Month: October 2023

It is great to have some positive news to report. Butterfly Conservation Ireland’s reserve at Lullybeg has benefitted from a generous grant provided by Kildare County Council and the Department of Housing, Local Government and Heritage (NPWS). This article describes the reserve and explains how the grant has been applied to fulfil our conservation objectives.

Lullybeg Nature Reserve is a Bord na Móna rehabilitated cutaway, managed since 2010 by Butterfly Conservation Ireland (BCI). It is listed in the Bord na Móna Biodiversity Action Plan 2016-2021. It is described as a site of national importance in the Kildare County Development Plan 2023-2029. The reserve contains a butterfly transect walked up to 26 times each year between 1 April and 30 September. The records for the transect have been sent to the National Biodiversity Data Centre each year from 2008-2023. A report concerning the transect is published on the BCI website annually as part of the Annual Report.  Lullybeg Reserve is bounded by plantation forestry to the north and east and bare peat to the south and west. It lies on both sides of a waterway that is part of the Crabtree River.

The site contains several habitats existing as complex mosaics. Habitats found on the reserve include tall herb swamps, ponds, marsh, wet grassland, dry-humid acid grassland, dry calcareous and neutral grassland, wet heath, poor fen and flush, scrub and bog woodland. This is an important conservation location (rated Nationally Important) as it is home to a population of Marsh Fritillary Euphydryas aurinia, the only protected species of butterfly in Ireland (protected under Annex II of the Habitats’ Directive 1992). Other important butterflies present are Dark Green Fritillary Speyeria aglaja (ranked Vulnerable), Wall Brown (ranked Endangered) and Small Heath Coenonympha pamphilus (ranked Near Threatened). Twenty-six butterfly species have been recorded on the reserve.

The rewards of conservation management and scrub removal/control are evident as the already impressive list of flora and fauna recorded on site is increasing. As stated earlier, the site is used as a transect for the Irish Butterfly Monitoring Scheme (IBMS) run by the National Biodiversity Data Centre, with 15 years of IBMS records underlining the site’s importance for Lepidoptera.

Moths that are present on the site include species ranked Near Threatened on the macro-moth Red List published by the National Parks and Wildlife Service in 2016 (Allen et al. 2016), such as Small Chocolate-tip Clostera pigra, Dark Tussock Dicallomera fascelina, Small Purple-barred Phytometra viridaria, and species ranked as Vulnerable, such as Narrow-bordered Five-spot Burnet Zygaena lonicerae. Birds such as Teal (Amber-listed), Woodcock (Red-listed), and Snipe are among the breeding birds present. Merlin (Amber-listed), Buzzard, Kestrel (Red-listed), Sparrowhawk, Jay, Raven, and Linnet (Amber-listed) occur here.

The conservation work required consists mainly of scrub control and cattle grazing. Scrub must be controlled to maintain plagio-climax vegetation of flower-rich grassland, wet heath and fen with low scattered scrub over much of the eastern half of the reserve. The work of scrub control is labour-intensive and is done by hand and using power tools. Grazing is a vital conservation tool for maintaining grasslands for butterflies, moths and other invertebrates. A range of sward heights and periodic substrate disturbance is vital for habitat maintenance. To contain the livestock effectively, fixed and movable fencing is needed, as well as a safe, clean water source.

The National Parks and Wildlife Service is aware of the reserve and its importance. NPWS held a Marsh Fritillary survey methodology training day on the reserve, led by the state entomologist Dr. Brian Nelson. Butterfly Conservation Ireland’s Board of Directors includes Mr. Kieran Buckley recently District Conservation Officer for NPWS in County Kildare.

An annual report is written to describe the butterfly abundance trends on the reserve. These reports, titled Lullybeg Reserve Report, can be found under the Annual Reports tab on the Butterfly Conservation Ireland website. The most recent report, from 2022, can be found here:

https://butterflyconservation.ie/wp/report/butterfly-conservation-ireland-annual-report-2022/

Grant Expenditure

The grant aid, processed by Bridget Loughlin, the Heritage Officer in Kildare County Council was applied to the purchase of materials to manage the reserve. The fencing materials bought were conduction tape, fence posts, an electric battery, and a fencer. These were used to erect mobile fencing in the northeast section of the reserve in preparation for grazing by cattle.

