Making a difference

Pollinators are popular. That however hasn’t protected them from multiple challenges, and it’s a source of comfort that bodies such as Aberdeenshire Council go out of their way to help these important insects. Amongst the first councils in Scotland to launch a Pollinator Action Plan, they are now onto their third such plan.  And the good news is they are making a difference.

It was back in 2015 that Aberdeenshire got its first Action Plan, almost a decade on the latest iteration adds more measurable, time limited actions to the impressive suite of tools. 

There is no doubt we operate in challenging times when it comes to helping nature. As if changes in land use, fragmentation of habitats, pesticides and disease were not enough of a catalogue of issues, we are increasingly looking with concern to climate change. Rather alarmingly figures released recently showed that some parts of the UK endured their wettest 18-month spell since records were first compiled back in 1836. Four of the top ten wettest winters have now occurred in the last decade.

Such conditions aren’t easy for pollinators. And that is a problem for us, as pollinators are key to supporting healthy landscapes and habitats. 

In Aberdeenshire the Council’s Ranger Service, Greenspace Officers, Natural Environment Team and Community Groups have all looked to see what they can do to help pollinators in the immediate future. That typically means addressing concerns around a good supply of nectar and pollen, looking to achieve habitat connectivity, and planting with an eye to pollinator needs throughout the changing seasons and insect life-cycles. 

So, what have they been up to in Aberdeenshire? How do things look on the ground?

One particularly pleasing measure is that at least 80 school grounds are earmarked to be pollinator-friendly by 2027. Encouraging the next generation to appreciate and help nature is time well-invested. The creation of a Biodiversity Education Pack for schools is a logical way to bolster this work. In both practice and theory, the school environment is increasingly geared towards helping pollinating insects. An extremely popular and successful B-Lines project creating pollinator habitat with schools in the north of Aberdeenshire further shows their desire to engage, practically and has worked with 12 schools to date.  

Simultaneously, perennial plant promotion (as opposed to reliance on annuals) is gaining traction with the Greenspace Project initiative ‘Perennials for Pollinators’, running for its third year in 2024. This initiative supports the gradual shift away from the endless cycle of replacing annual bedding plants in community planting schemes to something with practical value rather than short-term narrow aesthetic appeal. It’s likely that increasingly natural regeneration will come to supplement this approach. With the growing enthusiasm amongst communities, the Council nursery facility is also being considered in its potential for perennial plant production in years to come.

At least 10% of council manged public greenspace in Aberdeenshire will be managed specifically for pollinators and biodiversity by 2027. The council is exploring habitat creation at woodland sites they own, with a shift to native tree species (hastened by significant storm damage and woodland loss in 2021/22), and shrub planting in open rides and around woodland edges an emerging preference. And in a welcome, and highly-visible move, wildflower areas are steadily becoming more prevalent in parks and recreation grounds, active travel routes, road verges, and school grounds.

Many have been created with the support and help of people power, highlighting the enormous social value of these biodiversity projects. Allowing grass to flower longer was trialled in 2023 with No-Mow May and Let it Bloom June being introduced at several sites across the Shire. A massive bulb planting effort, facililated by the Greenspace Project, saw over 300,000 flowering bulbs planted by over 100 community groups across the region. This will not only provide a source of nectar in the bulb flowers, but also allows the grass to flower for longer. 

Whilst the council pursues its agenda to help pollinators, it also enthusiastically embraces partnership working. They seek allies in neighbouring local authorities and the busy North East Scotland Biodiversity Partnership. Support also comes from NESBReC training courses which often focus on volunteer recording of pollinating insects and habitat surveys. There is also a supportive collaboration with Buglife Scotland in exploring opportunities for a B-Line project next to the River Don. 

Pollinators generally enjoy a high profile within the public perception. There is broad awareness of the threats they face but messages need to be periodically reinforced. In Aberdeenshire that takes many shapes, one of the most visible being the 150 or so Ranger Service sessions run each year with local schools, nature groups and communities to raise awareness of pollinators. There is also an online training course, “Mowing for Biodiversity” created by the Ranger Service. The course highlights the importance of pollinators to Council staff and elected members and shares information on what actions can improve habitats for pollinators.  

The new plan is evolving to build on success. Habitat creation and management, the creation of green networks and corridors, and raising the profile of the plight facing our pollinators are all positive actions which are retained.  The willingness to review and modify actions to help pollinators is a sign of not being prepared to rest on their laurels. It’s that observe and learn method which is a key strength of the Aberdeenshire approach. 

Find out more:

Aberdeenshire Council Pollinator Action Plan 2022 to 2027

NESBReC Biological records for the North East of Scotland

North East Scotland Biodiversity Partnership

Greenspace biodiversity – Aberdeenshire Council

Sometimes snips, snails and puppy-dogs’ tails, other times sugar and spice

By Athayde Tonhasca

As the story goes, during a tour of a government farm, American First Lady Grace Coolidge was being shown around by a farmer when she saw a cockerel and a hen romantically engaged. She asked her guide how often the cockerel would mate, to which he responded: ‘dozens of times a day.’ Good-humouredly, Mrs Coolidge retorted: ‘tell that to the President’. The farmer dutifully did so, and President Calvin Coolidge asked: ‘same hen every time?’, to which the farmer replied: ‘No, Mr President, a different hen every time.’ And the president: ‘tell that to Mrs Coolidge.’

Psychology Professor Frank A. Beach (1911-1988) saw this improbable anecdote as an ideal model to name a widespread phenomenon among animals: the Coolidge Effect, which is the enhanced sexual interest of males whenever a new female is accessible, regardless of the availability of previous sexual partners – a behaviour rarely reported for females. This shocking manifestation of male chauvinism has been offered a biological explanation.

The term ‘gonochorism’ makes us scramble for the dictionary, even though one of the first things we learned from our Birds and Bees lessons is that our species is gonochoric (or dioecious), that is, it has two sexes: the male sex produces or is geared up to produce gametes (reproductive cells) called sperm, while the female sex is equipped to produce gametes known as ova or egg cells. The lesson’s climax was the revelation that some types of frolicking could result in the fusion of these two types of gametes to produce babies. 

