I will lead them up and down

I will lead them up and down. (III. ii) Midsummer Night’s Dream

In the 1992 EU Habitats’ Directive, member states of the European Union were obliged to protect from harm certain habitats. Member states were to submit sites to the EU as Special Areas of Conservation (SAC), according to criteria drawn up by the EU. The Directive was transposed into Irish law in 1997. Some bogs both raised and blanket bogs were designated as SACs. These are to be maintained and in some or even in all cases restored to the condition needed for full ecosystem functioning.

6,345 sq. km. of our land is designated as an SAC or 9% of the land area of the Republic of Ireland.

So much for what was supposed to happen. Now the truth.

The SAC bogs, instead of being maintained, are being destroyed by mining operations, reducing the bog area until in many cases the bog no longer corresponds to the criteria for which it was designated as an SAC. There are now moves to de-designate some of the SAC bogs that have been destroyed.

This ongoing damage is well-known to the Irish Government. Here is an extract from the National Parks and Wildlife Service (NPWS) description of All Saints’ Bog SAC:

An extensive area in the north-east corner of the bog, representing about 20% of the bog surface, is being cut for turf, with drains running into the eastern edge of the birch woodland. This appears to be leading to the bog drying out, as the surface is reported to be much drier than when first surveyed in the mid-1980s. (https://www.npws.ie/sites/default/files/protected-sites/synopsis/SY000566.pdf)

The damage is ongoing and is observed by NPWS using drones and aircraft, but nothing is being done. The steady march to oblivion of our national heritage is being ‘monitored.’

There is a weak scheme dated July 2021 called the Protected Raised Bog Restoration Incentive Scheme (PRBRIS) which is a voluntary scheme for owners and those with turf-cutting rights. This scheme offers payments to owners and those with turf-cutting rights whose land is within an SAC or National Heritage Area (NHA). These can opt to sell the land to the state or accept compensation for not cutting the bog (see https://www.npws.ie/sites/default/files/files/prbris-terms-and-conditions-english.pdf). The document states the cessation of peat-cutting and non-interference with the bog hydrology must be in perpetuity for its land management agreement scheme.

According to The Irish Farmers’ Journal (https://www.farmersjournal.ie/state-paying-up-3-700-ac-for-raised-bog-721076) around 59 acres of raised bog have been purchased since 2020, a mere 23.9 hectares.

Why does the state not purchase the raised bog SACs and National Heritage Areas (NHAs), and avoid the damage being wrought on our most sensitive habitats? The EU Commission has finally lost patience with the Irish Government (after warning the Irish Government about its inactivity since 2011) and on September 29th, 2022 it threatened to refer Ireland to the Court of Justice of the European Union within two months unless the Government takes effective action to halt the continued cutting of peat within Special Areas of Conservation (SACs) designated to conserve raised bogs and blanket bogs under the Habitats Directive.

The Commission notes:

cutting activities are still ongoing and enforcement action appears to have stalled. Restoration activities have begun on some raised bogs SACs, but this is too slow given the importance of this priority habitat and its precarious state. With regard to blanket bogs SACs, there appears to be no regime controlling ongoing cutting with the cutting for domestic use exempt from control.

(https://ireland.representation.ec.europa.eu/news-and-events/news/commission-calls-ireland-halt-peat-cutting-activities-natura-2000-sites-and-restore-these-sites-2022-09-29_en)

The Commission has dragged its feet too, despite numerous complaints from Irish citizens and organisations. Soon there will be no bogs left to protect, and the issue will be dropped.

“Peat cutting is coming to an end.”
Desolate view across a despoiled landscape in south Kildare.

That is my personal reading of the situation and appears to be how turf-cutter representatives see it too. Recently, a spokesman for turf cutters countered calls for cutting to stop by saying that “It is coming to an end anyway.” It is coming to an end because the bogs are almost gone.

We are being led up and down. The Government has no interest in biodiversity, carbon absorption, flood and pollution control, or the rule of law when it comes to the environment, just doing as little as possible and getting away with it.

Without a dramatic change in attitude, there will be no chance for our bogs. Let us hope that attitudes don’t change when it is too late.

Bell Heather likes the drier areas of bogs.

Attitude lies at the heart of this existential crisis for our bogs. Bogs have often been ignored or dismissed. Even the great naturalist and botanist, Robert Lloyd Praeger, had nothing positive to say about Ireland’s bogs:

Offaly…is the most bog-covered part of the Central Plain, no less than one-fifth of its area buried under that strange vegetable blanket. But the remainder makes up for this by being often pleasant well-farmed country, with plenty of trees and some good towns. (The Way that I Went, p. 237)

Praeger was and is wrong. Bogs are crucial habitats for rare biodiversity, such as the Eurasian Curlew, Merlin, Hen Harrier, Eurasian Skylark, Meadow Pipit, the Large Heath butterfly, a range of mosses and other bog specialist plants like Bog Rosemary. The area just above the bog surface teems with activity from late April to October, with bees, flies, moths and butterflies with the soundtrack of bog birds, from the Cuckoo to Willow Warbler, adding aural texture and warmth to the wilderness experience of an undulating habitat extending to the horizon, engendering a feeling of being a small individual in a vast void, with nothing between you and the sky. It is a landscape of dreams, of imagination, of escape from today’s bland, impoverished agricultural land where little remains of wildlife that once found their homes on the farm.

Frogs love bogs.

Do not buy peat, wherever it comes from, in any form, for any purpose. This defends our peatland heritage although it must be admitted that for most of our bogs, it is too late to save them as they were when R.L. Praeger dismissed them in the 1930s.

This beautiful upland blanket bog in Donegal is being cut for peat. There is simply no need to behave like this in Ireland in the 21st century. The EU Commission noted in its statement published on 29th of September 2022, “With regard to blanket bogs SACs, there appears to be no regime controlling ongoing cutting with the cutting for domestic use exempt from control.”

All Photographs by J. Harding

 

 

 

Lullybeg Reserve News

Butterfly Conservation Ireland’s reserve at Lullybeg in County Kildare is one of only two reserves in Ireland managed with the needs of butterflies as the main priority. The other example is located nearby in Lullymore West, managed by the Irish Peatland Conservation Council.

Both reserves contain mosaics of grassland, scrub, woodland, and open water. In addition, Lullybeg Reserve contains bare peat and marl soil, which is very beneficial for butterflies. Both areas support orchids, which are mentioned not because these are particularly important for butterflies but because orchids are generally indicative of ecological richness.

Grazing and scrub control is applied on the reserve to maintain open habitats. These are rich and varied on Lullybeg; applying level 3 of the Fossitt Classification Codes and Descriptions, the grasslands/heath that Lullybeg contains are wet grassland (some is calcareous and in places wet grassland grades into poor fen and flush), dry-humid acid grassland, marsh, and wet heath.

These habitat conditions provide a home for a high range of moths and butterflies as well as hundreds of other invertebrate species.

The Migrant Hawker dragonfly, which has made Lullybeg its home in recent years, is now abundant on the reserve. Photo J. Harding

A bumper Marsh Fritillary population during the flight period in May and June is indicated by a transect count of 95 Marsh Fritillaries on the 27th of May with many other Marsh Fritillaries present elsewhere on the reserve outside the transect line (a transect is a fixed route where butterflies seen 2.5 metres on either side and 5 metres ahead are counted). A search on the 28th of August revealed 73 Marsh Fritillary larval nests, with a further nine nests on the ground directly adjoining the reserve located on the 1st of September. This figure of 82 larval nests represents the highest abundance yet recorded on the reserve and vicinity.

One of the Marsh Fritillary butterflies seen on Lullybeg Reserve in May 2022. Photo J. Harding

The positive conservation outcome does not end with the Marsh Fritillary butterfly’s upward trajectory, which has been building steadily from a low point in 2015.

The Marsh Fritillary breeds on a perennial flower called Devil’s-bit Scabious. The Marsh Fritillary caterpillars feed mainly on the basal leaves of the plant. The plant produces many nectar-rich flowers on branched stalks. These are in bloom mainly in August and September and into October. Because the plant which is abundant on the reserve produces a mass of flowers throughout late summer into mid-autumn, the reserve is very attractive to late-flying butterflies and moths.

One of the late flyers is the Comma butterfly. This species was not part of our butterfly fauna until the early 2000s, when it colonized the extreme southeast of Ireland, probably from southwest England. It was confirmed breeding in Ireland only in May 2014 and is spreading northward and westward. In 2019 the Comma was seen on the reserve when just one was seen. No Comma was seen there in 2020 and 2021, but several have been seen on the reserve this year, with 12 Commas seen on Devil’s-bit Scabious on the reserve on the 24th of September 2022, after five were observed on September 20th.

The Comma is now part of Lullybeg’s butterfly fauna. This male Comma is feeding on Devil’s-bit Scabious at Lullybeg. Photo J. Harding

This abundance strongly suggests local breeding. It might be using nettles on the reserve or nearby, perhaps on nettles growing on the bank of the Crabtree River. Unlike its relatives, the Small Tortoiseshell and Peacock, the Comma is rarely found in abundance so finding 12 individuals on the site is noteworthy.

