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.
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.
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.
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?
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.
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).
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.
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.
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.
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.
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.
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.
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.
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.
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.
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”.
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.
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.
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.
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.
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.
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 ……!
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.
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.
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.
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.
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.
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.
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 115km² 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.”
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.
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 speciesTrifolium 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.
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).
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.
Nobody can say with absolute certainty which specific plant is the “dear little shamrock” and perhaps it was a name given to several plants. The most widely accepted candidates are the species Trifolium dubium (Irish: Seamair bhuí), with yellow flowers or the white-flowered Trifolium repens (White Clover; Irish: Seamair bhán). The yellow-flowering one, a native plant to Ireland and the European mainland, goes by a number of common names in English: Lesser Trefoil, Suckling Clover, Little Hop Clover and Lesser Hop Trefoil.
Right now, the yellow is flowering. Once established, this plant thrives on lawns that are regularly mowed and it has little competition for light or alimentation (though it may not grow as lushly as in damper places) and there it establishes colonies, shamrock patches among the mown grass. Now, in early June, the lawn is dotted with patches of yellow flowers, to be visited by insect pollinators, soon to produce seeds. The plant, like the rest of its family, produces pods but in this 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).
People who like their lawns smooth and well-tended may resent clover patches since they tend not to wear as well as the mixed grasses with which lawns are seeded. Nevertheless, the plant is benefiting the soil and indeed the nearby grasses. It belongs to the clovers, belonging in turn to a very large group of plants in as different in appearance from one another as peas and beans on the one hand and furze (also known as gorse) on the other (but many bearing fruit pods). They are the legume group, plants that concentrate nitrogen in nodules around their roots, making many of them good crops with which to precede plants that require a lot of nitrogen, such as the cabbage family or cereals.
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.
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).
But nobody planted the yellow 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.
As we have been shown this year, if we did not already know, Spring comes in its own time. Roughly around the calendar yes, but not exactly. It’s not like the clothing merchants, who withdrew the gloves in March and left people like me, who regularly lose them, with frozen hands unable to buy cheap replacements while the models stood in windows in shorts and bikinis.
But spring wild flowers are already out and have been for weeks, though the city is not a great place to see them. However in gardens, parks, canal banks and on empty sites, the dandelion, much disregarded as a decorative flower has been flaunting its bright yellow flower for weeks and will continue to do so for quite a while yet.
In early April I spent a few days in Wicklow by the Dartry river. In a very short walk to Ashford I encountered eight types of wild flowers in bloom, including furze (or gorse), daisies,
groundsel, cat’s ear, speedwell, and of course dandelion. On a longer walk heading away from the river I came upon primrose, lesser celandine and wild or barren strawberry (not knowing how to tell the two apart at this time of year). And a mystery plant also (see photo). Swathes of wild garlic (creamh), grew both sides of the country road; I had long thought this plant a foreign import but it seems I was wrong. It certainly spreads when established however, as witnessed by this Wicklow road and wooded areas of Dalkey Hill where I have also seen large patches of it. My father transplanted some to our garden but rarely used it in cooking – or if he did, not often enough, for it soon took over large areas of the smallish garden.
At a Wicklow hotel garden’s bird feeder, blue tit, chaffinch and some other species flicked in to take a snack and flicked out again, making it very difficult to photograph them but which of course did not bother them at all.
Returning through Ashford (Áth na Fuinseoige) I came across one of our
feathered anglers, the smaller grey heron. Patience personified, this species stands in the water waiting for the appropriate moment to strike, apparently not feeling the cold. But perhaps this one did feel it, for it stood on the bank.
The Gael reckoned the start of Spring with the feast of St. Brigid (and probably the Goddess Brig before her), February 1st, when the ewes come into milk, with their expected birth of lambs. As Brigid/ Brig was associated with butter in some traditions it is possible that some early butter was made from sheep’s milk, though that is not recorded in records, as far as I know. The lambs and many other animals born in Spring had no choice regarding when to appear – that had been decided in the Autumn or Summer of the year before when their mothers mated. Birds, on the other hand, who are more vulnerable, mate in the Spring itself.