In addition, fixed fencing containing gates were installed along the front of the reserve to ease access for visitors and to make delivery of livestock to the reserve more manageable. An information board was produced to introduce the reserve and acknowledge the support of Kildare County Council and the Department of Housing, Local Government and Heritage (NPWS).

The addition of the drinking trough and pump means the livestock have access to clean drinking water, making it more attractive to the farmer who provides the cattle to graze the site.

The power tools purchased, chain saws, pole saw, strimmer, and hedge trimmer will enable BCI to manage the reserve. The strimmer has been used to cut the vegetation under the fence to prevent it from interfering with the electric current. The chain saws have been used to clear an area of dense scrub to extend the grassland and reduce shading in an area that has the potential to host the Marsh Fritillary butterfly.

The pole saw and hedge trimmer will help BCI maintain the habitat by keeping developing scrub under control. These tools have a long reach making the dense scrub easier to tackle.

Safety equipment to operate the tools safely supports BCI’s volunteers.

Fencing is installed with gates to allow visitor access and is convenient for cattle delivery to the reserve. Photos 26 October 2023.

BCI expects the support provided to assist us in protecting this very important reserve. The latest data published in the Irish Butterfly Monitoring Scheme Newsletter by the National Biodiversity Data Centre concerning butterfly abundance is deeply concerning (Judge and Lysaght 2023).

Results from the multi-species index of the 15 most common butterfly species highlight that there was a moderate decline (-57%) in the population of butterflies in 2022 when compared to the baseline year of 2008.

It is important to note that the multi-species index is a useful index to show overall trends in population changes of common butterflies of the wider countryside. However, it does not generate sufficiently reliable data to track how the populations of our more localised or specialised butter-fly species are changing. This is because there is currently not enough data being recorded for these species. In order to capture adequate information on these species additional species-specific schemes (like the Marsh Fritillary Monitoring Scheme) are needed.

The Marsh Fritillary is monitored on the reserve and continues to thrive, but there are indications that it is declining elsewhere. The most recent government report to the EU Commission concerning the Marsh Fritillary indicates that it is not in favourable status.

Perhaps of greater importance is the decline of non-specialist butterflies. The 2023 Irish Butterfly Monitoring Scheme Newsletter reports a strong decline for the Ringlet and Meadow Brown, both thriving on the reserve. The decline of common species suggests a deeper, more widescale biodiversity loss.

It is hoped that the management of the reserve will continue to show the way to protect our countryside and species.

Finally, BCI would like to record its gratitude to Kildare County Council Heritage Officer, Bridget Loughlin for her help in processing the grant application, to the Kildare County Heritage Officer Maebh Boylan, and to Kildare County Council and the Department of Housing, Local Government and Heritage (NPWS) for the grant.

Key Reference

Judge, M and Lysaght, L. (2023). The Irish Butterfly Monitoring Scheme Newsletter, Issue 15. National Biodiversity Data Centre

 

October is the last month of the year to see butterflies in any numbers. What can be seen is even more crucially weather dependent, but this year’s October has seen some exceptionally warm weather, with some good abundance figures for the time of year.

We are seeing some unseasonable behaviour. On 14/10/2023 I observed a courtship flight by a Red Admiral pair, and it appeared destined to culminate in mating. The gentle fluttering flight used by both sexes is a sign of female cooperation in this butterfly, and if the pair remained in the lane instead of slipping quietly into an adjoining field, probably to seek shelter from the stiff north-west breeze, I feel sure that I would have observed their pairing.

I have never seen the Red Admiral behave like this in autumn in Ireland, so perhaps we are seeing the species beginning to stay put, even 33km inland, rather than migrating south, the situation that traditionally applies in Ireland. Since the turn of this century, coastal breeding in two areas (Howth, Dublin and Ravenwood, Wexford) during late autumn has been recorded, but not inland, where the colder conditions destroy the Common Nettle.

Painted Ladies were still being seen, inland and on the coast. Like their relatives, their main and probably only nectar source in many areas is our Common Ivy. While they remain, we are holding on to the memories of summer.