The Small Tortoiseshell feeds on Devil’-bit Scabious in advance of hibernation. Photo J. Harding

After feeding for a few days, the Commas will settle deep in wooded cover, wings closed, until spring. There is an abundance of such cover on the reserve, so it is expected that the butterfly will use the wooded habitat for over-wintering as well as feeding up for their long sleep on the open grasslands.

The Red Admiral loves gorging on Devil’s-bit Scabious before migration. Photo J. Harding

This autumn the Red Admiral has been present in good numbers too, feeding alongside the Comma. But the Red Admiral has a different strategy for dealing with the long, cold, nectarless months: migration. When the reserve’s Red Admirals are well stocked with nectar, they will fly south, making landfall in warmer parts of Europe where they will breed. Red Admiral migration certainly occurred between September 20th when 41 were counted and September 24th when just six remained.

I saw what must have been a migration flight by a Red Admiral on the 24th of September 2022. It flew up from Devil’s-bit Scabious, directly over my head, and flew strongly upwards in a southerly direction until it vanished from sight. It began its upward flight at a c. 45-degree angle, ascending afterward at about 60 degrees, and before disappearing from view its angle of ascent increased. The wind was northerly, about force 2-3 on the Beaufort Scale, ideal for a southbound butterfly.

Finches, such as this Goldfinch, enjoy feeding on the seed after the Devil’-bit Scabious has bloomed. Photo J. Harding

These are just some of the highlights from the reserve. You can read a more comprehensive report on the reserve’s progress in our forthcoming Annual Report 2022.

Children are our Future

In all the maelstrom of climate change and biodiversity loss, it is so heartening to hear positive voices express hope for a better, happier, more nature-rich future. I heard these voices recently on the video linked here:

This wonderful group of young people teamed up to produce this wonderfully evocative, earnest and touching innocent plea for the preservation of the great wilderness and biodiverse paradise in northwest Kildare and east Offaly. The group is supporting the campaign for a new National Park to be located in the region. This would be the only national park in Ireland on raised bog habitat.

The young people will make their pitch to Kildare County Council on the 24th of October 2022 when they will meet all of Kildare’s councilors.

Butterfly Conservation Ireland asks you to support this vital proposal, which encompasses around 7000 hectares of habitat, by signing the petition at www.noplanetb.ie

The development of a national park in this area will enhance the protection of Ireland’s biological diversity, reduce pollution, store carbon and promote carbon sequestration. The tourism, commercial and amenity potential possibilities present opportunities for local communities and businesses in Kildare and Offaly.

The opportunities include the potential for rambling, cycling, horse riding, water sports, nature study, education, and research. The  Park will offer people a wilderness experience. Situated in the east midlands, it has the potential to attract visitors from the greater Dublin area and overseas, bringing opportunities to an economically depressed West Kildare /East Offaly area.

But it will do so much more; it will give hope to all who love our landscapes, want to see despoilation and biodiversity loss reversed, and see the faith of our idealistic young people affirmed.

Sign the petition!

Flooded cutover bog in the proposed new national park. Open country vistas offer a stunning experience of the landscape in this area. Photo J. Harding

September Moths

Below are some adult moths (and one caterpillar) that are active during September. ‘Foodplant’ and ‘breeding plant ‘refers to the plant eaten by the caterpillar. The following moth species are nocturnal.

All images J. Harding

This is the larva of the Pale Tussock moth. This larva can often be found on or near the ground in September. The tuft of pink hair marks the location of the tip of the abdomen. It pupates under or near the tree it fed on. The foodplants are varied and include native trees and shrubs such as birch, oak, and Common Hazel. The adult moth flies in May and June. The moth comes to light and does not feed, relying on fat stored by the larva.
Rosy Rustic. This light-attracted moth flies from August to October. It breeds on Broad-leaved Dock, Ribwort Plantain, horsetails, and Flag Iris.
Beaded Chestnut is a very numerous moth in wooded habitats, including gardens, during September. Its foodplants are buttercups, clovers, chickweeds, and, when larger, broadleaved trees and shrubs, especially Common Hawthorn. This moth comes to light in abundance.
Pink-barred Sallow. This has a short flight time, appearing in September and October. The adult comes to light and feeds on Common Ivy and over-ripe blackberries. The breeding plants are willows and poplars, and later on docks.
The Lunar Underwing is an abundant species. The adult flies mainly in September and October and takes nectar from ivy and sugar from over-ripe blackberries. It is named for its moon-white underwing, appropriately ‘clouded’ with hazy sooty markings, redolent of faint cloud partly obscuring the moon. It appears in some numbers at light traps, and its ground color varies from pale yellow to grey. The breeding plants are Yorkshire Fog and other grasses. 
The Willow Beauty has at least two generations, the first June-August the second from late August to October. Alder Buckthorn, birches, Common Yew, and Scots Pine are among its wide range of foodplants. It likes woods and mature gardens. The adult moth comes to light and enjoys nectar from Creeping Thistle and Common Ragwort.
Ripe and over-ripe blackberries are eagerly sought by September moths and butterflies.
Moths are a major prey item for birds, especially familiar garden birds like the Wren, Robin, and Blue Tit. Birds learn to forage for moths early in the morning in areas where outdoor lights are left on at night.

Calm, mild September nights often yield large populations of moths. A car journey home at around 10 pm along our rural hedged roads will often give an indication of the level of abundance, with ghostly wings flitting in and out of view in the car lights. A glance upward at hedge-top height might reveal bats that will dip down to snatch a moth meal. Some moths are disorientated by light and will flutter against the base of hedges, kerbs, or walls that the light falls on. If a car is parked with lights on for some minutes, these moths can fall prey to frogs and hedgehogs emerging from cover nearby.

Moths are very important food web components. A healthy moth population is a sign of environmental health. When you see plenty of moths in your headlights, feel good about the area you are in!

 

 

What to look for in September

September is an in-betweener, no longer summer but with some days bringing summer heat, not winter but with some sharp cold at night. The blooms of summer have mainly faded but new flowers offer sustenance to September moths and butterflies. Some fruits are available too; Rowan, bramble, and Elder offer their sweetness to species still in flight.

Oddly, September is a peak month for some species: Red Admiral, Comma and Speckled Wood are abundant in September.  Yesterday I counted 54 Speckled Woods in the rather cool, breezy Russellstown Wood, near Russborough House, in County Wicklow.  The butterfly is also extremely abundant in the scrublands of the Burren, where its copiousness astonishes, an apparently seasonally discordant richness.

Speckled Wood eggs being laid now are unlikely to produce pupae before winter, but the larvae will pupate next spring or early summer depending on development rates. The resulting adults are likely to fly in May and June after their aunts and uncles have flown in March, April, and early May. This prolonged emergence arising from individuals from more than one generation from the previous year provides a very long first brood, running from later in March to the end of June.  A gap occurs in the flight of this species during July, with few flying in this month. However, from August lasting well into September and even October, there is an extended emergence resulting from larvae produced during April-July. According to Thomas and Lewington (2014) not all spring larvae produce second-generation butterflies. Some develop slowly and form over-wintering pupae in autumn.

Speckled Wood in Russellstown Wood, Co. Wicklow.

The understanding of the Speckled Wood’s complex brood structure comes from studies done in Britain. Perhaps this applies to our Speckled Woods, but until breeding studies are undertaken in Ireland we cannot confirm this. While our records of the adult butterfly suggest that the butterfly has a similar brood structure here, when I reared the species from eggs laid in late June, all of these reached adulthood in late August and during September. If some spring larvae do not produce butterflies in the same year, do some summer larvae undergo slower development, producing over-wintering larvae or over-wintering pupae in autumn?

I suspect that there is more to learn about the Speckled Wood’s brood structure in Ireland, potentially including regional differences in its development rates.

Another species with a complex brood structure is the Comma, and in parts of Ireland where it is established, it is present in good numbers, feeding on autumn fruits and late flowers to store up fat for its long sleep. Unlike the Speckled Wood which over-winters as a larva or pupa, the Comma passes the autumn and winter in just one life stage, the adult stage.  With its dark, bark-coloured undersides and scalloped oak-leaf outline, it is perfectly placed to conceal itself in woods, on tree trunks, and among heaped leaf litter. By contrast, the bright orange uppersides now illuminate hedged country lanes, wood edges, clearings, and gardens. When a vivid example is perched on blackberries, the luminosity is striking. When the sun is obscured and sometimes when it detects approach, it shuts its wings and becomes a dead leaf trapped in the bramble.

A male Comma feeding on a blackberry, Mulhussey, Co. Meath.
A male Comma underside. The female Comma’s underside (see below) is much less variegated and may indicate a different choice of over-wintering site than that used by the male.
A female Comma feeding on Common Ivy.

The tiny Small Copper is still adorning our grasslands and the warm sunny August and pleasant September might see the third generation later this month. Two broods are seen each year with the third generation weather-dependent. Today (September 17th) I saw the pristine female shown in the photograph below. Shortly after I took the photograph, she was courted by two males. Her offspring will fly next year’s first generation, typically in May and June.

A newly emerged female Small Copper, Mulhussey, Co. Meath.

