Claire Pumfrey of Buglife Scotland is our guest blogger today. She takes a look back on a busy year of helping pollinators in the Strathmore area and the fantastic B-Lines project
The Strathmore B-lines project, which started in April 2022 and sadly comes to a close in March 2024, has been busy working with landowners, land managers and communities within the Strathmore valley to raise awareness of the importance of our native pollinators and increase flower-rich habitat within the Strathmore Valley.
It’s been a very busy 2023 field season so far with plenty of site surveys, habitat management workshops, pollinator identification training and ‘get close to nature’ events. One of the highlights included a Moth trapping event, held in partnership with Scottish wildflower seed producers, Scotia Seeds, at Mavis Bank Farm. It was fantastic to give members of the public an opportunity to get up close and personal with these insects – everyone loves a Poplar Hawk Moth!
Other successful events included our Pollinators Picnic held in partnership with Sustainable Kirriemuir, Bumblebee identification training held in partnership with the Bumblebee Conservation Trust, Yoga in the Meadow, and our two scything workshops delivered by Rob Brodie.
Moving into late summer and autumn, the project has been focusing on habitat creation and restoration at selected sites. Dedicated project partners and volunteers have been helping to sow Yellow Rattle seed and plant native wildflowers – so far 3,500 plants have gone in the ground! This has included at The Hermitage with The National Trust for Scotland, Loch of the Lowes with the Scottish Wildlife Trust, Montrose Kirkyard with Angus Council, and in Blairgowrie with Biodiversity Blair and staff from the Scottish Environment Protection Agency.
None of this would have been possible without all of the amazing volunteers and project partners – so a massive thank you to everyone who has helped out and got involved so far! We still have plenty of habitat work to carry out, including wildflower planting and seed sowing, and we are on the lookout for volunteers. If you would like to get involved please contact claire.pumfrey@buglife.org.uk
The work of Strathmore B-Lines has been made possible by funding from the National Lottery Heritage Fund and The Gannochy Trust.
Behind the door of an ordinary unit in a gritty industrial estate in Irvine some very inventive thinking is going on. It concerns meadows.
There is a lot of discussion these days around how best to convert great swathes of amenity grassland to flower-rich meadow. At times it can seem a daunting subject. It can appear costly, require specialist equipment, demand skills as diverse as ploughing, scarifying, cutting, gathering and disposing. However, the team behind the Irvine to Girvan nectar network has a rather nifty solution.
That was the reason I made my way recently from a wet and dreich Perth to balmy Irvine to visit Lynne Bates of the Scottish Wildlife Trust. Lynne had invited me to see operation ‘green hay’ and her mood was as sunny as the weather.
We gathered at Irvine’s Beach Park, a popular and expansive green space in Scotland’s only coastal new town. Here, for the past four years, Lynne has been working closely with North Ayrshire Council and an extraordinarily helpful agricultural contractor to expand a network of meadows into something that is a delight to people and pollinators alike.
Cutting swathes of grass to achieve a manicured appearance in such a rolling park would have been a tricky, and carbon heavy, task. What’s more it isn’t good value for nature. Lynne was quick to realise this, and set about persuading the council that there was another option beckoning. The Council were all ears and proved willing partners.
To get a sense of how the Irvine to Girvan Nectar Network has taken hold in this area I’d recommend heading to the north-eastern fringe of the Beach Park. Visit between April and July when the meadows will likely be a riot of colour, alive for pollinators and drawing admiring glances from the host of park-goers. You will be impressed.
I’m getting ahead of myself, let’s return to my recent visit. In mid-September the less showy side of the meadow operation swings into action, and that’s what I was keen to see.
Now, to establish a wildflower meadow isn’t an exact science. You can plough and sow seed. You can introduce plug plants. You can introduce relaxed mowing regimes, you can cut and lift for a period of time to reduce nutrients, and you can major on using yellow rattle to suppress vigorous grasses. You can even mix and match those approaches. All can work in the right conditions, and they can cost varying sums of money. What Lynne’s team are increasingly doing is using their initial meadows to create their subsequent meadows.
The approach uses green hay.
In a nutshell this involves cutting meadows at the end of the season, before they shed their seed, and using those cuttings (and the seeds they hold) to promote new meadows.
Lynne’s impressive exhibition began naturally enough with Irvine Beach Park’s first meadow and the jewel in the crown. It sits next to the sizable pond and has proved so popular than when I arrived, they were ploughing an additional strip to extend the meadow. The cuttings from the existing meadow would be used to kick start the new meadow extension.
Lynne has a secret weapon when it comes to mowing, gathering, levelling, spreading and ploughing – she works closely with Hamish Gilbert, a supportive local agricultural contractor who is keen help the Trust in nature restoration. His team were in attendance to plough any new areas required, scarify others, and spread the green hay when the ground was prepared. As that suggests he had brought along three tractors and various attachments.