Male and female Mandarin ducks (Aix galericulata), a gonochoric and sexually dimorphic (sexes have different morphological characteristics) species © Francis C. Franklin, Wikimedia Commons

Later in life, when we took biology courses, we were told that many plants and some animals are hermaphrodites (they produce male and female gametes), while other organisms don’t need sex to reproduce. But the overwhelmingly majority of animals, and all mammals and birds, are sexually binary: they either produce male gametes or female gametes – leaving aside the rare cases of individuals that don’t fit in either category. And, from humans to asparagus, that is, for virtually all multicellular organisms, the female gametes are larger – often much larger – than the male gametes; that’s to say they are anisogamous: the two types differ in size and shape. And anisogamy has much to do with the Coolidge Effect.

Because sperm are relatively small, energetically cheap gametes, males can afford to churn out and distribute lots of them. By mating with as many females as possible, males increase their chances of passing on their genes. If a male gamete ends up in an unsuitable female, it’s not a big deal: there are plenty more fish in the sea. It doesn’t work like that for females. They put a lot of energy into their eggs, which are gigantic when compared to sperm. So, a female can only make a few of them in her lifetime. Adding gestation and time spent nurturing their young, females have a much lower reproductive capacity. As they invest a great deal more in producing an embryo than males, they need to choose their mates well to maximize their chances of success; if their Romeos are weak and unfit, females may have wasted all their reproductive potential. For females, it’s a matter of quality, not quantity. 

Together at last. A human male sex cell (spermatozoon) penetrating a human ovum. The spermatozoon is ~100,000 times smaller than the ovum. Image in the public domain, Wikipedia.

These biological particularities are strong incentives to polygyny, the mating system where a male has multiple sexual partners while the female mates with one or a few males. Polygyny is the most common mating strategy for vertebrates; about 90% of mammal species are polygynous. These males are, like the Coolidges’ rooster, always ready for a new romantic adventure.

Angus John Bateman (1919–1996), a botanist who worked with fruit flies, found one important consequence of the Coolidge Effect. For most polygynous species, a small number of males monopolize the females and prevent other males from mating. That is, some males are highly successful in reproducing, while many more have no success at all. Things are more predicable for females: most of them will mate – the few successful males will make sure of that. The upshot is that males’ reproductive success is more variable than females’. 

The winner takes it all: while one red deer stag (Cervus elaphus) keeps harems of up to 20 hinds, other males go with no dates © Keven Law, Wikimedia Commons.

Enter evolutionary biologist Robert Rivers and computer scientist Dan Willard (1948-2023) to thicken the plot by proposing that differences in reproductive success can bias the production of male and female offspring. Trivers and Willard argued, reasonably, that sons and daughters of females in good condition (that is, well-fed, healthy, and not pressured by competitors) would also be in good condition, whereas sons and daughters of females in poor condition (malnourished or debilitated by parasites or competitors) would also be in bad condition. But, when the reproductive success of one sex – males, in the case of polygynous species – is more variable than the other, diverging strategies emerge. It pays for strong, healthy females to have many sons, who mate frequently and produce lots of grandchildren for their mother. Daughters on the other hand are a less promising investment because, despite being strong like mum, they are restricted by low reproductive rates. But if the mother is in poor condition, having daughters would be a better deal because despite being feeble like mum, those who survive to adulthood are likely to produce some offspring. Feeble sons on the other hand may never breed, as they would be no match for males in good condition (Trivers & Willard, 1973). In other words, when things get bad, it’s better to have more daughters than sons. This risk-spreading strategy is a form of biological bet-hedging to maximize fitness and applies beyond mammal polygyny. If females’ reproductive success is more variable, we should expect more sons than daughters when the going gets rough.

Representation of the Trivers-Willard hypothesis for polygynous species. Low-quality females are more successful than low-quality males, but high-quality males and more successful than high-quality females © Shyu & Caswell, 2015.

The Trivers–Willard hypothesis provides an explanation for a common occurrence among animals: sex ratios going astray. In theory, a species should produce about the same number of sons and daughters (1:1 ratio) to maintain long term stability. This is known as the Fisher’s principle – although it would be fairer to call it the ‘Cobb’s principle’ after the solicitor and amateur biologist John Cobb (1866-1920), who first proposed it (Gardner, 2023).

The Trivers–Willard hypothesis has had an enormous influence in evolutionary biology. Its predictions have been supported by studies with a range of species, although its universality has been debated and questioned. Nonetheless, the hypothesis has encouraged much theoretical and empirical research about sex allocation. This body of work has revealed that variation of reproductive success between sexes is not the only driver of sex ratio skewness. Food, mothers’ age, litter size, population density, the weather, or some other environmental or physiological factor may induce females to adjust the sex ratio of their offspring to maximise fitness. 

UK’s age-sex pyramid illustrating the population’s distribution by age groups and sex. The male to female ratio is 1.05 at birth, shifting to 0.73 for those aged 65 and over © Kaj Tallungs, Wikipedia.

It turns out that food availability is an important inducer of sex ratio fine-tuning for one group of animals of enormous ecological end economic importance: cavity-nesting solitary bees. Most of the 20,000 or so known species of bee build their nests in the ground, but about 30% of them took another path regarding housing. They occupy or expand naturally occurring cavities such as crevices under or between stones, cracks in a wall, holes in dead wood, hollow stems and tree bark, transforming them into cosy, safe environments in which to raise their young.

Like all solitary bees, cavity-nesting species are on the wing for a small portion of their lives, sometimes weeks. After mating, each female spends her short adult life tirelessly victualing her nest with pollen and nectar to provide for her brood. It’s a race against time and over hurdles such as bad weather, competitors, flower scarcity, pests and parasites. Reproductive success depends on the amount of food available for the young, and here their sex can be the decisive factor. Female bees – like most insects – are in general bigger than males, so they need more food. As these big eaters could be a survival risk, some tinkering may be in order.  

A red mason bee (Osmia bicornis) man-made nest with brood cells well-stocked with pollen.

A red mason bee couple. The female is 20-25% bigger than the male © Aka, Wikimedia Commons.

The orchard mason bee or blue orchard bee (Osmia lignaria), a cavity-nesting species from North America, is a valued pollinator of several fruit trees. During the early nesting season, when pollen and nectar are most abundant and mum is in top shape, her offspring comprise mostly females. As the season progresses, flowers become scarce, so she has to work harder to provision her nest. Now the sex ratio tilts towards the smaller males, who have better chances of survival because they need less food (Torchio & Tepedino, 1980). 