Another gorgeous butterfly, the Red Admiral, is present in our countryside and gardens, and in some abundance in flower-rich areas.  It has a broad taste, taking advantage of nectar, fruit juice, and tree sap. By contrast with the previous butterflies profiled here, this will leave our shores this autumn to breed further south, in Europe. A few stay behind to breed in coastal areas but this applies to a small number of individuals, as far as is known.

For now, enjoy this black and scarlet butterfly. It will fly throughout September and October, relying increasingly on ivy nectar as other food sources disappear.

Red Admiral basking on birch, Lullybeg, Co. Kildare.

The Small Tortoiseshell rounds off this article. This bright, friendly-looking butterfly is busy feeding up to spend the winter as an adult butterfly. Unlike its relative, the Comma, the Small Tortoiseshell will seek out buildings as well as natural places to over-winter. Like the Comma, its undersides are muted in colour blending it with the dark places chosen for over-wintering. All over-wintering butterflies close their wings when sleeping, so colourful uppersides are not on show. Like all species that over-winter as adults, the Small Tortoiseshell does not enter this state synchronously; rather individuals enter the over-wintering state over several weeks, so the individuals seen at any time during August-October represent those yet to close their wings for the year. This elucidates the paradox of seeing more individuals in spring than appear to have been active during the previous late summer and autumn.

If you are lucky to host a Small Tortoiseshell this autumn or winter, do not release it. Relocate any woken by the central heating to a cool place such as a shed or even a kitchen roll-lined Tupperware box with the lid on, placed in the fridge (never the freezer). Release the butterfly in warm, sunny weather in March. The individual in the photo below has traces of gossamer on its wings resulting from an encounter with a spider’s web. It overcame this survival challenge. Will it survive our long, dark foodless winter? For Small Tortoiseshells that take refuge behind our cupboards, wardrobes, picture frames, mirrors, and within curtain folds, that is for you to decide…

A Small Tortoiseshell on Rough Hawk-bit, Lullymore, Co. Kildare.

All photos by Jesmond Harding.

Key Reference

Thomas, J. & Lewington, R. (2014) The Butterflies of Britain and Ireland. (Revised edition) British Wildlife Publishing, Dorset.

 

The Importance of Scrub and Grassland Mosaics for the Butterflies and Moths of the Burren

Clooncoose Valley, County Clare.

The Burren is a region in North County Clare and South Galway. It is a karst landscape containing exposed limestone. The Burren as it appears today is mainly the result of the last glaciation and the impact of human activity, especially farming. It is a remarkable landscape, containing a variety of habitats that belies the seeming uniformity of appearance when viewed from a distance, particularly during winter. In addition to eye-catching geological features, the area has a range of habitats that add enormously to the region’s biodiversity and international reputation. This article focuses mainly on the value of scrub and limestone grassland for butterflies and moths, particularly in areas where these habitats exist close together.

Scrub is a broad term and includes areas that are at least 50% covered by shrubs, stunted trees or brambles. The term includes dense growth with little ground vegetation. The canopy height is usually below 5m. The scrub of most value to butterflies is open scrub on lightly grazed, herb-rich grassland that receives good sunlight. Scrub management is carried out by occasional burning, manual cutting or cutting using machinery, sometimes followed by herbicide application. The most important habitat in Ireland for butterflies is the open scrub on calcareous grassland in the Burren in County Clare and Galway. The main scrub components present in the Burren are Common Hazel Corylus avellana, Common Hawthorn Crataegus monogyna, Common Blackthorn Prunus spinosa, Bramble Rubus fruticosus agg. and erect or scrambling roses Rosa spp., in addition to several willows Salix spp., Ling Calluna vulgaris, Guelder Rose Viburnum opulus, Common Holly Ilex aquifolium, occasional Juniper Juniperus communis and Common Yew Taxus baccata.

Fahee North, County Clare. The closely cropped grassland is the result of year-round grazing on this site. The scrub and grassland here provide excellent habitats for rare Lepidoptera.

The grassland in the Burren clearings is often rich in flora, especially clovers Trifolium spp., violets Viola spp., Common Knapweed Centaurea nigra, Devil’s-bit Scabious Succisa pratensis, Selfheal Prunella vulgaris, Common Bird’s-foot Trefoil Lotus corniculatus, Cat’s-ear Hypochoeris radicata, Lady’s Bedstraw Galium verum and Oxeye Daisy Leucanthemum vulgare. The more calcareous grasslands are characterised by broadleaved herbs such as Cowslip Primula veris, Greater Knapweed Centaurea scabiosa, Kidney Vetch Anthyllis vulneraria, Mountain Everlasting Antennaria dioica, Yellow-wort Blackstonia perfoliata, Salad Burnet Sanguisorba minor and Carline Thistle Carlina vulgaris, and may also be important for orchids, including Ophrys and Orchis spp.

Flower-rich habitat (dry calcareous grassland) at Clooncoose, County Clare.

Grasses present often include fescues Festuca spp., Sweet Vernal-grass Anthoxanthum odoratum, Crested Dog’s-tail Cynosurus cristatus, Cock’s-foot Dactylis glomerata and Yorkshire-fog Holcus lanatus. Grasses that are indicative of strongly calcareous soils include Downy Oat-grass Avenula pubescens, Yellow Oat-grass Trisetum flavescens, Blue Moor-grass Sesleria caerulea and Quaking-grass Briza media.

These scrub and grassland mosaics are used for breeding by scrub/woodland and grassland butterflies. The butterfly species recorded breeding on herbs and grasses in open scrub in the Burren are Dingy Skipper Erynnis tages, Wood White Leptidea sinapis, Common Blue Polyommatus icarus, Small Tortoiseshell Aglais urticae, Peacock Aglais io, Red Admiral Vanessa atalanta, Painted Lady Vanessa cardui, Pearl-bordered Fritillary Boloria euphrosyne, Dark Green Fritillary Speyeria aglaja, Silver-washed Fritillary Argynnis paphia, Marsh Fritillary Euphydryas aurinia, Speckled Wood Pararge aegeria, Wall Brown Lasiommata megera, Grayling Hipparchia semele, Meadow Brown Maniola jurtina, Ringlet Aphantopus hyperantus and Small Heath Coenonympha pamphilus.

The species recorded breeding on shrubs in open scrub in the Burren are Brimstone Gonepteryx rhamni, Brown Hairstreak Thecla betulae, Purple Hairstreak Favonius quercus, and Holly Blue Celastrina argiolus.

Separating the species breeding in open scrub into (a) herb/grass feeders and (b) species feeding on shrubs ignores the complex habitat associations of several of the species listed here. The shade, shelter, and leaf litter provided by scrub influence conditions in the grasslands. This is vital for Lepidoptera, especially for the life stages lasting several months. The role played by scrub varies according to species, the time of year, and features such as the height, structure, composition, and management of the scrub and sward.

The Marsh Fritillary is a locally distributed, generally scarce species that requires grassland containing at least a 25% density of the larval foodplant Devil’s-bit Scabious, with the plants growing close together. The grassland that is most favoured has a sward height of 12-25cm. Some occupied swards are taller and even quite rank, but the foodplant is unshaded. The sward usually has tussock-forming grasses and flowers. There is usually some light cattle or horse grazing to maintain the grassland. In swards that are strongly exposed to the weather and that are moderately grazed during the summer, some sheltering scrub is important for the Marsh Fritillary. This species dislikes exposed grasslands unless there is a tall, (c.25cm) well-developed sward that is grazed irregularly and extensively or throughout the year if grazed extensively. Litter from easily warmed dead vegetation, especially from grasses, but sometimes from mosses, scrub foliage, and bracken, must be present for the Marsh Fritillary to be able to make use of the sward for breeding.

The Dark Green Fritillary enjoys superabundance in several areas in the Burren.

The scrub is also used by the Dark Green Fritillary. This eye-catching, dynamic species flies mostly from mid-June to mid-August. Eggs are laid on or near violets growing in grassy places with a fairly tall, well-developed sward, in open, exposed grassland, in sunlit clearings in open scrub, but also at the immediate edge of scrub where a lower, patchier sward exists. After about two weeks, the newly hatched larva eats the eggshell and immediately enters diapause (a rest phase with no feeding and little development), remaining in this state until March of the following year. Unless it has the shading effect of a well-developed sward or scrub, the unfed larva will desiccate in the summer heat.

A Wood White laying an egg on Bitter Vetch Lathyrus linifolius close to scrub, Knockaunroe, Co. Clare.

The Wood White has a highly restricted distribution in Ireland, where it has been found only on carboniferous limestone, from near Newmarket-on-Fergus in south County Clare northwards to Lough Corrib, County Galway on its east and west shores. Its stronghold is the Burren. It is scrub-dependent, breeding on vetches, especially Meadow Vetchling and Tufted Vetch, that receive direct sunlight but that grow in intimate contact with scrub. The adult has a weak, fluttering flight, and the shelter afforded by scrub appears necessary for it. The larva needs access to direct sunlight, shelter, and shade throughout its development. When feeding is complete, it pupates in the scrub or on vegetation growing among the scrub. Medium-tall vegetation in intimate contact with scrub is crucial for this species.

