daffodil is a lovely plant and safe to handle but digging up the bulbs and mistaking them for wild onions can have fatal consequences for the eater. And as we have seen elsewhere, leaves can become poisonous as trees mobilise chemicals from tree to tree when under attack by caterpillars.

Growing tips of the bracken fern, known as “fiddleheads” – poisonous to grazers.
(Photo source: Internet)

However, some plants welcome insects as protectors too, as for example with a species of ant that lives in some acacias and helps keep the tree free of pathogens.

When considering plant poisons we are reminded too of the stinging nettle, which introduces its defence to us in childhood, never to be forgotten. In North America, one would always remember a brush with its poison ivy. The Giant Hogweed, also a member of the carrot and parsley family but invasive to Ireland, causes a very painful rash following bare skin contact.

There are many localised wars going on out there.

FLAUNTING FLOWERS – AND FLIERS, SAILORS, ROLLERS AND HITCHHIKERS

          Along with all their other innovations, plants evolved some very impressive ones in procreation, particularly in dispersing the next generation. Pollen, a fine powdery substance that is the equivalent of mammal sperm could be and was spread by the wind. The development of the flower and blossom brought in a partnership with animal pollinators to greater efficiency. Attracted by nectar and to some extent pollen, both insects and some birds visited male plants flaunting their flowers and unconsciously picked up pollen which they deposited at another flower they visited, thereby soon fertilising female flowers.

Flowers were developed in a huge variety of shapes and colours in order to attract pollinators — and then came smell. Some botanists speculate that scent was first used by some plants to discourage insects and grazers which, if true, is amazing enough. To then go on to develop scent to attract pollinators is a leap that staggers the imagination. Flowers and blossoms using smell are particularly noticeable at dusk and night, a time when flowers are hardly visible, when presumably they are visited by moths.

A hive honey-been, one of the most common pollinators, approaching a flower (perhaps a dandelion’s) intending to collect nectar and perhaps pollen but will certainly collect the latter inadvertently. Note the collection bag on its legs.
(Photo source: Internet)

Early plants did not have seeds so the whole paraphernalia around them had to be developed from other existing parts with originally different functions (some of us could convert a bicycle, a machine for locomotion, into an electric power generator but still ….)

Behind the flowers of many species is a little node which when fertilised begins to swell and form a fruit, with the developing seeds inside — or single seed in the case of Prunus species, the plum family, for example. This is another amazing trick of the plant – it has produced attractive fruits, full of sugars when ripe, to attract animals (such as ourselves) to pick them and either discard the seeds as we eat the fruit or pass them through our gut to be deposited on earth — along with a handy dollop of manure. A botanist investigating the occurrence of isolated copses of trees on the grassy plains of the South American Pampas concluded that horses were eating the nuts of the parent trees some distance away then, as they travelled across the plains, at some point defecated with some intact nuts among their faeces: some years later – a grove of trees. Of course horses have only been in the Pampas for a few centuries and probably the other local grazers don’t eat saplings.

Nuts are also stored in different caches by some mammals and birds, for example here in Ireland by squirrels and magpies. They don’t always dig up all the stores later – perhaps they forget where some of them were – and in the spring, those nuts become saplings.

Well enough. But producing fruit and nuts is a lot of work and depends on the assistance of animals, especially mammals and birds, for dispersal. Some plants scorn to use them and instead employ the wind. Dandelions, thistles and many other plants send their seeds off on downy parachutes, often to land kilometres away. Some, like the sycamore, grow “wings” on their seeds which, when dry, spin away on the wind and not only that but when they strike mud are sometimes twisted by the wind on their “wing” to ‘screw’ the seed into the soil.

Many plants with pods, for example the legumes, will have their pods crack open when dry to “spill the beans” upon the soil. That is not good enough for the gorse or furze, the pods of which explode on a summer’s day, shooting the seeds away. One such day I sat among gorse bushes on Killiney Hill and was startled to hear what sounded like a weak pistol shot. Then another …. and another …. and all around me the bushes were shooting out their seeds, the lucky ones to create new bushlets (yes, I did just make up that word) the following year.

The casings of chestnuts, both edible and the ‘conker’ variety hit the ground, some cracking open as they do so and roll away from the tree. The casings of the edible ones are spiny, which no doubt afford the nuts inside some protection from being eaten (and trodden) until they are covered by fallen leaves or strike a root into the ground. Again, the lucky ones will become saplings and, enough sunlight (and goats) permitting, grow to become trees. The Mexican “jumping bean” rolls itself away from its parent, turning over and over, albeit slowly.