Another feature of change that has extended the pleasure of seeing butterflies deeper into autumn is the spread of the Comma, and its ability to produce a second generation in Ireland, a generation that hatches from the pupa in September and October.

This lovely addition to our butterfly fauna can be seen sunning its gleaming orange-red wings on shiny bramble and ivy leaves, feeding on their fruit and flowers respectively. After the feeding is complete, the Comma hides itself in dense wooded cover until spring’s rays warm it to action.

In some woods, a dozen or more will be found in March feeding on a flowering Grey Willow. Slightly later, dandelion comes on stream. By the time this occurs, the males are defending territories and seeking passing females.

What is much less visible is the activities of moth and butterfly caterpillars, many of them still busily feeding before colder weather pauses their activity. Autumn moths are still in flight, such as the Merveille du Jour pictured here. Last weekend I had 19 moth species in my garden trap, a good showing for October, but the night I trapped was very mild.

At this time of the year, sunny, sheltered south-facing hedges containing flowering ivy are the best places to look for butterfly life. In a week or so, even these places will hold little evidence of a fine summer for many of our butterflies, leaving us with our memories but also our hopes for next spring.

Photographs © J. Harding

Time, like an ever-rolling stream
bears all its sons away;
they fly forgotten, as a dream
dies at the op’ning day.

(O God Our Help in Ages Past, Isaac Watts, 1674-1748)

Since humans learned to manipulate the environment to produce food, the natural world has been changing. Some people try to help nature by trying to restore what once was. Conscious not just of nature’s fragility but also of our mortality, the desire to leave something good that will outlast us is a powerful motivation. The following article reviews, briefly, what we have lost, describes efforts to reintroduce lost butterflies, and assesses the validity of reintroductions.

Animal and plant population loss is a common theme across the world. Humans have been radically altering the natural environment for thousands of years, especially since the farming of plants and animals began during the Neolithic period about 12,000 years ago. Mesolithic man was a hunter-gatherer, who moved through the landscape, surviving on food he picked, dug and hunted. There were no permanent settlements, and in Ireland and in other places, he used waterways to reach new areas to find food. Plant and animal domestication made long-term and permanent settlements possible, and humans began to replace natural vegetation with crops and grazing for animals.

Animals that threatened domesticated animals were killed when this was possible, and humans learned to protect livestock using dogs, and walls and by removing habitat for predators. Determined attempts were made to extirpate predatory animals, with rewards offered for proof of kills. The environment we have inherited is quite different from before farming was used to feed people and build civilizations; the pollen records and archaeological evidence show evidence of radically altered ecosystems.

The Brown Bear, the Eurasian Wolf, Wild Boar and Giant Elk are long extinct from Ireland and Britain, with the Giant Elk lost from the world, a likely victim of overkill and perhaps natural climate change. Many habitats are at a fraction of their original extent, and no fully natural habitat exists in these islands and in most of Europe. What these looked like is very difficult to say; there is recent research that challenges the long-held view that woodland dominated our landscapes before humans dominated them. The widespread presence of open grassland invertebrates today suggests that large areas of natural grassland must have existed.

The pollen record is not an infallible guide; some plants produce far more than others and some plant pollen travels further. Scots Pine falls into these categories; we cannot deduce huge pine forests existed simply because its pollen is abundant in the archaeological record. The pollen record does indicate that grasslands existed along with woods.

A mixed landscape of wooded and more open areas is now believed to have existed before the onslaught on forested areas by humans. When we began reafforestation early in the 20th century, we decided to use fast-growing non-native coniferous trees which lack any relationship with the woods we once had, and this approach, recently modified in favour of including some native trees, has continued. The most severe recent habitat loss in this country following the loss of native woods and grassland is our raised bogs, mostly destroyed. I doubt there is a single raised bog in Ireland that is undamaged.

Animals and plants require suitable conditions for their survival. When a species is lost from an area, it is usually because important conditions it needs no longer exist on a sufficient scale. You cannot, for example, plough a field containing wild grasses and herbs and re-seed it with agricultural grasses and White Clover and expect all the original insects it supported to survive.

There are people who dream of landscapes filled with beauty, containing the species we know once existed more widely. We cherish the often-small areas that still hold these natural features and want them protected and restored. Restoration involves returning existing habitats to their best condition, usually through some form of direct management.

