Malta: Teeming with butterflies in Spring

One of life’s annoyances is arriving back in Ireland after a break in a sunny clime to be told by a grinning neighbour, “The weather was amazing here when you were away. It only started to rain yesterday.”

Anticipating this scenario while in Malta, I checked the weather report and forecast for Ireland online on RTE Radio. Rain, wind, thunderstorms, flooding, etc, etc! No mention of sunshine! Just lots of the wet and windy stuff.

That morning I gazed through the window of the apartment in Għajnsielem, Għawdex (Gozo, nicknamed Il-Gżira tat-tliet għoljiet, the island of the three hills), at clear skies lit by the Mediterranean sun. The smug feeling that comes from knowing that I wouldn’t be on the receiving end of a meteorological putdown and that I was feeling that glorious Vitamin D delivering sunshine on my pale skin was delicious.

Maltese Stocks Matthiola incana subsp. melitensis. The bay is Daħlet Qorrot Bay, a small inlet nestled between the northern cliffs of Gozo not far from in-Nadur, Gozo’s largest village.

Gozo, also known by its residents as Għawdex is the second largest of the Maltese Islands, which are the sunniest in Europe with over 3000 hours of sunshine a year. The sun shines for about 300 days each year. The winter temperatures are benign, with highs of 16-18 Celsius on many days. The average annual temperature is about 23 Celsius. In Ireland, the average is 9.4 Celsius.  This is considerably lower than the average of 12.4 Celsius in Malta’s coolest month, February.

Temperatures in April this year (2023) reached around 23 Celsius, a comfortable heat. It rained once during my two-week stay. It gets hot later, with June to September regularly having temperatures in the 30s Celsius and sometimes higher. The highest temperature in 2022 was in August when 39.2 Celsius was recorded. Being surrounded by sea means the very extreme high temperatures seen on the European mainland are avoided. Rainfall is low compared with Ireland and occurs mostly during winter. Summer rain is very rare. The islands get about 600mm of precipitation per year, sometimes much less.

The inhabitants accommodate themselves to the high day-time summer temperatures by closing businesses from 11 am to 4 pm (typically). Heat can be troubling for those with an aversion to high temperatures so if that’s you, avoid visiting from June to September because you will not enjoy your stay. During these months, there is persistent heat, even at night.

Malta Opera House, Valetta. It was not rebuilt after it was destroyed by bombing on 7 April 1941. A Government survey in July 2021 found that most respondents, 56.3 per cent, said they wanted the theatre to be built to its original structure.

The islands are special for their history, culture, and extraordinary architecture. The main island’s buildings were largely reconstructed after World War II when the island was essentially flattened by Axis bombing; Field Marshal Kesselring told the German High Command that “There is nothing left to bomb.”(Holland,  2003). The formerly iconic opera house in the capital Valetta (named after the French nobleman Jean de la Valette, who is recalled in the city’s name for his incredible feat in defeating the Ottoman invasion of Malta in 1565, one of the greatest sieges ever fought in Europe) remains a bombed ruin, a memorial to the devastation wrought on the island, a major strategic target in the Mediterranean war theatre.

Jean De La Valette, Valetta. He was about 70 years old when he master-minded the resistance to the Ottoman assault. Much of the evidence for the events comes from a first-hand account written by Francisco Balbi Di Correggio, of Italian birth who wrote in Spanish and Italian. His account of the Siege, published in Spanish in 1568, has been translated into English. It is remarkably detailed and highlights the frightening ferocity of the conflict, which ended in defeat for Sultan Suleiman.

For me, the islands are of immense interest, some of them rooted in the personal, given my Maltese heritage. The islands’ biodiversity is a big draw. As with isolated islands, the biodiversity count is lower than it is on continental land masses, but some of the species have developed unique characteristics, probably by being geographically isolated for thousands of years.

There are, for example, several endemic species and subspecies (an endemic is a species or subspecies that is confined to a restricted area) as well as near-endemics present, adding interest. Its strategic importance during conflicts also applies to biodiversity; it remains strategically important as a migration stop-over for many birds and insects.

The most eye-catching butterfly is Papilio machaon melitensis, the unique endemic subspecies of the swallowtail butterfly that occurs only on the Maltese Islands. Large, elegant and powerful in flight, it is undeniably beautiful. The subspecies rank of this butterfly was established in a study carried out by the University of Munich in 1936. Karl Eller researched the species based on specimens caught in September (probably the third generation).

Eller concluded that the Maltese swallowtail has a very long forewing, that the broad dark band running along the submarginal area of the forewing is strongly wedge-shaped and that this band, continued on the hindwing, is very broad there where it almost merges with the red spot. He also noted the finely scaled veins on the hindwing upper surface and found the red flame markings on the hindwing underside to be prominent. Eller considered the swallowtails he found in Malta similar in appearance to those in Africa.

Swallowtail (male), east of Qala, Gozo. Females look similar and are usually larger.

Recently, Leraunt (2016) stated his belief that the swallowtail in Malta is in fact a different species of swallowtail, mainly found in North Africa and the Middle East: “Illustrations on the Internet of melitensis Eller from Malta convinced me that it is indeed P. saharae melitensis Eller, 1936, stat. rev.” This view that the Saharan Swallowtail occurs in Malta was challenged by Louis Cassar (2018) of the Institute of Earth Systems at the University of Malta:

Leraut does not provide convincing evidence based, for example, on morphometric analysis (the study of shape variation of organs and organisms and its covariation with other variables) or molecular characterization to substantiate his hypothesis.

Given Louis Cassar’s morphometric study of both species (all life stages), I concur with his view. Differences exist, for example, in the antennae, the size and shape of the red hindwing spot, overall size, the appearance and length of the pupal stage, egg size and larval colour and the length and colour of the osmeterium (this is an eversible forked organ concealed just behind the larva’s head that emits an unpleasant smell used to repel bird attacks). This does not mean that the Saharan Swallowtail never appears in Malta; given the nomadic habits of many swallowtails, it may occasionally migrate there from North Africa and from Lampedusa, an island about 150 km WSW of Malta where the Saharan Swallowtail was recently confirmed (Cassar et al. 2023).

Butterflies don’t care about their own taxonomic identity, but we must. Species confined to a small island group deserve study and may require protection and our appreciation as we marvel at the ability of nature to adapt to conditions that may differ significantly from those on a continent.

Maltese Wall Lizard Podaris filfolensis maltensis is very common in the Maltese Islands. It occurs in Malta as an endemic subspecies. The females are brown.

Certainly delightful, the swallowtail in the Maltese Islands appears to be successful, moving throughout the landscape and even island-hopping to seek mates and breeding sites. Netted with black veins and bands over yellow wings, the sharp blue hindwing band and flame-red spot and black tails spell sophistication. So does its behaviour. It flutters delicately above blooms while dipping its proboscis to suck nectar, then surges powerfully away, defying gravity and gale in its onward propulsion.

One of the loveliest sights is a primrose yellow swallowtail fluttering around red or purple Bougainvillea climbing on mellow yellow ochre Maltese walls.

This butterfly is oddly elusive. You can look for it for hours, be on the brink of admitting defeat and then see three at once, battling for possession of ground or pursuing a mate. The courtship is dramatic. The sexes flutter around each other before rocketing to an impressive height and then plummeting to pair on a low shrub. Territories are often held on a patch of ground containing larval foodplants and nectar sources.

Some of these are at altitude and may also function as hill-topping sites where territorial possession and mate-seeking may occur at the same time or transition to hill-topping behaviour. This is when some butterflies, especially males, fly for hours around an exposed elevated site, with little or even no clear or discernible purpose. Mates may be encountered at hill tops but in some species, this appears not to be the purpose; for example, Peacock butterflies that are in a breeding delay phase (diapause) have been seen hill-topping in the Burren.

Swallowtail larva on Fennel, Il-Majistraal, Malta.

The swallowtail in Malta breeds mainly on Fennel Foeniculum vulgare which occurs widely and is often abundant. Fennel is also a nectar source. Fringed Rue Ruta chalepensis is also used for breeding. According to online sources, the adult butterfly flies from late February until November. It passes the winter in the pupa.

When I visited in the last two weeks of April, the adults I saw were mainly very fresh specimens. I also found young caterpillars on Fennel. It is possible that I was seeing some second-generation butterflies by late April, but I am not sure. The larvae were, I presume, the offspring of the first generation and will be second-brood butterflies.

Clouded Yellow, Xlendi, Gozo.

There were many butterflies flying in April. Small White, Large White, Eastern Bath White and Clouded Yellow were busy feeding and breeding. I saw Small White laying eggs on Caper Capparis orientalis, a lovely low shrub with striking flowers, especially the violet stamens. The flower buds are edible for humans.

Three blues were busy: Lang’s Short-tailed Blue, the Long-tailed Blue and the Southern Blue, previously believed to be the Common Blue. The classic migrants, Red Admiral and Painted Lady, were out too; some of the latter were faded and tattered, and others were perfect specimens.

The Long-tailed Blue is common in Gozo and northern Malta.
The Southern Blue is very abundant during July. It occurs in smaller numbers in spring.

The Wall Brown butterfly was abundant and I even saw a female on the main street in the Gozo capital, Victoria (Rabat). In Malta, none of these species needs very special habitats; they just need larval foodplants and nectar sources. I saw one Meadow Brown, on 29th April, near the coast east of Qala village. He was freshly emerged and I was excited to see it. However, the sight of what was recently a common butterfly should not typically evoke animation, but its populations on the islands are parlous:

A somewhat rare resident species that has experienced a sharp population decline in the last decade or so. The species still maintains small, fragmented populations in a couple of localities, but current trends do not bode well. (Cassar 2018)

The Meadow Brown exists in Malta as an endemic subspecies, Maniola jurtina hyperhispulla. Its extinction would therefore be especially tragic. The decline of this and other butterflies (Small Copper, Small Heath, Speckled Wood) might be linked with pollution, climate change and habitat loss, all in evidence on the islands. Chemicals are heavily used in farming to extirpate insects. Even in unfarmed land, bird trappers use persistent herbicides to remove vegetation from trapping sites. In recent years, precipitation levels have declined significantly below the average. The unrelenting building frenzy is swallowing precious land especially in Malta but also in Gozo.

A girna, Qala, Malta. These corbelled huts were and are used for storage and probably for dwelling and resting places in the past. These can be centuries old, but it is very difficult to date these structures.

Three ‘new’ butterflies have arrived on the islands in recent years. These are the Geranium Bronze Cacyreus marshalli, Dark Grass Blue Zizeeria karsandra and Desert Babul Blue Azanus ubaldus. The first occurs naturally in South Africa and may have arrived on imported Pelargoniums while the latter two are species of hot, arid lands, essentially eremic (desert) species. The survival of these three in Malta points, possibly, to the warming, drier climate there, and must be concerning for the habitats and native species currently supported.