In Dublin city until perhaps a week ago, there was very little sign of Spring apart from the lengthening of the day. The blind wandering poet Antoine Ó Raifteirí (1779-1835), writing in the month of January, was already anticipating spring in one of his better-known poems:
Anois teacht an Earraigh beidh an lá dúl chun síneadh,
Is tar éis na féil’ Bríde ardóigh mé mo sheol;
Ó chur mé ‘mo cheann é, ní stopfaidh mé choíche
Go seasfaidh mé síos i lár Chondae Mhaigh Eo.
He’s thinking of heading home to County Mayo, he feels Spring coming but will wait until Bridget’s feast day to “hoist his sail” and since it’s in his head now won’t stop till he gets there. We might have been anticipating Spring ourselves in January this year and into February — though cold and wet enough — but if so we were in for a shock towards the end of the month and into March with “snow dumps”.
The birds have to set up their territory even so and in fact the robin (Spideog) was marking its territory in song sporadically through December and January, often enough even at night in the city and particularly near street or train station lighting. The polygamous wren (Dreoilín), if not already at it followed in February. The seagulls at their nesting sites on roofs were calling and mating in mid-March but may have been delayed a little by the snow; however they are hardy birds. Some blackbird males have been singing since March and now are all in full throaty song. In March also we heard the high-pitched “peeps” of those acrobats, the tits as they foraged for invertebrates through the branches of tree and bush and at the end of April, also the bursts of chaffinch song which remind us often of caged canaries — and why not, when the canaries are often taught that very bird’s song to sing.
January was the time to hear adult foxes in the city, the somewhat frightening scream of the vixen and the two or three-times bark in quick succession of the dog fox. This month the cubs, born a month earlier, will venture out of their den and may be heard sometimes by night at play too, though this is more likely in the months to come.
The trees and ground plants apparently respond more to length and angle of sunlight to tell them it is time to grow from seed or to burst open into bud and some of them are doing so now in late April, for example the birch (Beith). Others delay and the ash trees (source of our camáin or hurley sticks and much else) are still in their black hard bud stage in late April and the oak waits along too. Trees that flower tend to do so first and put out leaf later, as the blackthorn (Draighneán donn) did in February with its little white blossoms which will develop into sloes (airne) later in the year. In March hawthorn (Sceach geal), willow (Sail, from which we get “The Sally Gardens”) and elder (Ceireachán), all of which may be seen in gardens or parks (and the elder growing even on empty sites) were already green-misting in tiny leaf and are now well advanced. The “candles” of the horse chestnut (Crann Cnó capaill), to be seen in parks and in some leafy suburb streets, are however forming alongside the tree’s large leaves right now at the end of April (Aibreán) and the rowan (Caorthann) and sycamore (Seiceamar) of the whirling seeds are also in stages of leaf.
Spring is really coming for us but for many plants, mammals and birds, it is already here.
PS: When checking The Tree Council of Ireland for tree species names in Irish, I was shocked to find that they do not supply them. Nor reference the huge number of places across the land whose names in English are corruptions of the original Irish place names derived from the names of trees.
They are all around us; they live but they are not animals. Nor are they micro-organisms – we see them clearly all in many places. They can grow on organic and none-organic surfaces. We might think they are plants – algae, moss or fungus but they are none of those — they are lichens. There are about 20,000 known species1 and they cover an estimated 6% of the Earth’s surface, able to exist in environments as different as beneath Artic snow, on salt spray-showered seashores and windswept mountain rocks and in tropical rainforest. An estimated 6% of the Earth’s land surface is covered by lichen species.2 Some are long-lived and include the longest-living things on Earth. There are species that require nothing to cling to while others can live inside rock, in the spaces between grains.3In Ireland, 1,134 separate species of lichen have been recognised, according to the National Biodiversity Data Centre – i.e over 5% of Earth’s estimated total species right here on this little island.4
When we look at some growing on tree bark or rock, we are tempted to think of them as fungus, algae or even moss. Mosses are ancient enough life-forms and are plants, which algae are too and almost certainly much older. Fungi used to be considered plants but are so no longer and in their structure and digestion and also genes, are more akin and more closely related to animals. This will not be good news to vegetarians or vegans but the evidence is difficult to deny.5 Indeed there are some feoilséantóirí (word in Irish for a vegetarian and more apt in the context of this sentence) who already dislike eating many fungi because the texture reminds them of meat.