With fruit and nuts we saw plant offspring being cached or stowing away inside birds and mammals. But some hitch-hike on the outside too, like the burs that work their way into animal fur and into our woolen clothing. These are seed cases covered in tiny hooks, said to have been the inspiration for the invention of velcro fastenings in clothes. The cleaver or “sticky-back” may attach many of its small burs to a passing mammal, while the burdock, with its much larger burs, is more likely to hitch a ride in ones or twos. Tiny seeds of many grasses stick to wool, fur and hair too, especially when damp. But many other grasses with larger seeds, including cereals, grow “ears” with spikes attached to each seed and these too, when dry and ready to go, get picked up by the wool or fur of passing traffic.

Hitchhiker seeds — the ‘fruits’ of the burdock after flowering become a bur to attach to passing traffic.
(Photo source: Internet)
All aspects of the Cleaver plant (“Stickyback”), another hitchhiker for its seeds.
(Photo source: Wikipedia)

The pines even use forest fires to spread seeds from inside their cones on the hot wind – each seed has a little vane around it to help it sail the wind. Sure, many will burn before they sail or blow into another fire – but some will survive. The alternative is just to burn.

The coconut, on the other hand, floats its fruit to distant shores – it is not for tourist brochures that the palms grew fringing tropical beaches. Falling coconuts roll away from the tree too – if they don’t hit some unfortunate large animal first. Many other plants use floods to populate different areas, often creating stronger banks or islands as their offspring grow, sometimes even changing the very course of a river or stream. The various willows and alders are adepts at this, as are many kinds of reeds and rushes.

The latter kind of colonisation may be by seeds but there are other methods too: severed branches or leaves that grow roots into water, uprooted saplings, tubers and bulbs. Bulbs, rhizomes and strings of tubers have been used by many plants to store food for offspring, nascent new plants hiding below or on the ground. Even when a field of potatoes is harvested, there are often tiny potatoes remaining that escaped the harvesting procedure – the following year, they may be seen, sprouting new plants.

Some plants are capable of employing all of the various methods of reproduction and distribution: seed, tuber, branch or leaf regeneration.

A somewhat similar method to strings of tubers – and possibly their actual origin – is the underground runner, like a root running just below and parallel to the surface, sending out shoots upwards and roots downwards at intervals, each of those becoming a new plant, a clone. Many grasses employ this procedure, some bunching close like the bamboo and others spreading away in different directions, as for example with the couch or scutch grass. The latter may be to the despair of the gardener, who however will use runners of the strawberry to grow new fruiting plants.

Grasses are a late and special kind of plant that can be grazed down to ground level and grow again, year after year. This provided a renewable food source for animals that could convert its leaves and seeds into sufficient energy – enter herds of goat and sheep, horse, donkey, zebra, deer, antelope, bison and cattle! And therefore enter their predators too, in particular the big cats, canines and – homo sapiens. She in turn would domesticate some of those species, including another predator as helper, the canine. That combination would change the world quite significantly and when homo sapiens learned to cultivate some of the grasses for their seeds, i.e cereals, well ……!

End.

NB: Thanks to Oisín Breatnach for editing work (all subsequent errors etc are mine) and Osgur Breatnach for reminding me of the onion in a separate discussion.

REFERENCES & SOURCES

Early appearance of plants: https://www.sciencemag.org/news/2018/02/land-plants-arose-earlier-thought-and-may-have-had-bigger-impact-evolution-animals

Leaves: https://en.wikipedia.org/wiki/Leaf

Native and invasive plants to Ireland: http://www.wildflowersofireland.net/

Deciding when to germinate: https://www.smithsonianmag.com/smart-news/seeds-use-tiny-brains-decide-when-germinate-180963625/

Tiny bristles in grass: https://www.quora.com/Why-does-grass-make-you-itchy

Ants protecting acacias from pathogens: http://www.messagetoeagle.com/acacia-tree-uses-ants-as-body-guards-and-rewards-them-with-shelter-and-food/

Plants inhibiting germination of competitors: https://en.wikipedia.org/wiki/Allelopathy

Poisonous effects of bracken on ruminants: https://link.springer.com/article/10.1007/s00580-018-2636-2