Large Star of Bethlehem, Il-Majistral, Malta.

All is not gloom. Maltese people are beginning to take their environment’s needs into account. A nature park covering 2.5 sq. km, Il-Majistral, was established in 2007 in the north of Malta. Malta has also declared protected areas covering about 29% of the land area and 35% of marine waters. No more bird-trapping licences are being issued, and shooting is less accepted now, but these activities continue. Some birds, like the Honey Buzzard and Marsh Harrier, are easy targets owing to their lazy, soaring flight. Further work will hopefully make shooting such species a thing of the past.

Crown Daisy Chrysanthemum coronarium (yellow) and French Honeysuckle Hedysarum coronarium, (red) Qala. The French Honeysuckle is often grown for fodder and for Honeybees.
Caper, Il-Majistral, Malta. This common plant is used for breeding by Large and Small White butterflies.

There is still much to see in the Maltese countryside, especially for a person from cooler climes unused to seeing the plant and insect life in the Mediterranean.

The friendliness and openness of Maltese people is a tonic too. A welcome is rarely if ever withheld. There is a distinctive culture. Signs of the religious culture are evident everywhere with churches in every village. Crucifixes hang in public places from government buildings to insurance offices. There is less restraint in speech, with a directness rarely heard elsewhere. The village is a key part of identity, and for many people the next village, a kilometre or two away, is considered a great distance to travel.

The church of St George, Victoria. Note the clock on the left shows the wrong time. This is to confuse the devil to ensure that he does not disrupt mass.

The squares are the centre of village life, and news travels fast. During the heat of summer, most social life occurs after dark, and the village squares come to life. Children chase one another around tables and street furniture and climb into niches in the baroque churches. Safe, friendly and memorable, you will certainly experience something different.

Ta’ Pinu, Gozo’s best-known church. It is located in a rural area without a parish and is an important shrine that receives thousands of visitors from Malta and elsewhere.

If there was only one thing I could change, it is the rampant construction of apartment blocks, which I would like to see ended. After that, I would ban pesticides. But that applies to Ireland too, along with massive fertiliser inputs.

Without a better way of managing food production, the glories of our world will continue to diminish. Wherever you visit this summer, try to visit sites with high nature value. The message that nature matters might hit home the better.

The Sardinian Warbler breeds in Malta and can be seen bringing caterpillars to its nest during spring.
Southern Star of Bethlehem, Qala, Gozo.
Wall Brown, Il-Majistral, Malta.
Egyptian Grasshopper Anacridium aegyptium, Qala, Gozo.  This is a large insect and a capable flyer. Younger individuals are green, with mature specimens typically pale brown or grey.
Maltese Glow-worm Lampyris pallida is endemic to the Maltese islands. The adult female lights up to attract a male at night, usually during early summer. The larva, seen here, is more often seen, during the day. This one is feeding on a snail near Qala, Gozo.

Photos J. Harding

References

Cassar, L. F. (2018). A Revision of the Butterfly Fauna (Lepidoptera Rhopalocera) of the Maltese Islands Summary. Naturalista Sicily, S. IV, XLII (1), 3–19.

Climates To Travel World Climate Guide (2023). Available at: https://www.climatestotravel.com/climate/malta (Accessed 06 May 2023)

Holland, James (2003). Fortress Malta: An Island Under Siege, 1940–1943. London: Miramax Books.

Ireland’s Blue Book (2023). Available at: https://www.irelands-blue-book.ie/IrishWeather.html#:~:text=Temperature%3A,C%20(60.3%20%C2%B0F (Accessed 05 May 2023)

Papilio machaon subsp. melitensis Eller, 1936 in GBIF Secretariat (2022). GBIF Backbone Taxonomy. Checklist dataset https://doi.org/10.15468/39omei accessed via GBIF.org on 2023-05-06.

Weber, Hans and Kendzior, Bernd (2006). Flora of the Maltese Islands A Field Guide. Marburg: Margraf Publishers.

 

The shocking story of Butterfly Declines Across Europe

Because butterflies are so loved and well-studied, there is good evidence of what butterfly species occurred in Europe, Britain, and Ireland over the past 100 years and further back, and the species that have flourished, declined, were gained, and lost.

For many countries in Western and Central Europe, the story is certainly very worrying. The countries that border the Mediterranean and those in the far north of Europe have suffered less decline and loss, but these areas are not without challenges that affect butterfly populations.

Since the early years of the 20th century, England has lost the Mazarine Blue (possibly c.1903 but may have disappeared in c. 1865), Black-veined White (1923), Large Tortoiseshell (c.1950), Large Blue (1979), and Chequered Skipper (1975). The Large Copper was lost c. 1864, due entirely to habitat destruction.

Large Copper is a beautiful species that can be used to publicise the need for conservation practices. This butterfly was lost from England when the fens were drained. The upperside can be seen below. Photos J. Harding.

In the UK, the Duke of Burgundy, High Brown Fritillary, and Heath Fritillary are in serious trouble and the High Brown Fritillary, in very deep trouble, may be lost. Several other species are falling in abundance and distribution there, including the Marsh Fritillary, Pearl-bordered Fritillary, and Small Pearl-bordered Fritillary. Just to take the statistics for one butterfly, the Wood White. This elegant, dainty creature has fallen by 82% in its population and 76% in its distribution during the period 1979-2019.

Wood White, ranked near threatened in Ireland, relies on wooded habitat on carboniferous limestone that is being destroyed, especially in areas outside the Burren, such as around Lough Corrib, County Galway. J. Harding

You will see from the dates that butterfly declines and losses have been taking place in England for a long time. The situation is also very depressing in parts of central Europe. The northern Belgian province of Flanders has seen steep losses. 20 butterflies have become extinct (29% of its species list), and between 1992 and 2007 overall numbers declined by around 30%. A study published in the early 2000s found that 18 species (28% of its list) were threatened with extinction. In the Netherlands, 20% of species have become extinct, and since 1990 overall numbers in the country declined by 50%. Denmark and the Czech Republic are in the same sorry category of loss and decline suffered by Belgium and the Netherlands.

The Black-veined White is now extinct in the Netherlands.

Just to give an indication of how grave the situation in the Netherlands is, consider the fact that the Silver-washed Fritillary, thriving in Ireland and rising in abundance in England is in deep trouble there. The Dingy Skipper, holding steady in the UK and Ireland, is very rare in the Netherlands. The Marsh Fritillary is now extinct in the Netherlands.

The Silver-washed Fritillary thrives in Ireland’s woods especially where native trees exist.  This butterfly is in trouble in the Netherlands. Photo J. Harding

Countries in Europe were ranked in 2019 in the Journal of Insect Conservation according to their butterfly red lists where species are ranked under threat categories. There are five rankings, excluding countries that lack data.

The next group of countries is in a loss category below that occupied by Belgium, the Netherlands, Denmark, and the Czech Republic. These are Germany, Austria, Poland, Slovakia, Romania, and the UK.

Ireland is ranked in the next group of countries; we are mid-table for losses, along with countries such as Ukraine, Switzerland, Hungary and Finland.

The two countries that fare the best, with the lowest declines, are Spain and Italy.

Chris Van Swaay, one of Europe’s most eminent butterfly experts, explains the declines in the Netherlands.

“Before 1950 or so, grasslands in the Netherlands very much resembled what we now only have left in some nature reserves – they were wet, they had lots of flowers, were lightly grazed and mown only once or twice a year. This was very low-intensity farming.

“In two decades after the 1950s, the countryside was rebuilt – land was drained and planted with one species of grass, large amounts of fertiliser was put on the land, and it was mown six times a year. There is no room for butterflies except on road verges and nature reserves. The countryside is more or less empty.”

The reasons for the declines in Europe, Britain and Ireland are quite similar and often the same. Modern farming methods are the greatest causes of decline and loss. These methods have caused massive habitat loss and degradation with large areas of our land mass devoted to production of one crop species with no room for any other plant. In areas where this has not happened, traditional farming methods that maintained biodiversity have fallen out of use, creating successional changes that have lost us heathlands and grasslands, while the cessation of traditional woodland management has changed woodlands, resulting in closed canopies and darker woods unsuitable for many woodland species.

The loss of habitats for other reasons, such as building, afforestation, land drainage, and peat mining has also contributed to losses.

More recently, the concern is growing about the impact of chemical pollution, which can damage habitats that are not directly affected by changes in farming practices or habitat destruction. The deposition of nitrogen from the air is believed to be responsible for changing the character and chemical content of vegetation, making the habitat and foodplant unsuitable for butterflies. This is a sinister threat because it can affect populations that occur a long distance from industry and intensive farming. It is also difficult to address, requiring, probably, a geographical-scale response, not simply a local or national strategy to reduce air pollution.

Climate change is a further challenge; this is complex because some species are beneficiaries of a warming climate, while others suffer. Cold-adapted species are driven further north or uphill, and warmth-loving species are extending their range northwards. A mismatch between the development of vegetation and emergence or breeding times may be driving declines in some areas. For example, increasing dryness and heat in the Mediterranean region may deprive some species of nectar and foodplants. Extreme climate events associated with climate change can have dramatic and sudden impacts. The Green-veined White’s abundance in many areas of Ireland crashed in 2019 following the drought in 2018.

The Small Copper is under threat in some hot, dry areas in the Mediterranean, with increasing aridity meaning its food is becoming scarce or unavailable. Elsewhere, the chemical inputs being absorbed by its foodplants in intensively farmed grassland is poisoning its larvae. Photo J. Harding

How do we deal with the threats to our butterflies?

We need policies and actions that reverse the damage described above.

Greening our urban and suburban spaces by allowing vegetation to grow and planting native plants from local seed will help. Avoid tidiness; relax management in gardens, parks, verges, and the grounds of businesses. Do not use chemicals in these areas.

Reserves will not save butterflies unless they are large and managed. Many protected areas are too small and are often badly managed and being damaged. Landscapes must be protected, and these must contain a range of habitats. A good example of where this is done is the Burren in Counties Clare and Galway.

Pollution must be tackled. Massive chemical inputs in agriculture and reseeding grassland is destroying nature in general. Monoculture grasslands should be replaced with multi-species swards generated by allowing the seed bank in the soil to germinate. In areas where intensive farming is needed, ‘wild’ land must be incorporated into the landscape, typically as unfarmed extended field margins adjoining hedgerows and wood edges.

Woodlands containing native trees grown by allowing woods to extend naturally would add habitat diversity, as would maintaining wide rides allowing light in the woods. New woods must not be grown on high nature value semi-natural grassland, heaths, and bogs. New woods should be planted on intensively managed farmland. Scrub must be allowed to develop at the margins of woods rather than having a sharp edge where woodland transitions directly to open grassland.

Encourage a love of nature in everyone. Most focus is on youth education, naturally, but highlighting the intrinsic importance and wonder of nature should be promoted at all levels of the population. Participate in citizen science monitoring of butterfly populations to help to build knowledge of the status of butterfly populations. Getting involved in conservation organisations is important because these do important practical conservation, monitoring and education. These organisations help to influence policy in favour of caring for our environment.