I arrived in time to see Hamish and his colleague, Hayley, a student at SRUC, complete the mowing of the beach meadow, plough the extension strip and then ‘grade’ or level it prior to spreading the green hay. Job done it was on to the delightfully name Dragon Meadows. If you know the park you will know the dragon sculpture that gazes out towards Arran, and to the north of this in the pronounced dip you will find the dragon meadows.
They have been a roaring success. Lying either side of a grass path, one was created on top of a ploughed area and the other was sown into scarified soil. To my untutored eye the previously ploughed meadow seemed marginally stronger, but there was little in it. But such compare and contrast methods are a valuable tool in deciding what approaches work best in the conditions. The cuttings from these meadows were going to be used to bolster the sea view meadow that sits behind the dragon sculpture.
The cutting, stacking and gathering of the green hay from Dragon Meadows was almost like a scene from Strictly Come Dancing as the three tractors deftly swung into action, almost pirouetting as they manoeuvred. You could have set it to music. In no time the muck spreader, which had been cleaned specially for the seed spreading operation, was used to carry out the spreading of the green hay on beach view meadow. Its load of seed rich cuttings carrying a lovely, heady scent of newly mown grass.
Seaview meadow affords wonderful views out to Arran and was only one year old and in need of a little bolstering. As we reached the summit an urban fox scuttled into the nearby bushes.
Prior to adopting this green hay method arisings, or cuttings, would simply have been pushed to one side into an unused scrub area to rot down. The new approach means that good use is made of the arisings.
As Lynne explained it is important to use the cuttings promptly. Left in piles they will heat up and the seeds won’t remain viable. It’s vital to get them spread as quickly as possible.
The final piece of action at Irvine Beach Park was near the two south car park meadows. Dissected by a grass path, they too were due to receive some of the green hay from the dragon meadows.
Content that all was in hand in the Beach Park we headed off to Lawthorn to have a look at the next meadow due to be cut and lifted. However, being adaptable is key to success, and when we reached Lawthorn it was clear that the meadow was still pretty much alive and providing a great food source for pollinators. Sensibly the decision was taken to delay cutting until a later date.
That decision of course revealed one of the discretionary elements you need to apply with this approach. You don’t need a strict timetable, rather you need a discerning eye. You also need fairly dry weather to cut the hay and spread, and the forecast was showing a break in the weather with a few wet days coming in. For Irvine Beach Park this meant that a window of opportunity had presented itself. It’s that kind of judgement that can be interesting and a bit of an unknown in advance.
Watching the cutting and lifting and subsequent spreading of green hay was a fantastic insight into a method that could potentially save money for many would be meadow-makers, and reduce the amount of materials going to waste.
In an era when we are rightly concerned with carbon footprint, costs and partnership working there are many elements of Lynne’s approach in Irvine that are crushingly logical.
Locals certainly appreciate it. When I was watching the cutting exercise in full swing one concerned cyclist approached me to say, “Oh no, you’re not getting rid of the meadow are you”. We were able to send him off content that not only was the meadow staying, but it was also going to breathe new life into other meadows. Impressively inventive thinking in any book.
We are delighted to feature another guest blog today. Rory McLeod works as Development Officer for Glasgow & Clyde Valley Green Network, and leads on the delivery of the grassland and wetland workstreams contained within GCVGN’s Green Network Blueprint.
Introduction
Glasgow & Clyde Valley Green Network (GCVGN) were delighted to recently launch our new Clyde Grasslands initiative that seeks to reverse the decline of grasslands and meadows across the Glasgow City Region. Supporting the launch was a new study, Mapping Species Rich Grassland Networks, which we hope will act as a catalyst for action and a framework for delivery. The work was led by GCVGN on behalf of partners Plantlife Scotland, Butterfly Conservation, Bumblebee Conservation Trust, and funded through NatureScot’s Nature Restoration Fund (NRF) development stream.
The study sought to identify remaining species rich grassland habitat, map their associated dispersal networks, identify opportunity areas for future restoration and expansion, and finally, to map grassland Nature Networks to target future work.
The work was carried out on our behalf by SAC Consulting, and we are now using the study outputs to work with local authority, NGO and utility provider partners to develop a programme of work planned within a framework that will maximise grassland habitat connectivity across our region.
This blog will describe the importance of grasslands in a regional context, the development of the Clyde Grasslands initiative, the methodology and findings from our report, and our future ambitions.
The importance of restoring grasslands in the Glasgow City Region
The pressing need we have to restore species rich grasslands for nature, people and climate will be well known to regular readers of this blog. The wider trend that has seen 97% of species rich grasslands lost in the UK since the 1940s, (Hooftman and Bullock – 2012) has been mirrored within the eight Local Authorities that make up the Glasgow City Region (GCR). This is a diverse area of over 330,000 hectares, that contains both Scotland’s largest continuous urban area, but also significant rural areas of lowland farming and upland sheep grazing. As such, the GCR has been highly vulnerable to changing land uses such as the intensification of agriculture and urban expansion, with only remnants of species rich grassland now remaining.
