I recently illustrated The Hidden Universe by Alexandre Antonelli.  This image of the zonation of a rocky shore ecosystem was one of the illustrations.

The timing of this illustration was an extraordinary stroke of luck.  Alex wanted a drawing that shows the different animals and seaweeds on rocky shores.  These plants and animals grow in different zones going up the shoreline.  The factors that cause these differences (also known as zonation) include physical forces such as salt levels, dehydration, physical damage from the waves.  There are also biological, or biotic factors at play, such as predation, competition for food, and competition for space.

How do I know?  Well, the week I started this project, I went on a fabulous weekend course.  All about Discovering life on rocky shores!  The course is hands on, so I took tons of photos and copious notes.  I sketched barnacle speciation, and shrieked with delight at Porcelain crabs.  I even saw my first blue-ray limpet.

My very poor photo of Blue-ray limpets

So when this illustration turned up, I was exceptionally well equipped.  Here’s the pencil rough, which I annotated so that it made a bit more sense.

Annotated rocky shores illustration

And here’s the final illustration.  Inking it up was an absolute joy, although it took a great deal longer than I would have liked!

Rocky shore line ecosystem zonation of species

In this blog, there are so many animals and plants discussed, that I’m taking the decision not to give every scientific name.  It’s just be a jumble of italicised Latin if I did. Apologies in advance to the purists among you!

Rocky shores: Splash zone

The very top of a shore is known as the splash zone.

Sea plantain Plantago maritima

The top zone has very little growing there except for the odd brave plant and Xanthora lichen.  you might get tough periwinkles, but the combination of dry and salty splashing is lethal to most organisms.

Plants that do survive here have amazing adaptations to allow them to tackle the salt.  They’re known as Halophytes, and I wrote a blog on them a while back.

Animal wise, shore flies visit, and slaters (relatives of woodlice) crawl about.  You get limpets, clinging on and anchoring themselves to the exact same spot for most of their lives.

Thrift Armeria maritima

Rocky shore Intertidal zone

Lower down, you’ve got the high tide or intertidal zone.  Animals and plants living here have to handle massive fluctuations in temperature and being out of water for 12 plus hours every day.  the crashing waves cause physical damage.  On the plus side, it’s so hard to survive here that there’s not a lot of competition.

Limpet (with mating barnacles on the side)

Chitons, whelks, winkles, and barnacles live here alongside hardy sea anemones and the toughest of all seaweeds, channelled wrack.

The whelks travel around when the tide is in, predating on mussels and other bivalves by drilling a hole through their shells and sucking out the meat.

Detail of the intertidal showing chitons, whelks, and a sea anemone

Rocky shore Mid tidal

This stretch is exposed for shorter times between tides.  There’s less wave action as a lot of the time the area is submerged.  You need to handle the changes in temperature and salt, but it’s a less extreme environment than the upper tidal or splash zone.

Mid tidal zone: Crab and Breadcrumb sponge with coral weed

More animals and plants live here.  Tons of shells like top-shells, barnacles, Perwinkles, and mussels, hang out amidst the seaweeds.   Different species of top shell and winkle favour different areas of the rocky shore.

Topshell

You can tell Periwinkle and Top-shell species apart by the shape of their operculum, the door at the bottom of their shells.  In top-shells this is invariably round.  Periwinkle operculum are tear shaped.

Detail of the mid tidal: Smooth periwinkle, Pin cushion starfish, mussels and bladderwrack

There are more sea anemones, and visiting shore crabs.  Sponges and starfish abound.

The drawback is that there are more animals surviving here, so there’s more competition for space.  Predation kicks in too, with the starfish feeding on mussels, flat periwinkles chewing seaweeds, and whelks feeding on bi-vales.  These are the biotic factors starting to kick in.

If space does become free, it’ll quickly be re-colonised.

Rocky shore Mid tidal: Barnacles

Barnacles have a good system; they can grow on top of other shellfish, and can extend their filtering arms from this substrate.  Barnacles are actually crustaceans, related to crabs and shrimp.

Free living barnacle larva land on intertidal rocks where their heads split and they establish themselves for a stationary life.  They filter food particles form the sea with their legs, which are adapted to work as sieves.