Most of our countryside looks the way it does because it is heavily plied with chemicals. Fields of uniform, sharply green sward without flowers is not the ‘natural way.’ Fertilisers exclude flowers by promoting accelerated grass growth and in some cases, by providing a  chemistry that kills flowers. Herbicides kill any flowers that remain. There is certainly no need for our gardens, parks, and hedge margins to look like this. Make sure your patch doesn’t.

References

Maes, D., Verovnik, R., Wiemers, M. et al. Integrating national Red Lists for prioritising conservation actions for European butterflies. J Insect Conserv 23, 301–330 (2019). https://doi.org/10.1007/s10841-019-00127-z

Warren, M.S., Maes, D., van Swaay, Chris A M, Goffart, P., Van Dyck, H., Bourn, N.A.D., Wynhoff, I., Hoare, D. & Ellis, S. 2021, “The decline of butterflies in Europe: Problems, significance, and possible solutions”, Proceedings of the National Academy of Sciences – PNAS, vol. 118, no. 2.

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

https://www.theguardian.com/environment/2019/apr/01/butterfly-numbers-fall-by-84-in-netherlands-over-130-years-study

https://www.gbif.org/dataset/f9af6ffd-febc-4626-b2e8-809b1c60fa01#description

 

 

 

 

 

Butterfly Populations in Trouble Across Ireland and Britain

Last August we reported the latest information concerning the state of Ireland’s butterfly populations. The picture painted by the Irish Butterfly Monitoring Scheme data for 2020 and 2021 was not positive, with no species showing positive trends in 2021 with only two, the Brimstone and Peacock, showing a stable trend since 2008, the baseline year. The most recent data from the UK is now available. 

In this article, we present the overall data for the UK report, the data for some of the species found in both the UK and Ireland, and comment on the findings.

Key findings of “The State of the UK’s Butterflies 2022”

In the UK, long-term trends show that 80% of butterfly species have decreased in abundance (the number of butterflies) or distribution (the areas where butterflies occur), or both since the 1970s. By comparison, 56% of species increased in one or both trends. These findings are very similar to the headline results of the previous assessment in 2015. As then, the report finds that there are winners and losers but, on average, UK butterflies have lost 6% of their total abundance at monitored sites and 42% of their distribution over the period 1976-2019. Considering only the changes that assessors have most confidence in (those that are statistically significant), almost twice as many UK species have decreased in at least one measure than have increased: 61% have decreased and 32% increased.

Most habitat specialist species, (species restricted to particular habitats such as flower-rich grassland, heathland and woodland clearings), have declined dramatically in the UK. As a group, their abundance has decreased by over one-quarter (-27%) and their distribution by over two-thirds (-68%) since 1976 (1976 is the baseline year used for UK butterfly monitoring; in Ireland, it is 2008). Wider countryside species, butterflies that can breed in the farmed countryside and in urban areas, have fared less badly, although as a group they have decreased since 1976 (-17% in abundance and -8% in distribution).

Multi-species indicators provide an overall summary of changes in either abundance or distribution by combining species-level indices for groups of butterflies sharing particular attributes. The report authors constructed abundance and distribution indicators for all butterfly species (including the common migrants), and separately for resident species classified as habitat specialists or wider countryside species, at the UK level and for each of the UK countries, where there were sufficient data. Multi-species indicators for abundance and distribution were also produced for Butterfly Conservation’s Priority Species at the UK level.

Multi-species distribution indicators at UK and country levels were also constructed by combining occupancy indices in three ways: for all species, for habitat specialists and for wider countryside butterflies.

Long-term UK abundance trends

Analysing the standardised count data from the UKBMS generated long-term trends for 58 species. UKBMS is the UK Butterfly Monitoring Scheme. It uses data gathered from transect walks, which uses the same methodology used by the Irish BMS in which recorders walk a fixed route (transect) in good weather each week from 1 April to 30 September and count every butterfly in an imaginary 5m box. Overall, more species decreased than increased in abundance: 30 species (52% of the total) had negative trends and 28 species (48%) positive trends. The statistical significance of trends provides a measure of the confidence that we should place in the changes they show. We can be much more certain that species with statistically significant trends have genuinely changed in abundance, irrespective of how large or small the change is. The UK long-term trends show that 19 species (33% of the total) have decreased significantly in abundance, 15 species (26%) have increased significantly and 24 species (41%) have non-significant trends. Only slightly more species decreased in abundance than increased at UKBMS-monitored sites. This represents a small improvement in the fortunes of UK butterflies compared to the previous assessment in 2015, when 36% of species with long-term abundance trends had decreased significantly and 23% had increased significantly.

Long-term UK Distribution Trends

Occupancy modelling of Butterflies for the New Millennium (BNM) species occurrence records was used to produce long-term UK distribution trends for 58 species. This method uses non-standardised recording, where recorders log any life cycle stage of any butterfly species, anywhere in the UK on any day of the year. This flexibility encourages large numbers of contributors leading to very widespread coverage of the UK landscape every year. This is the same system used by Butterfly Conservation Ireland’s recording scheme; see https://butterflyconservation.ie/wp/records/.

Overall, 43 species (74%) had negative distribution trends and 15 species (26%) positive trends. Far more species have decreased in distribution than have increased. The same pattern is found just for those species with statistically significant distribution trends: 30 species (52% of the total) had significant decreases in distribution, eight species (14%) significant increases and 20 species (34%) showed changes in distribution that were not statistically significant. Nearly four times as many species have decreased significantly in distribution as have increased. The occupancy modelling approach used differs from that in the 2015 assessment, so a direct comparison is less valid than for the abundance trends. However, fewer species show significant distribution trends (both decreases and increases) now compared to the 2015 report.

Combined Assessment (Abundance and Distribution)

Considering just the statistically significant trends, 36 species (61%) had decreased significantly in one or both trends and 19 species (32%) had increased significantly in one or both. Almost twice as many species had a significant negative trend in at least one measure than had a significant positive trend in one or both.

Although it remains widely distributed, mainly around the UK coastline, there is increasing concern about Grayling, which has suffered a severe long-term decline. Since 1976, the abundance of this species has decreased by 72% and its distribution by 92% at the UK level, and with major declines in both measures in England, Scotland and Wales. The data from Northern Ireland was insufficient to produce trends. These ongoing, rapid declines recently led to Grayling being upgraded from Vulnerable to Endangered on the GB Red List. Dependent on fine leaved grasses growing in sparse vegetation with much open ground or rock, the butterfly faces threats from habitat degradation due to ecological succession and nitrogen deposition, and from consequent small population size and increasing isolation.

The trends for Large Heath, another Priority Species, provide a positive picture, with a very large (407%) increase in abundance at monitored sites and little change in distribution (-2%) since the 1990s. Although present in all four UK countries, the remote location of most colonies means that few are monitored, and data are only sufficient to produce a UK-level abundance trend. Many of the monitored sites are managed for biodiversity and Large Heath populations have benefitted, for example from peatland restoration on lowland bogs in Scotland. However, there are concerns elsewhere in its range. For example, at some sites on the North York Moors and in Northumberland, there has been a substantial reduction in the amount of cottongrasses, the Large Heath’s larval foodplants, perhaps due to climate change. In many other areas, particularly in the uplands, data on how the butterfly and its habitats are faring are lacking.

Marsh Fritillary is the focus of conservation efforts in all four UK countries. Its distribution has decreased by 43% since 1985.

Marsh Fritillary underside, Kildare. © J. Harding.

The report then focussed on the individual countries in the UK.

England

In England Wood White has decreased by 82% in abundance (1979-2019) and by 77% in distribution (1992-2019), is classed as Endangered on the Red List and is a Priority Species for Butterfly Conservation. Most of the long-term abundance decline took place during the 1980s and recent signs are more positive, thanks to intensive conservation efforts in many parts of the Wood White’s range.

Northern Ireland

The multi-species indicators for Northern Ireland’s butterflies show decreases of 17% in abundance (2006- 2019) and 10% in distribution (1993-2019). However, only about half of the resident and regularly breeding butterfly species in Northern Ireland had sufficient data to calculate long-term trends up to 2019, so these indicators are not necessarily representative of all butterflies. In particular, habitat specialist species that are of conservation concern in Northern Ireland, such as Large Heath, Small Blue and Dingy Skipper do not, as yet, have sufficient monitoring coverage to produce trends. (The Small Blue and Dingy Skipper have highly restricted distribution in Northern Ireland, especially the Small Blue.)

The Wall butterfly has suffered a precipitous decline in Northern Ireland and appears to be on the verge of extinction. Formerly found in all six counties, a rapid decline since the 1990s reduced the species to the coastline of Co. Down, where there were only three records in the period 2015-2019. A single Wall was also seen in 2021, so the species is still clinging on. The cause is not known with any certainty, but the decline mirrors that experienced by Wall in England and Wales, where it is also among the most severely declining butterfly species, and in other parts of Europe.

Small Heath is another species, like Wall, which is associated with short, sparse turf, and which has undergone a rapid distribution decline (40% decrease 1995-2019) in Northern Ireland. Indeed, Small Heath has decreased significantly in all four UK countries. Loss and deterioration of habitat seem the most likely drivers of this decline, with factors such as climate change and nutrient pollution stimulating greater vegetation growth resulting in longer, denser swards even on sites managed for biodiversity. Small Heath caterpillars fail to survive on grasses when fertilizers are applied at the levels typically used in intensive agriculture, which suggests that the species may also be harmed away from farmland by smaller amounts of atmospheric nitrogen pollution.

Dingy Skipper declined by 15% in abundance and 35% in distribution 1976-2019.

Orange-tip declined by 26% in abundance and 1% in distribution 1976-2019.

Small Copper declined by 39% in abundance and 37% in distribution 1976-2019.

Small Tortoiseshell declined by 79% in abundance, but its distribution increased slightly up 0.2% 1976-2019.

Comma increased by 203% in abundance and 94% in distribution 1976-2019.

Silver-washed Fritillary increased by 284% in abundance and 1% in distribution 1976-2019.

A male Orange-tip rests during overcast weather. Have you seen one this year? Photo J. Harding

Regarding Cryptic Wood White Butterfly Conservation UK’s new analyses provide a more optimistic picture with nonsignificant trends suggesting an increase in abundance over the past decade and a stable distribution trend from 1993-2019. Unlike Wood White, which is mainly a woodland species in the UK, Cryptic Wood White uses more open habitats such as grasslands, and colonies are at risk from urban development and agricultural intensification. Other species that appear to be experiencing recent upturns in their fortunes, even if data are currently insufficient to demonstrate it quantitatively, include Dark Green Fritillary, Silver-washed Fritillary and Holly Blue. All three appear to be continuing to expand across Northern Ireland, where suitable habitats exist.