We have a good understanding of the benefits restoring grassland habitats across our region will bring. For wildlife, it will create habitat for a large number of species, both flora and fauna, including plants, fungi, invertebrates and birds. Pollinators are a particular focus for our project, and with 84% of all EU crops dependent on pollination, (Klein et al., 2007), species rich grasslands are a vital pollinator resource. To focus on just one type of pollinator, butterflies, Butterfly Conservation have advised we could reasonably expect a number of species to benefit and spread in our region as a result of the delivery phase; including three species of Skipper, Small Copper, and Common Blue.
A less known benefit of grasslands until relatively recently has been their capacity to sequester and store carbon. With up to 30% of the earth’s carbon stored in grassland carbon sinks, grasslands are every bit as important as forests and other ecosystems in the fight against greenhouse gases. A recent Plantlife study has sought to deepen our understanding of this relationship, and points to evidence that increased species-richness in grasslands increases carbon sequestration. Whilst soil carbon markets are still emerging, and some research gaps remain to quantify grasslands’ carbon storage and sequestration ability, the potential for grasslands to play a significant role in the City Region’s future drive for Net Zero seems clear.
The need for the Clyde Grasslands study
In 2019 GCVGN published a Green Network Blueprint for Glasgow City Region. At its core was an ambition to restore, enhance and connect habitat networks strategically across the region, with neutral grassland a key habitat type. Habitat or nature networks are critical to ensure grasslands are not created in a piecemeal, ‘opportunistic’ way, but rather as part of a larger coherent network. Ensuring functional connectivity between grassland habitats is critical for pollinator species to be able to move through the landscape to forage, breed, disperse or migrate.
Whilst the Blueprint identified some spatial priorities for neutral grassland, the data was ultimately not comprehensive enough to provide a framework that would allow the targeting of effort to best effect. The Clyde Grasslands study sought to fill this knowledge gap, building on previous analysis and understanding, and providing a robust evidence base to target limited resources for the best outcomes.
Project methodology
The Clyde Grasslands study made three significant changes to our earlier Blueprint methodology: – the types of grassland habitats included; the dispersal distances used to model pollinator movement through the landscape; and the approach to data collation.
The first was to broaden the range of species rich grasslands we considered. Whereas previous studies modelled solely neutral grasslands, we expanded our focus to include the four species rich grassland types identified by NatureScot guidance – acid, neutral, wet, and calcareous.
Secondly, we revisited the dispersal distances used in the GIS based “least cost modelling” which underpins the analysis and outputs. “Least cost modelling” estimates how permeable or impermeable different land cover is for a chosen “focal species” to move through. This creates an “intelligent buffer” or network around habitat patches indicating how far species can move through the landscape, and how connected the networks are.
The Blueprint was based on a 300m dispersal distance for a generic neutral grassland focal species. The Clyde Grasslands Study used two dispersal distances: 300m was used once again to maintain consistency with the original work, but applied to the wider range of grassland types. 300m represents the lower dispersal capabilities of some grassland species such as solitary bee. We also used 800m to reflect wider dispersal capabilities for more mobile species such as the carder bumblebee.
Finally, we took a much wider approach to data collation. The original Blueprint work drew solely on existing habitat records, some of which were 30 years or more old. This time we combined grassland plant and butterfly indicator records from BSBI, Plantlife and Butterfly Conservation, with the habitat data to act as a first line of verification that the grassland still existed, and as a proxy for quality. We then drew upon the wealth of local knowledge that exists across the region, and tested draft outputs for each local authority area with local experts. This identified errors, omissions and provided qualitative information.
For a fuller account of the GIS methodology we would recommend reading the detailed Clyde Grasslands report produced by SAC Consulting for our project, which can be found here
Summary of outputs and findings
The outputs identified over 1,800 habitat patches with strong potential to be species rich grassland. These were typically small, fragmented habitats, with over 67% less than two hectares in size. As expected, larger patches tended to exist in upland areas with less intensive agriculture and development.
The outputs also identified over 400 “opportunity areas” where the targeting of new habitat creation could potentially connect currently fragmented habitat networks. Given our 2019 Blueprint identified 92 neutral grassland opportunities, we were delighted with this outcome! It provides us with a much broader framework from which to develop project work, across a much more diverse range of opportunity types spanning urban, peri-urban, lowland rural and upland rural situations.
However, given the decimation of species rich grasslands in our region post-WWII, unsurprisingly the report also flagged a number of concerns. Habitat patches in our region remain largely small, particularly in urban and per-urban situations, isolated, and fragmented. Habitat networks based on species with higher dispersal abilities were, as expected, better connected, however even these networks were still highly fragmented. This means that species which depend on these habitats remain vulnerable, particularly those with lower dispersal capabilities, and in urban areas where buildings and roads are barriers to movement. This report finding makes an early focus on habitat creation in built up urban/peri urban areas essential, and helped to shape our approach outlined in next steps below.