The scenario is similar for the related red mason bee, a Eurasian species, but here parasites play a part. As the nesting season advances, females become less efficient and take more time to gather food, creating opportunities for nest-invading parasites. Females deal with the problem by reducing the amount of food stored, with a corresponding shift in the sex ratio towards the less demanding sons (Seidelmann, 2006). In the case of the Australian endemic banksia bee (Hylaeus alcyoneus), the growing food scarcity causes the reduction of the brood’s body mass and a shift in their sex ratios. But contrary to the prevailing pattern found in bees, male banksia bees are significantly larger than females. So unsurprisingly, the energetically cheaper daughters became more abundant late in the season (Paini & Bailey, 2002). Other cavity-nesting bees have also shown declines in foraging efficiency as the season progresses, and these changes have been linked to reduced size of their offspring and shifts in their sex ratios. 

Seasonal variation in sex ratio of emerging banksia bee adults (sex ratio = number of males/total number of emerging adults) © Paini & Bailey, 2002.

A male banksia bee. They become progressively scarce in coastal areas of southern Australia as the season advances © The Packer Lab, Wikimedia Commons.

The facultative, condition-dependent shift of sex ratios is a remarkable survival tool. The power to quickly tilt the offspring’s sexual balance could make the difference for a species’ success. In the non-nonsense, unforgiving great outdoors, where long-term existence hangs on the ability to adapt to changes, boys and girls are not always equally valued: these are the times when a Sophie’s choice of sorts is necessary.

Biodiversity and Glasgow University

You have to go back to the fifteenth century to trace the roots of the University of Glasgow. Fast forward to the present, and you find a highly respected academic institution that remains relevant and dynamic. One area of increasing activity is the University’s approach to greenspace management. Paul Brannan is the Grounds Operations Manager, and in this guest blog he outlines many of the actions taking place across the University estate to help nature.

Founded in 1451, Glasgow University has more listed buildings than any other university in the United Kingdom. With such a remarkable architectural legacy you might think that greenspaces don’t get much of a look in. However, that’s not the case, the university has vigorously embraced action to help nature around its estates.  

There are three sizable Glasgow University estates dotted within Greater Glasgow. They are very different from each other, yet each has the common task of ensuring their natural spaces deliver a range of benefits, complement historic surrounds, and support the academic energy of the university. 

At the best-known of the trio — Gilmorehill campus, in Glasgow’s West End — David Jamieson as the University’s Grounds Lead, works with his team to achieve a nature-friendly environment within a bustling urban location. He and his team spend considerable time looking at ways the site can be made appealing to the students and academics who use it, whilst benefitting biodiversity. 

Arguably dominated by the famous Gilbert Scott building, the Gilmorehill campus sits amidst a wealth of mature trees. Beneath the impressive canopy David and his colleagues transform areas of shrubbery with native plant species, and enhance lawned areas with swathes of nectar-rich bulbs which increasingly support early-season pollinators.

The university recognises the opportunities presented by its location in the heart of the city, and acknowledges it can ‘dove-tail’ its own efforts with the wider Biodiversity Action Plan of the City of Glasgow. Their sites can contribute to green corridors and stepping stones, and thus boost pollinator-friendly work being carried out by the city council.

There is certainly more open space and greenery to tap into four miles along the road at the university’s Garscube estate just beyond Maryhill. 

Spanning 200 acres, Garscube is home to Veterinary Medicine students, the Wolfson Hall of Residence and impressive outdoor sports facilities. It was bought in 1947 and added to the university’s property portfolio as a solution to overcrowding at the popular Gilmorehill campus.

David’s enthusiastic team are taking decisive steps this year to encourage emerging pollinators, and to this end will be joining the increasingly high profile ‘No Mow May’ campaign. This fits neatly with the goals of the University’s Biodiversity Action Plan.  

Heading out beyond Garscube’s leafy surrounds, the next significant property in the University’s ownership is Cochno Farm. 

The estate was purchased in 1954 when it consisted of 220 acres, including 42 acres of woodland. Today the site, which lies just north of Clydebank, extends to approximately 850 acres. It is the Scottish Centre for Production Animal Health & Food Safety, as well as housing the University’s College of Medical, Veterinary & Life Sciences. 

During 2023 around 20,000 additional trees were planted here as part of the university’s long-term sustainability strategy and climate change response. Director of Sustainability Dr Roddy Yarr notes the impact this will have; “The new forest will increase our biodiversity effort, creating and enhancing habitats on the farm”.

Among those 20,000 or so trees planted at Cochno Farm are various native species, including Scots Pine, Silver Birch, Downy Birch, Rowan, English Oak, Sessile Oak, Hawthorn, Black Elder and Goat Willow.

This all chimes neatly with the University’s latest Biodiversity Action Plan. Built around Phase-One habitat surveys carried out at Cochno, Gilmorehill, and Garscube, the findings have emphasised the need to reduce non-native species across all of the university sites. 

David senses that within the University community his work to deliver positive biodiversity outcomes has strong support.  “We want to help biodiversity across the University campuses as much as we can,” he notes, “and our grounds management approach is one way we can do this. The mapping and surveying carried out by our students has been extremely valuable, and has helped direct us towards focussing time on reducing our non-native species during a period when traditionally we would normally be focussed on mowing areas. This, of course, will give pollinators a significant helping hand”. 

Telling contributions have been made across numerous spheres by University of Glasgow staff and graduates. From the fields of politics and medicine, through to famous authors and notable scientists, the list of high achievers is lengthy.

Today, the University of Glasgow remains one of the top universities in the world, and the drive to nurture a range of biodiversity-rich habitats on its estates is testament to a desire to merge local action with international vision. Scotland’s first university to declare a climate emergency, Glasgow University has always had an eye as much on the future as the past.

Further reading:

University of Glasgow, Biodiversity Strategy and Action plan (2022-2027)

The Glasgow University team: Stephen McAnenay (Biodiversity & Arbioculture Co-ordinator), Stewart Miller (Sustainability Team), Dr Stewart White (Senior Lecturer), Samantha Gibbons (Biodiversity Promoter with GUEST (Glasgow University Environmental Sustainability Team)) and Molly Davidson, GUEST Biodiversity and Gardening Coordinator.

Overhead image of Glasgow University courtesy and (c) Glasgow University website.