Trees summoning the predators on caterpillars: https://lt.org/publication/how-do-forest-trees-defend-themselves-against-insects-under-natural-conditions-and

Features of the alder: https://books.google.ie/books?id=uvNgBQAAQBAJ&pg=PT46&lpg=PT46&dq=how+long+does+alder+timber+remain+waterproof&source=bl&ots=h-

NATURE DOESN’T CARE

Diarmuid Breatnach

(Reading time: 3 minutes)

A number of people have commented on Nature proceeding unaffected by the crisis of humans faced with the current Coronavirus pandemic. Although not entirely unaffected, it certainly seems that is so but it is a reflection of our generally subjective view of the natural world around us that we should be surprised at all.

The grass does not grow for us though we may have sown some of it, the leaves do not open nor flowers bloom to please our eyes, the birds do not sing to bring us pleasure through our ears, nor do blossoms and flowers pump out fragrances to please our nostrils. They are engaged in the deadly serious business of alimentation and procreation.

Here in early April the leaves unfurling and already unfurled from their winter sleep inside their branches of willow, sycamore, birch, rowan, elder, lime, alder, oak and chestnut will not notice much difference this year as they spread their catchers to collect the rays of the sun, the chlorophyll working to feed a new year’s growth. The ash is a little behind, its hard black protective bud-covers about to break open. Flower racemes are already well advanced on the invasive and poisonous cherry laurel and making a good start on the horse chestnut tree. If they are aware of anything, it is probably that suddenly the air has become much cleaner, as the volume of industrial and vehicle air-pollutants has suddenly dropped dramatically.

Weeping willows (saileach shilte) along the Tulcadh (Tolka), Griffith Park, Dublin. early April.
(Photo source: D.Breatnach)

Not that it’s all peaceful out there – they all have their own struggles, competing for light and moisture, resisting attacks by insects, fungi and even other plants like ivy.

The robin (spideog), blackbird (londubh) and finch (glasán) are not singing for us nor even “merrily”, as the poets would have it – it’s a serious business, attracting a mate, fighting off competitors, then building a nest and raising young in safety from predators. The lowering of the air pollution level might bring a bloom in some invertebrate populations, animals without backbones like insects and snails, which would be welcomed to feed the birds’ young.

Birds (éanlaith) that will probably miss our usual level of activity will be those heavily dependent on human activity and some of its waste products, i.e the city pigeons (colúir) and seagulls (faoileáin), while the latter at sea might well do well from less commercial fishing and pollution. The fish will certainly benefit from a reduction in human activity.

In the streams and rivers the finger-length three-spined stickleback male will soon be establishing and defending his territory, where he will build a nest into which to entice an egg-filled female, there to lay her many eggs for him to fertilise. She’ll be off then, thank you ma’am and dad will raise the young until they are capable of free-swimming and feeding themselves, though still tiny. These are those that in parts of Ireland are called “pinkeens”, an interesting combination of two languages: the English “pink” and the diminutive ending “ín” in Irish (however the Irish name is completely different: “garmachán”). Look at the female and you’ll see no hint of the “pink” but the male in full breeding colour is something to see alright: throat and chest in bright red, an almost luminous green upper body and head with bright blue eyes.

Male Three-spined Stickleback in mating colours showing bright red belly and blue eyes.  This is a sub-species from British Columbia — the Irish version has a green head and body.  (Source photo: Internet)

In the city, with less waste on the street, the population of rats (francaigh) and mice (lucha) might be in for some tougher times, as might the foxes (sionnaigh). Developing a life-style as a scavenger on the refuse of other life-forms can be very beneficial but such populations are vulnerable to the fate of their unconscious benefactors.

Much animal and plant life benefits from the activity of humans, it is true – but a lot more suffers from it and would not be harmed at all by our disappearance.

A stand of different species of trees with cherry in blossom, Griffith Park, early April.
(Photo source: D.Breatnach)

End.

DATE-CALLING ACROSS THE CITY

(Nature In the City series)

Diarmuid Breatnach

(Reading time: 5 mins.)

These nights in March and early April you might hear and might have heard as far back as January, nearby or in the distance, a short sequence of barks: Bar! Bar! Bar! – something like that. Or rarely, a sequence of four. These are calls from a male fox, telling any vixen within hearing distance that he’s available – and any other males, to keep away.