The problem with living on a shellfish is that if and when that shell dies, you get plunged to the floor where it’s every likely you will die.

Blue mussels Mytilus edulis with barnacles and bladder wrack

Rocky shore Mid tidal: Seaweeds

Seaweeds thriving in the mid-tidal zone are bladder-wrack, egg-wrack, toothed wrack, spiral wrack.  These grow at very specific heights along the shore, depending on their adaptations and tolerance to heat and dry conditions.

Bladderwrack Fucus versicolor

Rocky shore Lower tidal zone: Species

The lower tidal zone is altogether more comfortable.  Exposure to air, desiccation and the heat of the sun is far less frequent.  In fact, it only happens at low tides.  The waves are less problematic.

The bladder wracks give way to kelp.  Brown algal wracks are unpalatable to most animals.  In the UK, it’s only the Flat periwinkle that can handle eating it.  Oar weed and sugar kelp are an entirely different prospect and are clearly much easier to eat.  If you are lucky and look closely at low tide, you might see the tiny and stunning Blue-ray limpets grazing on a blade of Oar weed.

Edible crab, sea urchins, tube worms, star fish, brittle stars, more sea anemones, sea lemons and nudibranch hang out here, along with bivalves.

You also see Porcelain crab with their strange, squashed bodies.  Decorator crab, often festooned with bits of seaweed can be seen too.  Hermit crabs spend much of their time in this zone.

Lower tidal zone: Spiny Decorator crab, Sugar kelp, and blue ray limpets

Rocky shore Lower tidal zone: Biotic factors

Flip side? Biotic (rather than physical) factors. Far more predation.  And intense competition for space and things to eat.  Of course, with the physical factors being so much easier to handle, many organisms will migrate from this zone to the Mid tidal once the sea covers them.  There they can eat and predate on other species before retuning to the safety of the lower shore before the tide exposes them again.

Rocky shore Lower tidal zone

You even get sun-stars.

The biological factors such as predation and competition are extreme here.  Predation is fierce.  And competition for space in intense.  Yes, you don’t get smashed up by waves or dried out twelve hours a day.  But you do get eaten, and may well find it impossible to get a foothold in such a heavily populated zone.

Seahorse family groups

Some seahorse and pipefish species will spend time in this zone, although drying out is a real problem for them, so they tend to stay in the sub littoral.

Rocky shore: Sub littoral

Below the lower tidal zone is the sub littoral.  This area of the shore is never exposed to the air, not even at the lowest of tides.  It tends not to figure in rocky shore zonation as it’s more like shallow ocean than the shore.  Fish, crabs, lobster, kelp forests all abound here.

American lobster Homarus americanus

Complicating factors: Rockpools

Rockpools are vital for lots of these organisms, although they can suffer from enormous halinity and temperature fluctuations.  But to the aspiring rocky shore ecologist, rock pools can be confusing,  As they remain wet, you get organisms living there that should not be seen in the Upper tidal zone, or mid tidal areas of the beach.  Luckily, this is catered for by ecologists who examine rock pool life as a subset of the larger ecosystem.

The illustration above was done many years ago.  I now know that brittlestar (lower littoral specialists) and razor clams (sand living specialists) are unlikely to appear in any European rockpool.  You live and you learn.

Complicating factors: Exposure

It should also be remembered that the exposure of a rocky shoreline will have an enormous effect on the life there.  High exposure means it’s even harder to exist in the splash zone and Upper tidal.  More sheltered shores offer an easier existence.

Conclusion

This is truly a whistle-stop tour of the zonation of the rocky shoreline.  I have no doubt this blog is peppered with mistakes.  The FSC course tutor, John Archer Thompson probably has his head in his hands as he reads my version of his wonderful teaching.

As an excellent launch pad to much more on this subject, thanks to John, please check out his FSC rocky shore pages.

The post Rocky shore ecosystem illustration appeared first on Lizzie Harper.