In Ireland, the Pearl-bordered Fritillary breeds on Common Dog-violet Viola riviniana growing among open scrub and open woodland on the carboniferous limestone in the Burren, Counties Clare and Galway, and in similar habitat near the Burren. In Ireland, it is restricted to these areas. According to Nash et al (2012), it has been recorded in just twelve 10 km squares, 35 tetrads. In two of the 10km squares, on Inishmore and Inishmaan, where single individuals were seen, it appears that these were wanderers from the mainland.

The breeding habitat for the Pearl-bordered Fritillary is the same as that used by the Wood White. The larva requires shade and direct sunlight. Direct light is required by the larva for it to be active and for digestion while the shade is needed to cool it down. During hot sunny weather in summer, the larva feeds in strong sunlight but quickly retreats to a shaded location. Cooling shade is needed during the larva’s long diapause from mid to late summer until feeding resumes in March. Furthermore, unshaded violets wilt and turn yellow, which makes make them unsuitable. In part-shaded areas, the foliage remains green.

A male Pearl-bordered Fritillary basking on limestone at Fahee North, Co. Clare. During overcast conditions, the exposed stone helps this species to maintain its body temperature.

The question of why the Pearl-bordered Fritillary’s distribution in Ireland is limited to the Burren is an interesting one, with the answer likely to be found in the conditions needed by the larva. It needs the Common Dog-violet, usually with low herbs and dry moss on dry, free-draining, warm, sheltered, usually south-facing sunny habitats containing leaf litter build-up against scrub on open limestone rock. The larval micro-sites have low grass density; the grasses present are typically scattered tufts of Blue Moor-grass and fescue grasses containing standing and lying warm, dry litter, particularly in spring. Plant litter is used by larvae for basking, concealment, and over-wintering. It may be important for the larva to have Common Hazel leaf litter. Hazel produces a leaf litter that is substantial without shading the foodplant. Dead hazel leaves curl, producing hiding places for resting larvae. The dead leaf dries quickly, and the larva needs dry conditions (Harding 2021).

Two other features favouring the species are the frequent rainfall that prevents the foodplant from losing moisture while the free-draining limestone provides the dryness needed by the larva. Grazing by cattle or horses during winter and spring, and periodic scrub cutting, but not scrub clearance, is beneficial.

The adult feeds mainly in the clearings in the scrub, especially on Common Bird’s-foot-trefoil, Bugle Ajuga reptans, buttercups Rununculus spp., and Dandelion Taraxacum spp. Thus, the butterfly needs the grassy areas adjoining the scrub, as well as the shadier areas occupied by scrub.

Pearl-bordered Fritillary breeding habitat near Clooncoose, Co. Clare. This photo was taken in early May.

The Peacock, a species distributed throughout Ireland, uses the Stinging Nettle Urtica dioica as a foodplant, and it selects unshaded nettles growing close to scrub or woodland. It is possible that the scrub provides the warmth and shelter required for larval development. Fully fed larvae leave nettles to pupate on trees and scrub.

Speckled Wood, another widespread species, has a complex relationship with scrub. Known as a butterfly of hedges, scrub and woodland, it is our most shade-tolerant butterfly. The adult uses scrub for food (feeding on flowers such as bramble and Common Ivy Hedera helix, on ripe blackberries and aphid ‘honeydew’), for shelter from the rain and heat, resting and roosting, territorial perches, patrolling areas, mating stations, and dispersal routes. The butterfly breeds on native grasses growing at the edge of scrub, hedges, and woodland, but a seasonal difference exists in the egg-laying sites chosen. Early and late in the year, warm clumps of grasses in full sun are selected for oviposition, while during the summer heat, partly shaded lusher grasses in humid locations are selected. However, a female will adjust her choice of egg site according to temperature, so that grasses in shaded positions will be selected during hot weather in autumn.

Four butterfly species that breed on shrubs, Brimstone, Brown Hairstreak, Purple Hairstreak, and Holly Blue, use foodplants that receive direct sunlight. While often regarded as woodland species, none of these can breed within shaded areas of woodland or scrub. In the Burren, the eggs of the Brown Hairstreak are found on young growth on Common Blackthorn plants at the edge of a hedge,  scrub patch or woodland edge that is unshaded and south-facing.

Some butterflies enter a prolonged rest phase in their adult state. Four of our butterfly species undergo reproductive diapause in summer; these feed to build fat reserves before entering dormancy (quiescence) until the following spring when conditions favour breeding. The Brimstone, Small Tortoiseshell, Peacock, and Comma pass the winter in cool, dry conditions in scrub and woodland. It is likely that the Small Tortoiseshell, Peacock, and Comma require dense scrub for over-wintering. For this part of their life cycle, scrub and woodland habitats are vital.

Grassland/scrub mosaic in the Burren. These grassland/scrub transitional zones are excellent places for many butterflies and moths, but the development of scrub presents a challenge to farmers and conservationists attempting to protect orchid-rich grassland.

The removal of large areas of scrub over an extended area can produce severe survival challenges for rarer, scrub-dependent butterflies. Any remaining areas may be too small to support populations. Where suitable habitat patches are isolated, a species may modify its behaviour to secure its survival. There may be selection for sedentary individuals. Highly localised, sedentary populations are vulnerable to extinction arising from causes such as habitat destruction, bad weather, parasitoids, or perhaps inbreeding. Selection for more sedentary races of the Pearl-bordered Fritillary is suspected to have taken place in England in areas where the butterfly depended largely or fully on coppicing for its habitat (Thomas and Lewington 2014).

Climate change is expected to produce warmer, drier summers in Ireland. Many of the warmest years on record have occurred since 2000. According to the Copernicus European State of the Climate report in 2020, 11 of the 12 warmest years occurred since 2000. The projected decreases in rainfall for Ireland are largest for summer, with reductions ranging from 0% to 13% and from 3% to 20% for the medium-to-low and high emission scenarios, respectively. Projections indicate an increase of 1–1.6°C in mean annual temperatures, with the largest increases seen in the east of the country. Warming is enhanced for the extremes (i.e., hot or cold days), with the highest daytime temperatures projected to rise by 0.7–2.6°C in summer and the lowest night-time temperatures to rise by 1.1–3°C in winter (Nolan 2015).

Burren vegetation showing the effect of prolonged hot, dry weather in June 2018.

During recent hot, dry summers such as in 2018, desiccation of larval foodplants was observed in open, unshaded grasslands. During the hot weather, some species that usually frequent open areas during the day were observed sheltering in scrub. Interestingly, the Common Blue, which breeds on plants such as Common Bird’s-foot-trefoil growing in open grassland, was observed laying eggs on the foodplant growing in the shade. There may be several reasons for this untypical behaviour; the plants in open areas were in poor condition while in shaded areas they were not shriveled, the plants in shaded places were probably growing at the correct temperature during the heat of that summer, while during a more ‘typical’ summer, shaded plants will not support the larva. Finally, stress from extreme heat may be driving the adults to choose plants in less suitable micro-sites.

Breeding on plants shaded by scrub may be an adaptive behaviour by open grassland breeders under a warming climate. The increasing heat and dryness over the coming years may increase the importance of scrub for some Lepidoptera and other invertebrates.

The vast majority of Irish Lepidoptera are moths. There are about 1567 moth species recorded in Ireland with about 970 of these occurring in the Burren (D. Allen pers.com.). About 600 macro (larger) moths have been recorded. The following figures show the foodplants used by macro-moths; note that some species are polyphagous and use several of the following scrub species. 121 species have been recorded on willows, 96 species recorded on birches Betula spp., 61 species recorded on oaks Quercus spp., (the latter two tree groups are uncommon in the Burren scrublands), 26 species recorded on Aspen, 29 species recorded on Common Blackthorn, 36 species recorded on Common Hawthorn, 44 species recorded on Common Hazel, six species recorded on Purging Buckthorn and five on Alder Buckthorn (Waring et al 2004).

Scrub and limestone grassland on limestone pavement in the Burren National Park.

Hedges, scrub, and woodland are vital for our moth species, and not simply for larval foodplants. Moths use wooded habitats in similar ways to butterflies. One example is provided in a study by Coulthard et al. (2016) which showed that hedges are very important flight paths for moths. 68% of moths in the study were observed at 1m from the hedge, and of these 69% were moving parallel to the hedge. Hedges are believed to provide the sheltered corridors needed by flying insects in our generally open, farmed landscapes. This is likely to be especially relevant in open, exposed areas like the Burren.

The Silver-washed Fritillary breeds in scrub where abundant light reaches violets, the larval foodplant.
Silver-washed Fritillary larva prepares to pupate in a clearing in hazel scrub containing abundant violets.

There is an overwhelming body of evidence that supports the idea that more heterogeneous habitats can support more species diversity (Broeker 2018). Habitat heterogeneity, or small-scale changes in resource composition and structural complexity, provides more possible niche space for organisms to occupy and exploit (Tews et al, 2004). The range of habitats in the Burren, especially in the eastern areas, where complex mosaics of fens, cutover bogs, grasslands, heaths, limestone pavement, woods, and scrub exist support more butterfly species than anywhere else in Ireland. The scale of the habitats supports connectivity/dispersal, and genetic diversity and provides a range of niches in the face of the impacts of climate change, offering the prospect of adaptation when species are confronted with survival challenges. Maintenance of these conditions not only supports biodiversity generally, it preserves the magnificence of the region, touching those who experience the Burren with “the joy of elevated thoughts” (Lines Composed a Few Miles above Tintern Abbey, On Revisiting the Banks of the Wye during a Tour. July 13, 1798).

