Category Archives: Pollinators

A new review gives us a deeper understanding of the evolution of plant-pollinator interactions

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If you’ve read my book Birds & Flowers: An Intimate 50 Million Year Relationship, you’ll know that I spend a few pages discussing the long-standing paradigm of how interactions between plants and their pollinators evolve and result in the formation of new plant species. This is referred to as the Stebbins (or Grant-Stebbins) Most Effective Pollinator Principle (MEPP). The MEPP is fairly straightforward and intuitive: flowers evolve their colour, shape, scent, rewards, and so forth as adaptations to the type of flower visitor that successfully moves the most pollen between flowers.

However, the MEPP is not the only Principle in town – there’s also Aigner’s Least Effective Pollinator Principle (LEPP) which is not so intuitive. In the LEPP, flowers can adapt to pollinators that are less successful at pollination, as long as those adaptations do no interfere with the pollination services provided by other flower visitors.

As I note in Birds & Flowers, we don’t know which of these Principles is more frequent in nature, because the LEPP has been much less intensively studied than the MEPP. That’s in part because it’s less well known, but also because the field work and experimental procedures required to test the LEPP are much more challenging.

Hopefully this is about to change with the publication of a brilliant critical review of the MEPP by pollination ecologists Kathleen Kay and Bruce Anderson published in the journal Annals of Botany, entitled: Beyond the Grant–Stebbins model: floral adaptive landscapes and plant speciation. The paper is open access – follow that link and you can download a copy.

Kathleen and Bruce discuss not just the MEPP v the LEPP, but also other ways in which flowers can evolve, framed around the idea of floral evolution as movement across an “adaptive landscape,” where plants are not shaped only by one pollinator but by the need to maximise overall reproductive success. This perspective allows us to explore how flowers evolve when influenced by multiple pollinators, how transitions between floral forms take place, and how speciation occurs through a combination of factors beyond pollination alone. It emphasises that pollinators are important drivers of floral change, but speciation is more likely when divergence happens across several aspects of a plant’s ecology, not just through its flowers.

It’s a great review and well worth your time reading in detail. Perhaps my favourite line in the paper comes from the abstract: “The Grant–Stebbins model, while inspiring decades of empirical studies, is a caricature of pollinator-driven speciation and explains only a limited range of adaptive outcomes.” This is something that many of us have been arguing for years: the natural world is extremely complex, so we should not expect these ecologically critical interactions between flowers and their pollinators to have simple origins or ecologies.

Join me for a “Birds & Flowers” talk in Cambridge on the 12th September!

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If you are in or around Cambridge next week, I’m giving a talk on Friday 12th September at the Cambridgeshire Bird Club about my recent book Birds & Flowers: An Intimate 50 Million Year Relationship.

The event takes place in the Wilkinson Room, St. John’s Church, Hills Road. Doors open at 7pm and the talk begins at 7.30pm. There’s a £2.00 charge for non-members – more details can be found by following this link.

I’ll bring copies of both Birds & Flowers and Pollinators & Pollination: Nature and Society, if anyone wants to buy a signed book.

I hope to see you there!

Flowers, feathers and time: a new study of the temporal dynamics of plant-hummingbird interactions just published

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What happens when you spend an entire year watching hummingbirds and the plants they visit in one of Brazil’s most unique ecosystems? You begin to unravel the complex, ever-changing relationships that tie together birds, flowers, and the environment they share.

In a new study jointly led by Steffani Queiroz and Marsal Amorim — and part of my ongoing collaboration with a brilliant team of Brazilian hummingbird researchers — we explored how plant–pollinator interactions shift over time in the Campo Rupestre, a montane tropical ecosystem rich in biodiversity and endemic species. Despite the region’s relatively stable climate, we found that the relationships between hummingbirds and flowers are anything but static.

Over the course of 624 hours of observation spread across a full year, we recorded over 9,000 hummingbird visits involving nine bird species and 47 plant species. Many of these plants — and one of the most frequent visitors, the stunning Hyacinth Visorbearer (Augastes scutatus) — are found nowhere else on Earth.

Our goal was to understand how the structure of this ecological network — which plants interact with which hummingbirds, and how often — changes over time, and what drives those changes. Are they shaped by morphological fit (the match between beak and flower shape)? By phenology (when plants bloom)? By nectar characteristics such as the amount produced and its sugar concentration?

What we discovered is that different factors dominate in different seasons. During the rainy season, when hummingbirds are more abundant, interactions were shaped mostly by morphological matching — suggesting that competition leads to greater niche partitioning. In contrast, during the dry season, the network became sparser and was more influenced by nectar sugar content and flowering patterns.