But lichens are neitherfungi nor plants.
So if lichens are not plant or fungus, what are they? Another kind of life-form? Well yes … and no. They are a combination of both, fungus and plant. At some point in the evolution of life on earth, logically after plants and after fungi had evolved, somehow some species of fungi combined with some species of alga and/or cyanobacteria6 and produced a symbiont or biont: lichen. Scientists maintain that the 20,000 estimated species did not evolve from one common ancestor but that different species appeared separately at different times during the history of the Earth.
Plants draw their nutrients from sun and elements in the soil (or in some cases, in the water). Fungi, like animals, cannot get their nutrients straight from sun or soil and need to break down their alimentation materials, whether flesh or plant, in order to feed on them. In doing so, fungi are important decomposing agents – in fact, the principal ones.
Vascular plants need roots not just to cling to soil but even more importantly, to draw up water and nutrients but algae don’t; when they have any kind of roots, it is to cling to a surface and that is exactly what the lichen needs too. Fungi extend and feed through root-like growths usually under the surface of what they are feeding upon, extending from the tips; they are not roots, however and break off easily.What we see of fungi is usually the spore-bearing parts above the surface, often much the smaller part of the organism.
Plants seem to grow above ground also by elongating their tips but in fact are extending from further back, adding cells to cells to lengthen the body. All plants need a constant supply of water (cacti and succulents store water but still need to draw on the supply to live). Fungi need damp conditions. But when combined into lichens, the new species can live without water for a considerable time. So, a marriage, as they say, “made in Heaven” … or perhaps in a Hell, an environment of very dry and hot conditions alternating with the very wet and cold , where the newly-wedded ancient algae and fungi set out to build their homes.
Some lichens contain not only algae combined with a fungus but also a cyanobacterium; this partner is capable of fixing nitrogen extracted from the air and is a valuable addition to the menage-a-trois.
It has been remarked by some that the marriage of plant and fungus is not an equal one, is not true symbiosis, since the fungal partner or symbiote benefits more than does the algal. The algal symbiote produces sugar through photosynthesis and the fungus only chitin, or ‘hard‘ structure, it is argued. However, if both partners (or three) are content with the arrangement, is that not a happy marriage? More seriously, the fungal partner may contribute other factors to the symbiosis of which scientists are only just becoming aware – for example, chemicals to repel organisms attempting to graze on them and protection from the sun.
And scientists do not treat them equally either, since the species of lichen is always determined and named by them according to the species of fungus, not of the alga or bacterium.
COLOURS IN THE RAIN
So, if the claim is that we see them all around us, where are they? They may be seen on slate roof-tops, in patches of roughly circular white (not to be confused with pigeon or seagull excrement, which may also be in evidence). Yellow or orange patches are typically seen on stone, as is a black or dark brown one by the seaside. A bright yellow-green one may be seen on fallen twigs or on tree-bark, as may also a tufted-form green one growing on rock or tree.
The colours tend to be particularly vivid during or soon after rain when the cortex becomes translucent and, if there were no other reason to be grateful for the precipitation levels usual in Ireland, that would be reason enough, perhaps, should we take the time to admire the little things of beauty. Of course there are other reasons and as a Basque once said to me about the green of his native country and could perhaps even more accurately said about colour associated with the “Emerald Isle” — “It’s not green because we paint it.”
Some of the bright colours in lichens, produced by the fungus, are thought to be of use in protection from the rays of the sun and become more vivid after rain due to rapid absorption of water by the chlorophyl-holding part of the symbiont (or biont).