Some go further; rewilding is their goal. Rewilding is the restoration of an area of land to its (original) natural uncultivated state; the idea is to remove human influence. In pursuit of these dreams, some people want to return animals that once existed in our environments. This has happened in Ireland, with the state-funded projects to restore the extirpated Golden and White-tailed Sea Eagles and Red Kite. Eurasian Beavers were reintroduced to parts of England and Scotland, many unofficially. Beavers are sometimes admiringly referred to as “ecosystem engineers”. By damming streams, they reshape valley bottoms, creating new ponds and waterways that rapidly fill with birds, amphibians, dragonflies, and other insects and fish. Research also shows how dams filter polluted water, and store huge quantities of floodwater. Beavers’ dams can even prevent towns from being flooded. But the water must go somewhere – and the farmers whose fields are flooded as a result tend to detest these rodent engineers.

One animal group that might be less controversially reintroduced is Lepidoptera, butterflies and moths. Some are easy to breed and easy to introduce. Just to be clear, reintroduction is the intentional movement and release of a species within an area that was once part of its historical range, but from which it has become extinct.

This has occurred in well-organized ways in England, with the reintroduction of the Large Blue (wiped out in 1979) and Chequered Skipper (went extinct in 1977). These reintroductions were underpinned by painstaking research and habitat restoration; the stock for the reintroduction of the Large Blue was sourced from Sweden while the Chequered Skippers were taken in Belgium.

But these were professionally executed and scientifically informed. Some people, however, are impatient with the slow progress of official reintroduction programmes and have decided to do it themselves.

Martin White from Nottinghamshire was a rewilder passionate about the reintroduction of extinct butterflies. He bemoaned the slow pace and cost involved in official reintroductions. He said that his first attempt to reintroduce the Mazarine Blue cost him less than £10. Contrastingly, official programmes cost much more. Transporting the Chequered Skipper to Rockingham Forest, Northamptonshire (north of Milton Keynes) via Eurostar cost £10,000.

White has introduced thousands of butterflies to various places; many of these efforts failed. But some succeeded; he closed a 90-mile gap in the Marbled White’s distribution between the midlands and the Yorkshire Wolds. He reintroduced the Purple Emperor to Lincolnshire. He has introduced the Dingy Skipper onto former mine sites, with success. Some butterflies cannot reach suitable sites because the intervening countryside is so hostile to insects that seek to move. Migrating insects must brave herbicides, pesticides, foodless ground, and long distances to reach areas that have become suitable again. Unless you are a powerful species, like the Red Admiral, the chances of natural recolonisation are very low.

But will these efforts succeed over the longer term? If a butterfly or moth is missing from a site, there is reason for its absence. Unless dealt with, simply releasing fertilised females will not help, even if the larval foodplants still occur on the site. Some species have highly specific needs that extend far beyond the presence of their foodplant. What often seems to happen is that the released butterfly breeds for a year or two before dying out.

What annoys nature reserve managers is the clamour to ‘save’ a reintroduced butterfly that reached the reserve via the car boot. People want to see rarities, such as the Marsh Fritillary or Glanville Fritillary so insist on this one butterfly being accorded conservation priority. This can reach extreme levels of attention. The only known Marsh Fritillary colony in Lincolnshire (courtesy of Martin White) exists in two fields, 100 miles from the nearest colony. The caterpillars are collected by volunteers and replaced on their foodplant after the area is mown. This is certainly not natural, and one wonders what the argument is for artificially maintaining this population. This is a gardening exercise, not a conservation one.

What is perhaps a more serious concern is using butterflies sourced in Europe to reintroduce a butterfly to an area in Ireland or Britain when the species still occurs in these countries. For example, Purple Emperors sourced in Germany were used to re-populate woods in east England. This might be harmful to native populations of the butterfly if pests or pathogens arrive with them. It might also change the genetic makeup of native Purple Emperors, which may have developed the genome to cope with English conditions.

There is evidence that introduced or reintroduced butterflies might create difficulties for other butterfly species. The arrival of the Map butterfly in southern Sweden (which it reached unaided) coincided with increased rates of infection by parasites of two other nettle-feeding butterflies, the Small Tortoiseshell and Peacock.