Interestingly, while the overall annual network wasn’t especially nested (a common pattern in mutualistic networks), it was highly modular — meaning that it contained distinct clusters of species that mostly interacted among themselves. This structure changed significantly across months, highlighting the dynamic nature of tropical plant-pollinator interactions, even in environments with relatively little climate variation.

This work highlights the importance of long-term, fine-scale studies in uncovering how interactions among species shift through time. It also underscores the remarkable biodiversity and ecological complexity of the Campo Rupestre — and the need to understand and protect it.

Here’s the reference – if anyone wants a copy, drop me a message via my Contact page:

Queiroz, S.N.P., Amorim, M.D., Lopes, S.A., Vizentin-Bugoni, J., Jorge, L.R., Ollerton, J., Santos, T. & Rech, A.R. (2025) Temporal dynamics of a Neotropical plant-hummingbird interaction network. Austral Ecology 50:e70089

And here’s the full abstract:

Species interaction networks are expected to vary following temporal changes in the environment and the composition of the local community. However, there are still gaps in our knowledge about temporal variation in networks in tropical areas, where less variable climates are expected to produce more stable community structures over time. Here we describe a plant-hummingbird network in the Brazilian Campo Rupestre ecosystem and investigate multiscale temporal variation of interactions in this community as well as the possible mechanisms underlying the frequencies of species interactions. Plants visited by hummingbirds were observed monthly for a year and each species had morphology, phenology and nectar traits measured. During 624 h of observation we recorded nine hummingbird species visiting 47 plant species, amounting to 9015 visits to flowers. Most plants (28 species) were endemic to the Campo Rupestre and mostly visited by the also endemic hummingbird Augastes scutatus (the Hyacinth Visorbearer). The annual network was not nested but presented high modularity and intermediate specialisation. While the overall (annual) frequencies of interaction were primarily defined by morphological matching and phenological overlap, we found a remarkable temporal change in community structure over the year, with different processes underlying interactions among plants and hummingbirds at different seasons. The interaction pattern during the rainy season was more similar to the annual network than the dry season (when nectar sugar content and plant phenology were also important), with more links per species and lower specialisation. The higher importance of morphology to predict interactions during the rainy season suggests higher niche partitioning when more hummingbird species are present in the community. Our results exemplify the importance of considering the temporal dynamics of the community to advance the understanding of the processes defining species interactions over time in the tropics.

My sincere thanks to Sinzinando Albuquerque-Lima for the photograph, which was taken in the Amazon, not where the research described above was conducted.

A new study examines why data quality matters in plant–pollinator databases

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Imagine trying to put together a giant puzzle where each piece represents an interaction between a flower and the insect, bird, bat or other animal that helps it reproduce. In recent years, scientists have gathered millions of these “puzzle pieces” into massive online databases, offering an unprecedented view of how plants and their pollinators connect around the world.

But there’s a catch: not every entry in these databases is equally reliable. Did the researcher actually watch the insect brush pollen against the flower’s stigma? Or did they simply note that the insect visited the blossom and assume pollination happened? Without clues about how each plant–pollinator link was documented, users can’t tell solid evidence from a best guess.

That’s why a growing number of projects are now tagging every interaction with a “data quality badge”—a short note explaining the exact kind of proof behind the record. For example:

  • Direct observation: A scientist observed an animal pollinating a specific flower.
  • Pollen analysis: Pollen grains matching that flower were found on the insect’s body.
  • Inferred pollinator: The animal regularly visits those flowers and shares similar traits with known pollinators.

Initiatives like the Pollinators of Apocynaceae Database and the Database of Pollinator Interactions (DoPI) have already adopted these quality flags. The upcoming USDA-NRCS PLANTS database is doing the same, and Brazil’s REBIPP network has developed a standardized set of terms—rooted in the global Darwin Core standard—to make sure everyone speaks the same “pollinator language.”

Why is this important? When you know the strength of the evidence behind each plant–pollinator link, you can:

  • Fill in real knowledge gaps with confidence.
  • Identify weak spots in our understanding that need more fieldwork.
  • Build better conservation plans, targeting the most critical pollinators for at-risk plants.

Ultimately, adding clear data-quality labels turns these massive collections of observations into powerful tools for science, restoration, and education. And that’s good news not only for researchers, but for every garden, farm, and wild ecosystem that depends on diverse and abundant pollinator communities.