PIONEERS AND SURVIVORS
Lichens are considered “pioneer organisms” by botanists and geologists, i.e organisms that set out to colonise new territories. These maybe new territories in the sense that a geological change has exposed them to air, e.g from the seabed or from under ice, or from inside the earth by volcanic action or by tectonic plate collision.
Pioneer organisms need to be tough and adaptable and they often create footholds for other species, not quite so tough or adaptable, to follow after. However, given that logic dictates that algae and fungi existed before some of them combined to form lichens, the latter could not have been among the earliest colonisers of the Earth’s crust. On Earth then, they are later pioneers of newly-created inhospitable terrain.
May they be used to help create habitable environments elsewhere? It’s perhaps worth quoting these two paragraphs from Wikipedia in their entirety:
In tests, lichen survived and showed remarkable results on the adaptation capacity of photosynthetic activity with the simulation time of 34 days under Martian conditions in the Mars Simulation Laboratory (MSL) maintained by the German Aerospace Center (DLR).
The European Space Agency has discovered that lichens can survive unprotected in space. In an experiment led by Leopoldo Sancho from the Complutense University of Madrid, two species of lichen — Rhizocarpon geographicum7 and Xanthoria elegans — were sealed in a capsule and launched on a Russian Soyuz rocket 31 May 2005. Once in orbit, the capsules were opened and the lichens were directly exposed to the vacuum of space with its widely fluctuating temperatures and cosmic radiation. After 15 days, the lichens were brought back to earth and were found to be in full health with no discernible damage from their time in orbit.
In some areas, soil lichens help to bind the sand-crust or soil-crust together but lichens have also been shown to chemically attack stone, thereby helping to create soil. Lichens can also help create little environments where soil may be retained and seeds of plants germinate. However, like all species, lichens are out to help themselves and some produce chemicals to restrict the march of mosses (another pioneer species but more water-reliant), with which lichens would have to compete in many areas).
When growing on tree bark, lichens do not parasitise on the tree nor harm it in any way, merely using it as a secure base. Older trees are often covered with lichen and dead trees or branches more so, associating in some people’s minds the ill-health in a tree with the growth of lichen upon it. Circumstantial evidence may suggest the guilt of the lichen but it is completely a case of coincidence: lichen is slow-growing and the older the tree, the more time lichen has had to grow and extend upon it; the tree dies because it grows old.
The lichen will survive the dead tree for a period but it is not the killer. Now come decomposers: insects, snails, slugs and especially, distant relatives of the lichens: fungi. Without concern for their relatives, the fungi, along with the other decomposers, will reduce the tree to soil ingredients and thereby deprive the lichens of their base but, in time, providing more soil for more trees to grow and for new generation of lichens to attach themselves to the bark.
The fungus is not too discriminating and a particular species may combine with different algae species; the resultant lichens may appear to be different species but (since 2014) will be classified as the same lichen species, i.e containing the samespecies of fungus.8
The alga can also exist independently in nature but the fungi cannot. Two species in two genera of green algae are found in over 35% of all lichens, but can only rarely be found living on their own outside of a lichen.9
Sex and Reproduction
It is only the fungal part of the symbiote that reproduces sexually. When doing so, it produces spores (as do ferns and mosses) which must find a compatible alga in order to produce a new lichen, a symbiote of the fungus of the parent fungus and a new alga.
Some lichens reproduce or extend asexually, advancing across a surface and merging with another of the same species.
Uses of lichens:
When we discuss “the use” of some thing we generally mean its use for humans; lichens no doubt have many uses for other organisms, whether as food for reindeer during non-growing seasons or as micro-environments for tiny creatures. But for humans, the uses are mostly in the areas of
geological age indicators
Dyes and Pigments:
Dyes were made from the orange Xanthoria Parietina and the grey-green branched Parmelia Saxitillis to dye wools used in traditional tweed (Harris) weaving in the Scottish Highlands10and I myself have had the second of the two pointed out to me by an Aran Islander woman as the source for the rarely-used green wool knitted into a geansaí (pullover or jumper). Material for other natural dyes exist for example in Ireland but the issues are how easily they are obtained, how true they dye and how long they remain the desired colour and shade.