Discussion

There are strong similarities in the population declines and increases seen in the UK and the Republic of Ireland. Looking at the species that occur across these islands that are under pressure, most are species that occur on grassland. Grayling, Gatekeeper, Small Heath and Wall breed on grasses, which are almost certainly being affected by agriculture and industry adding nitrates to soils. This is being done directly, by the application of fertilisers and indirectly, by nitrates arising from farming, nylon manufacture and burning fossil fuels deposited from the atmosphere on soils, either in precipitation or as trace gases and particulate matter. There is good evidence that this is poisoning larvae feeding on nitrogen-enriched foodplants and cooling the temperature around the foodplant, which prevents or slows larval development. There is evidence that some non-grass feeders, like the Small Copper, which breeds on sorrels, are poisoned by fertiliser uptake by the foodplant.

The fact that declines are noted in areas where there is no agricultural activity suggests atmospheric pollution. There is very little farming activity along the Dublin coastline, and the Grayling and Wall are extremely rare on the coastal dunes where they used to be abundant and well distributed.

Quite concerning is the information from Department for Environment, Food and Rural Affairs (DEFRA) that the largest amounts of wet deposition inputs of nitrate (NO3) and ammonium (NH4+) (deposited from the atmosphere by rain and snow) are found in the uplands of Wales, northern England and western Scotland, away from industrial areas.

Nitrogen transformation and plant uptake of mineral nitrogen involve the production and consumption of protons and can, therefore, contribute to soil acidification. Where this occurs, plants that occur only or chiefly on alkaline soils, such as Kidney Vetch and Common Bird’s-foot-trefoil, may disappear, impacting on butterflies that breed on calcicoles (plants that need lime-rich soil), such as Small Blue and Common Blue.

There is also evidence that the poor recovery of sensitive species of Sphagnum moss in the southern Pennines (Lancashire and Yorkshire) is largely due to toxicity of ammonia NH4+ and nitrate NO3 deposition. Loss of moss and lichen species in Cumbria over the past 30-40 years may also be due to increased nitrogen deposition over that period. This has implications for the health of our bogs, and for the Large Heath which relies on peat bogs for its survival.

The loss of Marsh Fritillary populations in the UK appears to be due to loss of habitat. This is where habitat is simply removed by agricultural intensification such as ploughing and reseeding. Habitat loss is also taking place in Ireland, where land drainage, agricultural ‘improvement’ and afforestation is taking a toll, but natural succession, where scrub and woodland is developing on grassland no longer grazed, and on cutaway bogs where machinery disturbance has ceased and scrub develops, is also resulting in habitat loss.

There is some good news. The Small Tortoiseshell, its abundance in decline in the UK (-79%), appears less affected here. Between 2008 and 2021, it declined in abundance by 49%. A new enemy, Sturmia bella, a parasitoid fly that colonised Britain from the continent has affected Small Tortoiseshell populations. This fly has not been recorded here, but it is possible that Irish and British (but probably not Northern Irish) populations are being reduced in abundance by drought conditions that force the butterfly to enter hibernation in mid-summer and cancel a second generation typically seen in September.

Better news is the advance of the Silver-washed Fritillary, thriving in new woods developing on cutaway bogs and abandoned farmland. This handsome butterfly increased in abundance in the UK but has not notably risen in distribution there; it has, it appears, always been more widely distributed in Ireland.

The Comma is thriving in the UK. It is one of the outstanding successes there, and it is rapidly expanding its distribution here, having begun its colonisation of Ireland in the early 2000s. The Comma appears to be benefiting from the warming climate and may also be thriving on nitrogen-enriched Stinging Nettles, its main larval foodplant. We now know that it is double-brooded in Ireland, and this may be boosting its colonisation.

The Pearl-bordered Fritillary is named for the seven pearls bordering the underside of the hindwing. J. Harding

The story of the fate of our butterflies is a developing narrative, with diverging fortunes for the cast of characters that comprise our butterfly fauna. Unless we continue to monitor our populations, we will lose the thread of the plots, and may lose our focus altogether. Having some very rare species, like the elegant Pearl-bordered Fritillary, which occurs only in parts of the Burren, we need to maintain our monitoring and conservation focus. The UK has seen a decline of 64% in abundance and a disastrous 88% in the distribution 1979-2019.  A leading butterfly scientist, Professor Jeremy Thomas, commented in 2010: “Unbelievably for entomologists of my generation, the butterfly is extinct in Dorset, Kent and Somerset…reduced to single sites in Surrey and Gloucestershire.”  In Ireland, the Pearl-bordered Fritillary only occupies ten 10 km squares. We cannot such losses to happen here.

 

References

Fox R, Dennis EB, Purdy KM, Middlebrook I, Roy DB, Noble DG, Botham MS & Bourn NAD (2023) The State of the UK’s Butterflies 2022. Butterfly Conservation, Wareham, UK. Available at https://butterfly-conservation.org/sites/default/files/2023-01/State%20of%20UK%20Butterflies%202022%20Report.pdf

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

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

Nash, D., Boyd, T. and Hardiman, D. (2012) Ireland’s Butterflies a review. Dublin Naturalists’ Field Club, Dublin.

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

https://butterflyconservation.ie/wp/2022/08/29/irelands-butterflies-continue-to-decline/

https://uk-air.defra.gov.uk/assets/documents/reports/empire/acidrain/nitdep.html#:~:text=A%20key%20effect%20of%20N,indicators%20of%20increased%20N%20deposition.

 

 

 

 

 

A Plastic World

Today’s Irish Examiner has a feature concerning the use of artificial lawns. The introduction followed by Butterfly Conservation Ireland’s contribution to the feature article is shown below.

The full article is available at

https://www.irishexaminer.com/lifestyle/outdoors/arid-41106382.html

Plastic grass: Low-maintenance fuss-free greenery — or a menace to the environment?

CAROLINE DELANEY examines the backlash against synthetic lawns, and asks environmental experts for their observations
Plastic grass: Low-maintenance fuss-free greenery — or a menace to the environment?
The idea of durable low-maintenance fake grass is attractive but environmentalists say it is not as fuss-free as we may believe — and it has several drawbacks that ought to be considered before we invest in it.

It’s sold as low-maintenance, fuss-free and durable. And artificial grass is definitely gaining a foothold here. There are dozens of plastic grass specialists across the country offering ‘instant lawns’ to playschools, cafés, hotels, and homeowners. Then, there’s the DIY option with retailers such as Co-Op Superstores, Homestore & More, and Woodies — and even carpet outlets — offering grass tiles or rolls of artificial grass which can be laid in a manner similar to carpet.

SUSTAINABILITY & CLIMATE

Check out our Sustainability and Climate Change Hub where you will find the latest news, features, opinions and analysis on this topic from across the various Irish Examiner topic desks and their team of specialist writers and columnists.

But when we have an official biodiversity emergency as noted by the Dáil in 2019 and the Citizens’ Assembly on Biodiversity Loss in 2022, and when there is a commitment in the Programme for Government to tackle the climate and biodiversity crises, is there still a place for artificial grass?

Bloom controversy

Artificial grass has been banned from Chelsea Flower Show but, controversially, showed up in displays at Bloom here in Ireland last year. However, this year there will be no plastic grass at Ireland’s largest garden festival which this year takes place from June 1 to 5.

A Bord Bia spokesperson confirmed: “Bord Bia Bloom actively discourages the use of artificial grass in any on-site activation from sponsors on-site, and there are no artificial grass providers registered to exhibit at this year’s event.”

The garden designers at Bloom are also unlikely to use plastic grass this year, the spokesperson said: “Bord Bia Bloom actively encourages show garden designers to use natural materials where possible.”

Referring to last year’s festival when some visitors and environmental experts said they were disappointed to see plastic grass on display, the spokesperson said: “There are some instances, such as at last year’s event where an exhibitor requested that a very small section of an accessible garden feature artificial grass as natural grass would not have supported the weight of a mechanised wheelchair. However, we strongly recommend to all of our designers that they incorporate natural, sustainably produced plants and grass in their gardens.”

This follows moves in recent years to ban artificial turf from the Chelsea Flower Show which this year runs from May 23-27, and other events run by the Royal Horticultural Society. The RHS, Britain’s leading gardening charity, said no fake grass would be allowed because of its damaging effect on the environment.

What the experts say

Overwhelmingly, experts in biodiversity and environment are calling to ban the use of plastic grass, or put prohibitive tax on it.

Jesmond Harding

The installation of artificial lawns and shrubbery offers convenience but nothing else. The materials used contribute to pollution and the finished product offers nothing but damage to biodiversity. Synthetic plants are made from petroleum and fossil fuels used in their manufacture generate pollution that damages soils, plants, insects, birds, and mammals. Visually, the effect is ugly, and reflects a lack of care for the natural environment. It highlights the disconnect from nature and the idea that natural surroundings are inconvenient rather than a source of wonder and pleasure. I have observed an increase in the use of artificial lawns and plastic shrubs in tubs, and my reaction is to ask why. What is the appeal?

Jesmond Harding is the author of The Irish Butterfly Book.
Jesmond Harding is the author of The Irish Butterfly Book.

Artificial plants look tasteless and cheap. Even those that appear lifelike show an unvarying flat, empty gleam. Sanitising one’s surroundings might be a motivation. Bizarrely, the use of artificial lawns is promoted as a response to climate change, as these do not need watering during drought. The irony of promoting materials that produce climate-warming gases as a solution is exasperating and perverse, an offence to common sense.

There has been an incremental advance in the appearance of synthetic plants. We used to see artificial house plants, such as lilies for indoor vases, progressing to potted shrubs and now to outdoor shrubs and lawns.

On one journey through a local housing estate, I counted the number of hard surfaces replacing grassed gardens, which proved to be two-thirds of the outdoor spaces observed. This trend appears to be influencing new housing developments, with hard-surfaced front gardens or with no front-of-house space, just adjoining on-street parking slots.

There are studies that show links between the decline in butterfly species and atmospheric nitrogen deposition, some of this caused by burning fossil fuels to make artificial plants.

There is no pressure to produce food crops in gardens, so there is no need to apply nitrogen fertilisers which create nitrous oxide, a greenhouse gas that has 300 times the heating power of carbon dioxide. Gardens can be a haven for species fleeing the onslaught of chemically-mediated farming, but only if we grow native grasses, flowers, shrubs and trees in our gardens.

Butterfly Conservation Ireland has found that about half of our butterfly species visit butterfly-friendly gardens, and around one-third of our butterflies breed in gardens containing the right plants and conditions.

A plastic garden has no appeal for our wildlife.

The convenience argument for artificial grass can be answered by using low-maintenance alternatives such as pea gravel sown with drought-tolerant native plants such as kidney vetch, bloody cranesbill and Common Bird’s-foot- trefoil — all great for pollinators and providing a long flowering period giving colour and texture from May to October. There is no such thing as effortless management.