These issues are explored in a new, open-access paper written by colleagues from Brazil, the USA and myself. In the paper we discuss the importance of data quality in plant-pollinator databases and suggest methodologies for improving it. Here’s the reference with a link to the paper:

Ollerton, J., Taliga, C., Salim, J.A., Poelen, J.H., & Drucker, D.P. (2025) Incorporating measures of data quality into plant-pollinator databases. Journal of Pollination Ecology 38: 151-160

This paper is a direct output from the EU-funded WorldFAIR Project in which I was involved, though we also acknowledge the SURPASS2 project as a precursor to this. Looking ahead, we’re also going to be adopting the recommendations from our paper in the new Butterfly Project (also EU-funded). Finally, by way of a teaser, I can tell you that our new paper will also be relevant to another large project in which I’m involved, that has successfully secured funding…but you’ll have to wait until later in the year to hear about that!

Thanks to Chris Taliga for the photo.

A new study shows how garden flowers keep city pollinators flying all year round

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When we think of cities, gardens might not be the first thing that comes to mind. But these green patches — whether in private yards, parks, or balconies — play a surprisingly important role in supporting urban wildlife. Among their most crucial guests? Pollinators like bees, butterflies, and even birds and bats.

In a new study just published, I teamed up with some Brazilian colleagues to explore how the different features of garden flowers help sustain pollinators throughout the year in a subtropical urban garden. While we’ve long known that garden flowers provide food for pollinators, what’s less clear is how specific floral traits — like shape, flowering time, and type of nectar or pollen — influence who visits which plants and when.

To get a clearer picture, we conducted weekly surveys of pollinators visiting garden flowers over the course of a year. We paid close attention to traits such as the depth of flower, the kind of resources offered (nectar vs. pollen), how closely related different plants were, and when they flowered.

What we found was striking: the network of interactions between flowers and pollinators was highly organized. Plants grouped into clusters, or “modules,” that tended to share similar physical traits and evolutionary histories — but interestingly, not the same flowering times. This meant that within each module, different plants flowered at different times of year, effectively staggering their blooms so that there was always something on offer for pollinators.

Even more intriguing was the discovery that most plants had just a few connections in the network, usually restricted to a single module. These “peripheral” plants accounted for over 85% of all pollinator visits. Meanwhile, a few special species acted as bridges between modules — their role in linking different parts of the network made them key to its stability. These connector species didn’t flower at the same time, which helped to maintain a steady supply of food for pollinators across seasons.

Not all interactions between plants and pollinators are “legitimate” in the sense of leading to pollination. Some animals visit flowers just for the food, without helping with reproduction. But our study found that these interactions still played a valuable role in supporting a diverse pollinator community.

So what does all this mean for urban gardeners and city planners?

First, it highlights how important it is to plant a variety of flowers that bloom at different times of year. Second, it shows that even seemingly minor plants or interactions can contribute to the ecological resilience of urban green spaces. And finally, it underscores that thoughtful planting — considering things like flower shape, blooming schedules, and diversity — can help keep pollinators thriving, even in the heart of the city.

Urban gardens aren’t just pretty — they’re powerful allies in the fight to support biodiversity.

The study was led by Brazilian research student Luis de Sousa Perugini. Here’s the reference with a link to the paper:

de Sousa Perugini, L.G., Jorge, L.R., Ollerton, J., Milaneze‑Gutierre, M.A. & Rech, A.R. (2025) High modularity of plant-pollinator interactions in an urban garden is driven by phenological continuity and flower morphology. Urban Ecosystems 28, 126

Here’s the abstract:

Garden flowers play a vital role in urban environments, supporting pollinator communities. Yet, the extent to which floral traits shape urban pollination networks remains poorly understood. This study investigated how garden plants shape year-round pollination networks, sampled in weekly surveys in an urban subtropical garden. We focused on the role of floral morphology (corolla depth), type of resource, relatedness, and phenology in the organization of interactions. We determined whether modularity and species roles were influenced by these floral traits, comparing if legitimate pollination, illegitimate (i.e. non-pollinating) interactions and all interactions had similar drivers. All networks were modular, and in the overall network plants within the same module were morphologically and phylogenetically similar while their phenology was significantly overdispersed throughout the year. Peripheral species, those with few interactions and restricted to a single module, dominated all networks, representing over 85% of interactions. We found that phenology was related to the species role of overall network connectors (species that connect modules) and legitimate module hubs (species that connect their own modules). Both showed no overlap in their flowering periods, providing floral resources at different times of the year. Each module functioned as a distinct unit, showing year-round availability of resources to support its pollinators. This suggests that resource continuity and trait-based filtering may shape pollinator assemblages influencing ecological resilience in urban habitats. Even interactions that do not contribute to plant reproduction can sustain a diverse fauna, highlighting the importance of these interactions in urban green space planning and management.