But first, coffee

By Athayde Tonhasca

Charles II (1630-1685), king of England, Scotland and Ireland, had a reputation for benevolence and learning – the Royal Society came to be thanks to his auspices. But the good king wasn’t happy at all about the gossiping trickling from coffeehouses. Londoners from all walks of life would get together in one of the city’s dozens of coffee establishments to socialise, enjoy their pipes, comment on the news and, alarmingly, discuss theology, social mores, politics and republicanism. The king, anxious about potentially seditious blabber, issued a proclamation in 1672 aiming to ‘Restrain the Spreading of False news, and Licentious Talking of Matters of State and, Government’ because some folk  ‘assumed to themselves a liberty, not only in Coffee-houses, but in other Places and Meetings, both publick and private, to censure and defame the proceedings of State, by speaking evil of things they understand not, and endeavouring to create and nourish an universal Jealousie and Dissatisfaction in the minds of all his Majesties good subjects.’ 

Nobody paid much attention to the king’s gripe, so two years later he came down hard on the miscreants with another proclamation: merchants were forbidden to sell ‘any Coffee, Chocolet, Sherbett or Tea, as they will answer the contrary at their utmost perils.’ But Charles had underestimated how much his subjects cherished their coffee: the proclamation triggered a huge outcry, and there were signs of public disobedience. Perhaps thinking of his father, who lost his head (literally) for being inflexible, the king quickly backpedalled. The proclamation was abolished within two weeks, and Londoners could go back to their chatting, reading, and sipping strong, bitter coffee.

Charles II, who was concerned about Fake News. Portrait by John Riley, The Weiss Gallery, Wikimedia.

Coffee made its way to Europe from Turkey in the mid-1600s, and the new drink quickly became popular and fashionable. The first British coffeehouse was opened in Oxford in 1652, and soon others popped up all over the realm. No alcohol was served, so sober and caffeine-boosted patrons could exchange and debate ideas or do business: Lloyd’s of London and The London Stock Exchange trace their origins to coffeehouses. In Oxford, they became known as penny universities: for one penny, the cost of a cup of coffee (the admission fee), any man – women’s presence was not encouraged – could rub shoulders with learned patrons and find out the latest on science, literature and philosophy. John Dryden, Isaac Newton, Samuel Pepys, Alexander Pope and Christopher Wren were some of the famous coffeehouse fans.

A 17th century London coffeehouse. Image in the public domain, Wikipedia.

Eventually, as the British empire expanded through the East India Company‘s endeavours from 1720 onwards, tea became the country’s most popular hot beverage. Coffee began to make its way back to the top position in the late 1990s and early 2000s, helped in part by the arrival of mass-market coffee chains. Britain is not alone: coffee has become one the most popular drinks around the world, and consumption is increasing. 

The expanding coffee market is good news to millions of small farmers and land holders in about 80 countries, who supply the bulk of the internationally traded coffee. Brazil accounts for ~40% of the global trade, followed by Vietnam, Colombia, Indonesia and Ethiopia. Coffee is the most valuable crop in the tropics and a significant contributor to the economies of developing countries in the Americas, Africa and Asia. Arabica coffee (Coffea arabica) makes up 75-80% of the world’s production, and the remainder comes mostly from Robusta coffee (C. canephora), which is easier to cultivate than Arabica but produces an inferior beverage.

The Brazilian Empire (1822-1889) showed its gratitude to the two addictive drugs that sustained the county’s economy by displaying them on its flag: coffee (on the left) and tobacco © Almanaque Lusofonista, Wikimedia Commons.

Arabica coffee has long been understood to be an autogamous plant, that is, it fertilises itself. This reproductive mechanism has the obvious advantage of doing away with pollinating agents such as insects. On the other hand, self-fertilising plants lose out on genetic diversity, so that they are more susceptible to unpleasant surprises such as novel pathogens. And autogamy does not guarantee fertilisation for species as finicky as C. arabica. Plants bloom a few times during the season, but flowers come out all at once and don’t stick around: they wither and drop off in 2-3 days. And if it’s too hot, too cold, too dry or too wet, flowers don’t even open. A coffee plant produces 10,000 to 50,000 flowers every time it blooms, but almost 90% of them fall without being fertilised. So, Arabica coffee bushes could use a little help with their pollination.

Coffee plants in bloom ©FCRebelo, Wikimedia Commons.

It turns out that the autogamous label is not quite correct for Arabica coffee. A growing body of observations and research have shown that fruit size and overall yield increase when flowers are visited by insects, especially bees. The proportion of well-formed, uniform berries also increases, resulting in a better-quality beverage. These results demonstrate that Arabica coffee relies on a mixed mating system: some flowers are self-fertilised, others are cross-fertilised by insects. And the figures support this view. On average, insect pollination increases fruit set by about 18%. The naturalised European honey bee (Apis mellifera) is one of the most important contributors to this service, but several other native bees visit coffee flowers, attracted to their abundant nectar and pollen.

The stingless bee Partamona testacea is one of the many coffee pollinators in Central and South America © John Ascher, Discover Life.

There could be more to the pollination of Arabia coffee than the abundance of bees. Some studies suggest that having lots of bee species around also helps, possibly because a range of pollinators provide greater temporal and spatial flower coverage, thus reducing the chances of a receptive flower going without pollen transfer. If it’s proven to be the case that bee diversity makes a difference (the jury’s still out), the conservation of forest remnants that typically border coffee fields would be a judicious crop management practice, as they are home for many native bees.

Shaded coffee plantation, a habitat favourable to native bees © John Blake, Wikimedia Commons.

When you are in the queue for your over-priced double espresso, long macchiato or cortado, you may have a negative thought about greedy coffee barons. In fact, for a £2.30 cup of coffee, the retailer keeps £1.70; five pence (~2%) goes to the grower. Fairtrade estimates that 125 million people depend on coffee for their livelihoods, but many of these small growers can barely scrape a living (World Economic Forum). Boosting productivity is one sure way of increasing farmers’ income, and here bees have much to contribute. Higher productivity also reduces the pressure on natural habitats, as  coffee is often planted in areas previously occupied by native forests.

A typical coffee plantation in low or mid-elevation areas adjacent to native forest remnants © CoffeeHero, Wikimedia Commons.