The Irish Butterfly Book: A Complete Guide to the Butterflies of Ireland by JM Harding.
The Irish Butterfly Book: A Complete Guide to the Butterflies of Ireland by JM Harding.

While spot weeding is needed in a gravelled garden, it is also a requirement in artificial turf, where weeds will appear, despite the promise of maintenance-free convenience.

I would like to see the use of artificial plants banned or at the very least subject to high taxation to take account of the environmental damage involved in the production and use of such material. The use of such materials accelerates biodiversity loss; any activity that creates environmental damage should be discouraged or banned.

Jesmond Harding is the author of The Irish Butterfly Book and runs the charity Butterfly Conservation Ireland.

 

The mystery and beauty of the Brimstone butterfly

This week will have unsettled weather with plenty of cloud and rain. These conditions do not allow our longest-lived butterfly, the Brimstone, to emerge from its over-wintering quarters to begin its breeding cycle. Late in March is typically when it emerges to seek mates, feed and begin to look for breeding plants.

The Brimstone has one generation a year. In Ireland and Britain, eggs are laid during spring and early summer on two small native trees, Purging Buckthorn and Alder Buckthorn. Purging Buckthorn is found mainly on rocky ground in the midlands and west of Ireland, but also on fen peat on cutaway bogs and in hedges on lime-rich soils. Alder Buckthorn occurs mainly on boggy soils, especially in alkaline peat on cutover bogs and fens, in and at the edge of bog woodland, on moist heaths and limestone pavement. Both plants occur together in some places, such as in and at the edge of turloughs in the west of Ireland, notable in the Burren.

These trees have a highly localised distribution in Ireland with Alder Buckthorn much the rarer of the two plants. The only region where these tree species are relatively abundant is the Burren, in County Clare and Galway, the only area in Ireland where the Brimstone is plentiful. Elsewhere, the Brimstone occurs in scattered locations mainly across the midlands. The butterfly does not occur in Northern Ireland, the northwest, or the southeast and is very rare in the east and southwest. The butterfly breeds only where its breeding plants occur but it does not occur in every place its larval foodplants are found.

After mating and laying eggs in spring and early summer, the adults die off, but quite slowly, with some surviving as late as early July. During July and August, the new generation is emerging as adult butterflies, but unlike most of our butterflies, they do not breed until the following spring after hibernation is complete.

So how does the Brimstone deal with several months when breeding is impossible, when the weather is unsuitable, and food is unavailable?

The article looks at how the Brimstone manages to survive adverse conditions and why it appears to be more numerous in spring after hibernation than it was during the previous summer.

The Brimstone, unlike most of our butterflies, is sexually immature when it hatches from the pupa. A reproductive diapause occurs in this butterfly. Diapause is the suspension of development or activity in any life stage of a butterfly. This strategy is used to survive months of unsuitable weather which often corresponds with the period during which its breeding plants are unsuitable. Diapause is a rest period undertaken by butterflies, moths and other insects with a seasonal life cycle.

Diapause aligns the butterfly’s complete life cycle to seasonal changes in the environment to ensure that further development occurs in the most suitable conditions. Diapause is controlled by the neuro-endocrine system (hormones released by the nervous system). Furthermore, it is genetically determined for each species and once initiated, it is not influenced by surrounding climate developments, even when these are favourable for development. Diapause usually occurs in response to environmental stimuli that precede unfavourable conditions, such as declining hours of daylight (Nash et al. 2012).

In the case of the Brimstone, diapause occurs in the winged butterfly and takes the form of delayed sexual maturity. This is likely an adaptation to the coldest months of the year and the condition of the foodplants from July to April. Between July and October, buckthorn leaves are tougher than they are in April-June and perhaps contain toxins making them unsuitable for the larvae. In March and well into April, leaves have yet to appear on the plants.

Brimstone eggs on Alder Buckthorn, 20th April 2022. The females frequently lay on the base of unopened leaves during April. Photo J. Harding

In males, sperm develops during summer and autumn but the duct through which sperm passes during mating is narrow and contains few sperm before hibernation, but the duct is swollen and filled with sperm after hibernation. Female Brimstones hatch without developed eggs (which are small, unyolked and without an outer membrane), and these are fully developed only after the females spend several warm days on the wing in spring after hibernation.

Given that males are sexually mature immediately after emerging from hibernation, males immediately seek mates. However, females do not begin emergence at the same time as males. The males spend several days on the wing before the first females appear.

This mismatch in emergence is not unusual in Ireland’s butterflies. In most if not all our butterflies, males emerge first. What is the advantage of this pattern of earlier male emergence?

The advantage is that the females are located quickly and mated, and they can concentrate on laying their eggs. In most of our butterflies, females hatch from their pupae with fully developed eggs so laying starts soon after mating.

But the female Brimstone is not ready to lay her eggs on emerging from her pupa or even after several months of life, including for a period in spring after hibernation.

Yet there must be an advantage for male Brimstones to emerge earlier from hibernation. What this might be, appears to be unknown. Here are some possibilities. Female Brimstones, it appears, mate once, while males certainly mate with as many receptive females as possible. It might be an advantage for males to emerge earlier to seek females, including females that have yet to emerge from hibernation. The earlier the male emerges, the more mating opportunities he has.

Furthermore, it is possible that the older he is, the more fertile he becomes. It has been shown that the male Monarch butterfly Danaus plexippus older males produce a higher ejaculate mass, which means females receive more nutrients from older males, increasing female reproductive productivity (Wicklund et al. 1996).

Are there advantages for female Brimstones of earlier male emergence? It is possible that male Brimstones may be sensitive to pheromones released by other males during mating. This might mean that recently mated females are less attractive and less likely to be courted by males, allowing these females to develop and lay their eggs without the inconvenience of male harassment and the dangers associated with prolonged, conspicuous male attention, which must draw attention from birds and other animals.

An advantage for later female emergence is that the foodplants have extra time to develop. In March, neither of its foodplants is in leaf so food is unavailable for the caterpillar. By the time females are ready to lay, the leaves are further on in their growth, although the leaves are often unavailable until well into April. In cool spring conditions, eggs take longer to hatch, and this delay should help the larvae to appear when the leaves are available. It is important that newly hatched larvae have young, tender leaves, so synchronizing emergence, egg development, mating and egg laying with the development of the foodplant is very important.

A final stage Brimstone caterpillar on 17th June 2022. The larva is on Alder Buckthorn. Much smaller larvae were found in the same area in mid-June, suggesting the prolonged breeding period. Photo J. Harding

Before adult butterflies hibernate, they must feed on nectar (and, in some species, fruit, and tree sap) to build reserves to survive the colder months without food. However, the Brimstone butterfly shows some surprising results. Release and recapture experiments in Sweden show that wild Brimstones put on weight within one or two weeks of first being caught but that when caught later weight did not increase but was maintained at a steady rate. Despite males having to devote resources to developing their reproductive system over winter males have not been observed to feed more than females before hibernation. It might be expected that having to devote resources to reproduction over the winter would reduce male survival rates. However, both sexes have similar winter survival rates (Wicklund et al. 1996). As far as I know, this has not been explained.

The Brimstone shows other unusual characteristics. A study carried out in central Spain during the period 2006 to 2012 looked at uphill and downhill migrations of the Brimstone. These movements are influenced by the resource needs of the butterfly at different times of the year and by temperature during the summer, in this case, the need to avoid extreme heat downhill. One aspect that surprised the researchers was the abundance of over-wintering Brimstones was higher than it had been the previous summer because the numbers must decrease during hibernation (some die of starvation, and some are eaten).

It is ecologically impossible that the population of a single-brooded over-wintering butterfly is higher in spring than in the previous summer before it over-wintered. The researchers rule out the possibility of immigration boosting abundance (the Brimstone is not a migrant) and state that the reason is unknown but it may be linked with differences in behaviour in summer and the following spring. They state that “reduced summer activity could also make (it) difficult to quantify potential downhill movement in late summer” (Gutiérrez, D., & Wilson, R. J. 2014)

While the Brimstone will behave differently under the climatic conditions in a mountainous region in central Spain and in a lowland area in Ireland, it is possible that the researchers miss an important detail about the Brimstone’s behaviour during the summer.

I have often been struck, as have others, by the often excellent condition of Brimstones in March and early April. Some individuals look pristine, very few have faded and tattered individuals are very rare. How is it possible that a butterfly can be active from July to late September and still present in excellent condition the following spring?

Intriguingly, Brimstones do self-care rather well. During the first few days after they hatch from the pupa, the butterfly is quite sedentary. It sits quietly in bushes or trees and does not draw attention to itself. It does not bask with its wings open but sits with leaf-like venated undersides on show, blending with ambient vegetation. In hot or cold summer weather, it takes to cover in foliage, concealed to great effect. On summer days when it is active, it is rarely out of cover before 11 am or after 4 pm, roosting early, sometimes before that that, reducing exposure time.

Brimstones are very good at not getting caught by the onset of bad weather. They are rarely seen away from sheltering trees, bushes, ivy, or dense sedge clumps, and react quickly to changes in weather. Brimstones can forecast rain, even when it is sunny, and will take cover in advance of rainfall (Adrian Hoskins, pers. com.). They know the difference between a cloudy spell and a lengthy period of overcast conditions; a feeding Brimstone will rest on vegetation during a cloudy spell and go to roost during persistent dull weather (Harding, 2021).

The butterfly’s general behaviour is quite conservative. While it can fly at a strong pace, it usually flutters from bloom to bloom in summer, avoiding the need for lengthy or conspicuous flights. It does not fling itself into tangled vegetation at any time of the year like some species do when mate-seeking or egg-laying.

The Brimstone cleans itself, using its legs to remove dust and debris from its head and thorax, and unhooks its proboscis to remove sticky pollen.

Despite these behavioral traits, a delicate insect is expected to show wear and tear after months of active living. Their generally good condition in early spring is a key reason why I do not believe the Brimstone spends several months in an active state before entering hibernation. While records show that the new generation of the Brimstone is active from July to late September or even early October, my transect records which extend over more than 10 years suggest that individuals are active for a few weeks and that most enter hibernation during the summer. The timing of over-wintering is likely dependent on when it hatched from the pupa and the weather.

Brimstone eggs are laid over several weeks, from late March to mid-June. Therefore, adult butterflies emerge from the pupa over an extended period. If a Brimstone hatched at the beginning of July it is probably in hibernation before the end of the month. If it hatches early in August it is likely to over-winter before the month is over. Prolonged bad weather during summer will see pupae lasting longer and adults resting in cover until conditions favour hatching from the pupa and feeding on flowers. If correct, this would explain why Brimstones are often seen during September, especially following a wet August. Finally, it makes no sense for a butterfly to expose itself to danger for months, especially when it is not in breeding condition.