If there is a primary concern identified in the report, it is the lack of high-quality spatial datasets. Remote sensing techniques are still insufficient to accurately identify grasslands which are trickier than other habitats, such as the tree cover in woodland. This means as technological advances continue to be made, – whether remote sensing, the use of drones, or AI bio-acoustics, ground-truthing in the field remains vital. The difficulties associated with the mapping of species rich grasslands has often meant they have received less consideration in decision-making processes than other habitats, and this continues to make them vulnerable to a wide range of developments today, including tree planting targets!
Next steps… Grassland Nature Networks
As mentioned at the outset, there is a very wide range of land uses in the GCR, and the reality is that some of the opportunities identified in our study will be easier to deliver than others. Rural, privately owned land currently has no obvious mechanism or incentivisation for delivering at scale. We hope the emerging Agriculture and Rural Communities Bill will start to address this.
With council bodies across Scotland tasked to deliver “Nature Networks” under the newNational Planning Framework,we have been working closely with the eight City Region local authorities to produce a regional approach to Nature Networks. This has highlighted the scale of the task they face, and also where some early opportunities lie. Our initial programme of work will therefore focus largely on urban and publicly-owned land, and we are working with local authority partners to explore options on land they either own or manage. This has involved an analysis of our study outputs (habitat networks and opportunity areas) in the context of a range of other data, such as green space, open space audits, golf courses, protected sites, the NHS Estate and utilities, to develop a regional framework for Grassland Nature Networks.
We have been guided in this process by the concept of habitat corridors and ‘stepping stones’, which are one of five key elements of a Nature Network (Lawton, et al. 2010), as well as Buglife’s approach to developing BLines, (3km-wide pollinator corridors mapped across the UK). Our work has focused on what grassland Nature Networks would look like in a more granular, regional context, using the study outputs and local expertise to develop a connectivity framework, based on 600m wide corridors (twice the minimum dispersal distance used in the study). Discussion with local authority colleagues has been key to this work, ensuring the identified Nature Networks are aspirational but realistic. Working at a regional level it is also critical that cross-boundary connections are identified and link up. From this work we are currently developing a suite of potential projects in council-owned greenspaces that would contribute to the identified Grassland Nature Networks.
We hope this approach will form the basis of a future funding bid, while also providing a rationale for public landowners and managers to target their own resources towards delivery on these sites. The scale of the ambition for Clyde Grasslands means that it is a long-term project, however, action is needed now. We intend to drive forward those opportunities most easily deliverable in the short-term, while planning for longer-term opportunities as new delivery mechanisms emerge in the future.
Final thoughts
One area of concern that we feel it is important to highlight is overall delivery capacity, both for GCVGN (two FT members of staff) and also for our local authority partners. The outputs from our study have been enthusiastically received with a high level of engagement, and we also feel confident we will be able to identify an extensive and realistic suite of delivery projects from our analysis. However, with many local authorities significantly depleted in terms of staff resource and expertise, capacity is limited.
Although currently receiving a ring-fenced allocation of NRF funding, we have encountered local authorities with funds to spend but not necessarily the means to spend them. Others have employed private sector contractors to help with delivery work, but report these contractors are becoming oversubscribed from demand. We raise this as a point of concern which could have a significant impact on our collective regional (and national) ability to deliver the Nature Networks we all want to see happen.
Thanks!
We would like to thank our steering group members, Gill Perkins, (Bumblebee Conservation Trust), Phil Sterling & Julie Stubbs, (Butterfly Conservation), and Alistair Whyte, (Plantlife Scotland), for the time they invested to help develop this project.
We are hugely grateful to Dave Lang (NatureScot), Scott Shanks (RSPB Scotland), and Anthony McCluskey (Butterfly Conservation) for their input, and to colleagues in the eight Glasgow City Region local authorities whose generous allocation of their time has been invaluable.
We would also like to thank Dr Lorna Cole and the SAC Consulting team for their technical expertise and enthusiasm.
During the Victorian era, many naturalists pursued bucolic, relaxing subjects that would elevate their standing among peers, yet suitable to be discussed during social soirees. Shocking the ladies with matters of a raw nature was frowned upon. Dr Murray Galt Motter had no such compunction. On learning that 150 corpses from a cemetery in Washington, D.C., were going to be exhumed for reburial somewhere else, the good doctor saw a rare research opportunity. He assembled a team to help him investigate the invertebrate fauna colonising those cadavers. The resulting report (Motter, 1898), comprising species descriptions, and notes on the state of the bodies, soil type, grave depth, etc., became a landmark in the field of forensic science.
Dr Motter’s fauna of the grave contained mostly worms, beetles, bristletails, mites and flies, but one type of creature was predominant: the aptly named coffin flies (family Phoridae). Particular species were not identified in the report, but they were likely to include Megaselia scalaris and Conicera tibialis. These flies feed and breed in decaying organic matter, including human corpses. And C. tibialis has an uncanny ability to find them: gravid females can burrow to a depth of 2 m to reach bodies laid to rest 18 years previously (Martín-Vega et al., 2011).