The Arabica coffee story exemplifies the reach of pollination services. The income of small farmers, revenues of developing countries, the conservation of tropical forests and related matters such as carbon storage and global temperatures, let alone your morning caffeine kick, are all linked in different degrees of relevance to the diligence of bees, some of them poorly known. Keep that in mind while you enjoy your next cup of coffee.

Ad for A Brasileira, Lisbon’s oldest coffee house. Selling Brazilian coffee since 1905. Image in the public domain, Wikipedia.

Loving a cold climate

At this time of year I try to make a trip to Perthshire’s Ben Vrackie. Truth be told it’s a fairly unspectacular mountain.  Neither too long or difficult a climb, occasionally a wee bit busy, it fits the bill for a short day rather than an epic outing amongst the hills.  Nonetheless, it has a ‘hidden’ allure that belies its familiarity.  It offers beautiful views, and, here’s the clincher, it’s a great place to see purple saxifrage.

Purple saxifrage (Saxifraga oppositifolia) is a good indicator that spring is rolling in. It  also has that ‘Location, Location, Location’ appeal. Given its preference for the uplands it connects with hill-walkers in the same way that a glimpse of other mountain specialists such as golden eagles, dotterel or dashing mountain hares lift the spirits.  

With tightly-knit rosettes of small, vivid pinky-purple flowers, purple saxifrage is a prostrate beauty which can add a splash of dense and welcome colour to what are often otherwise monochrome days.

It’s a tough wee critter too.  Those purple flowers, each with five petals, withstand punishing conditions from perishing sub-zero temperatures to howling gales. 

That hardy quality means this is truly a plant at home in the mountains.  You will find it in some of the coldest areas of Northern Europe and beyond. Apparently, it has been recorded at 4,500 metres in the Swiss Alps. 

This begs a question. ‘How does a plant which emerges before the bulk of our pollinating insects achieve pollination in such a forbidding setting?’   

The answer lies with flies. Not those mesmerising, boldly coloured, hoverflies which we often see in our parks and gardens, but rather in ordinary looking dull black flies related to house flies. 

In mountain situations, above the altitude where heather is abundant, and in more northern parts of the world these types of flies are often successful pollinators.

The combination of cool, windy weather and a relatively low number of flowering plants creates a difficult environment for bees which have a relatively high energy requirement for themselves and their brood. And bees which favour higher ground, such as monitcola, are still in hibernation come early spring.

On the other hand, many of our upland-based flies over-winter as adults in sheltered spots amongst nooks and crannies in rocks. From there they can dash from their ‘cosy’ resting state relatively quickly if the weather warms up just a little. Thus they are on the wing before bees emerge, and they rely on the likes of early flowering saxifrages as a nectar source.

In an environment where the weather is often highly changeable these pollinating flies also ride out bad weather by retreating and finding temporary shelter. Thank goodness they do, for we depend on these little, rather obscure, insects to pollinate many of our specialised mountain plants, including our beautiful purple saxifrage. 

The appeal of purple saxifrage is widespread. Not only is it admired in the far north of Europe and the Alps, it’s the national flower of Nunavut, a huge northern territory in Canada. Closer to home, there is a record showing it spotted at 1,210 m on Ben Lawers and I once read an update celebrating that it had been found flowering on Snowdon on 26 January. Amongst Yorkshire walkers, purple saxifrage can enliven a spring trip to Pen-y-ghent or Ingleborough. Dip into the Cairngorm Club journals and mentions of purples saxifrage are not hard to find.

Scotland is the British stronghold for this botanical gem. Draw a line on a map, roughly from Greenock to Brechin, and north-west of that line you’ll find plenty of places to see purple saxifrage. Luckily for me Ben Vrackie is one of them, and it’s an annual delight to see this spectacular and hardy little plant confirm that spring is here again.

Find out more:

Botanical Society of Britain and Ireland on purple saxifrage

The RHS purple saxifrage introduction

Menacing tenants

By Athayde Tonhasca

In an apple orchard somewhere in the American state of Pennsylvania, an adult Japanese horn-faced bee (Osmia cornifrons) has just emerged from its nest and makes its way into the big wide world. The apple grower has high hopes for that bee; in fact, he bought many of them when they were still inside their cocoons. The Japanese horn-faced bee was introduced from Japan in the 1970s, and since then it has been widely used in the Eastern United States to improve the pollination of apples and other fruit trees such as peaches, pears and cherries.

A female Japanese horn-faced bee © Chelsey Ritner, Exotic Bee ID.

In their natural habitats, the Japanese horn-faced bee and similar species such as the red mason bee (O. bicornis) nest inside natural cavities such as hollowed reeds, tree holes and cracks in stones. Females use a range of materials, especially mud and pebbles, to build individual nest cells in which they lay an egg. When bees are done, they seal off the nest entrance with mud – so they are known as mason bees. Fruit growers offer bees nesting alternatives such as drilled blocks of wood or bunches of cardboard tubes tightly packed together.

Two types of mason bee nests used in orchards: cardboard tubes (a) and wood blocks (b). Pictures by N. Joshi © Kline et al., 2023.

The future seemed promising for that Japanese horn-faced bee in Pennsylvania. But opportunists were on standby, ready to pounce when an unsuspecting bee leaves its nest. In the blink of an eye, a gang of hypopi (singular hypopus) jumps on the bee, holding on for dear life as their ride flies away.

Hypopi, also known as hypopodes, are a special nymphal stage found in some mites. In this case, the hairy-footed pollen mite (Chaetodactylus krombeini). Hypopi have no head or mouthparts, but are armed with special structures for hanging on; either powerful claws or a sucker plate to glue themselves to their host. These adaptations greatly facilitate phoresis, which is when an organism attaches itself to another for the purpose of transportation. Phoresis is typically found in small and poorly mobile organisms such as nematodes and mites. But curiously, the hypopus stage is usually facultative for mites; it occurs only when conditions deteriorate (food scarcity, overcrowding, dry climate, etc.), so that skedaddling increases the likelihood of survival.

A hypopus, the stage adapted for phoresis © Reynolds et al., 2014.