Thus, perhaps there is no time during most Irish summers when one sees most Brimstones that reside in an area. However, in spring when all Brimstones are in the adult state there is a mass emergence from hibernation which in spring sees them concentrated in their often-discrete breeding grounds rather than dispersed across larger areas of flower-rich habitats. In the early stages of good spring weather, most of those seen are males but soon the females appear; the sexes are very active in spring, intent on finding mates and breeding plants. This behaviour makes counting large numbers easier, but the butterfly is not more abundant in spring than it was the previous summer before over-wintering.

However, the large concentration of these large, bright, characterful butterflies on bright sunny spring days is exhilarating after the drudgery of our muddy, damp, drab winter. The daffodil yellow males’ dash along the wood, hedge, and scrub edges brings vitality and pure joy to the nature lover, while the pale females delicate fluttering around buckthorns evoke living blossoms, their glowing leaf-like wings translucently petal-like in the crystal spring sunshine. Little wonder people see their first Brimstone as announcing the beginning of spring; little wonder English naturalist Matthew Oates called this mass emergence phenomenon, “National Brimstone Lift-off Day, the first truly warm day of the year”(Oates, In Pursuit of Butterflies, p. 220). It must be warm and sunny to tempt the Brimstone out in spring so when you see it, you know the weather offers the promise of happiness.

While the Brimstone offers the fascination of investigation, discovery, and ongoing inquiry, it offers much else besides, a view of a flower-rich countryside in the finest weather. The Brimstone is our ultimate sunshine butterfly, especially when back-sunlit wings are enjoyed. The male turns suddenly from matt yellow to gold in such light, inspiring for anyone, particularly for a photographer seeking to preserve the memory of a perfect experience, when the moment literally turns golden.

Look out for this moment in the weeks ahead…

Male Brimstone showing bright yellow wings. J. Harding
Female Brimstone on Rough Hawkbit, Lullybeg, County Kildare.

 

References

Gutiérrez, D., & Wilson, R. J. (2014) Climate conditions and resource availability drive return elevational migrations in a single-brooded insect. Oecologia, 175(3), 861–873. doi:10.1007/s00442-014-2952-4

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

Learnaboutbutterflies.com

Nash, D., Boyd, T. and Hardiman, D. (2012) Ireland’s Butterflies a review. Dublin Naturalists’ Field Club, Dublin.

Nelson, B., and Thompson, R. (2006) The Butterflies and Moths of Northern Ireland. National Museums Northern Ireland, Belfast.

Oates, M. (2015) In Pursuit of Butterflies. Bloomsbury, New York.

Wiklund, C., Lindfors, V., & Forsberg, J. (1996) Early Male Emergence and Reproductive Phenology of the Adult Overwintering Butterfly Gonepteryx rhamni in Sweden. Oikos, 75(2), 227. doi:10.2307/3546246

Hedgerow Cutting Ban starts today, March 1st, lasting until September 1st

Under the Wildlife Acts, hedgerow cutting is banned during the period March 1st to August 31st inclusive.

This ban is legally enforced, and many prosecutions have been taken by excellent National Parks and Wildlife conservation officers charged with protecting our diminishing heritage. Burning, cutting, and grubbing vegetation during this period is also prohibited.

If you see anyone breaching the law, take photos of the incident and machinery and contact your local National Parks and Wildlife Service officer. You can also contact the Gardaí.

The following are the contact details for the National Parks and Wildlife Service.

The Eastern region:

https://www.npws.ie/contact-us/eastern-division

Northern region:

https://www.npws.ie/contact-us/northern-division

Western region:

https://www.npws.ie/contact-us/western-division

Southern region:

https://www.npws.ie/contact-us/southern-division

Hedges are especially important for butterflies and moths. 65% of Irish butterflies use hedges. Some use hedgerow trees as breeding plants, some use grasses and flowers growing on the warm margins for breeding. In addition, many adult butterflies use hedges as territory, mating stations, nectar sources, flight paths, dispersal routes, and hibernation sites. The Brimstone butterfly uses hedgerows for all these reasons, while the Brown Hairstreak uses hedges for breeding, meeting and mating, feeding, and as a flight path.

A study by Merckx et al. (2012) found the hedgerow trees and extended width margins locally increased the number of larger moth species (also known as macro-moths) but not the abundance. Interestingly, they found that species richness and abundance were not affected by intensive farming, measured by the amount of arable land in the landscape. Both mobile and less mobile larger moths did better when extended width margins and hedgerow trees were present.

Hedge and herb-rich margin, County Meath. The flora present here includes Lady’s Bedstraw, Tufted Vetch, and Upright Hedge-parsley. Photo J. Harding

The benefits of trees in the hedgerow were especially strong for tree-feeding species. Increasing the density of hedgerow trees was recommended to lessen the effects of agricultural intensification. The study underlined the value of hedgerow trees, claiming “a disproportionate effect on ecosystem functioning given the small area occupied by any individual tree”.

The study also found a link between increased macro moth populations and ecosystem functioning (in other words, the higher moth abundance and species richness improve biological community functioning).

Why is this? Moths are associated with higher pollinator success, which benefits crops and animals, and moths are an important prey base for a range of species.

A study by Coulthard et al. (2016) 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.

These studies highlight how crucial hedgerows and hedgerow trees are for butterflies, moths, and biodiversity generally. It is crucial that hedges are protected and correctly managed. A badly managed hedgerow can be disastrous for some of our rarer species. For example, many species that breed on hedges lay eggs on the newest growth. Unfortunately, it is this outer part of the hedge that is removed by cutting. The Brown Hairstreak butterfly is extremely vulnerable for this reason, and Berwearts and Merckx (2010) report studies that found that annual mechanical cutting of hedges removes 80-99% of Brown Hairstreak eggs. A rotational cutting system that involves cutting one-third of the hedgerows in an area each winter resulted in the butterfly’s longer-term survival.

The Brown Hairstreak relies on hedges for survival. Management that allows large areas of hedging and scrub to remain uncut is crucial. Photo J. Harding

Even more serious is the removal of hedgerows by farmers who want to increase field sizes. Outside protected areas, this can be done between August 31st and March 1st. Given the importance of hedgerows to butterflies, moths, and many other species, our landscape cannot afford such losses. Another damaging though the smaller-scale practice is the replacement of hedgerows comprising several native species with a single species hedge, often non-natives such as Common Beech, laurel, and leylandii, among others. In some parts of the west, non-native fuchsia hedging has become naturalized, disfiguring the landscape, displacing native species, and reducing biodiversity. These alien species are of much less value because they have not co-evolved with the other species naturally present here.

Our hedges are crucial to our landscapes, giving our countryside character, building a sense of place, and hosting much biodiversity. The poet Wordsworth described the hedgerows at Tintern Abbey as “Little lines of sportive wood run wild”. While some management is necessary, a more relaxed attitude would be a great boost to butterflies and much else!

References

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.

Merckx, T., Marini, L., Feber, R.E., Macdonald, D.W., Kleijn, D. & Sveriges lantbruksuniversitet 2012, “Hedgerow trees and extended-width field margins enhance macro-moth diversity: implications for management”, The Journal of applied ecology, vol. 49, no. 6, pp. 1396-1404.

 

The Irish Butterfly Book available now

The new book on Ireland’s butterflies, The Irish Butterfly Book, is available now.

Here is some of what Michael Viney said about The Irish Butterfly Book in The Irish Times:

Harding is quite used to overwintering small tortoiseshells and feels “a burst of delight to watch the butterfly surge into the sunshine in spring”. It’s part of the 25 years of his study that distinguishes a €35 quality paperback on sale from his home in Co Kildare.

The Irish Butterfly Book is definitive, engaging and heavy with glossy illustration. It covers the ecology, life cycles and food plants of Ireland’s 35 butterfly species, many of them around Harding in the midlands and more in some 40 habitats from Cork to Donegal. The sites are mapped and photographed, along with their likely species.

It’s a book full of knowledge, from Harding’s own painstaking observation and also new lepidopteral research. Most people are content just to have a name for a butterfly, but his essays on each species open up fresh worlds of interest, observation and mystery. Butterflies, their caterpillars and chrysalises don’t lead such casual lives after all.

The review is here: https://www.irishtimes.com/news/environment/another-life-what-to-do-if-you-disturb-a-butterfly-s-winter-slumber-1.4759961

Here is an extract from a review of the book by Seán Lysaght ( Seán is a poet and nature writer. His prose includes Eagle Country (2018) and Wild Nephin (2020). He has published several collections of poems and translations with Gallery Press, including The Mouth of a River (2007) and Carnival Masks (2014). His forthcoming collection, New Leaf,  was published by Gallery in May 2022).

Ireland’s butterflies have now got the study they deserve in this extraordinary, landmark publication by Jesmond Harding. Harding, who is indisputably the leading national authority on the subject, has been studying and recording this insect group for many years; remarkably, in an age of specialism and science, he works independently of any institution. His Irish Butterfly Book is the latest in a long and distinguished amateur line of Irish natural history, which includes William Thompson’s Natural History of Ireland (1849-56), Robert Lloyd Praeger’s Irish Topographical Botany (1901), RF Ruttledge’s Ireland’s Birds (1966), and Zoë Devlin’s Wildflowers of Ireland (2014).

Harding’s Irish Butterfly Book is a treasure of fascinating detail and no doubt will motivate many wonderful summer excursions in future years; it will be an indispensable reference book for experienced nature watchers, and it should charm and inspire less specialist lovers of Ireland’s natural heritage. In time, also, it is to be hoped that this superb book will have a future life as a redesigned pocket guide, perhaps in a second edition from a commercial publisher.

The mysterious behaviour of Ireland’s butterflies is explored in this book.

  • Why do some female Speckled Woods flaunt themselves at males, while others behave so evasively?
  • Can Brimstone butterflies forecast the weather?
  • How do male Small Coppers react to persistent attacks from larger males?
  • Why do some Small Tortoiseshells hibernate in July, months before they hibernate in other places nearby?
  • How does the male Green-veined White react when he faces a highly competitive mating environment?
  • Do social caterpillars cannibalize?
  • Why do male Brown Hairstreaks ignore females after 11 am?
  • Why do we never see Painted Ladies leave Ireland during autumn?
  • Why do some male butterflies check caterpillar foodplants?
  • Is the warming climate making life easier or harder for Ireland’s butterflies?

The culmination of over 25 years of study and based on thousands of records, THE IRISH BUTTERFLY BOOK  documents the full life cycle of every Irish butterfly from egg to adult butterfly and includes over 400 original colour photographs. There are one or more photos for each life stage of every species making this book the first of its kind.

Among the contents of this book are:

  • Butterfly ecology
  • Gardening advice
  • Butterfly life cycles and behaviour
  • A site guide detailing the best places in Ireland to see butterflies

THE IRISH BUTTERFLY BOOK also has its own YouTube channel (linked to within the book) where you can enjoy film footage of Ireland’s butterflies.

Beautifully presented and designed, with large font size and accessible text, this book is a great addition to the Irish wildlife bibliography.