Coffin flies are just a segment of the family Phoridae. The 4,000 or so described species – the total is believed to be much higher – have a wide range of lifestyles: some are plant feeders (one species is a pest of cultivated mushrooms), others are predators, parasites or parasitoids; the zombie fly parasitises and changes the behaviour of European honey bees (Apis mellifera). Many species are synanthropes (organisms that live in close association with humans and their surroundings); you probably have seen some of them near drain pipes, compost piles or rubbish bins. Phorids look like fruit flies with arched backs, and when spooked they run away before taking flight. Such behaviours explain their other common names: hump-backed flies or scuttle flies.
Phorids have the greatest ecological diversity of all fly families, but most species share one characteristic – their larvae feed on decaying organic matter: dung, carrion, dead plants – and human corpses, if available. This behaviour may be off-putting to us, but if plants manage to take advantage of it, they will have an assortment of diligent and resourceful visitors at their disposal, which could be quite handy for pollination services. And that’s exactly what some birthworts, aka pipevines and Dutchman’s pipes (Aristolochia spp.), have done.
Aristolochia is a varied group of about 450 species of shrubs, herbs, vines and lianas from predominately tropical areas. Most species have remarkable adaptations to lure the smallest flies (micromyiophily), or flies that are attracted to dead animals or dung (sapromyiophily). Their flowers are usually large and showy with a spherical base that forms a chamber known as a kettle trap, which allows visitors to get in easily, but entraps them until the following day (Arums have similar contraptions). When insects finally manage to leave, chances are they will have pollen grains attached to their bodies.
Birthworts dupe their unsuspecting pollinators with scents, and since flies are their target, typical flowery smells won’t do. Different birthwort species produce a range of bouquets that remind us of carrion, rotten fish, dung, sweat, cheese, yeast fermentation or decomposing plants. These aromas are irresistible to many insects, but only phorids, blow flies (Calliphoridae), midges (Ceratopogonidae), gnats (Mycetophilidae, Sciaridae), fruit flies (Drosophilidae) and frit flies (Chloropidae) are known to pollinate the flowers. Among this lot, Megaselia coffin flies are particularly well represented.
With nearly 1,700 described species (about 300 of them in the British Isles), and certainly a much larger number to be discovered, Megaselia is one of the largest genera in the animal kingdom. Like the other members of the family, they range from parasites, parasitoids, predators and fungus feeders to saprophages (organisms that eat decomposing organic matter). Several birthwort species take advantage of these omnipresent flies by producing scents loaded with oligosulphides, which are the main volatiles released by decomposing flesh.
Besides birthworts, Megaselia flies are known to pollinate some orchids and a handful of other plants, but this meagre list of hosts is more likely to reflect our ignorance than their true contribution to pollination; the same can be said about flies in general (Raguso, 2020). Flies are not the most glamorous insects, and their reputation is not helped by their involvement with unsavoury business such as decomposition. But we need to keep in mind that recycling of nutrients and organic matter depends on these filth-muckers. They are also important for plant reproduction, even though we have only an inkling about their workings. We may not pick a fly as our favourite animal, but it would be unwise to ignore their value for biodiversity and the functioning of ecosystems.
Yarrow is an understandably popular with pollinators. The densely-packed five-petaled flowers create ideal landing pads to easily access pollen and nectar, and the plant enjoys a long flowering period. Delicate looking, yet undeniably robust, yarrow is a mainstay of many grasslands and gardens.
One of those plants that comes in many varieties, yarrow also boast many common names. Amongst them are Doggie’s brose, old man’s pepper, devil’s nettle, staunchweed, and soldier’s woundwort.
The latter is telling, for yarrow was long used as a wound-healer. It was used widely for this purpose because the stems and leaves apparently have, amongst other things, coagulant properties. It is not surprising therefore to learn that it was used on battlefield injuries, so it was also known as herba militaris.
In 1753 Linnaeus, the father of modern taxonomy, gave yarrow its binomial scientific name Achillea millefolium. The first part of the name is a link to the Greek warrior Achilles, who was said to be made immortal by virtue of being dipped in the River Styx. Alas he was held by his heel whilst being submerged, thus his heel wasn’t in contact with the water. This was his vulnerable spot, and the story goes that he was killed by Paris whose arrow struck Achilles’ heel. The second part of the name refers to “thousand-leaf”, one of yarrow’s common names.
Cultivated varieties of yarrow are garden favourites that come in all sorts of colours, heights, and hues. Yellow and pink are amongst the more striking, but some gardeners plant it for the feathery leaves, which have a distinctive aroma. Others are drawn to the fact that it self-seeds quite well and spreads readily.
Taller yarrow varieties are often associated with damp areas and woodland, whereas shorter versions tend to be found along the coast or on higher ground. Starlings are apparently known to have used yarrow in their nest-building according to some studies, drawn perhaps by that distinctive aroma mentioned earlier, potentially tapping into the plant’s medicinal values, keeping the nests fresh (particularly as many nests are re-used) and deterring parasites. In the past, Scots also liked the fresh quality of green shoots of yarrow, chewing yarrow to freshen their breath.