          I think I have only heard them after midnight but then at various times throughout the night.

While humans in our society are practicing social distancing due to the Coronovirus-19 pandemic, the foxes are seeking social closeness. Or some of them are.

The dog fox is not after casual sex – if he mates, he will stay with the female and, when she is lactating, feed her and the cubs. Of course, that is more easily done in the city than in many rural locations, with the amount of food that is discarded by human society. Also, foxes are generally not hunted in the city where, if humans carry guns, it’s usually in order to shoot other humans.

The fox has to advertise and so does the vixen, because she will only come into estrus for one three-week period in the year. If dog fox doesn’t come calling then, he won’t be welcome later. If you have heard her calling for a mate, you won’t forget it: an almost unearthly scream which, if you didn’t know about it, would have you believing in the bean sí (banshee) or possibly a woman being attacked.

Should she find a mate, she will prepare a den, usually an adapted or newly-dug burrow, where the cubs will be born around 50 days later. They need the mother’s warmth until three weeks old to avoid hypothermia, so she cannot leave the den. Her mate, the dog fox, will go out each night and bring her back food and, when the cubs are but a little older, bring them some too – in his stomach. Regurgitated semi-digested food might not sound salubrious but the cubs could not manage anything else along with their mother’s milk. Sometimes there might be another but unmated female in attendance too; unmated companion females can give the vixen a break a little later so that she can go out foraging and hunting for herself.

Humans wean their young off milk with finely-mashed or even partly-chewed solids which, before baby foods were widely available, had to be prepared by parent or child-minder (frequently an older sibling). But then the human child has many years to come to full adulthood whereas the fox has to accomplish that in a year or a little over. In the wild, adult foxes generally live only as long as five years, while in captivity they can reach three times that.

The European Red Fox (Photo sourced: Internet)

A PEST?

           It is probably best not to feed foxes, which are after all wild animals that may become overly familiar, not only with their feeder and with their belongings – but with their neighbours’ things too. On an allotted piece of ground I rented from the local London authority years ago and where I cultivated vegetables and some fruit bushes, by day I often came across a chewed toy or a shoe, presumably taken from a nearby back garden and played with for awhile.

Finishing at dusk, I sometimes saw the ghostly shapes of adults and cubs, not fleeing but giving me a wide berth nevertheless.

Stories of them attacking and killing small dogs and cats are probably apocryphal for a number of reasons, chief among them being that they have no need to attack such animals since they have no shortage of food in the city. Also little dogs are not usually roaming around at night and, in a fox-watch documentary about urban foxes in I think Bristol city decades ago, every time a confrontation between a fox and a cat was filmed, it was the fox that backed down.

Unless one is keeping poultry or rabbits in pens or runs outside, it is hard to see how foxes can be classified as pests or seen as causing us problems. Even in rural areas, a ewe is quite capable of protecting a lamb from a fox, an animal which after all is not much bigger than a cat.

None of that information prevented Boris Johnston, when he was Mayor of London, from proposing a cull of the city’s foxes. Having observed this gentleman in action as the Prime Minister of the UK, most people will probably not be surprised that he had failed to learn from a comparatively recent history, because despite a large and expensive culling program in the 1970s, the fox population jumped right back.

PROTECTION?

          In a previous article published on the Rebel Breeze blog (Scream on a December Night) I wrote the following:

Some people have suggested that the red fox should be granted protected species status but it is difficult to see the rationale for this, since it is on the species of “least concern” list of the International Union for the Conservation of Nature. Pigeons receive no protection and, though often fed by people who consider them cute or pretty, do have a negative effect on our urban environment and, in the case of seagulls, who are protected, may be responsible for the disappearance of the many species of ducks that once were common in Stephens’ Green. Rats and mice are not deliberately fed or considered cute by most people (though I have kept both myself and found the individuals tame and harmless and, in the case of rats, quite intelligent) and humanity wages war upon them with traps and poison.

Do urban foxes require management? Zoologist Dave Wall, who has studied Dublin’s urban foxes for some years, thinks not. In his opinion, the fox population in Dublin has remained constant since the 1980s. According to statistics regularly quoted but never referenced that I can find, Dublin fox families occupy on average 1.04 Km². Given a rough and probably low estimate of six individuals per fox family (a mated pair and two unmated females and two cubs) and a Dublin City area of 115 km² would give us a fox population of 663 in the city. That might seem a lot, until one hears that London holds an estimated 10,000.”

end.