Clouded Yellow

The Clouded Yellow, Colias croceus, travels to Britain every year from southern Europe and Africa.  Nine out of ten years, they’re around, but not terribly common.  But about once a decade you get a “Clouded yellow year”, when loads of these insects arrive.  In fact, so many arrived in 1947 that the military, “saw them approach the coast in the form of a great golden ball, which they thought at first to be a cloud of poison gas drifting over the water” (L. Hugh Newman, quote taken from The Butterflies of Britain and Europe by Lewington and Thomas, a volume I’ll be referring to throughout this blog.)

They’re unable to survive the British winter, but are found all across the UK, feeding on clovers and legumes.  In late summer the new generation hatch, and will migrate back across the English channel as autumn approaches.

Female Clouded Yellow

Females and males are both a rich gold, with dark wing margins.  In fact, they were once known as the “Saffron butterfly” in the UK, which is entirely understandable.

Both sexes have a pair of orange spots amongst the yellow of their lower wings, and a pair of small, ragged, dark spots on the upper wing. Unlike the males, the females have pale spots in their wing margins.

At rest, they are less striking, showing paler yellow underwings.  They rarely flash the brighter top wings when at rest, so can be harder to spot.

Clouded yellow at rest on clover

Possible confusion with other species

Occasional migrants of the Pale and Clouded Yellow butterfly make it to the UK (Colias hyale and Colias alfacariensis).  These are tricky to tell apart, and equally difficult to tell from a pale helice form of the Clouded Yellow.

However, the other common yellow butterfly is the Brimstone, Gonepteryx rhamni.  Brimstone are a very different, paler and brighter shade of yellow, and almost seem to have a pale glow to them that’s absent in Clouded Yellow.  The lack of dark wing margins also makes it really easy to tell the two species apart.

Brimstone butterfly Gonepteryx rhamni

Comma Butterfly

The Comma, Polygonia c-album, is one of my favourite butterflies.  It’s instantly recognisable, with its orange and brown colouring, and its ragged wing edges.  Both sexes look alike, although the undulating wing margins are more pronounced in the male.

 At rest, the underwings resemble a dried out leaf.  The little white comma at the centre of the lower wing looks like a tiny hole in an old leaf.  The camouflage is remarkable.

Commas have two visually different populations, discovered and researched back in the 1890s by Emma Hutchinson.  The earlier population, which is produced from the first of the season’s caterpillars, is known as the Hutchinsoni form.  It’s a paler and more golden orange, and behaves rather differently to the browner, deeper orange form produced later in the summer.  Unlike the early butterflies, these later ones will be overwintering, so need to focus on feeding and stocking up reserves for their hibernation.  They spend this time hidden in woodlands, amongst roots and holes in trees, trusting autumnal leaves to help their camouflage.

In truth, unless I see a Hutchinsoni form alongside the later population, I can’t readily tell them apart.  Hopefully, having researched this blog, my skills in this department will improve!

Commas used to feed on hop plants, but have managed to adapt by using the equally nitrogen-rich nettle as a host plant.  This has enabled them to survive the decline in hop crops.

In the late 1880s, Commas became incredibly unusual, and many naturalists thought they were gone for good.  Perhaps the beginnings of insecticide use on hops around then, and a new procedure of burning hop remnants may have triggered the decline.  Wonderfully, now the population is stronger than ever.  An increasingly warm climate, and the use of nettles may well be the reason.  Either way, it’s a truly welcome development.

Possible confusion with other species

Due to the distinctive ragged wing edges, the Comma is unlikely to be confused with any other British butterflies.

Common Blue

The Common Blue butterfly, Polyommatus icarus, is one of the most widespread of British butterflies, and can be found everywhere except the highest mountain tops, and north Shetland.  It is unable to survive on improved pasture, so look for it on farmland where trefoil and clover crops are used instead of agro-fertilizers.

Common blues can be distinguished from other blues as their wing margins are white.  Those of the Holly and Adonis blue have black stripes which stretch across the white, to the very end of the wing edge.

Females vary massively in colour.  This is partly individual, and partly geographic and seasonal.  They can be almost totally dark brown, or entirely blue.  However, females always have distinctive orange edges to upper and lower wings.