The departing bee has no chance of avoiding the lurking hitchhikers who react instantaneously to the slightest touch to their dorsal setae (bristles) or to air movement caused by a passing body. And the feats of some of these mites defy credulity; the tiny Histiostoma laboratorium (formally known as H. genetica), a scourge of vinegar fly (Drosophila melanogaster) laboratory colonies, lurches into the air to grab fruit flies flying above them (Hall, 1959. J. Kansas Entomological Society 32: 45-46). Some species that have hummingbirds as hosts rush to the birds’ nostrils at a rate of 12 body-lengths per second, which is a speed similar to a cheetah’s (Colwell, 1985)

Hypopi attached to their host © D.E. Walter, Invasive Mite Identification, Colorado State University and USDA/APHIS/PPQ Center for Plant Health Science and Technology.

After being mobbed by hypopi, the bee carries on with its life. If it’s a female, she will mate and start a nest of her own. When her brood cells are ready, her unwanted companions come out of their lethargic state, jump off and resume their development, maturing and reproducing very quickly, all the while feeding on the pollen and nectar gathered by the bee. When their numbers reach certain levels, they may feed on the bee’s eggs and larvae (details are sketchy). In a few months the mites may reach thousands and overrun the brood cell, leaving space for nothing else.

Hairy-footed pollen mites inside a mason bee nest cell © Pavel Klimov, Wikimedia Commons.

Such massive numbers of kleptoparasites (organisms that steal food from another one) spell serious trouble for Japanese horn-faced bees; their eggs and larvae die or develop poorly for lack of food or direct attack from mites. Some adult bees may not even have a chance to start a new family; they may be so burdened by mites that they cannot fly. They fall to the ground and become easy pickings for ants and other predators.

A mason bee loaded with pollen mites © GeeBee60, Wikimedia Commons.

Several mason bee species are susceptible to the hairy-footed pollen mite, but managed Japanese horn-faced bees have been hit particularly hard, with losses reaching up to 50% of the population. It’s not difficult to understand why. The same way slum housing conditions make people more vulnerable to all sorts of diseases, jam-packed nests increase the chances of mites passing from one bee to another. And the hairy-footed pollen mite does not even depend on phoresis: adults can walk from one nest to another nearby, getting inside through holes in the sealing mud made by parasitic wasps. To make the situation worse, this mite can turn into a dormant stage that survives several years inside an empty nest, rousing back to activity as soon as new tenants arrive.

The effects of the hairy-footed pollen mite on the Japanese horn-faced bee are a reminder of the unintended consequences of well-intentioned actions. Bee houses or bee ‘hotels’ have been promoted as enhancers of wild bee populations, but there’s no indication of such effects. They do however increase the risk of pathogens and parasites: not only mites, but a range of fungi, parasitic flies and wasps bedevil mason bees (Groulx & Forrest, 2017).

A bee hotel: not such a great idea © Colin Smith, Wikimedia Commons.

American fruit growers do their best to keep mites under control by replacing the nesting tubes yearly, sterilising wood blocks, or removing and storing bee cocoons during the winter. If you have a bee house but don’t have the resources, time or inclination to do the same, you should follow Colin Purrington‘s advice: buy a garden gnome instead.

Glasgow’s engineering shift

Glasgow, Scotland’s biggest city, is affectionately nicknamed as the ‘dear green place’. It’s a long-standing label the city is proud of, and the city retains a special fondness for its many green spaces.  So much so, that Glasgow City Council implements its own Pollinator Plan.

The existence of a well-crafted and carefully thought through plan ensures a sustainable vision in creating pollinator-friendly habitat. Of course, a pollinator plan isn’t a ‘create, launch and walk away’ project. It’s a commitment, a durable framework, for ensuring that the conditions are created and then managed to ensure pollinators can prosper in a sympathetic urban setting. 

Readers of our annual Pollinator Strategy Progress Reports will be familiar with the fact that Hogganfield Park Local Nature Reserve and the iconic Queen’s Park are now designated Pollinator Parks and embrace Glasgow’s enthusiastic improvements for nature. They are rightly viewed as examples of work well-delivered; a bold visual and environmental break with an historically heavy industrial past.

Quality greenspaces aren’t of course the only thing Glasgow is famed for.  Once renowned for shipbuilding, tenements and engineering, Glasgow has gradually been crafting an alternative vision.  This is after all the home of Scottish Opera and the Burrell Collection, the city that hosted a solo show by artist Banksy, a vibrant urban centre with fantastic architecture and revamped river front.  In short, an evolving blend of attractions means that there is more to Glasgow than a busy industrial past, and the Pollinator Plan was just one more piece in an ever-diverse jigsaw. 

Last year the impetus for a better future for pollinators in Glasgow was maintained. Successful examples abound. Six meadow sites across the city are now managed by a well-briefed contractor to ensure that 17 hectares are sympathetically managed for wildlife. What’s more The Conservation Volunteers manage a further five meadow sites with a mixture of enthusiasm and expertise that makes the likes of Cathkin Braes Local Nature Reserve and Springburn Park sites to be proud of.

The numbers behind the Glasgow operation are impressive. Last year around 22,000 small bulbs and 16,500 wildflower plugs were planted across swathes of the city’s greenspaces amounting to 5500 square metres. A whopping quarter of a million daffodils were planted city wide. But perhaps the pièce de resistance was the successful move to create seven new meadows. 

It probably helps that the council have hung onto Pollok Country Park’s nursery.  Flower power and volunteer support are to the fore here and the legacy is growing – last year 28 Hub training participants carried out 42 volunteer hours seeding and caring for nursery.

It pays to have an open mind and a welcoming nature. 

Glasgow’s green aspirations have in the past included welcoming Butterfly Conservation to run a ‘meadow creation and maintenance’ workshop at Kelvingrove. The same organisation has also helped the famously friendly city host ‘meadow discovery days’ at Ruchill, Springburn and Elder Parks, introducing people to the plants and insects found in urban meadows.

Bumblebee Conservation Trust are another valuable ally. They co-ordinated nine Beewalk transects last year and supported a new addition to their ranks of Beewalks at Hamiltonhhill Claypits LNR.

And Hamiltonhill Claypits is a good place to end our story. Opened in the summer of 2021, this local nature reserve boasts wooded walks and paths alongside the once bustling Forth and Clyde Canal, in North Glasgow. It’s fine example of what was once an industrial hub transforming, over many years, into a place for nature and wildlife to thrive. That’s good news for pollinators, and good news for Glaswegians.