Available directly from the author. ISBN 978-0-9560546-1-6. Softback. Full-colour printing, 328 pages. €35 inclusive of postage within the Republic of Ireland.

Contact: jesmondmharding@gmail.com.

Also available in selected bookshops. These are listed below.

For more, see https://www.facebook.com/profile.php?id=100078056964282

Book Sample Pages

A page from the section, Gardening for Butterflies
A page from the Clouded Yellow Essay

 

The Painted Lady Essay, where you can learn about its amazing migration to and from Ireland and how you can play your part in conserving its population.

 

The Pearl-bordered Fritillary essay contains a detailed account of its ecological requirements and important conservation advice to protect the species, which has the smallest area of distribution of Ireland’s butterflies.

Two pages from the Site Guide

Text and photographs © J. Harding

The book is also available from:

Antonia’s Bookstore, Navangate, Trim, Co. Meath

Bandon Books, Cloghmacsimon, Bandon, Co. Cork

Banner Books, The Square, Ennistymon

Bargain Books, High Street, Butter Slip, Kilkenny

Barker and Jones, 2 Poplar Square, Naas East, Naas, Co. Kildare

Books Upstairs, 17 D’Olier Street, Dublin 2

Bridge Street Books, Bridge Street, Wicklow Town

Charlie Byrne’s Bookshop, The Cornstore, Middle St, Galway City

Constantia, Unit 2, Supervalu Plaza, Navan Rd, Dunboyne, Co. Meath

Hodges Figgis, Dawson Street, Dublin

Just Books, 23 Pearse St, Mullingar, Co. Westmeath

Liber books, 35 O’Connell Street, Sligo

Maynooth Bookshop, Main Street, Maynooth

Midland Books, High Street, Tullamore, Co Offaly

The Castle Bookshop, Castle St, Gorteendrunagh, Castlebar, Co. Mayo

The Ennis Bookshop, 13 Abbey St, Lifford, Ennis, Co. Clare

Swift Books, 19a Burrow Road, Sutton, Co. Dublin

Vibes and Scribes Books, 21 Lavitt’s Quay, Cork

Woodbine Books, Lower Main Street, Kilcullen, Co. Kildare

The Irish Peatland Conservation Council: http://www.ipcc.ie/nature-shop/#!/The-Irish-Butterfly-Book/p/432271396/category=139703608

Birdwatch Ireland: https://birdwatchireland.ie/shop/

 

 

 

The Joys of Summer

I hated school. That sounds bizarre after a career in education, but it is true. School was incarceration, an ordeal to be suffered, in my case, between the ages of 4 and 17.

I have very few positive memories of my years as a primary and second-level student. Endurance not fulfillment was the objective. Happiness was sought elsewhere.

Sunshine and butterflies and birds and wildflowers, the great ingredients of a countryside yet to be sullied by chemical fertilisers, were the antidote to school and much else.

School ends when summer begins and begins when summer ends. And the summer was the time of happiness. On the last day of school each year, always a half-day, I sprinted not home but to the fields where so much life was taking place. Fox cubs gamboled in June’s buttercup meadows, Chaffinches crafted their very beautiful nests in shrubs and Orange-tips, looking tropical against the emerald verdure, dashed along rides and hedges.

The former paradise close to my childhood home lies buried beneath the concrete of monotonous housing, roads, industrial estates, a massive shopping centre, and Tallaght Hospital. Staring into the wet dark of January from an upper floor room in the hospital two years ago, I ruminated at the grim transformation of the area, from happy farmland where Bord na gCapall had its leafy, wooded grassy home to the dark hulls of massed buildings, dimly outlined by the orange street lamps.

June is not really a school month; in primary school, June means school trips and for second level it’s a holiday month unless you’re caught for state exams. For me, June was Friday. July was Saturday; the school became a distant memory, and summer eternal. August was Sunday. As August aged, the ache in my stomach intensified. September was Monday.

The sun and glories of summer fade rapidly during September. Butterfly abundance diminishes before crashing at or even before the month’s decease.

Some years evoke the beguiling illusion that summer will be a permanent fixture. The summer of 1976 was a standout. I remember the hot sun, a life lived outdoors, and masses of ladybirds, their cheery red, black-dotted carapaces a fun sight. But the Mediterranean summer vanished, drowned by the retaliatory downpours of September, all the butterflies over for the year, overnight. No lead-in. No Ode to Autumn. No illusion that ice cream weather could extend into school time.

In fact, while my classmates and I stared in awe at the ferocity of the rain in September 1976, we were observing the end of summer for the rest of the decade.

Autumn held some pleasures. Before the dark, short days ushered in winter, there were Small Tortoiseshells, Peacocks, Red Admirals, and Speckled Woods to enjoy. In fact, in some years, like 2022, there were so many autumn Red Admirals and Speckled Woods I really imagined that winter was abolished and that the swallows wouldn’t return to Africa. A few days of cloud, heavy rain, and violent wind tore down that dream along with the leaves.

September saw me scouring the bleached grasslands and bedraggled hedges for lingering symbols of summer. I discovered a curiously late blooming bank of bramble, occupied with final fling Red Admirals,  year after year. Annoyingly, the exquisite scarlet and black creatures often perched out of reach, like a gleaming fruit that gleams all the more when unattainable. When my pocket money did extend to a butterfly net from the newsagents (there was a recurring conflict in my heart: HB Dracula ice-pop or net) the net was often impaled then ripped among the treacherous thorns or, more maddening, it detached from the bamboo and was marooned high on the bush. On occasion, a butterfly would heap the humiliation by entering the stranded net tented over a spray of the pink blooms to sup on the nectar. Why, I wanted to know, did everything always conspire against me?

A beautiful autumn Red Admiral, September 2022. Photo J. Harding

Another winter-beating strategy was to bring summer indoors. One autumn I caught a newly hatched Red Admiral and attempted to overwinter it in a shoe box stowed below the stairs. I read, in one of my few butterfly books, that Red Admirals hibernate in central Europe. So why not here? This hibernation information is not correct, but it was a while before I realised that.

My strategy to prepare my pet for a lengthy overwintering phase involved sitting in the front room, TV on but lights out, a piece of cut fruit, usually peach, in my hand with my Red Admiral feeding on the fruit’s sweet juice. Seated siblings were under sit-still orders. This worked quite well. It taught me patience and stillness and afforded close observation over a lengthy period. I noticed how it sometimes lodged its feet in the exposed parts of the fruit, and gracefully dipped its antennae towards its often-stationary proboscis, ‘smelling’ its nourishment. Sometimes it dabbed its proboscis impatiently, possibly because the juice dried or hardened.

Newly hatched autumn Red Admirals spend several days feeding and will become quite docile. What happens when they are ‘full’ is not, as I believed, a long winter sleep but a long migration flight. After being tame for some days, my pet duly became restive, flying across the room to the TV screen. I turned the central heating off to simulate winter cold but parental interference kicked in when ice formed on the inside of the windows. Containment in the shoebox did not create slumber. Even in the pitch dark, the butterfly tossed its migration-ready self against the cardboard and never settled, eventually perishing, to my bemusement and grief.

During my formative years in the 1970s and 1980s, the talk was not about global warming but contrarily, a new ice age was expected. The rotten weather from 1977-1981 seemed to support this idea, and aside from 1983, 1984, and outstandingly, 1989, the 1980s had miserably wet ‘summers’, especially the three years following 1984.

The climate has certainly been feeling the increased heat since 2000, and we are seeing the response of nature to this warming trajectory. The colonisation and rapid expansion of the Comma butterfly in Ireland are believed to derive in part from the warming climate and associated causes, such as fossil fuel burning contribution to the nitrogen enrichment of soils, leading to healthier, more nutritious Stinging Nettles for the Comma’s larvae. The rising air temperatures allow the Comma’s solitary larva to warm up enough to digest protein-rich nettle. The solitary habit of the caterpillar is speculated as one of the factors telling against successful breeding here in the past because, unlike social caterpillars, the Comma caterpillar does not gather in a cozy gregarious heat ball the Peacock and Small Tortoiseshell caterpillars form.

The solitary Comma caterpillar is able to develop in Ireland, probably because the Irish climate is warmer than it was in the past. Photo J. Harding

The Comma is breeding here twice a year, with a second brood flying well into October, and in good numbers, enjoying the season’s delights, especially blackberries, ivy nectar, and overripe orchard windfalls.

These well-fed Commas then identify a secluded sylvan retreat to see out the winter.

But there is a butterfly that is really excelling itself at extending summer. For over twenty years, Frank Smyth, who observes butterflies along parts of the north Dublin coastline, has chronicled the radically altered circumstances of the Red Admiral in the Howth area.

In some milder coastal areas, nettles do not die back, and egg-laying late in the year has been observed many times since 2000 on Howth Head, County Dublin by Frank. He has also observed larvae throughout winter and spring and expects to see Red Admirals there every time he looks for them. In November 2021, I observed breeding behaviour inland in County Meath, 34 km from the coast. If recorders check nettles for eggs when they see the adult in late autumn, we may discover it has become a resident species over more of this country.

It is worth describing how the Red Admirals breeding in Howth responds to the low temperatures there from November to March. Frank Smyth’s observations show that the egg lasts a good deal longer than usual, up to ten weeks, and that the larval stage takes months to complete. This ability to prolong its development cycle enables the species to survive the coldest months and allows the adult to emerge when conditions are more favourable.

This prolonged breeding cycle over the winter has also been observed in Sussex, on England’s south coast, where Red Admiral eggs laid late in the year took 65-90 days to hatch (David Harris pers. com. per Frank Smyth). The Howth Red Admirals appeared as adults in late April and May (Frank Smyth 2018 pers. com.). In Southern England, eggs hatching in late November and early December produced adults by the third week in May of the following year (Eeles 2019). The offspring of those that migrated to breed in the warmer Mediterranean region emerge as adults in March and April (Thomas and Lewington 2014).

Remarkably, on March 7th, 2021, Frank Smyth observed egg-laying at Howth on small, unshaded south-facing nettles. Frank believes the female he saw laying her eggs to be a migrant, given he saw no other adults in the area. This is likely to be the earliest egg-laying recorded in Ireland to date by any species, and a fascinating example of what this beautiful butterfly is telling us about changes in our world.

This is a developing story. Frank has recorded good numbers of Red Admirals in Howth throughout autumn and on November 18th, 2022 he found 10 Red Admirals, some laying eggs, and a Painted Lady. It is late in the year for all (or perhaps for any) of these to be home-grown. They might be migrants from warmer parts of Europe, assisted on their journey by recent mild southerly winds which have been followed in recent days by gentle airflows. The still-lush nettles and flowering ivy give them what they need for breeding and feeding.

This is a new development. Red Admirals leave Ireland during autumn. That is well established. I have observed this myself, as have many others, especially birdwatchers along the south coast who see a large build-up of the butterfly in October, within sight of the sea, and then the butterflies suddenly vanish. Radar has also picked up southward migration in autumn, from England.