“There are reports dating almost 2000 years old of lichens being used to make purple and red dyes. Of great historical and commercial significance are lichens belonging to the family Roccellaceae, commonly called “orchella weed” or “orchil”. Orcein and other lichen dyes have largely been replaced by synthetic versions.”11
We know that red and purple dyes were much sought after and in some medieval civilisations the wearing of those colours was restricted to certain social classes and even to one individual (e.g the purple for the Emperor). Once Europeans had gained familiarity with indigenous civilisations of Central and South America, the red dye obtained from the parasitic cochineal insect Dactylopius coccusbecame an important export product to Europe until the late 19th Century, when synthetic pigments and dyes were invented. Despite this development, traditional hand-made textile producers, for example in regions of Mexico, continued to use cochineal dyeing. However, health concerns associated with some or all of those synthetic colourings in food have once again created a demand for cochineal and cultivation of the insect is once again economically viable, with Peru being currently the main exporter.12
Drugs and Medicine:
There is reason to believe that metabolites produced by lichens may have antibiotic effects and usnic acid, the most commonly-studied metabolite produced by lichens, is being investigated as a possible bactericide, in particular against Staphylococcus and E.coli.13
Lichens were also used in European traditional medicine, in particular based on the theory that plants that resembled human organs would be efficacious in treatment of illness of those organs. Some American Indigenous people also used them in traditional medicine treatment.
Lichens as Indicators of Geological Age and of Pollution Levels:
The science of lichenometry is a relatively new one in which measuring the type and size of lichen is used to indicate the age of exposed rock. It takes the known slow growth-rate of different lichens to arrive at an estimate of how long the rock in question has been exposed. This can be used on rock formations, landslides, stone buildings and statuary.
The tolerance (or lack of tolerance) of different species of lichen to certain types of air and rain pollutant can be used as bio-indicators. In general the “frond” or “bushy” types are less resistant to some air pollutants and the flat or “crusty” types more so. Lichens take their water from the surfaces to which they are attached and from the air and are therefore quickly affected by the water quality in rain and air.
Readers may find it worthwhile to take some time to examine the lichens growing around us, to think about their unusual ‘domestic arrangements’ and their pioneering habits. Or to inventory them as indicators of the level and content of pollution in a specific area.
And in particular, to put on rainproof or resistant clothing and to view lichens during rainfall or at least very soon afterwards.
Cycling through Griffith Park off the Mobhi Road, after a walk in the nearby Botanic Gardens, a flurry of wings and a flash of colours attracted my attention. Three birds came down with a splash into the Tolka.
You don’t need to be any kind of expert to identify the Mandarin Duck, especially the males and that’s what two of those birds were. The dowdier third one was the female.
I have often noted two male mallard ducks peacefully accompanying one female and wondered whether they had a menage-a-trois going or what the arrangement was. But there was nothing like that going on with the Mandarins as the males made clear quite quickly. After briefly circling around one another they were quickly into fisticuffs (or beak-and-wing-cuffs), scuffle-splashing, clucking insult or challenge, until the rival to the established male would take to the wing either for a break or to get next to the female. In the latter case, the male would take to the air also, in pursuit.
The female? She swam demurely apart waiting for the victor.
There was clearly one established male who for the moment was the dominant one but the rival kept coming back while I was watching and they were still at it when I left. The established one has the psychological dominance factor on his side, which is a strong advantage but it is by no means a guarantee of success. The rival might wear him down. Or the established one might become injured. Being a male and keeping one’s bird is not easy.
According to Charles Darwin, genders of many species but many birds in particular have become colour-differentiated through part of the evolutionary process described as sexual selection (The Descent of Man and Selection in Relation to Sex, 1871). This has reached amazing and one might say even bizarre though beautiful extremes with such birds as the peacock and the bird of paradise.