The colour of Common Blue Butterflies

The amazing colour, a sort of iridescent lilac-blue, is due to various factors.  The helicoidal structure of the scales causes light diffraction.  This creates a “glittery” effect.  (For more on iridescence in nature, check out my earlier blog).  Pigments are synthesized and laid down days before emergence from the chrysalis.  Then further pigments, which boost the absorption of UV light, are added.  These are made from pigments in their food plants, flavonols.  Female Common blues who have high concentrations of flavonols in their wings seem more attractive to the males.

Male Common blue specimen and illustration (see my blog for more)

Blue butterflies and Ants

Common blues interact with ants.  The caterpillars and chrysalis emit tapping noises, or “songs”.  These attract the ants who come and tend them.  Others in the Lycaenidae family of butterflies also do this (check out my earlier blog for more on this).  Ants are rewarded with sugary secretions.  Unlike their cousins, the Adonis and Chalkhill Blues, these secretions are low in protein.  Perhaps that’s why the Common Blue has less ants tending to it than the other species?

Possible confusion with other species

There are several species of Blue butterly in the UK, although none so widespread or common as P. icarus.

Chalkhill blue Polyommatus coridon is far paler, and has dark wing edges.

Chalkhill blue

Adonis blue, Polyommatus bellargus is a vivid, bright, glowing blue.  It also has thin black stripes to the edge of the wing.

The Holly Blue, Celastrina argiolus, could be confused with the Common Blue, especially the males.  However, the underside has no orange markings and is far paler and less busy than P. icarus.  Yet again, the presence of black lines on the wing margins shows it cannot be the Common blue.

Holly blue female Celastrina argiolus

Cinnabar Moth

Our last species isn’t a butterfly at all, but an arctiid moth.  The Cinnibar, Tyria jacobaeae, is a common sight in Coastal areas, and is strikingly beautiful.

With black forewings, edged with a red stripe, and crimson hind wings with a black border; this truly is an elegant insect.  It’s name refers to Cinnibar, a red mineral derived from mercury ore.

Caterpillars are blatantly obvious, striped with yellow and black bands.  They can be seen smothering their host plant, Ragwort Senecio jacabaeae (note the similarity in species name).  They obtain toxic alkaloid chemicals from the ragwort, and this deters predation as caterpillars.

The caterpillars are voracious.  They often devour the entire plant before pupating.  This seems to lead to random acts of cannibalism.

In the USA, Cinnibar moths are used to control the highly successive invasive Ragwort.  This seems to be working.

Ragwort Senecio jacobaeae

Possible Confusion with other species

There aren’t any other day-flying moths that look quite like the Cinnibar.

Burnett moths are also red and slate-black.  However, they bear spots, not the wing bars seen on the Cinnibar.

Six spot Burnett moth Zygaena filipendulae emergent adult

Conclusion

Spending a day researching four fairly common British butterflies and moths for this blog is a treat.  There’s so much to learn about each and every species!  I am indebted to “Butterflies of Britain and Ireland” by Richard Lewington and Jeremy Thomas.  It’s a gorgeous book, and fascinating too.

It also gives pause for thought.  Four insects, chosen only because of their shared habitat, are utterly fascinating.  Expand this out to every insect, plant, bird, mammal, and microbe that one encounters…  There truly is an endless source of wonder in nature.  I’m glad this little corner of sand dunes in Bantham, Devon will be managed to preserve and encourage that diversity.  And I’m so pleased that I have the chance to help share that vision with the public, through my illustrations.

The post Butterflies of Bentham Sand dunes appeared first on Lizzie Harper.

Planning the illustration, and roughs

The species list for this commission was imposing.  There are 28 plant species, and 17 animals pictured.  There’s also the concept of succession – plants prevent dunes from eroding and the habitat ends up as a stable thicket of brambles, evening primrose, wild carrot and other dune species.  Management practice is included too, with the volunteer controlling bracken with a horse-drawn roller.

I begin by drawing up and submitting a rough illustration, then a detailed pencil drawing which I annotate so the client can see where each species will sit.

Unfortunately, there was a change of focus, and the detailed drawing had to be re-done, making sure the succession and establishment of stable dunes was the main visual message.