LION’S TEETH IN BLOOM FOR SUMMER

Diarmuid Breatnach

(Reading time: 7 minutes)

No, that title is not a cryptic clue for a crossword but instead refers to a very common and much-despised plant with a truly remarkable story. A plant that has found amazing ways of propagation and distribution.

         The week before last I saw my first dandelion of this year in bloom in Dublin. On a cold, dark and wet day, it had its sunny bloom shining on a bit of waste ground. And not far from it, a coltsfoot (Tussilago farfara) in bloom too, a relative in the same genus sometimes confused with the dandelion, also in bloom. But this is the story of the ubiquitous dandelion, which we knew as “Piss (or Wet) the Bed”, from a mistaken belief that keeping the blooms in one’s bedroom would make one void one’s bladder while sleeping.

We have two common species of dandelion in Ireland, T. vulgaris and T. officinalis, Caisearbhán and Caisearbhán Caol Dearg (?) respectively in Irish. They belong to the genus or larger family of Asteraceae, one of the two largest genera of the flower family, including so many species, from the diminutive daisy to the giant sunflower.

It is an important early source of pollen and nectar for insects in this latitude, when not many other blooms are about.

The name “dandelion” is a rendition of the pronunciation in French of “dents de lion”, i.e “lion’s teeth”, said to refer to the serration of the leaves reminding people of lion’s teeth. Well, perhaps of a cartoon or heraldic lion, or one as imagined by Europeans who had never seen the animal.

As the season progresses, soon those cheerful yellow blooms will be seen everywhere, on roadside verges and waste ground, in gardens and fields, in woodlands, on hillsides ….. Except in bogs and strangely in some parts of the Burren1, there is hardly a place where it cannot be found, which makes us see it as common and perhaps view it with disdain.

But it is far from being an everyday plant.

PUFF CLOCK AND PARACHUTE BABIES

       As children, we thought to tell the time by blowing on the fluffy balls that develop from the bloom in late Summer or Autumn, each puff being an hour and the correct time being the number of puffs to blow the last seed parachute away. It seems unlikely such an impractical idea would have occurred to us and we only did so because we had been told about it by adults.

But there is some wonder in those fluffy balls, full of separate parachutes, each bearing one seed. This is possible because what I have been deliberately calling a “bloom” rather than a “flower” is, properly speaking, a capitulum, a head actually containing many, many little flowers, or florets – and each one of those will bear a seed. It is a wonderful arrangement capable of producing a multiplicity of seeds even if parts of the bloom are damaged.

Each floret grows a silky “parachute”, the plant not only using the wind for seed dispersal (as do grasses with pollen) but developing such a means of delivery to cover great distance.

Seed-bearing puff-ball or “clock” of the dandelion (Source photo: Wikipedia)

Upon hitting disturbed ground or even a crevice with soil, the seed takes quickly – the dandelion’s children are great opportunists — and sends down a long taproot, while above ground, leaves grow in a rosette shape upon rosette, later sending out hollow stalks that will bear the bloom of florets. Each bloom responds to changes in light, in fine weather stretching the florets to the sun and following its course across the sky, or closing the head up as soon as rain threatens, opening also for sunrise and closing at evening.”1 As the florets die, their bracts close and the seeds and parachutes develop inside; then their surrounding bracts drop, allowing the expansion of the full ball of silky parachutes – i.e the maximum possible number of seed-carriers.

When the seeds have gone with the wind, the hollow stem dries up and falls away. The tap-root regularly shrinks and pulls the rosette of leaves tight to the ground: maximum absorption of sun and moisture but also maximum possible cover on ground, making it difficult for other plants to compete close to it.

Unless I dreamed it, somewhere I came across a phrase and image that I considered very democratic but have not been able to find it since. I had thought it spoken by a Shakespearian character but no search has turned it up. As I recall it, a worker or person of “low” social status says that his blood is as good as any royal person’s, for “a king on the march scatters his seed like a dandelion”!

Stages of flowering dandelion from bud to puff-ball, showing also leaves and root. (Photo sourced: Internet)

To the average flower or vegetable gardener, the dandelion is an invasive noxious weed, rapidly colonising newly-dug, hoed or even raked soil and competing with what it is desired to grow. And the fact that hoeing the leaves off even a couple of times will not kill the plant, the root sending out new shoots, makes it worse. Using a rotavator chops up the tap root but many of the resulting sections can regenerate and start a new plant.