References

Broeker, H. (2018) Habitat Heterogeneity, Morphospecies Richness, and Niche Exploitation in the Human Skin Microbiome. Online at https://www.lakeforest.edu/news/habitat-heterogeneity-morphospecies-richness-and-niche-exploitation-in-the-human-skin-microbiome, accessed 11 September 2022

Coulthard, E., McCollin, D. & Littlemore, J. (2016) “The use of hedgerows as flight paths by moths in intensive farmland landscapes”, Journal of Insect Conservation, vol. 20, no. 2, pp. 345-350.

European Commission (2020) Warming trend shows 11 of the 12 warmest years occurred since 2000, according to the Copernicus European State of the Climate report. Online at: https://climate.copernicus.eu/warming-trend-shows-11-12-warmest-years-occurred-2000-according-copernicus-european-state-climate, accessed 10 September 2022

Fossitt, J.A. & Heritage Council Ireland (2000) A guide to habitats in Ireland. Heritage Council/Chomhairle Oidhreachta, Kilkenny.

Harding, J. (2021) The Irish Butterfly Book. Privately Published, Maynooth.

Nash, D., Boyd, T. & Hardiman, D. (2012) Ireland’s Butterflies: A Review. Dublin Naturalists’ Field Club, Dublin.

Nolan, P. 2015. EPA Report: Ensemble of Regional Climate Model Projections for Ireland. EPA climate change research report no. 159. EPA: Wexford. (show me this citation)

Tews, J., Brose, U., Grimm, V., Tielbörger, K., Wichmann, M. C., Schwa­ger, M., & Jeltsch, F. (2004) “Animal species diversity driven by habitat heterogeneity/diversity: the importance of keystone structures.” Journal of Biogeography, 31(1), 79-92.

Thomas, J. & Lewington, R. (2014) The Butterflies of Britain and Ireland. (Revised edition) British Wildlife Publishing, Dorset.

Waring, P., Townsend, M., & Lewington, R. (2004) Field Guide to the Moths of Great Britain and Ireland. British Wildlife Publishing, Hampshire.

 

 

 

 

 

Some Butterflies and Moths Flying Now

In late summer and early autumn, we still have a large number of species flying.  A good, ‘natural’ garden stocked with native herbs and trees can attract all of the species featured below. Here is a selection of these butterflies and moths. All but one of the moths shown are strictly nocturnal and spend the daylight hours concealed among the leaves of trees and shrubs.

Scorched Carpet, double-brooded in the south and midlands of Ireland, breeds on Spindle. This foodplant relies on calcareous soil, which means the moth is found in limestone areas and areas with lime in the soil. The moth occurs in areas of scrub and hedgerows, including some gardens.
The Canary-shouldered Thorn breeds on a range of deciduous trees. It flies mainly during September and is striking for its canary-yellow thorax. Despite the bright colouring, the moth is rarely seen unless a light trap is used to attract it. It likes wooded areas, including mature gardens.
The Frosted Orange breeds on thistles, particularly on Creeping Thistle, where the larva feeds internally on the plant stems. Despite the abundance of the foodplants, the moth is not very abundant in Ireland. It flies in August and September.
The Gold Spot likes wet areas, including marshes, where its wetland foodplants, like Flag Iris, occur. It flies in two broods, in June and later in August/September. It is common in Ireland. It can sometimes be seen flying during daylight, during overcast, mild weather.
The Common Blue (male pictured) is widespread in Ireland in grassy places, using a number of vetches and clovers as larval foodplants. Black Medic and Common Bird’s-foot-trefoil are commonly used where these grow in suitable conditions. The species flies in at least two generations annually, and responds to summer drought by producing very small individuals in late summer. In some years it flies into early October.
The Small Copper belongs to the same butterfly family as the Common Blue. It breeds on Common and Sheep’s Sorrel, both dock species. This beautiful, active butterfly is widely distributed in Ireland but it is rarely numerous in any one place. Two or even three broods can be seen per year. In years with three broods, it flies from May to October, with an overlap between the second and third broods in years with prolonged warm weather in late summer and autumn.
The Brimstone butterfly (the male is brimstone yellow on the upperside of his wings) produces just one generation each year. It is our longest-lived butterfly in the adult form, lasting up to a year. This one hatched in August and is feeding for a few days before disappearing for the rest of the year, reappearing in March to breed. Eggs are laid, in Ireland, on two small trees, Purging Buckthorn and Alder Buckthorn. A puzzling feature of this species is that the abundance of the insect in spring is often unmatched by its apparent relative scarcity during the previous summer and autumn.
Red Admiral on Devil’s-bit Scabious. The butterfly in this photo is perfect, having emerged the day the photograph was taken. After feeding, this butterfly is likely to migrate southwards, heading to the continent to breed. Some will stay put, breeding here, in warmer coastal locations, where the immature stages will develop slowly during the colder months. This is a recently noted change; before 2000 all autumn Red Admirals were understood to leave Ireland in autumn. Now, most still do so, but this is changing.

All photos J. Harding

Ireland’s Butterflies Continue to Decline

The National Biodiversity Data Centre (NBDC), based in Waterford, has been tracking the fortunes of Ireland’s butterfly populations since 2008. Using 2008 as the baseline for abundance, the recording scheme used by the NBDC the Irish Butterfly Monitoring Scheme (IBMS), involves 26-weekly transect walks carried out during the main flight period from April 1 to September 30. This scheme tracks abundance and flight periods. In addition, the Five-visit Monitoring Scheme also collects data on abundance.

The news emerging from the NBDC over the past two years is concerning. In 2020 and last year the multi-species index showed that once again there was a moderate decline in the number of butterflies flying when compared to the baseline year of 2008 (the start of the monitoring scheme). In terms of the individual species trends, no species shows a positive trend with only two species having ‘stable’ trends and all other species showing either ‘declining‘ or ‘uncertain’ trends when compared to the baseline year of 2008.

In Britain, a new Red List has been published this year, showing that half of Britain’s remaining butterfly species are listed as threatened or near threatened. The Irish Red List, published in 2010 and outdated classifies 33% of our species as threatened or near threatened. The List should have been re-evaluated in 2020 but will now be revised following the collation of data for the Irish Butterfly Atlas 2017-2021, probably in 2023.

When the Irish list is re-evaluated, it is likely that some additional species will be red-listed.

Nostalgia often leads us to think that the past was a better time, and butterfly memories charm reminiscence. We recall times of butterfly abundance in fields and gardens, but the absence or scarcity of data means verification of abundance trends is elusive. What can be gleaned from records taken before 2008 are some indications of distribution change.

It is quite clear why some butterflies are no longer found in certain places. Clearly, when land is built on, the composition of species that live on the land will change, with some doing well, such as the Holly Blue, which finds suburbia highly convivial, and others, like the Wall Brown, disappearing. The more disturbing and mysterious feature of butterfly loss is when a species has vanished, but the habitat remains, apparently unchanged. Subtler forces are at play when this occurs, and such circumstances can be difficult to discover and may be beyond our ability to address.

Some land use changes that cause distribution loss are avoidable and often irreversible. The widescale drainage of bogs, afforestation of bogs and peat extraction has certainly reduced the distribution of bog species, especially the Large Heath butterfly. Extensive changes in land management, particularly farmed land, have powerful impacts on butterflies, especially because 85% of our land is farmed.

A relatively new threat is the impacts arising from introduced invasive alien species, especially along hedges and stone walls in the countryside. The rampant weed, Montbretia, is a serious pest species, forming dense bands along hedgerows, eliminating all native herbs that butterflies, moths and other invertebrates require for their life cycles. This problem is increasingly acute, because of the increased relative biodiversity value of our native hedges and associated extended margins. Recently, Montbretia is appearing along the boreens of the Burren to sinister effect.

We appeal to everyone, especially if you live in a rural area, to remove this plant. It can be easily pulled up and the bulbs will yield easily. These must be destroyed. There are websites that advise on the eradication of this extremely damaging weed.

Montbretia makes up 100% of the flora on roadsides, eliminating native plants (it even excludes nettles) used as food for butterfly larvae. Montbretia does not belong in our ecosystems and must be eliminated before severe damage is done. The four new corms arising from one plant in the photo above show how invasive the plant is. The photograph was taken at Fanore, in the Burren, County Clare.

Another culprit is Fuchsia, a shrub that often accompanies Montbretia, and which is another invasive alien species that displaces native plants. While undeniably pretty, the plant has very little value as a breeding plant, unlike the native shrubs it crowds out. It is hard to get rid of once established and may need to be killed using an herbicide. Our advice is to avoid planting it and grow a native shrub instead.

Fuschia is a dominant shrub on many parts of the Dingle peninsula, and in other areas, and is replacing native food sources for invertebrates. Never allow this plant to naturalise near your home. This photo was taken at Fanore, in the Burren, County Clare.

If the avoidable threats from introducing non-native plants cannot be dealt with, our deeper problems are even less likely to be tackled. However, conservation is also about what not to do.