Let’s end with a Gaelic link, for yarrow was once used to determine if a romantic relationship had any substance. Placed under a pillow, it was believed to induce a dream that would reveal if a relationship was blooming or doomed. For pollinators there is no such question. From what I see they are thoroughly in love with yarrow.
Cities matter for people and pollinators. Currently around 60% of the world population is living in cities, a figure likely to climb to 70% by 2050. We know too that urban areas can be a major refuge for many insect pollinators. In gardens, parks and greenspaces our pollinators find forage and nesting sites, often in a greater scale and variety than can be found in agricultural areas where intensive farming, pesticide use, and habitat fragmentation are issues of concern.
Jonathan Sorel is advisor to the mayor of Paris on public space, transport and nature in the city, and at a recent Euro Cities conference revealed a string of actions taking place designed to help pollinators and biodiversity in general across this most glamorous of cities.
As you can imagine there is, from time to time, tension around how to use public space in such a densely populated setting. How best to balance all the urban functions expected of a modern greenspace? On the one hand, when the weather it good, people want to go out into these spaces to relax, play and enjoy nature, on the other the city is working to protect nature year round. This is a delicate balancing act for the iconic capital’s team of gardeners and professionals.
There can be intense pressure on Paris’ green spaces in the summer
Despite those challenges, increasingly Paris can be seen as a pollinator friendly city. Fortunately, the city enjoys a legacy of green space appreciation that stretches back to the 19th century. This was the period when Haussmann renovated Paris by changing the heart of the city to adapt to the damage visited by overcrowding and rapid urbanisation. Around this time the look and arguably purpose of the city altered dramatically, and nature (in the shape of parks and gardens) was introduced in a massive way throughout central Paris. The dramatic transformation created big parks and tree lined boulevards. It’s a strong biodiversity legacy and a great ‘skeleton’ to build on.
Today Jonathan is quick to tell listeners that Paris has an impressive variety of insects and boasts a range of butterflies, moths, wasps, hornet, bumblebees, and dragonflies. However, there is a desire to do more for bees in particular. Last year a study was commissioned to look more closely at pollinators in Paris and compare the suitability of certain plants for pollinators and their relative success in several areas of the city as against in the surrounding countryside.
The report noted a rich pollinator network in the city, but conceded that this included fewer ground-nesting bees, solitary bees and specialised feeders, and more social and generalist bees. There was also an acknowledgement that whilst honeybees are part of the city biodiversity, there were too many and this was placing a strain on wild pollinators when it came to sourcing food.
Paris has decreed that no more new bee hives are approved, as there is a drive to stabilise the number of hives. It is reckoned somewhere in the region of 2,500 hives are in the capital. Another interesting finding of the report was that the window for efficient pollinator activity was found to be longer in the urban environment, and that pollinator activity was found to be more effective and efficient than in the nearby countryside.
To keep the city’s pollinator goals well informed Paris has a dedicated team of ecologists and is home to a relatively new biodiversity observatory. It cherishes its strong links with academics and publishes a detailed nature survey every decade.
Never a city to rest on its laurels, there are big changes in how Paris manages its greenspaces. In the last two decades there has been a swing to managing things differently. The city banned the use of chemicals in its public gardens in 2001 – which was a big change for the 2,000 gardeners it employs. In turn it brought a gradual change in the public perception of chemical use. The last public area to be dramatically altered in this way was in the city’s cemeteries which have gradually changed to accommodate nature. To begin with Parisians were a bit surprised by this development and asked why this was happening. Some even felt it was a bit disrespectful to allow wildflowers to flourish in graveyards. Today, however, the evidence suggests that more and more people appreciate the different look, they enjoy the relaxed atmosphere, and the splash of colour which helps nature.
Partnership working so often lies at the heart of successful urban transformation, and it is no different in Paris. Working with NGO’s and leading environmental charities the council has helped develop areas where nature has strong local protection. There has been a welcome increase in gardens and parks in the city since 2001 and a surge in the creation of greening spaces including converting disused rail routes into wildlife havens.
The work of citizen scientists is important in the Paris work. More and more inventories, or surveys, are being carried out by local groups. Simultaneously community growing areas and small plots containing ‘pavement’ trees are proving increasingly popular. Paris has 150 community gardens and stipulates that owners should not use chemical treatments. The small street plots containing fruit tree areas are a strong community asset when a local group takes ownership and they have the option to plant local and native wildflower seeds provided by the council in the understorey which is clearly good for insects. There are now around 2,000 of these plots in Paris.
One issue that has tested the Paris team is how to integrate biodiversity and climate plans. Initially not all Parisian climate change policies considered biodiversity. A famous example arose concerning the collapse of the city house sparrow population. When Paris developed a policy to renovated buildings to reduce carbon and household bills, they didn’t consider biodiversity. As a result, the renovations contributed to a 70% drop in the sparrow population over 20 years. The loss of nesting sites in renovated properties lay at the root of the problem. That’s an example of how the two issues weren’t taking account of each other. Now it is unthinkable for one stream of work not to factor in the other.