All this is amazing enough, were it not for the plant’s sex life – or absence of it!

SEEDS WITHOUT SEX

       Most flowers, blossoms and blooms exchange pollen, usually with the assistance of pollinators – generally insects and in particular, bees. This fertilises the plants and causes the production of seeds, whether in the form of fruit or nuts or just plain “seeds”. The shape and colour of the bloom attracts the pollinator, knowing that inside there is nectar and pollen to be eaten (or collected, in the case of bees).

Well, dandelion blooms contain nectar and are visited by many insects, including bees – but the plants don’t exchange pollen in order to produce seeds. They produce the seeds alright, as we have seen – but asexually. Without sex. So why produce blooms and nectar at all?

Each new plant is a copy of the parent but no breeding occurs. Another mystery: there are a huge number of different microspecies of dandelion, differing in sometimes minute ways from one another and living and seeding in the same general area (more than 70 in Co. Dublin alone3). ‘In the British Isles alone, 234 microspecies are recognised in nine loosely defined sections, of which 40 are “probably endemic.”4

Let’s imagine an ancestral dandelion plant – how did it come to produce all these micro-species, seeding true but each separate and without cross-breeding? Botanists don’t seem to know: ‘the humble dandelion is, indeed, as the new Webb’s An Irish Flora confirms, “a very difficult genus”, its flowers not always to be told apart, even in the hand. The American ecologist Paul Ehrlich once described the reproductive policy of dandelions as “perhaps the greatest mystery in the world of plant sex”. 5

FOOD, DRINK, DYE …. AND RUBBER?

       All over Europe and Asia the plant has been known for culinary and/ or medicinal qualities but rather than just quote hearsay and unverified publications, I prefer to pass over most of the detail of these alleged qualities as the subject requires more research than I am prepared to undertake at this time.

All of the dandelion plant is edible1, except perhaps the bloom-stem: root, leaves, buds and blooms. Which is probably how this native Eurasian plant came to colonise America (though North America does have its own native species too) – brought there as a culinary plant by European colonists. The green leaves are likely to be too bitter for many tastes unless blanched first – i.e covered to deny them sun for a week or so, when they will turn yellow and lose much of their bitterness but still remain crisp.

The typical rosette growth-pattern of the dandelion leaves.
(Photo sourced: Internet)

Dandelion wine has been made from the flowers (a gallon of flowers for a gallon of wine7, but some other ingredients must be added, as with all European plants with the exception of the grape or the gooseberry). A mildly-fermented drink, dandelion and burdock8, has also been made from a combination of the dandelion flowers and burdock roots.

Dandelion wine
(Photo sourced: Internet)

The flowers have also been dried, then ground into a powder to make a light yellow dye but I lack information on its colourfastness.

The white sticky liquid (latex) in the stems and along the main rib of the larger leaves has been said to remove warts but having tried it myself without success I doubt this claim. Furthermore, I believe the remedy may be confused with a similar-looking white sap from a completely different plant, the petty spurge (also known as “milkweed” and other common names), Euphorbia peplus, which I have found efficacious. However, the white sap in the dandelion has been developed by selective cultivation in one species to replicate the latex of the rubber tree9 and dandelion rubber may one day become a familiar product.

Soon, this seemingly ubiquitous flower of many “cousins” and many uses, an opportunist colonist with thousands of daughters sailing the wind, will be brightening our ways everywhere. Once we know even some of its qualities, can we ever again look at the dandelion with disdain?

End.

 

A field of dandelions. (Photo sourced: Internet)

FOOTNOTES

1In New Atlas of British Irish Flora, quoted by Michael Viney, “Pissey beds lion’s tooth” etc (see Sources, References)

2Ibid, also Taraxacum – ‘A very difficult genus of a multitude forms, which set seed without pollinating, and never, therefore, interbreed.’ An Irish Flora by D A Webb, Sc.D. 1977, quoted in Wildflowers of Ireland (References, Sources).

3Ibid.