Do not grow non-native plants, unless you want them in your garden, but make sure they stay there. Do not buy peat for the garden or the fireplace. Leave peat where it belongs, in the bog. Do not buy electricity from wind or solar suppliers if the electricity they generate is derived from infrastructure built on bogs. Our bogs have taken all the abuse they can, and more. They must be re-wetted and allowed to begin recovery of their distinctive habitats and carbon capture capacity.

On top of the things that we need not do, there is a lengthy to-do list. Much of this relates to changes needed in the way our land is farmed, and this is a huge policy question internationally. The widescale use of chemicals is a very significant challenge along with the use of single or reduced-species swards to graze livestock.

A related, and global challenge to biodiversity, of which butterflies are one of the most charismatic and visible symbols, is climate change. Climate change is strongly associated with the over-exploitation issues already stated, as well as its link with industrialisation. Pollution, which is a driver of climate change also changes the soil conditions needed by butterfly foodplants, while increasing temperatures cause a complex range of challenges and outcomes which vary according to species and location.

Therefore, issues such as land use changes and climate change influence butterfly distributions, but the NBDC report quoted in the introduction deals with abundance trends (and flight times) in other words, how large our populations are compared with their 2008 baseline.

When only two out of our 35 butterfly species are recorded as having a stable population, we should not doubt that our butterflies and wildlife generally are under pressure, as a direct result of our behaviour.

The two stable species are the Peacock and Brimstone, although the evidence so far submitted to Butterfly Conservation Ireland this year suggests abundance declines for both in 2022.

The really worrying feature is the decline of very common, widely distributed species. Our best-distributed butterflies are four whites: Large, Small, Green-veined White and Orange-tip, the Small Tortoiseshell, and three browns: Speckled Wood, Meadow Brown and Ringlet.

Selecting one year only will not tell us much if anything about trends. Let us see how these did in 2008-2020 and 2012-2021.

 Large White:

Trend 2008 – 2021 – Strong decline (-76%)

Trend 2012 – 2021 – Moderate decline (-34%)

Small White:

Trend 2008 – 2021 – Strong decline (-77%)

Trend 2012 – 2021 – Moderate decline (-44%)

Green-veined White:

Trend 2008 – 2021 – Strong decline (-87%)

Trend 2012 – 2021 – Strong decline (-59%)

Fertiliser use is removing habitat for the Green-veined White which is also at risk from drought caused by our longer, drier summers.

 Orange-tip:

Trend 2008 – 2021 – Strong decline (-68%)

Trend 2012 – 2021 – Moderate decline (-20%)

Small Tortoiseshell:

Trend 2008 – 2021 – Moderate decline (-49%)

Trend 2012 – 2021 – Uncertain (no significant change, changes likely to be >5% per year)

The familiar Small Tortoiseshell loves human company. This lovely butterfly is feeding in our gardens now, and entering our houses to seek roost and over-wintering sites.

Speckled Wood:

Trend 2008 – 2021 – Strong decline (-78%)

Trend 2012 – 2021 – Moderate decline (-40%)

Meadow Brown:

Trend 2008 – 2021 – Strong decline (-86%)

Trend 2012 – 2021 – Moderate decline (-70%)

The Meadow Brown was once described as “a butterfly that is hard to get rid of.” Not any longer, according to the decline statistics.

Ringlet:

Trend 2008 – 2021 – Strong decline (-88%)

Trend 2012 – 2021 – Strong decline (-62%)

 There is a group of butterflies that are not as widespread as these but are still widely distributed but more specialised in their requirements. Two examples are given here.

Small Copper:

Trend 2008 – 2021 – Moderate decline (-69%)

Trend 2012 – 2021 – Uncertain

Small Heath:

Trend 2008 – 2021 – Moderate decline (-76%)

Trend 2012 – 2021 – Uncertain

The IBMS report 2021 does not make any attempt to interpret the reasons for these declines but changes in how land is farmed must be the greatest influence on populations. Chemical usage is a major factor driving declines. Two doses of NPK fertiliser per year plus an application of herbicide rids grasslands of plant diversity and benefits a small number of vigorous grasses. Add to that the spread of non-native, invasive species on the last strips of farmland, the hedge and strip of parallel land at the field margins, especially adjoining public roads, and the last vestige of habitat is lost.

There is little doubt that habitat loss is the major factor driving the current declines of widespread butterflies, and that widespread, severe environmental degradation is the key issue. With a degraded environment, resisting and adapting to climate change is becoming impossible.

Moreover, add cobblelock and tarmacked driveways replacing gardens, public green spaces planted with useless and harmful non-natives and mismanaged, and our best wild places neglected.

We get what we deserve.

In F. Scott Fitzgerald’s novel, The Great Gatsby, an incident occurs when a drunken guest who attended Gatsby’s party crashes the car into a wall, causing it to lose a wheel.

“But how did it happen? Did you run into the wall?”

“Don’t ask me”, said Owl Eyes, washing his hands of the whole matter. “I know very little about driving-next to nothing. It happened, and that’s all I know.”

“Well, if you’re a bad driver you oughtn’t to be driving at night.”

“You don’t understand,” explained the criminal. “I wasn’t driving. There’s another man in the car.”

…a pale dangling individual stepped out of the wreck, pawing tentatively at the ground with a large uncertain dancing shoe.

“Wha’s matter?” he inquired calmly. “Did we run outa gas?”

“Look!”

Half a dozen fingers pointed at the amputated wheel-he stared at it for a moment, and then looked upward as though he suspected that it had dropped from the sky.

“It came off,” someone explained.

… “Wonder’ff tell me where there’s a gas station?”

At least a dozen men, some of them a little better than he was, explained to him that wheel and car were no longer joined by any physical bond.

“Back out,” he suggested after a moment. “Put her in reverse.”

“But the wheel’s off!”

He hesitated.

“No harm in trying,” he said.

(The Great Gatsby, Penguin edition, pp. 55-56)

This incident foreshadows a much more serious car accident later when the consequences of human excess, irresponsibility, and delusion destroy the most vulnerable in the story. The motor car operates as a symbol of wealth, status, individualism, and human achievement yet it plays a major role in the destruction of idealism and happiness. The novel implies the moral and ecological bankruptcy of man’s exploitation of nature when the serious accident occurs in a grotesque “valley of ashes,” an industrial wasteland presided over by a billboard showing pair of sightless eyes, mistaken by a grieving character for the eyes of God. Without seeing where we are heading, without heeding the relationship between our treatment of  Earth’s ecosystems and our reliance on them, we will lose more than our butterflies.

The butterfly is a symbol of all that is good and healthy in our world. Where they abound in their diversity of species, the ecosystems are healthy and functioning as they should be. As August stands on the doorstep of September, enjoy the butterfly spectacle now on show in nectar-rich gardens. Spectacular though it is it will be of short duration. Their brevity and vulnerability should touch us to respect and love our butterflies and the landscapes they represent even more.

Flower-rich semi-natural grassland is just a memory in many places. Soon areas like this will be a myth.

Key Reference

Judge, M and Lysaght, L. (2022), The Irish Butterfly Monitoring Scheme Newsletter, Issue 14.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Climate Change, Biodiversity Crisis and Butterflies: What has happened to the Peacock?

When will we ever learn? Nature is in crisis. Changes in land and sea use, overexploitation of biological resources, climate change, pollution, and invasive alien species have eroded our once rich natural capital and pushed more species to the edge of extinction than at any other point in human history. In the last four decades alone, global wildlife populations have fallen by 60% because of human activities, and nature is now in steep decline in almost every corner of the planet.

We face the extinction of three-quarters of global biodiversity by 2100 if we continue to pump the same quantity of greenhouse gases into the atmosphere as we have during the past decade.

The effects of climate change on animal and plant populations can be simple and complex. A relatively simple example is that some animals that favour warm conditions are shifting their European distributions further north, and to sites with a northerly aspect and to more elevated altitudes as these areas, now warmer, become suitable. Some species that favour cool conditions are responding in the same way, to avoid the habitat and other changes created by increasing warmth and because the increased temperature is enabling these cool climate specialists to use areas that had previously been too cold.

There are limits to the success of these responses. In a scenario of continued temperature rises, some species, such as the montane and arctic butterflies (such as Lapland Fritillary Hypodryas iduna), will run out of higher ground and cooler terrain to retreat to. This species breeds in damp habitats such as bogs and marshes. Increased heat will change the character of these areas resulting in habitat change and likely extinction. One of the world’s rarest species, the Sinai Hairstreak Satyrium jebelia, breeds on buckthorn bushes growing at altitude on the Sinai Peninsula. High-mountain endemics with very restricted ranges are likely to have a high risk of extinction under the various scenarios of global warming.

Endemic to the high mountains of the St Katherine Protectorate in South Sinai, the total world population in 2012 was estimated to be 1,010 individuals. Aspects of hostplant and habitat quality were significant predictors of the presence of Sinai Hairstreaks on individual trees. No immediate threats are evident except global warming: if current climate-change predictions for Egypt are correct, the quality of habitat and plant diversity will decrease in the St Katherine Protectorate, with negative conservation results likely (Power et al. 2014).