Darwin’s ideas make more sense than other explanations being proposed but it is nevertheless hard to credit that a female’s appreciation of colour, shape and behaviour would so impress upon the male the need to flaunt gaudy colour and shape in direct contravention of the need to survive predators by NOT calling such attention to himself. Still, there is no other viable contender explanation around (as distinct from the Mandarin contender, who may still be biding his time or pressing his suit, which if the established male has anything to say about it, is all he is going to press).
Aix galericulata is the Latin species name and the only other species in the Aix genus is the North American Wood duck. A chromosome in the Mandarin makes hybridisation between the two impossible.
Mandarin Ducks originate in East Asia but have been kept in Europe in aviaries and in ponds and lakes. Stephens Green used to have some, along with many other kinds of wildfowl, until the OPW allowed the Herring Gulls to take over to the extent that they have. I have not seen them do it but would not be in the least surprised if the gulls ate the chicks of many of the waterfowl species until they died out or took off somewhere else.
However, there have been feral Mandarin populations in Ireland for some time, notably in Co. Down and in Wexford and pairs may be establishing themselves in other places, including in the Glasnevin/ Drumcondra area, based around the Tolka (and perhaps the Royal Canal).
The Mandarin is a perching duck and this kind have feet capable of grasping a branch. They build their nests in hollows in trees which is good for the safety of the nesting female and the eggs. But what of the chicks or ducklings? As we know, ducklings take to the water long before they can fly. So what can these ducklings in tree hollows, many feet from the ground, do? They simply jump. A veritable leap into the unknown.
When they hit the ground, which at first sight seems to ensure they have broken practically every bone in their little bodies or a least concussed themselves and messed up their insides, they bounce a little, get up and waddle to their mother. Yes, she called them out, which is why they came.
One needs to see the process to believe and I have included some Youtube links. It would seem at first that they need soft leaf litter or water in which to land but one of the links I have posted shows Mandarin ducklings jumping from a nestbox on to bare stone — and getting up, apparently unhurt. It is difficult to understand, even with accounting for the relationship of weight to surviving a fall. We probably know that we can drop lots of insect species on to the ground and they don’t get hurt but the principle goes farther — apparently a mouse can survive a fall from a great height (unless a hawk gets it on the way down, or a cat is waiting below); conversely a fall of four foot on to its feet can kill an elephant (so it is said — I have not actually tried this with elephants but I have inadvertently confirmed the mouse theory).
Often invasive species should not be welcomed as they upset the natural ecological balance. The grey squirrel in the nearby Botanic Gardens, originally from the USA, may be cute but it is helping to wipe out the native red species. And that’s just one of the invasive species of animal and plant that are causing problems in Ireland (see https://rebelbreeze.wordpress.com/2014/07/01/the-scent-of-intruders/). On the other hand, the widely-distributed Red Valerian (also with white and pink varieties) does not seem to be causing any problems and it is difficult to see how the Mandarin can become a serious problem either. But of course, one does not know for sure. It can be stated that the populations so far established in Britain and in Ireland do not seem to have caused any ecological problems. And it is true that we don’t have many dense woods in Ireland anywhere (thanks to certain human invaders in our history), least of all close to slow-flowing water, although some species have shown remarkable adaptability, witness in these climes the rat, fox, pigeon, herring gull and, of course, homo sapiens.
One of the curious things about the Mandarin is the name we have for it. Apparently, it is a Portuguese word for the Chinese government bureaucrats in existence when the Portuguese first began to trade with them (before they and other Europeans decided to invade China and confiscate areas, in particular ports and islands). How they became associated with the duck was not revealed in my short internet search.
However, in China and in Korea the mandarin duck is associated with fertility, good fortune and constancy in monogamy, so that it is often presented as a wedding gift, either as living pairs or symbolically in an ornament. It is not currently considered an extermination-threatened species.
Video links (second one is of merganser ducklings and is even more impressive):
I once knew a cat but, what is more to the point, the cat knew me.
I knew the cat not well, but as a kind of nearby resident I had helped a little once and made friendly overtures to. He or she (I suspect she and will refer to it so from now on) first came into contact with me when a racket of magpies not far from my home attracted my attention. I found magpies harassing a marmalade (orange tabby) cat in a tree and the cat seemed trapped there.