This time, the illustration (65cm x 40cm) got the go-ahead.  In this annotation, ecological and management constraints are in dark red.  Animals are in purple.  Plant species are in green.  Let me lead you through some of my favourite parts.

Birds: Wheatear

The male Wheatear Oenanthe oenanthe (pictured here) is a delicate colour, with a pale peach chest and distinctive black eye stripe.  It’s name refers to its’ white rump, which has a black “T” on it.  The Wheatear is a migratory passarine.  It spends its’ winters in tropical Africa, but comes north in summer to nest.

Spending much of its’ time on the ground, the Wheatear nests in holes amongst rocks, and young emerge after a couple of weeks.  They learn to fly soon after.  Wheatears feed on invertebrates.  Their call is a mix of high whistles and chattering.

In this illustration you can also see a Clouded yellow butterfly, a Great grey Bush cricket, and a White-tailed bumble bee.  Plants include Evening Primrose, Goats’ beard, red and white clover, Lady’s bedstraw, Restharrow, Speedwell Yarrow, Carline thistle, and Stinking iris.

Birds: Herring Gull

This illustration doesn’t feature many birds.  A Whitethroat was removed at an early stage, leaving only the Wheatear, Linnet, and a couple of Gulls.

I loved painting the summer shadow on this Herring Gull Larus argentatus.  The purple-blue shadow reminded me of summer days, and the yellow beak with scarlet spot made for the perfect contrast.  It’s a small part of the illustration, but I quite like it.  To balance the beak spot I slightly bumped up the pink on the legs, in reality they are a little paler than this.

Herring gulls are common along coastlines, and in city centres.  They exploit our refuse dumps, and farming practices as well as the fishing industry.  Bold birds, they have been known to steal food from holiday makers’ hands, and are vocal.  I regard them as admirable survivors in a world which is increasingly anthropo-centric.

Other gulls to look out for on the coast are the Great and Lesser black-backed gull , and the Kittiwake.  Make sure you look closely at the colour of the legs, this can be vital in telling species apart.

Reptiles: Common Lizard

The Common Lizard is not unusual, although it will scamper away with amazing speed if you spot one and try to get close.  Often seen basking on sand or stones in heathland habitats, they’re Britain’s commonest lizard.  You may also see them in grassland, and visit gardens too.  They’re the only reptile native to Ireland.

As their latin name Zootoca vivipara suggests, they give birth to live young.  Well, this isn’t strictly true.  They incubate their eggs internally, “giving birth” in late spring.

A female is pictured here.  They have highly varied markings, mostly greys and browns.  The yellow lateral stripes are a common feature.  Males have yellow or orange undersides, while those of the females are paler and cream-coloured.  For more on Common lizards, check out my blog on British lizards.

Here’s another illustration of the Common lizard, done for the Bumper Book of Nature by Stephen Moss.

Reptile: Adder

There is also an Adder Vipera berus lurking in this illustration.  Famed as our only venomous snake, Adder are far more likely to slither off than to attack a human.  Adder bites are unusual, and though painful, are rarely fatal.  Like the Common lizard, adders incubate their eggs internally, “giving birth” to a batch of little snakes.  Adults emerge in March, and have normally taken to hibernation by October.

Adders can be identified by the dark zig-zag along their backs.  They bask in grassland and heathland, and also favour wooded areas.  Their venom immobilizes their prey; small mammals, lizards, invertebrates, and ground-nesting chicks.  For more on Britain’s snake species, click here.

You can also see the White-tailed bumble bee on a Carline thistle, Yarrow, Stinking iris, Speedwell, and Kidney vetch in this snippet.

Insects: Green Tiger Beetle

The Tiger beetle is one of my favourite beetles.  It’s the ferocity of character, coupled with the dazzling, metallic green sheen on their wing cases (or elytra).  The species illustrated here is the commonest in the UK, the Green tiger beetle Cicindela campestris.  The fact that it has bronze or purple legs makes its’ appearance even more magnificent.

It’s one of our fastest insects, and ambushes prey at alarming speed.  It eats other invertebrates which it seizes with mandibles.  Tiger beetles are built for speed with their long legs and strong jaws.  You may see them on bare patches of earth, or sand.  It’s mostly been hot and dry when I’ve spotted them out hunting.  The plant growing along the sand is Biting stonewort.