Let us look at just a couple of our butterflies, the Small Tortoiseshell and Peacock butterflies.

The Small Tortoiseshell butterfly is faring better in Ireland than in Britain. Here the population is regarded as showing a moderate increase (Judge and Lysaght, 2020) while in the UK it has shown a significant major decrease in abundance of -73% from 1976-2014 (Fox et al. 2015). It should, however, be noted that the Irish abundance study covered a shorter time (2008-2020) than the UK study. The species has declined in abundance by over 70% in Europe (Van Swaay, pers. comm. April 2021).

However, we should not be complacent about the butterfly’s abundance in Ireland. The arrival of the parasitoid, Sturmia bella, a fly species, in England in the late 1990s (first confirmed in Peacock caterpillars in Hampshire in 1998) has had a significant impact on the Small Tortoiseshell (and to a lesser extent, on the Peacock butterfly) in England. S. bella occurs naturally in Europe and its appearance in England may be the result of accidental or deliberate introduction or the result of climate change. S. bella lays its eggs on nettle leaves which are ingested by Small Tortoiseshell and Peacock caterpillars. The egg hatches inside the caterpillar. The parasitoid kills its host after the caterpillar pupates. The grub descends from a thread to pupate on or in soil.

A study by Gripenberg et al. (2011) found that the fly was present in 26% of larval groups of the Small Tortoiseshell assessed and that survival was 25–48% lower in batches of Small Tortoiseshell larvae where S. bella was present, indicating that S. bella causes host mortality in addition to that caused by native parasitoids. In some batches, all the caterpillars were infected. S. bella was found as far north as Lincolnshire, and the Small Tortoiseshell has declined significantly south of Lincolnshire but not north of this county. The report concludes that S. bella may be playing a role in the recent decline of the butterfly but “further research is needed to establish its effects relative to other potential drivers of trends in the abundance of this butterfly.” (Gripenberg et al. 2011)

S. bella also attacks the Peacock, Comma, Painted Lady, Speckled Wood and other butterfly species, but none of these are in decline in England. The Peacock’s stable status might be partly because the Peacock favours different breeding sites, particularly nettles close to woods, where S. bella is less common and because the Peacock, which is single-brooded, produces its larvae mainly between April and June, when S. bella is not numerous. The Small Tortoiseshell produces two or even three broods, and the second brood of larvae, in July, coincides in time with the abundance of S. bella.

The Small Tortoiseshell continues to thrive in Ireland, occurring in up to three generations in some areas during favourable years. Photo J. Harding

A further climate-related problem for the Small Tortoiseshell is that prolonged dry weather in mid-summer reduces foodplant quality which may cause longer development times for the larvae or which results in the butterfly cancelling reproduction in the year of its birth and undergoing a reproductive diapause until the following spring. This necessitates a prolonged hibernation with adults entering their dormant state in July instead of September/October. This strategy helps the butterfly avoid second brood production which is more at risk from the effects of malnutrition and S. bella than its first brood, produced in spring. But it would certainly be at increased risk from animals that have not yet over-wintered and that use Small Tortoiseshell hibernacula as roosts or breeding sites, such as Brown Long-eared Bats Plecotus auratus.

The Small Tortoiseshell and Peacock have several native parasitoids to contend with. Larvae of the Small Tortoiseshell and the Peacock are also attacked by several other parasitoid species, of which the most common ones are the ichneumonid wasp Phobocampe confusa Thomson, the braconid wasp Cotesia vanessae, and the tachinids (fly species) Phryxe spp., Pelatachina tibialis, and Compsilura concinnata. These are all endoparasitoids (the parasitoids develop inside the host), and in all cases the parasitoid larvae emerge from the fully developed caterpillars before host pupation.

Small Tortoiseshell pupae (and the pupae of several butterfly and moth species) are attacked by a wasp, Pteromalus puparum, discovered in Ireland in 2002 (but present before that date, with the earliest known museum specimen dated 1928) which lays its eggs into newly formed, still soft pupae. Although the pupa is aware it is being disturbed and wriggles vigorously, it has no defence. Instead of a butterfly emerging from the pupa, tiny wasps, which may number over 100, bite their way out and exit through tiny holes. This parasitoid wasp is widespread in Ireland and has been found as far apart as Warrenpoint, County Down (1928), Glengariff, County Cork (1943) and Drumachon, County Kildare (2015).

This newly formed Small Tortoiseshell chrysalis is being infected by Pteromalus puparum, on August 18, 2015, Drumachon, Co. Kildare. Photo J. Harding

Aside from S. bella, the native parasitoids have been present in England and Ireland for a long period, and these did not cause a prolonged decline in the species. However, irresponsible behaviour such as deliberate introduction can bring in a new parasitoid that creates severe difficulty for our native species.

A warming climate also encourages colonisation events, bringing threats to our indigenous species. It should be underlined that S. bella is native to Europe, so the great decline in the Small Tortoiseshell in the continent has not been explained by reference to the fly, and the causes of decline are currently unknown. However, could the decline be attributed to a warming climate favouring the fly?

And does the warming climate mean that the fly can make greater use of other host species? One reason for the Peacock’s lower vulnerability to S.bella is its use of nettles at wood edges, where the Peacock has a warmer micro-climate. However, recently the Peacock has also been observed using nettles in more open situations, possibly because the warming climate now makes these suitable; I have encountered several Peacock larval clumps on nettles along a track running through an open field.

For the second year in succession, the Peacock has shown a great decline in abundance in many areas in Ireland. This has been noted as a widespread reduction, in areas as distant as the Burren, County Clare, Lullymore, Co. Kildare, and County Antrim. This is a sudden and dramatic abundance decline, following the Peacock showing a “strong increase” 2008-2020 (Judge and Lysaght, 2020). The Peacock is believed to have benefited from the warming climate. In the 1960s it was a rare migrant to northern Scandinavia. In the 1970s it began to acclimatise, beginning to survive hibernation over the winter. Today, it is one of the most abundant Nordic species in late summer (Haahtela et al. 2011).  Parasitoids might be responsible, however for the population reduction during the past two years. The coming years will tell us if this decline is a trend, but it is far too early to make any assessment.

Peacock butterfly, August 2022. The large populations frequently observed in flower-rich sites from 2008-2020 have not been repeated in the past two years, 2021-2022. Photo J. Harding

One useful conservation response the gardener can make is to allow nettles to grow in different areas, in semi-shaded, unshaded, exposed and sheltered locations. Heterogeneity in the location of the nettles offers the best hope of satisfying the breeding requirements of the Peacock under the changing circumstances wrought by the changing climate.

We are incapable of reversing climate change as individuals, and whatever the causes driving the decline of the Small Tortoiseshell in England, one fact is at least clear. One should not bring plants (including from overseas nurseries), eggs, larvae or pupae from Europe into Ireland or Britain, or from Britain into Ireland. The immature stages of butterflies often contain parasites or even viruses which our butterfly populations do not need, especially with climate change and habitat change and loss added to the challenges faced by our beleaguered butterflies.

Key References

Fox, R., Brereton, T.M., Asher, J., August, T.A., Botham, M.S., Bourn, N.A.D., Cruickshanks, K.L., Bulman, C.R., Ellis, S., Harrower, C.A., Middlebrook, I., Noble, D.G., Powney, G.D., Randle, Z., Warren, M.S. & Roy, D.B. (2015). The State of the UK’s Butterflies 2015. Butterfly Conservation and the Centre for Ecology & Hydrology, Wareham, Dorset.

Gripenberg, S., Hamer, N., Brereton, T., Roy, D. B., Lewis, O.T. (2011). A novel parasitoid and a declining butterfly: cause or coincidence? Ecological Entomology, 36, 271–281.

Haahtela, T et al. (2011) Butterflies of Britain and Europe. A&C Black, London.

Judge, M and Lysaght, L. (2020) ‘2019, the year of the Painted Lady’, The Irish Butterfly Monitoring Scheme Newsletter, Issue 13.

O’ Connor, J. P. 2002, “Pteromalus puparum (L.) (Hym.: Pteromalidae), a chalcid new to Ireland” The entomologist’s record and journal of variation Vol. 114 pp. 111-112. Available at https://www.biodiversitylibrary.org/part/194950 (Accessed 22 August 2022)

Power, A., Zalat, S. & Gilbert, F. 2014, “Nowhere left to go: the Sinai Hairstreak Satyrium jebelia”, Journal of insect conservation, vol. 18, no. 6, pp. 1017-1025.

 

From Junior Infant to Senior Citizen: How the world will look for our Five-year-Olds

Cast your imagination back 125,000 years. The climate then was as warm, on a sustained basis, as it has been in the past decade. Where Trafalgar Square stands today, alligators, hippopotami, and lions roamed the savanna while elephants grazed the banks of the Thames. Today,  Sir Edwin Landseer’s bronze lions guarding Nelson’s column grandly survey the Square where the wildlife consists mundanely of feral pigeons.