Since there was no nest in the tree for the magpies to be protecting, I chased them off some distance with the aid of shouts and stones, then tried to persuade the cat to come down but she just looked at me – afraid of me too, I thought. Some days later, I came across a marmalade cat outside some nearby houses and called to her and, when she came, stroked her and then went on my way. She made as if to follow me but then gave up.
A few weeks later, I was coming up the road when I saw a marmalade cat about 50 yards away and wondered if it was her. She however looked up, saw me and hurried over, then began rubbing her body against my leg.
So how did she recognise me? Cats have very good hearing but I very much doubt she could identify my footsteps on a concrete footpath amidst all the traffic noise from so far away. Cats also have a good sense of smell but I don’t think it’s good over distance. They are not good at recognising human faces, according to tests. So, she probably recognised my shape and gait (like those recognition software programmes the secret services have developed and with which they monitor a lot of CCTV coverage — reassuring, huh? Not so much!).
It is true I have a somewhat identifiable gait, so I am told – a swagger learned as protective colouring in my teens but about which I am nearly always unconscious and when I am, try to control. Once doing that in New Cross in SE London, a black youth I knew from my work in a local youth club shouted from across the street: “Walk like a white man!” Apparently my attempt to control the Dublin swagger was resulting in the kind of walk adopted by many Afro-Caribbean youth.
But, back to the cat. Anyway, it was an amazing feat of recognition of an individual of a different species and of minimal acquaintance and I think she would have recognised me no matter how subdued my usual type of walk. I wonder how many individuals considered friendly or otherwise a cat can identify by sight at a distance – just how big is their database?
Another time I came upon this cat, she was stretched out on a warm sunny pavement but being persecuted by a pair of magpies (probably the same ones as before). The cat saw me and so did the magpies but I stopped at a distance to observe what was happening.
One magpie distracted her attention by strutting up and down in front of her head, but out of reach of swipe or sudden rush, while the other waited its chance and pecked at the cat’s tail. She lay there suffering this persecution, only twitching her tail from time to time in a futile attempt to keep it away from the bird or perhaps out of tension.
“But why don’t you move, Cat?” I asked her, half in amusement and half in sympathy.
She looked at me and seemed to say:
“Why should I? This is MY pavement and I am harming no-one! I am not going to let two BIRDS chase me off!”
“Well, you could spring at them …”
“What’s the point? They keep just out of range and I’d miss, giving them a reason to mock me.”
The Magpies, in turn, might have been saying:
“This has nothing to do with you, Mister. This is a Cat, ancestral predator on birds and fair game for us at any time. Keep out of it!”
“Yeah, we remember you butting in before!”
And magpies probably can identify human faces – at least tests with their close relatives, crows and jackdaws, show that they can. And magpies are the only bird so far shown able to identify themselves in a mirror.
I did keep out of it. I had things to do and left them to it – the cat after all had the option to leave and even were I to chase them off, the birds would only fly a little distance and then come back. I’ve seen magpies do this “torment-the-cat” thing before. And cats will kill a magpie, if they can.
The cat’s refusal to move or to make a lunge she knew the birds would easily evade, the provocative tormenting by the magpies and the way they worked in unison, all seemed to me so very human, even allowing for anthropomorphism.
But thinking about it later, I came to a different conclusion: it is not the animal behaviour that is human-like – it is OUR behaviour that is animal-like! After all, are we not descended from a common ancestor, albeit nearly 300 million years ago?
In total, I saw that Marmalade Miss maybe four or five times and then no more. Perhaps her owner(s) moved – I hope so and that she was not killed by traffic.
I had nothing I could gain from the cat, other than a kind of feeling of kinship perhaps. Other than a stroke now and again, she had nothing to gain from me. It was an uncomplicated friendship and not, like with some dogs, a dependency by either of us. I know she is gone but years later, as I pass near that street, sometimes still look out for her.