4 Stace, C.A, New Flora of the British Isles, quoted in Taxacum (References, Sources)

5Michael Viney, Irish Times (References, Sources)

6Taraxacum (Sources, References)

7Michael Viney, Irish Times (References, Sources)

8Not the commercially-produced and carbonated drink

9Taraxacum, ‘As a source of natural rubber’ (Sources, References)

SOURCES, REFERENCES:

https://en.wikipedia.org/wiki/Taraxacum

In Irish: https://blogs.transparent.com/irish/blath-bui-eile-an-caisearbhan-dandelion-in-irish/

http://www.wildflowersofireland.net/plant_detail.php?id_flower=86

https://www.irishtimes.com/news/environment/pissy-beds-lion-s-tooth-it-has-to-be-the-dandelion-1.515483

Petty Spurge as cure for warts (and variety as cure for skin cancer): https://en.wikipedia.org/wiki/Euphorbia_peplus

and https://www.teagasc.ie/media/website/crops/horticulture/vegetables/Illustrated_Guide_to_Horticultural_Weeds.pdf

DON’T CARE ABOUT HISTORY?

(Reading time: three minutes)

Diarmuid Breatnach

You don’t care about history? Well, perhaps but history cares about you. Or rather, it affects you and the world you live in, explains how you got to where you are, your successes and failures – and where you might yet go.

          Of course, what I said earlier was kind of a slick answer; history doesn’t really care about you …. or about me …. or anyone else. The wind moves the trees, fills the sails, cools us or brings rain or snow – it affects us, moves us and things around us …. but is not moved by us. That is a useful metaphor because often people think they can stop some things happening by wishing strongly that they would not. Liberals and social democrats, for example …. But the metaphor breaks down – unlike our relationship with the wind, we can move things.

The shape of a tree testifies to the forces that have come to bear upon it as it was growing and its bark rings tell us of years of plenty or scarcity. To say that you don’t care about history is like, in a way, saying you don’t care about your childhood. That period of your past life and the influences that came to bear upon it and how you reacted to them have made you, to an extent, who you are today. Certainly they have hugely affected you, as any psychologist will tell.

Tree Bent by Wind in Grass
A tree shaped in its growing by prevailing wind etc, revealing an important part of its history. (Photo source: Internet)

If you really don’t care about history, you should not care whether you experience pain or pleasure. Typically, humans like to repeat pleasure and to avoid pain. But how do we know in advance what will give us pleasure or instead cause us pain? Experience. And that too is a kind of history. Which may also teach us what pleasure may be reached through pain, as for example in certain kinds of exercise – or what pleasures may end in pain, as with addictions. And we don’t only have our own experience to go on but that of many others, in their stories and in the accounts of those who have studied them. Another kind of history.

To say that you don’t care about history is to say that you don’t care about cause and effect. You don’t care about science, in other words. Science, in the sense of observation of processes and in the sense of experiment, is a kind of history. If you do this to that, in this atmosphere at that temperature, this will be the result. How do we know? It has been observed or tested, time and time again and recorded. Very like history.

Perhaps history was not taught to you in the way most suited to you at the time. Or rather, perhaps it was not introduced to you as it would best have been. A required subject to study, to gain marks and to ignore forever afterwards is hardly likely to inspire. A list of dates, of kings and queens, of prime ministers, along with their desires, though they figure in it, is not really history. “Facts” without encouragement to challenge, to interpret, to ask and to search for why and how – these drive some minds away while others learn them – but only as dogma.

History Cursive Script Blackboard

Kings, Queens, Generals and Leaders of insurgents helped make history – but they didn’t really make history, though we are told they did and often say it ourselves. No king built a castle or a city though we are often told that is what happened. People build castles and cities: they dig foundations and sewers or latrines, dig wells or canals, cut timber and stone, mine and forge metal, construct buildings, grow food, settle, take up livelihoods, raise children, study nature, perform arts, record in print or orally …. History was made by people, ordinary people mostly with a few extraordinary individuals; history was made by people like you and I.

Or perhaps you acknowledge all that but think ok, as an ordinary person, there is nothing you can consciously do to alter the course of things now? Yes, our masters would like you to think that. The reality is that you can make choices: to join that organisation or movement, participate in that action or demonstration …. or not. To vote for one person or party or another – or to abstain. To treat people in this or that way.

What will help you make those choices? Well, for a start, your experience. And experience is a personal history. I did that and this happened; I didn’t agree with that outcome so now I will do something else. But we also have the experiences of millions of others upon which to draw, across thousands of years. History.