The useful interloper

By Athayde Tonhasca

Among the world’s myriad natural habitats, mangroves are not likely to be voted the most beautiful or inspiring. Mangrove forests consist mostly of monotonous swathes of twisted, stunted-looking trees with exposed roots that grow on harsh, muddy, hot shores of tropical and subtropical regions. Mangrove species thrive in these places because they are not put off by oxygen-starved, waterlogged mud; and they are halophytes, that is, adapted to saline or brackish water, conditions that would kill most plants.

A mangrove forest © Leon petrosyan, Wikimedia Commons.

Although mature mangrove plants don’t mind too little oxygen and too much salt, their seedlings would die or develop poorly is such environment. To get around the problems caused by inhospitable nurseries, mangrove species adopted the form of reproduction found in mammals, some reptiles and a few fishes: vivipary, which is embryo development inside the mother’s body. In the case of plants, the seeds germinate and develop into seedlings while still attached to the parent tree, which supplies water and nutrients to its offspring. When the seedlings – called propagules – are sufficiently mature, they drop and take root near the parent tree or float away with the tides to establish somewhere else. You can follow the amazing life cycle of the red mangrove (Rhizophora mangle).

Red mangrove cigar-shaped propagules about to drop into muddy waters © Katja Schulz, Wikimedia Commons.

You may not choose mangroves for a picnic or camping site, but their value should not be underestimated. By hugging the coast, mangroves are barriers against waves, forming a line of defence of increasing importance as the changing climate makes storms and flood surges more frequent and severe (watch a simulation of how mangrove forests protect the shoreline). Their dense, labyrinthine roots filter and purify the water, at the same time creating sediment deposits that reduce coastal erosion. Mangrove roots also act as nurseries for a large number of marine species, many of them vital sources of protein for low-income communities. These apparently impenetrable forests are safe havens for hundreds of plant and animal species, some of them rare and threatened. Although confined to warmer regions, mangroves have a global importance, especially because they absorb and store more carbon than tropical rainforests. Despite their value, mangroves are one of the most threatened habitats on the planet, encroached by coastal development and seafood farms.

Global distribution of mangrove forests © Pinpin, Wikimedia Commons.

Some mangrove species are pollinated by the wind or bats, but most require insects. Bees, ants, flies and butterflies have been identified as potential pollinators in different mangrove regions, but we have a poor understanding of these interactions – with at least one exception:  the European honey bee (Apis mellifera) has proven its credentials as an effective mangrove pollinator. 

The grey mangrove or white mangrove (Avicennia marina) is distributed throughout Africa and south-east Asia, and is the most common and widespread mangrove species found along the Australian coast. Dozens of insects visit this plant, but only the European honey bee has been shown to remove pollen from a flower and deposit it on another one (Hermansen et al., 2013), which are the necessary steps for plant fertilisation. This industriousness created a conundrum for Australian conservationists and policy makers.

Grey mangrove. Native Australians and European settlers use its light but strong wood for construction and boat building © Kahuroa, Wikimedia Commons.

Since its introduction to Australia in the 1800s, the European honey bee has made good use of the country’s favourable climate and extensive areas of native vegetation: it spread out quickly and widely. The bee’s seamless adaptation to its new habitat has created a bonanza for the thousands-strong Australian beekeepers, and for countless farmers who benefit from an efficient and reliable pollination service. But not all was well. 

Trees are the European honey bee’ ancestral habitats; before they became intensively bred and managed, honey bees nested in tree holes and collected pollen and nectar from tree canopies. When swarms escaped into the Australian wilderness, they readily went native by moving into tree cavities and ejecting – and sometimes killing – local residents like cockatoos, parrots, kingfishers, opossums and bats (Western Australia Museum). Feral European honey bees may also outcompete the 2,000 or so native bee species for food and nesting sites, and help spread weeds, pests and diseases. These impacts have been reported elsewhere, but in Australia the data are incomplete or inconsistent (Prendergast et al., 2022). The best we can say is that the interloper may interfere with a flora and fauna that have evolved together for millions of years.

European honey bees help sustain populations of grey mangrove in Australia, with substantial economic and ecological benefits; but these latecomers to the Aussie scene may also disrupt other species interactions and processes. Such dilemmas and uncertainties are nothing new in conservation: only hard work and good data can help us learn which way the balance tilts.

Grey mangrove flowers are irresistible to European honey bees © Dave Britton, Australian Museum

Shetland shines

One of the first naturalists to capture my imagination was Bobby Tulloch of Shetland. His tales of otters and snowy owls captivated me, and brought a touch of the northern isles and ‘simmer dim’ into my New Town home in East Kilbride. Tulloch was, to borrow a good old Scottish phrase, a ‘Lad o’ Pairts’, an all-rounder, and his photographs of flowers and ferns suggests he probably had a keen eye for the less obvious and smaller species like pollinators.

A road verge managed for visibility and wildlife. Image courtesy of http://www.austintaylorphotography.com

Few of the actions that help pollinators embrace glitz or glamour. Often the actions that deliver most are cheap and easy, requiring minimal investment. Indeed, in many instances it is simply to manage things differently, to ease back a little, that makes a telling difference. 

Shetland Islands Council has taken a leaf from that book and introduced a few measures which give nature a helping hand.  For example, they have amended their roadside verge cutting policy.  This means verges are often only being cut for safety reasons, for example in visibility splays, at junctions, and where pedestrians require access to the verge so as they can easily step off the road to avoid approaching traffic. It’s a sensible and pragmatic approach.

Another welcome development is very much ‘on the money’ in terms of modern environmental actions. Shetland Islands Council has begun to replace some conventional street lighting with LED equivalents. This has brought a new look to many lamp-posts around Shetland. The new ‘down lighters’ are not only fantastic when it comes to reducing light pollution, but by being deliberately dimmed after midnight they deliver a further aid to local wildlife, especially night-flying pollinators such as moths. This sympathetic action adds a whole new meaning to ‘northern lights’.

Across Scotland altering mowing regimes on public greenspaces is an action that many councils are embracing. In Shetland this has caught hold too, with some large areas of grass, which were previously cut several times during summer months, now being left to grow naturally. It’s another rather simple, basic step, but one which is potentially a fantastic boost for biodiversity. In places the only cutting is beside footpaths, with a narrow edge strip being the only intervention needed. This leaves an extended area that was previously cut on a regular cycle, undisturbed for wild birds, insects and small mammals.