Increasingly Paris looks to use nature as a weapon to tackle climate change. For example, Paris is taking back hard space dedicated to cars. It is estimated that almost 50% of the city was dedicated to car use in the last century, so moves are underway to supress parking lots, and instead plant trees and flower areas.
Paris will try to transform from being ‘a city with gardens’, to ‘a garden city’ where nature is all around. In front of schools there is a Paris policy to close 300 roads, and in those streets, concrete and tar will be replaced with vegetation. The aim is that youngsters swill be able to play without cars being around and this ‘green revolution’ will in turn will help nature.
The mindset in the French capital is changing rapidly. Their previous Urban Master Plan was very much focussed on construction. Now the world has changed, and the new plan has nature at its very heart. Trees, biodiversity, green roofs – these are the new drivers. A new Climate Plan will emphasise tree planting as a major tool in tackling climate change. This has to be pragmatic, for whilst the focus is on native trees there is an acceptance that some trees which are not necessarily native can in certain circumstances be the strongest and most resilient against climate change. An index of the best trees to plant in each situation lies at the heart of advice.
Finally, Jonathan spoke about a policy to support night pollinators. Previously policies around street lighting focused on energy conservation, on LED lamps and changing to new bulbs Now consideration is given to the biodiversity situation and the team will cross reference their nature maps with their dark maps to try and reduce lighting or change the lighting colour in a bid to help moths and other night pollinators.
When we think of Paris we might think of the Eiffel Tower, Notre-Dame, the Arc de Triomphe, the River Seine … in years to come we might also include the green corridors and nature networks which run through this famous old European capital.
Scientific reports can be dull and impenetrable, but that’s not the case for the 1878 ethno-botanical account from Madagascar by a Dr Carle Liche. The explorer spoke of a ceremony performed by Malagasy tribesman where a young woman was forced to climb a sacred tree, and he detailed what happened next: “Suddenly I realized what was happening, and I seemed to be paralyzed with horror. The tree, seemingly so dead and motionless a moment before, had come to life. The palpi, so frail looking, had suddenly ceased to quiver, and had coiled themselves about the girl’s head and shoulders, holding her so firmly that all her efforts to free herself remained absolutely useless. The green branches so rigid before began to writhe, and coiled themselves round and round like snakes. Then as that mass struggled there arose a horrible sight I shall never forget the great leaves began to rise slowly, very slowly. Those evil looking thorns were now closing on her with the force of a hydraulic press. As they came together tightly there trickled down the trunk a pinkish mixture, which the maddened natives fought and trod each other down to get one mouthful of the intoxicating fluid from the tree and the blood of the human sacrifice”. You can read Dr Liche’s full story and other terrifying botanical tales in Prior (1939).
Stories about killer plants have a long tradition, but picked up momentum during Victorian times with the widely circulated spiel about the upa tree (Antiaris toxicaria) from Java. According to a Dutch surgeon named Foersch, the upa tree releases poisonous fumes potent enough to leave the ground covered with skeletons of birds, mammals and people within a 20-km radius. This tosh fired up the public imagination, and authors such as Charles Dickens, Thomas Carlyle and Charlotte Brontë began using the word ‘upa’ as a metaphor for a person or thing with a poisonous, destructive atmosphere (Price, 2013).
Victorian tales about evils of the plant kingdom relied heavily on personal accounts from faraway places, where the likes of Dr Liche and surgeon Foersch could have been influenced by attention-seeking tendencies or over-indulgence in mind-altering substances under the tropical sun. But back home, their countrymen could satisfy their curiosity and fascination and get the facts straight from an easily accessible killer flora: carnivorous plants. That’s exactly what Charles Darwin did for 16 years in his glasshouse: his research and observations resulted in the 1875 book Insectivorous Plants. In a letter to Asa Gray, Darwin wouldn’t contain his awe towards his favourite carnivorous plant, the common sundew (Drosera rotundifolia): ‘I care more for Drosera than the origin of species … it is a wonderful plant, or rather a most sagacious animal. I will stick up for Drosera to the day of my death.’ (Jones, 1923).
The common sundew is one of the approximately 630 plant species around the world that attract, trap and consume animals – generally insects and other invertebrates, but occasionally small vertebrates. Most carnivorous plants produce enzymes that digest their prey, but for some species the job is done by symbiotic bacteria. Plant carnivory has evolved independently several times, and species from about 13 families have come up with elaborate stratagems and structures to lure and catch their quarry such as nectar-scented volatiles, colour mimicry, slippery pitchers, sticky appendages, and snap traps – watch the exploits of the Venus flytrap (Dionaea muscipula), a species from the coastal bogs of North and South Carolina in the United States.
Carnivorous plants are usually found in nutrient-poor habitats, so they rely mostly on insect prey to supplement their required nitrogen and other nutrients. But these plants also need insects for their pollination. This dilemma, known as the pollinator–prey conflict, is circumvented in a variety of ways. For some species, morphological features keep food and pollinators apart: their flowers are high above ground to attract flying pollinators while their traps are close to the ground to catch other insects as prey. Separation could be temporal: for some species, flowers and traps develop at different times.