But inward Red Admiral migration in late autumn into Ireland was unknown until now. Frank’s observations of their development overwinter in recent years suggest that the Red Admirals laying now will be successful breeders. Intriguingly, there was a single, freshly minted Painted Lady with them. A fellow migrant, this species should not be here in late November, according to our knowledge of this butterfly.

The habits of these species are changing quickly, but these changes are not uniform. Most of our Red Admirals still leave in autumn, but a few now remain and, it now appears, some even migrate here to breed. The species is showing flexible responses to changes in the climate. It is this ability to respond to change that makes the Red Admiral a successful butterfly, and in this regard, it has some vital advantages. It is cold-hardy, which allows it to remain active in cool weather as long as it is sunny, and can fly in dull weather as long as it is mild. It is highly mobile, having the ability to abandon unsuitable areas and reach a habitat containing healthy foodplants hundreds of kilometers distant. It breeds on a robust plant that occurs in a range of habitats right across Europe, temperate Asia and north-west Africa. It is not capable of over-wintering as an adult butterfly, like the Peacock, but it can take shelter and rest for several days, possibly for weeks, without feeding. The immature stages are able to prolong their development times in cooler conditions, a feature crucial for successful development during an Irish winter and spring.

There are species that our warming climate will not suit and there is some indication that some of our butterflies are struggling to cope with changing temperatures and rainfall patterns. There are winners and losers in circumstances of change. But summer can still be found at Howth, even at the end of November, and despite our queasiness at climate-related changes, including changes that bring pleasure, the Red Admiral testifies to the resilience and adaptability of some of our butterflies.

Will the Painted Lady join the Red Admiral by becoming a year-round resident as well as a migrant? Photo J. Harding

 

Key References

Eeles, P. (2019) Life Cycles of British & Irish Butterflies. Pisces Publications, Berkshire.

Harding, J. (2016) The Comma (Polygonia c-album (L.)) (Lepidoptera: Nymphalidae) breeding in Ireland, with notes on larval development. Irish Naturalists’ Journal 35: 63-65.

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

Smyth, F. and Nash, D. W. (2008) Overwintering of the Red Admiral butterfly (Vanessa atalanta (L)) on the Howth Peninsula, County Dublin. Irish Naturalists’ Journal 29:81-86.

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

 

 

 

 

 

 

 

 

Butterfly Conservation Ireland Submission to the Consultation on the Draft Forest Strategy (2022-2030)

Submission to the Consultation on the Draft Forest Strategy (2022-2030)

This submission is prepared by Jesmond Harding, a director and Conservation Officer of Butterfly Conservation Ireland. Jesmond is the author of two books on Ireland’s butterflies, Discovering Ireland’s Butterflies & their Habitats (2008) and The Irish Butterfly Book (2021). This submission addresses some of the content of Ireland’s Forest Strategy Implementation Plan (draft) the Stage 1 AA Screening and Stage 2 AA Natura Impact Report (NIR) produced for Department of Agriculture, Food and Marine (DAFM).

The Need for More Native Woodland Cover

Ireland needs more native woodland cover, especially with just about 2% of the land surface of the country used for native trees. The sensitive design and creation of native woodlands, using seed sourced from indigenous woodlands within Ireland, has the potential to create badly needed woodland habitats for Ireland’s native woodland bryophytes, plants, invertebrates, and vertebrates.

At a landscape scale, the most important consideration in terms of native woodland expansion is to reduce fragmentation and provide connectivity for species between woodlands and other semi-natural habitats within the surrounding area. Analyses show that 30% woodland cover within the landscape is a critical threshold – for most woodland species, this is the minimum proportion at which the landscape begins to function as a single, large wood. [1]

Given the size and distribution of native woodlands in Ireland, it will be difficult to achieve these targets regarding size and woodland cover. This, however, may be possible within some of our larger SACs and proposed NHAs and where native woodlands adjoin conifer plantations. A good example is found in the Woodford area of Co. Galway, where several native woodlands, including the Derrycrag (110 ha), Pollnaknockaun (39 ha) and Rosturra (18 ha) Nature Reserves, are embedded within an extensive forest area. In the context of limited resources, emphasis should be placed on expanding individual woodlands within existing forest matrices, rather than creating or expanding isolated woodlands in landscapes that are largely agricultural in nature. Suitable areas include, for example, parts of Waterford, east Wicklow, southwest Cork/southwest Kerry, central Clare / southeast Galway, and northeast Donegal, where there are already significant concentrations of native woodland. An exception should be made for isolated ancient woodlands, the boundaries of which should be expanded, where possible. The expansion of native woodlands can be achieved by native woodland afforestation on greenfield sites or by converting non-native conifer, broadleaved or mixed stands to native woodland. Where practicable, the latter is the preferred option.[2]

Ireland’s Forest Strategy Implementation Plan (draft) proposes new forest types, especially Emergent Woodland/Rewilding, which is especially welcome in the context of the foregoing. The document also proposes Forests for water, Amenity forests and Neighbourwoods. There is no need for non-native tree/shrub species in such woodlands. I strongly urge the use of native seed, collected in the vicinity of these proposed woodlands, to establish these woods.

Impact of Afforestation on the Marsh Fritillary butterfly

Ireland’s Forest Strategy Implementation Plan (draft) the Stage 1 AA Screening and Stage 2 AA Natura Impact Report (NIR) produced for the Department of Agriculture, Food and Marine (DAFM) indicates Annex II Species, Conservation Status and Forestry Related Pressures and Threats in Table 3. On page 32, the table quotes the 2019 Article 17 report as identifying no threat or pressure to the Marsh Fritillary butterfly relating to forestry.

This is not accurate reflection of the report  The Status of EU Protected Habitats and Species in Ireland (2019), or the threat posed to the species by afforestation. Page 52 of the report contains the following sentence:

Sites (occupied by the Marsh Fritillary) are often on marginal land in upland areas and the edges of wetlands and peatlands which are subject to pressures from agricultural conversion and afforestation.[3]

Analysis of Article 17 Reports submitted by  EU member states carried out by Butterfly Conservation Europe noted the following problems with protected grassland habitats. The prevalence of threats to grasslands described in the Article 17 reports show that abandonment of grassland management (no grazing or cutting of vegetation) is the chief threat, with 385 mentions in the reports. The second most prevalent is mowing or cutting of grasslands at 254 mentions, followed by overgrazing (240), natural succession resulting in change in the species present (148), use of chemicals to protect certain agricultural plants (111), afforestation (110), conversion from one type of farming use to another (87), conversion from other land uses to housing, settlement and recreational use (78), use of synthetic fertiliser on farmland (76), collection of wild plants and animals (72) and conversion to other forest types including monocultures (70)[4]. All these factors, except the collection of wild plants and animals, applies to Ireland’s grasslands. This information is derived from EU member state Article 17 reports, so the causes of decline across Ireland and the EU and the improvement steps needed are known. This needs to start in protected areas and in any new protected areas.

A key requirement of the Habitats Directive is that the effects of any plan or project, which is not directly connected with or necessary to the management of a European site, but which alone, or in combination with, other plans or projects, are likely to have a significant effect on a European site, should be assessed before any decision is made to allow that plan or project to proceed. The obligation to undertake a screening for AA, and if necessary, an AA, derives from Article 6(3) of the Habitats Directive (92/43/EEC) and both involve a number of steps and tests that need to be applied in sequential order.

The Marsh Fritillary occurs in several European sites, including where the butterfly is not listed as a qualifying feature of the site (the species is listed as a qualifying feature in 16 Special Areas of Conservation in The Republic of Ireland). The species (which has a highly localised distribution in most of the areas where it occurs in Ireland) exists in a metapopulation structure, meaning that it has a central population with outlying colonies that are lost during the periodic declines which are characteristic of this butterfly’s ecology, and which are then re-occupied during periods of expansion (one such expansion occurred in the long, hot summer of 2018). This means that the Marsh Fritillary’s large colonies must be protected and that corridors to outlying areas must also be preserved, which involves protecting the landscape. Without a network of managed habitats, the isolation of populations will result in the loss of this largely sedentary butterfly. Thus, a habitat beyond the boundaries of a European site occupied by the Marsh Fritillary or a breeding area that is not currently occupied by the butterfly requires protection from negative impacts to ensure the long-term survival of the species. [5]

At 4.6.4 Ireland’s Forest Strategy Implementation Plan (draft) refers to Molinia meadows as holding populations of the Marsh Fritillary, and correctly identifies the threat to this habitat type from afforestation. However, the Marsh Fritillary occurs in a wide range of grassland habitats. These include limestone grassland, grassy heaths, humid grassland on cutover bogs, the grassy, heathy margins of intact bogs, fens, eskers, wet meadows, marshes, woodland clearings, fixed sand dunes, and machair grassland. (One example of the damage done by plantation forestry to machair grassland and fixed dunes and dune slacks can be seen at  Murvagh Special Area of Conservation, Co. Donegal Site Code: 000133 where the plantation of conifers and the spreading of self-sown conifers has and is reducing the areas of habitat available to the Marsh Fritillary). The impacts on these habitats, also used by the Marsh Fritillary, must be considered, especially in view of the metapopulation structure and the need to protect a network of habitat areas up to 15 km (the furthest distance from a known population the adult has been found in Ireland) from European sites to protect the species.

Flower-rich area in Murvagh with the conifer plantation close by.
Conifer encroachment on protected habitat at Murvagh, Donegal Bay.

Conclusion

The overarching statement for the Shared National Vision for the role of trees and forests is

‘The right trees in the right places for the right reasons with the right management supporting a clean, healthy and well protected environment and a sustainable economy and society’.

Butterfly Conservation Ireland agrees with this vision. The right places for the right trees are not high-nature-value lands badly needed by some of our threatened species and habitat types. A mosaic of open and wooded habitats can hold a great range of grassland, heath and wetland species, and return parts of the landscape to what may have been its natural state.

Jesmond Harding 10/11/2022

[1] Peterken, G. 2002. Reversing the habitat fragmentation of British Woodlands. World Wildlife Fund (WWF)-UK.

[2] Cross, J.R. & Collins, K.D. 2017. Management Guidelines for Ireland’s Native Woodlands. Jointly published by

the National Parks & Wildlife Service (Department of Arts, Heritage, Regional, Rural & Gaeltacht Affairs) and the Forest

Service. Forest Service, Department of Agriculture, Food & the Marine, Kildare Street, Dublin 2, Ireland.

[3] NPWS (2019). The Status of EU Protected Habitats and Species in Ireland.

Volume 1: Summary Overview. Unpublished NPWS report.

[4]   https://www.youtube.com/watch?v=D1PUk__cO_o&t=2180s

[5] Harding, J. (2021) The Irish Butterfly Book. Privately published, Maynooth.