Have we passed “peak honey bee” in Britain? An update of hive numbers for World Bee Day 2025

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Since publishing what I believe are the most comprehensive data on the number of honey bee hives in Britain in my book Pollinators & Pollination: Nature and Society, I’ve posted occasional updates on my blog as more recent data become available. I believe that the last of these was in 2022 – see Have honey bees declined in Britain? An update of the numbers – so it feels like it’s time for another. And what’s more appropriate than to post this on World Bee Day 2025?!

Rather than the complex, multi-coloured graph that I’ve produced in the past, I’ve decided to streamline the presentation and simply fit a smoothed LOESS line with a 95% confidence ribbon to the (sometimes contradictory) data points, in order to show the overall trend (see the graph above). If you compare it with the 2022 update you’ll see that the general message from the data is the same: a peak in numbers of hives in the late 1940s (which may or may not be an artefact*), then a steep decline into the 1970s and 1980s, followed by recovery from the 1990s onwards. Note that I’ve removed the two very early data points because I don’t think that they are at all accurate.

The most recent data (2015 to 2024) come from the National Bee Unit which relies on beekeepers to submit their own records, but are probably no less accurate than some of the other data that’s available! If we take a close look at that time period we see something interesting – honey bee hive numbers are decreasing:

What are we to make of this? In an analogy with peak oil, why do we seem to have passed ‘peak honey bee’? If this is a real pattern (and only time will tell) I suspect that it’s because of at least two factors. The first is that interest in beekeeping reached a peak in the early 2020s, after which some initial enthusiasts discovered that beekeeping is actually quite a technical and demanding hobby, and gave it up. The second factor is that word has spread that, globally, managed Western honey bees are not declining, and too many bee hives in an area can have negative impacts on other, wild pollinators. This may have convinced those people who were persuaded by “Save the Bee” campaigns to take up the hobby, to give up beekeeping.

There could well be other reasons that I’ve not considered and, as always, I’d be interested in your thoughts – please leave a comment below. I’ll finish by saying that I make no judgement on this. There’s no doubt that there are too many hives in some parts of Britain, especially in London, and if the trend I describe reduces the pressures on wild pollinators, that’s a good thing. At the same time, honey bees are important agricultural pollinators in some circumstances, especially where there’s mass-flowering crops that require huge numbers of pollinating bees to be available over a short time period. And I like honey as much as the next person.

Happy World Bee Day to my readers!

*There’s a long-standing suggestion that beekeepers in the post-war years inflated the number of hives that they kept in order to obtain a larger sugar ration.

Mindful Mow May!

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As April comes to a close, many people with gardens will be considering having a No Mow May in which, to quote Plantlife (who have trademarked the phrase!), you ‘pack away the lawnmower, let wildflowers grow freely and help nature’. On the face of it this is a positive thing and (hopefully) it gets people thinking a bit more about the impact of gardening practices on wildlife. However, I do worry that its message is too simplistic, as I’ll explain in the rest of this post. Let me say at the outset that I’m using the word ‘mindful’ in its sense of ‘paying attention to’, rather than in relation to mental health mindfulness. Though there are certainly connections between lawns and both meanings of this word, for example mindfully watching pollinators in your garden.

I’ve previously written about the garden that Karin and I developed in Northampton, including a ‘defence’ of its lawn. During the lockdown spring and summer of 2020, when I coordinated a loose consortium of scientists to collect standardised data on the flowers and pollinators in their own garden, our lawn was one of the areas that I surveyed. In that year, as every year, we had no intention of not mowing the lawn, but of mowing it in a mindful way that left some flowering patches of the main nectar sources: Dandelion (Taraxacum officinale), White Clover (Trifolium repens), and Daisy (Bellis perennis). It also allowed a patch of Common Ragwort (Jacobaea vulgaris), and the Cinnabar Moths (Tyria jacobaeae) that depend on it, to come back year after year.

In the graph below you can see the nectar production of dandelions, clovers and daisies over the course of the late spring to late summer. For each species, I have multiplied the number of flower heads I counted by the average amount of nectar sugar per flower head from the data collected by the Agriland project. Clover produces 48.97 micrograms of sugar per day, by far the highest amount of the three. Daisy produces the least, just 0.84 micrograms, and dandelion is in the middle with 22.57 micrograms.