Some carnivorous plants resort to clever trickery to sort out the pollinator–prey conflict. Tropical pitchers or monkey cups (Nepenthes spp.) capture mostly ants that slip while walking on a wet peristome (the ring surrounding the entrance of the trap) and fall to their deaths. But most potential pollinators of tropical pitchers such as flies, moths and wasps are active in dry weather, when the peristome is not slippery and almost no insects are captured (Mithöfer, 2022).
The judicial use of attractants is another mechanism of differentiation, as El-Sayed etal. (2016) demonstrated for fly-pollinated sundew species from Australia and New Zealand. For D. auriculata (D. peltata for some authors), flowers are adjacent to traps, but both structures release different odours. As a result, flowers attract pollinators and prey, while traps attract only prey. There are no attracting scents for D. spatulata and D. arcturi, but flowers and traps for these two plants have different colours and are spatially separated: the combination of these two factors discriminates pollinators from prey.
The strategies employed by carnivorous plants to avoid the pollinator–prey conflict seem to work very well because almost no species show a substantial overlap of prey and pollinators. This was demonstrated by Youngsteadt et al. (2018) for the Venus flytrap, one of the better known carnivorous species. The researchers captured insects found on flowers at several sites during the blooming period and checked whether they were carrying Venus flytrap pollen. They also searched traps for their catches. The result: prey items consisted mostly of spiders, ants and beetles, while the sweat bee Augochlorella gratiosa and the checkered beetle Trichodes apivorus, which were the main pollen carriers, together with other potential pollinators, were hardly ever found in the traps.
All these contrivances employed by carnivorous plants to attract and snare their prey, at the same time protecting their insect pollinators, make up one of the most alluring file cases to demonstrate the power of natural selection. It’s not surprising that Darwin was captivated (his son Francis inherited dad’s enthusiasm, doing his own research of plant carnivory). Carnivorous plants offer much more interesting stories than man-eating trees.
When I was younger, so much younger than today … I used to think knapweed was a thistle. The march of time has taught me otherwise. They might look vaguely similar, but they are quite different. Grasp a prickly thistle and you will see, and likely feel, what I mean.Nevertheless, I still regularly mis-identify plants.
Common knapweed often catches my eye due the number of pollinators it attracts. I no longer feel too bad about misidentifying it in my youth. The Wildlife Trust website has been a source of comfort, describing it thus “The tightly packed, thistle-like purple flower heads of common knapweed bloom on all kinds of grasslands. Also regularly called ‘black knapweed, this plant attracts clouds of butterflies.”
When talking about wildflower-rich grasslands the Bumblebee Conservation Trust website understandably majors on the value for bees and says of knapweed that it is an important nectar source. Knapweed flowers are easy for bumblebees and other pollinators to land on. The cushion like flowers offer a platform that is easily accessible. It’s a great plant to linger around if you want to photograph or sketch bees.
Knapweed is also a sturdy plant and the rigid stems can support the weight of the flower head when visited by a larger bumblebee. I love the simple clarity of the reference in one of my all-time favourite books ‘A Sting in the Tale’ by Dave Goulson, where he talks of males in the mating season … “They sit around flowers drinking nectar; they prefer flowers with big, sturdy heads such as thistles and knapweeds”
The National Botanic Garden of Wales carried out a study into the foraging habits of insects. Dr Abigail Lowe, Botanical and Invertebrate Researcher examined the pollen found on hundreds of hoverflies, honeybees, bumblebees, and solitary bees collected between March and September over two years, amongst her conclusions was the fact that ‘bees particularly like knapweeds’.
Greater knapweed (Image courtesy and copyright of Margaret Miller)
The name knapweed is perhaps unfortunate, it isn’t inspiring, but it’s a plant that comes in various forms. The UK Pollinator Monitoring Scheme recognises this and not only has knapweed as one of its target flowers, but sensibly suggests that citizen scientists needn’t distinguish between common and greater knapweeds, Centaurea nigra and Centaurea scabiosa . For most of us in Scotland we will come across common knapweed which is found in meadows and pastures, on sea-cliffs, along roadsides and railway embankments and of course on waste ground and field borders. You are not likely to come across its showier cousin, greater knapweed, in Scotland since it has a liking for calcareous soils. On the north coast, where greater knapweed does occur, it is sometimes visited by the magnificent great yellow bumblebee.
The great countryside poet John Clare refers to knapweed in his ‘May’ poem:
They pull the little blossom threads From out the knapweeds button heads
The pinky, purple flowers of common knapweed are also striking, as are the knobbly brown ‘doorknobs’ that sit beneath the flower petals. These give knapweed one of its alternative names – ‘hardheads’. But whatever you call it, the impact of this unassuming little flower for pollinators is substantial, just like those hard heads.
Scottish pollinators 