The three species’ caterpillars overlap in their occurrence, but there are phenological differences (differences in the timing of the hatching of the caterpillars).

The Map might be causing higher infection rates by shared parasitoids by providing a host for the parasitoids when the larvae of the Small Tortoiseshell and Peacock are scarce.

Therefore, there are times in the year when Map larvae are plentiful but those of the Peacock and Small Tortoiseshell are less numerous. Phenological differences in the parasitoids between hosts might also mean the Map is assisting increased infection rates in its butterfly relatives. If correct, the Map is reducing the competition for its food (nettles) during its establishment phase, but if the Map recruits more parasitoids, as the Swedish study indicates is likely, a balance between these butterflies might be struck.

But the study did not look at the parasitoids that the Map may have introduced to the other three butterflies, only looking at shared parasitoids, and looked at larval parasitoids, not egg or pupal ones.

The relationships are therefore not well-known and extrapolation from the Swedish experience may not be possible in another area with different conditions. Therefore, harm might be caused to native populations by reintroducing a butterfly or moth; however, after establishment, a balance might develop as the new arrival becomes subject to biological controls.

This is where the need to investigate impacts arises. The most useful step is to protect existing habitats, restore them where needed and extend them so that populations can move through the landscape. Where large areas of suitable habitat exist whether this is mainly the result of long-term favourable management, restoration, rewilding, or natural processes, then the conditions for the reintroduction of animal or plant species might be reached. Given the state of our habitats, reintroduction might even be necessary.

The severe reduction in the area of the Small Blue’s habitat along the Dublin coastline due to serious coastal erosion, management problems and the creation of golf links prompted an introduction of the species in extensive suitable habitat in County Meath and Louth. This attempt has been very successful. Meanwhile, the donor population has lost about 90% of its original habitat, which has been swallowed by the sea. The remaining population is hanging by the proverbial thread.

If the dune habitat on the donor site is restored by natural or human action, the new populations might return the compliment! This has already happened in England. Black Hairstreak butterflies from Monk’s Wood, Cambridgeshire were used to establish a new population at Warboys Wood. When Monk’s Wood lost its population during the Great War, it was repopulated from its receptor site. The restored Monk’s Wood population still exists to this day!

Considerable resistance to unauthorised, unofficial reintroduction exists and has for some time. It is illegal to introduce an exotic animal into the wild in Ireland and illegal to introduce or reintroduce, without consent, any animal or plant not already present in certain protected areas after a Statutory Instrument has been signed. It is a great pity that this is not the case for non-native plants in the general countryside. Biological recorders resent their maps being compromised by records of unofficially released species. This makes it harder to calculate the true distribution of a species, especially given the often transient presence of introduced species. Others hate the idea, captured in naturalist  Robert Lloyd Praeger’s phrase of ‘forging nature’s signature’, by introducing species in areas where they might never have occurred.

There are very good reasons for not interfering with nature. There are very good reasons for interfering with nature. In the absence of good motives and good research, reintroduction should not be tried. Bad motives include removing rarities from a site because it is about to be destroyed by a development or introducing rarities to a site that is about to be destroyed by a development. Martin White carried out his introductions because he loved butterflies and wanted to leave a legacy, to feel that his life was not a waste. Martin White died on 12 October 2020. He knew his time was coming months before. He was still releasing butterflies in the summer of 2020. Whatever the ecological impacts of his efforts, it is touching to see his drive to see nature flourish.

The damage we have done places a moral obligation on us to atone. Reintroductions might be part of this process. It might be a question of how these are done, not whether they are done. But let’s focus chiefly on looking after our habitats and extending them. Without good, large-scale habitats, many species don’t stand a chance.

 

Key References

Audusseau, H., Ryrholm, N., Stefanescu, C., Tharel, S., Jansson, C., Champeaux, L., Shaw, M.R., Raper, C., Lewis, O.T., Janz, N. & Schmucki, R. 2021, “Rewiring of interactions in a changing environment: nettle‐feeding butterflies and their parasitoids”, Oikos, vol. 130, no. 4, pp. 624-636.

https://www.theguardian.com/environment/2020/oct/13/maverick-rewilders-endangered-species-extinction-conservation-uk-wildlife Accessed 01/10/2023