Imaginative indulgence conjures dreams of restoration ecology, beloved by hankerers for the recovery of ecosystems deficient in parts of the puzzle. In Ireland, such projects are usually concerned with iconic apex predators, such as the Grey Wolf, Red Kite, White-tailed Sea Eagle, and Golden Eagle. The latter three have been introduced to Ireland while the Grey Wolf is busy recovering lost territory throughout western Europe, under its own steam, but benefiting from the ban on poisoning and hunting that brought the animal to the edge of oblivion in most of Europe in the late 1970s.

But clocks are not easily turned back, and as the Covid pandemic demonstrated, we are not in control. The greater powers, the wrath of whom we have provoked, are in the ascendant. We are reactors, employing a scattergun approach to problem-solving that Manchester United’s transfer negotiator John Murtough would recognise, but be embarrassed by.

Our vulnerability to greater power than our meagre selves was spelled out to the cabinet committee on the environment and climate change in early May 2022 by Professor Peter Thorne, a lead author on the Fifth Assessment Report of the Intergovernmental Panel on Climate Change and one of the world’s leading climate experts.

Professor Thorne told the Climate Committee, which consists of the Taoiseach (Prime Minister), Tánaiste (deputy Prime Minister), Ministers of Public Expenditure and Reform, Social Protection, Agriculture, Climate Action, Tourism and Housing, that to keep the temperature below 1.5 Celsius above the pre-industrial era temperature, we need net emissions to reach zero by 2050. This requires halving methane emissions and getting carbon emissions to net zero.

You probably knew that. But then the devastating news was delivered that stabilisation of all effects of climate change is impossible in the next few centuries. Sea levels will rise by five metres.

There is nothing we can do to change this.

If you live in Cork City, Limerick, Galway, or Belfast you are in peril, especially if you are in junior infants’ class, typically a five-year-old. Here is what the sea level rise means for Dublin.

By the time our five-year-olds reach old age, Dublin will no longer contain Sandymount, Blackrock, Monkstown, Sandycove, Dun Laoghaire, and Ringsend on the south side and Malahide, Clontarf, Portmarnock and Sutton on the north side of the River Liffey. The Hill of Howth will be an island and there will be no Bull Island. The Liffey, by then hundreds of metres in width, will enter the sea at Phoenix Park. Dublin Bay will stretch from Cabra on the north side to Donnybrook to the south. The flooding will reach Lombard Street, near Trinity College.

Flood Map of Dublin 2100 (Image Climate Central)

The past 10,000 years have seen a remarkably stable global climate, allowing humans to develop from nomadic hunter-gatherers to settle in great urban centres facilitated by the industrial and agricultural revolutions. This climate stability is rapidly unraveling, according to Professor Thorne.

It will be worse elsewhere, such as on the Indian sub-continent, but we will feel the shocks, directly, economically, and in human terms, with mass migration to this country. We are at the edge of human livability in some areas already, such as the Horn of Africa, and this year, in parts of India.

If we are stupid enough to go to three Celsius above pre-industrial temperatures by the time our Junior Infants reach advanced old age, and this is where we are heading with current emission levels, 75% of all the planet’s biodiversity will be lost. Imagine what such a world would look like.

Many of our familiar plants and animals have ceased to exist. The photographs in The Irish Butterfly Book will likely show several extinct species. I wonder if the Wall Brown, Hedge Brown, Small Heath and Large Heath will still exist. These species are already in serious decline, and climate change and issues driving climate change are among the causes. The extinction list is also likely to contain the species that need well-drained skeletal soils: Dingy Skipper, Small Blue, and Pearl-bordered Fritillary.

The Pearl-bordered Fritillary breeds on violets growing on thin, fertile soils over free-draining carboniferous limestone in the Burren. These soils are vulnerable to water loss if hot, dry summers, as are the plants and dependent invertebrates. Photo J. Harding

There are studies concerning the link between the warming climate and butterfly declines. There are indications that a combination of climate change and pollution is damaging the habitat of the Wall Brown. Kurze et al. (2018) suggest that it is very likely that nitrogen enrichment from fertilisers is killing some species larvae on farmland while Habel et al. (2015) suggest that increased plant growth rates arising from nitrogen deposition, increased rainfall and climate warming are cooling the micro-climate at larval sites, driving declines of species that depend on nutrient-poor habitats.

Hazel bushes suffered dehydration during drought conditions on July 1, 2018. Photo J. Harding

A study that looked specifically at the Wall Brown’s decline, Impact of nitrogen deposition on larval habitats: the case of the Wall Brown butterfly Lasiommata megera by Klop et al. (2014) found that nitrogen addition to potted foodplants on which larvae were fed had beneficial effects on larval development. However, the study found the influence of nitrogen deposition on larval micro-site cooling the most likely reason for the decline: “The raised levels of green plant biomass under excessive nitrogen availability leads to an increase of both shading and green: dead ratios in the vegetation, which should be expected to result in a cooling of microclimatic conditions.”

Like Habel et al. (2015), Klop et al. (2014) believe the decline of heat-loving species “could be explained by a combination of excess nitrogen and climatic warming, with both factors enhancing plant growth in early spring and reducing the availability of warm microclimates.” Elevated temperatures at the larval micro-site, typically arising from a combination of unshaded bare patches of ground containing sparse foodplant vegetation and warm, dry, dead plant litter are critical to the caterpillar in spring when air temperatures are cool. If these findings are correct, geographical scale pollution reduction measures must be implemented along with measures to tackle climate change. If not, we could be lamenting the extinction of one of our formerly common and widespread butterflies.

However, in such a devastating context that Professor Thorne outlined, the fate of our butterflies may seem of small consequence, a trivial footnote to a doomsday of mass extinction and global crisis for mankind, with continued human existence at stake.

Thorne stated that a brief and closing window exists to secure a livable future if concerted global action takes place.

But the past decade has had the highest greenhouse gas emissions in human history.

Professor Thorne stated that technological solutions exist to produce low emissions, but investment, which is available, and leadership, are needed.

How, then, did the cabinet committee react to Thorne’s presentation? A few polite questions later, the ministers began to discuss sectoral contributions to emission reduction targets. The Irish Government reacted by producing, according to the Environmental Protection Agency (EPA) report published three weeks (May 31, 2022) after the briefing, an emissions policy that adds up to 28% of greenhouse gas (carbon dioxide, methane, and nitrous oxide)  reductions by 2030, not the required 50%.

When RTE’s HOT MESS programme sought an interview with any of the ministers who attended the briefing, no minister was made available.

Before we blame the Government, let’s look at ourselves. Do you want to sell your second car, get rid of your beloved SUV, pay higher taxes, and pay more for food?

I doubt it. But politicians need to lead public opinion, not follow it. Opportunities for leadership exist. Jim Hacker, the fictional minister in the British comedy, ‘Yes, Minister’, when asked to defy public opinion for the good of Britain, responded, “I am their leader. I must follow them.”

No more of that.

Policies that are unpopular now, will become more popular, over time, as people realise how crucial they are. Let us act so we don’t run out of it.

Limestone grassland in the Burren, June 29, 2018. The heterogeneity of these grasslands is threatened by the predicted hotter, drier summers predicted to be the norm by 2050. Photo J. Harding

Sources

Dublin Live (2022) Terrifying flood map shows what Dublin will look like by 2030 https://www.dublinlive.ie/news/dublin-news/terrifying-flood-map-shows-what-23608348 (Accessed 19 August 2022)

EPA (2021) EPA Greenhouse Gas emissions projections highlight the need for urgent implementation of climate plans and policies. Available at: https://www.epa.ie/news-releases/news-releases-2022/epa-greenhouse-gas-emissions-projections-highlight-the-need-for-urgent-implementation-of-climate-plans-and-policies-.php (Accessed 19 August 2022)

Habel, J., Segerer, A., Ulrich, W., Torchyk, O., Weisser, W., and Schmitt, T., (2015). Butterfly community shifts over two centuries. Conservation Biology, Volume 30, No. 4, 754–762, accessed 28 December 2020, https://conbio-onlinelibrary-wiley-com.jproxy.nuim.ie/doi/epdf/10.1111/ cobi.12656

Harding, J.,(2021) The Irish Butterfly Book, privately published, Maynooth.

Klop, E., Omon, B. & Wallis DeVries, M.F. (2015) Impact of nitrogen deposition on larval habitats: the case of the Wall Brown butterfly Lasiommata megera. Journal of Insect Conservation 19, 393–402. https://doi.org/10.1007/s10841-014-9748-z

Kurze, S., Heinken, T. & Fartmann, T. Nitrogen enrichment in host plants increases the mortality of common Lepidoptera species. Oecologia (2018) 188: 1227. https://doi.org/10.1007/s00442- 018-4266-4

Natural History Museum (2014) London’s Wild Times: Past and Present https://www.nhm.ac.uk/natureplus/blogs/whats new/tags/britain_one_million_years_of_the_human_story.html (Accessed 19 August 2022)

RTE (2022) Episode 12 Getting Hotter. Available at: https://www.rte.ie/radio/podcasts/22110709-ep-12-getting-hotter/ (Accessed 19 August 2022)

World Wildlife Fund (2021) The Return of the Wolf in Europe https://www.worldwildlife.org/stories/the-return-of-the-wolf-in-europe#:~:text=Wolves%2C%20along%20with%20other%20predators,effort%20to%20prevent%20livestock%20predation. (Accessed 19 August 2022)