Rights Man Book Cover Penguin French Revolution
Thomas Paine’s writings influenced republican thinking which in turn led many to revolution. A tree shaped in its growing by prevailing wind etc. (Photo source: Internet)
USA Emmet Washington DC monument
Washington DC Monument to Irish Republican revolutionary Robert Emmet, a United irishman (a copy of the monument is in Stephens Green, Dublin). He was part of a historical process. A tree shaped in its growing by prevailing wind etc. (Photo source: Internet)

You are not an isolated individual and your people, your nation or state, is not an isolated mass. The productive forces of emerging capitalism struggled with monarchy and feudalist systems and elites and produced republicanism. Republican ideas were promoted by English and French intellectuals, for example and found receptive minds among the capitalist sons and daughters of English colonists in Ireland, bringing about the bid for a democratic parliament of all the people in Ireland. When that attempt failed, the ideas impelled some to found the United Irishmen, which hundreds of thousands of others supported because they wished for freedom from the colonial power. Less than a decade after the failure of Grattan’s Parliament to admit representation by Catholic and Dissenter, the United Irish rose in revolutionary upsurge. That was in 1798 and they looked for support from republican France, which had its revolution less than a decade earlier, in 1789. The Irish and the French republicans were encouraged by the American Revolution, which had begun in 1765 and emerged victorious in 1783.

The republican revolutions were carried out by the ordinary mass of people but it was the capitalist class that they brought to power; today the working class struggle to overcome them and come into power themselves, for the first time a majority class taking power and holding up the possibility of the end of classes and therefore of class exploitation. “The history of all hitherto existing society is the history of class struggles”, wrote Karly Marx and Frederick Engels in the Communist Manifesto, published in 1848.

Communist Manifesto Clenched Fist Book Cover

You are in history. You are a product of history. What you do now affects the historical outcome to some degree at least – to one degree or another you are making history. You might as well study its process and use its lessons to illuminate your way: the distilled and concentrated experiences of millions of human beings like you.

End.

THE SHAMROCK IS BLOOMING

Diarmuid Breatnach

 

This month the shamrock is blooming all around. The cluster flower is not very prominent individually but together can produce a yellow-green carpet effect, yellow for the flowers and green for the leaves.

The flowering shamrock in short grass in Dublin north city centre
(Photo: D.Breatnach)

 

Who is to say that the shamrock has a yellow flower? Why not the white clover? Well, amateur botanist and zoologist Nathaniel Colgan (1851-1919) once asked people from around Ireland to send him specimens of what they believed to be an Irish shamrock and identified the five most common plant species, of which the two most common were the yellow (flowering) clover followed by the white. A hundred years later, Dr Charles Nelson repeated the experiment in 1988 and found that yellow clover was still the most commonly chosen. According to Wikipedia, yellow clover is also the species cultivated for sale in Ireland on Saint Patrick’s Day and is the one nominated by the Department of Agriculture as the “official” shamrock of Ireland.

But sometimes, the yellow-flowered species Trifolium dubium (Irish: Seamair bhuí) can be found growing next to the white-flowered Trifolium repens (White Clover; Irish: Seamair bhán), although they never really intermingle.

White Clover and flowering Shamrock growing near one another in Glasnevin, Dublin.
(Photo: D.Breatnach)

The clover family belong to a group of plants that have the ability to fix nitrogen in nodes around their roots and, as a result, provide nutrition for plants that need nitrogen. The plant, like the rest of its family, produces pods but in the shamrock’s case, the pods are tiny and contain only a single seed. Pods protect the development of seeds until they are ready to shed (or in some cases, like the gorse or furze, to explode!).

In cropped or mown lawns, or in poor soil, the shamrock hugs the ground. However, given conditions for growth but having to compete with other plants for sunlight, it will grow long stems reaching upwards.

Once flowering is over, probably in August, one can dig up a small section and transplant to flower box or pot in order to harvest sprigs of it for St. Patrick’s day on March 17th (a tradition that is nothing as old as people might think).

Closeup view of the flowering shamrock, Glasnevin, Dublin.
(Photo: D.Breatnach)

But nobody planted the shamrock in the lawn – it got there by its own natural methods, possibly by wind or in animal excreta. Unlike the lawn on which it has set up its colonies, which was seeded on raked earth or, more likely, laid in grass turf rolls, it is in fact a part of wildlife in the city.

end