A bumblebee feeding. (c) Austin Taylor

Lerwick is Shetland’s largest community. Just over 7,000 people live in the town and they will have noticed the changes made at Jubilee Flower Park.  Originally waste ground, the park was created by the council in the early 1950s and rapidly became a popular spot. The Council has recently adopted a policy in the park of no chemical use when it comes to eradicating weeds. Instead, these are manually removed by hand and the park is rapidly becoming a sanctuary for wildlife. And that’s not the only change that has been eased in. Around the perimeter of the park, walls and fences are being used for growing a wide variety of climbing plants, which of course will provide shelter and a food source for invertebrates and birds.  On a windy island the walls are much appreciated, by people and nature.

Many will be familiar with the vibrant wildflowers that pepper Shetland, such as red campion and pink sea thrift. When it comes to gardening, however, the challenge is considerable. Yet to visit Jubilee Flower Park is to wander into a scene framed by a range of impressive plants. From elder, hebe and flowering currant, through to lupins, oxeye daisy and poppies there is floral variety that bees and other pollinators will eagerly exploit. 

There is a sense that Shetland is at the start of its pollinator journey, and the actions of today will hopefully be bolstered by increasing steps to help pollinators. With further improvements and refinements the picture should look increasingly rosy.

The Shetland Isles are rightly famed as a nature haven. Understandably there is a big focus on the fantastic bird life, the thrilling marine wildlife, but there is much more besides. Shetland Islands Council is doing its bit to help pollinators in what can be a testing environment. I’m pretty sure Bobby Tulloch would have approved of their efforts. 

Links:

Insects of the Shetland Isles

The bumblebees of Bressay

Crumbling, dusty, ugly – and valuable

By Athayde Tonhasca

‘Picture to yourself everlasting bleak sand dunes with no buildings. Only rabbits find a little nourishment here; they eat a substance which quite unjustifiably goes by the name of grass. It is a sand desert where the wind always blows often howls filling the ears with sand. Between us and America, there is nothing but water a sea whose mighty waves are always raging and foaming. Now you will have some idea of the place where I am living. Without work the place would be intolerable.’  

Thus Alfred Nobel (1833-1896) – of Nobel Prize fame – described to his brother the Ardeer peninsula, the Scottish site chosen to host his British Dynamite Company in 1871. The Scottish tourism board might have looked askance at Nobel’s verdict, but Ardeer was the ideal place for the manufacture of temperamental products such as dynamite and gelignite (blasting gelatine). The peninsula was relatively isolated from skittish neighbours, yet fairly close to Glasgow ports. As a bonus, the site was covered with dunes, which were an abundant source of building material for blast walls that protected life and property against accidental explosions. 

The tip of Ardeer peninsula © Largsnaturalist, Wikimedia Commons.

By 1902, Nobel’s explosives factory was the largest in the world. Manufacture shifted to other products after the plant became part of Imperial Chemical Industries (ICI) in 1926, but production started to dwindle. By the 1980s, most operations ceased:  Ardeer train station, the dining hall, engine houses, boilers, warehouses and countless other buildings were abandoned: a large portion of the Ardeer Peninsula had become derelict. 

Today, a visitor to the once mighty Nobel Enterprises site will find crumbling sheds covered by graffiti and half swallowed by the sand, tracks of weedy tarmac, rusty pipes and barbed wire, and pieces of broken equipment scattered everywhere. Such a place definitely would not qualify as a beauty spot. But these eerie remnants have a significant ecological value.

The remains of Ardeer railway station platform © Dreamer84, Wikipedia.

Land that has been previously built on or developed such as the Nobel factory is classed as a brownfield site – as opposed to greenfield sites, which are land that has never been developed. Some brownfield sites are inhospitable places, layered with tarmac or concrete, and often contaminated with toxic chemicals. But many of these areas are not hazardous; quite the opposite. They are usually populated by patchy, thin vegetation (sometimes because of poor soils and lack of water) comprising weeds, grass and scrub; the landscape is a mixture of bare ground, temporary pools, scattered logs, stones or rubble. These post-industrial sites, old quarries, disused open mines, spoil heaps, gravel pits, and other abandoned enterprises may look like the settings of a Mad Max film, but they are great opportunities for pioneer species – those first to colonize a newly created environment. Ecologically, open ground areas function as habitats in the initial stages of succession – that is, on the way to becoming closed-canopy forests.

Abandonment kick-starts ecological succession, beginning with pioneer species and ending with an old-growth forest © Joshfn, Wikimedia Commons.

Many species benefit enormously from these semi-open spaces that are not yet taken over by strong, dominant competitors. Pollinating insects in particular have at their disposal sunny spots for basking, a variety of wildflowers for nectar- and pollen-feeding, patches of bare ground for nesting, and some solid, sheltered structure such a pile of rubble for hibernation. They have it all. Even better, these sites are mostly free from human interference – people tend to avoid them. Evolving brownfield sites have their own special name: open mosaic habitats. They are sufficiently valuable to biodiversity to be considered a category of UK priority habitats. 

A typical open mosaic habitat © Richard Croft, Wikimedia Commons.

Ardeer is an exemplar evidence of the value of open mosaic habitats. It harbours the most diverse assemblage of bees and wasps in Scotland: 113 species, including many scarce ones such as the northern colletes (Colletes floralis) and the coastal leafcutter bee (Megachile maritima). Beetles, moths and butterflies are also richly represented (Philip et al., 2020).

The hairy-saddled colletes (Colletes fodiens) is common in southern Britain, but with only two records in Scotland, one of them in Ardeer. This bee is considered vulnerable in continental Europe (European Red List of bees, 2015) © Rick Geling, Wikimedia Commons. 

By their very nature as successional habitats, brownfields are ephemeral; in 15-20 years, they are likely to be overtaken by scrub and eventually become woodland. They may not even last that long, as they are prime targets for makeovers; Ardeer itself is being considered to become a housing development, a golf course, a marina, a wind farm, or even a site for a nuclear fusion reactor. The limited aesthetic appeal of brownfields induces few objections to their re-development. But considering their value for biodiversity, their keeping and management to retain their successional nature are equally valid options for their future.

Derelict sites: dumping grounds, eyesores, a waste of space – and hotspots of biodiversity © Graham Horn, Wikimedia Commons.