The larva are predators too.  They live in burrows in the sand, where they over-winter, and seize on passing prey.

Insects: Sand and Digger Wasps

I completely love these two solitary wasps, and want to do them justice with a lager and more detailed illustration some day.  They are female Red Banded sand wasp Ammophila sabulosa and Sand Tailed Digger wasp Cerceris arenaria, both found in dune habitats.

The Red banded sand wasp (on the left) will dig her nest, then provision it.  If (as pictured here) she finds a large caterpillar, there may only be one in the nest cell.  Five to eight smaller caterpillars have been found in other nest cells.  The caterpillar is brought to the nest on foot as it can be up to 10 times her body weight.  Having laid one egg on the caterpillar, she deposits the paralysed food-store into the nest cell and plugs up the entrance so neatly that it’s impossible for us to spot.  The whole process takes about 9 hours, and she will lay and provision 10 nests a year.

The Sand tailed Digger wasp is larger, and looks similar to the Bee wolf Philanthus triangulum. Unlike the other wasp, the Digger preys on weevil species, catching them and bringing them to the nest.  Her nest is not a solitary cell, but an underground network of cells radiating from a central burrow.  They’re about 25cm deep in the soil, and each cell contains one larva and 3 to 15 weevils.  I’m indebted to the excellent Nature Spot for this information.

Sand Dunes Management: Depicting Succession

This was the hardest bit of the commission.  I want to show how sand dunes slowly become more stable, thanks to the network of  roots grown by pioneer species such as Couch grass, Lyme grass, and Marram.  These cling onto the sand, making it less likely to erode.  For more on Marram grass, check out Karen Netto Andrew’s guest blog.

These early stages of dune development are prone to collapse, known as blowouts.  These needed to be incorporated into the illustration too.  They look like craters of sand, often in the midst of more vegetated areas of dune.

Marram grass Ammophila arenaria

Once the dunes are less vulnerable to the wind and winter storms, more vegetation can grow which in turn allows a further assortment of species to colonise the dunes.  These secondary species include Evening primrose, Stinking iris, Sea bindweed, Restharrow.  Then shrubs such as Bramble and Sea-buckthorn can become established, along with plants like Sea carrot, Sea holly, and Sea rocket.  For more on these coastal plants check out my blogs on salt tolerant plants, and costal flowers illustrated for the FSC identification chart.

Sea bindweed Calystegia soldanella

Sea Buckthorn Hippophae rhamnoides

This growth starts on the leeward side, away from the wind, which is easy enough to show.  It’s the thickening of the vegetative mat that’s a challenge, showing how the plants become closer packed, and how the species change with the establishment of the dunes.  Luckily, flowering plants follow the grasses, so I can use colour to show the succession.

Sand dune succession showing growth only on leeward sides, and a blow out

I had to do some swift learning of basic geography here, and am indebted to the concise and useful overview provided by Liverpool Hope University.

Sand Dunes Management: Suppressing bracken with Rollers

If left un-managed, Bracken Pteridium aquilinum can take over.  One of the methods Bantham estate is using to control this plant is horse-drawn rollers.  This is the third year using this technique, and it’s not only effective, but also picturesque.  Rollers are more effective than cutting the bracken, which allows it to grow back and may even promote growth.

The rollers crush and bruise the stems of the bracken, damage from which the plants cannot recover.  Thinner areas of bracken mean other plants have a less densely vegetated habitat in which to compete.  For more on this management scheme, please look at the Southhams Today article.

Conclusion

I was planning on putting all the details in this illustration into one blog, but on reflection I’ll pause here, and discuss the butterflies pictured in my next blog.  If you’d like to know more about the coastal meadows further inland at Bentham (pictured below), please check out my earlier blog.

Bentham Hay Meadow

You may also be interested to know that although the Coastal meadows illustration has been sold, the original Bentham Sand dunes illustration is still available to buy.  It’s about 65 x 40 cm, and costs £ 275 unframed.  Please email me on info@lizzieharper.co.uk if you’re interested.

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