Because these species vary in their peak flowering, there’s a continuous supply of nectar in the lawn over this time period and mowing does impact the immediate availability of nectar. Using green shading, I’ve marked the two days when I know for certain the lawn was mown and you can see that there’s an immediate drop in the nectar. Here you can also seen that both dandelions and daisies re-flower quite soon afterwards – it’s not a permanent effect by any means. The same is probably true of clover later in the season, but unfortunately I didn’t record the exact mowing dates.

The important thing to appreciate here is that without mowing, these three species would probably disappear from the lawn because all require that grasses are suppressed in order for them to flourish. Not only that, but most ground-nesting bee species need either very short turf or bare soil in which to nest. And most bees, at least in the UK, are ground-nesting.

The image at the top of this post is from my book Pollinators & Pollination: Nature and Society, and it shows two views of the same grassy, south-facing bank in Kettering, Northamptonshire. I included it because it’s a nice example of the mindful approach to lawn mowing that I am describing: bees are able to nest in the low-cut turf and collect the nectar and pollen from the flowers in the unmown areas. Later in the season that unmown area will be cut. This is referred to as ‘matrix mowing’, which is to say that by cutting some areas and leaving others, you create a matrix of different lawn lengths that has a greater overall benefit than is obtained by either cutting everything at the same time or cutting nothing for a whole month. It’s even better if you have the space to leave some patches unmown for a year or two. That way you create longer grassy areas in which insects can over winter and some bumblebees can nest.

It’s worth mentioning at this point that I know of only one published study that’s assessed the impact on No Mow May on pollinators, and that study was retracted shortly after it appeared. If I’ve missed other studies please do let me know in the comments.

I’ll finish with the Royal Horticultural Society, which was in the news recently with an announcement that it’s collaborated with gardener Monty Don to come up with ‘hard-wearing flower lawn that is good for pollinators, dogs and people’. This is hardly rocket surgery, it’s the sort of diverse, low-input, low maintenance lawn that many of us have been advocating for years, but if it brings these ideas to popular attention, so much the better.

So, consider engaging in Mindful Mow May* (and April, and June, and all the other months!) As always, feel free to comment below or get in touch with me via my Contact page.

*In the past I’ve also used the term “Matrix Mow May” which amounts to the same thing – being mindful of exactly where is mown and where is not.

Project ‘Butterfly’ takes flight in Paris!

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At the end of last week I joined researchers from across Europe and beyond who gathered at Norway House on the campus of the Cité Internationale Universitaire de Paris, for the official launch of the EU-funded project ‘Butterfly’. This bold, four-year interdisciplinary initiative is focused on the future of pollinators and the ecosystems that depend on them, and is one of a series of projects that have spun out from the EU’s Pollinators Initiative.

Over two days of lively discussion, the project’s key themes came into focus: the urgent need to restore pollinator populations, the value of integrating ecological and economic data, and the importance of including people—farmers, citizens, policymakers—in shaping practical, long-term solutions to pollinator decline.

Connecting Science and Policy

I arrived in Paris early Wednesday evening to be fresh for the meeting’s opening session the following morning. This set the stage by grounding the project in real-world policy contexts, including the EU Pollinators Initiative and the Nature Restoration Law. These frameworks are increasingly recognising the vital role pollinators play not just in nature, but in the economy and public well-being.

Nine Work Packages, One Mission

Participants got a crash course in the project’s structure through short presentations from each of the nine work packages. These range from ecological modelling and ecosystem valuation to resilience thinking, communication tools, and understanding human relationships with pollinators. A strong emphasis was placed on collaboration—how each work package connects with the others and contributes to the project’s broader vision. For example, one of my roles will be to work closely with Maria Clara Castellanos and her team at the University of Sussex on the integration of the UK-focused Database of Pollinator Interactions (DoPI) and the Global Biotic Interactions (GloBI) platform, to create an online European Atlas of Plant-Pollinator Associations (EuroAPPA). This in turn will feed plant-pollinator data into the modelling and economic valuation tasks in some of the other work packages.

Living Labs and Global Perspectives

One of the most exciting aspects of the Butterfly project is the network of “Living Labs” being established across Europe and the test sites in overseas territories. From Murcia to Martinique, each site represents a unique ecological and cultural landscape with its own pollination challenges. These test sites, some of which are shared with a parallel project called RestPoll, will serve as experimental spaces to co-develop and test strategies for enhancing pollinator resilience in real-world contexts. Another of my roles in the project is to help with the field work on the Caribbean island of Curaçao, where we will be assessing birds and bats as pollinators, as well as insects.

Thematic Sessions and Cross-Pollination

The meeting featured targeted discussion sessions on everything from economic modelling chains and ecosystem indicators to human dimensions like eco-literacy, historical agency, and “slow hope.” Again, one of my contributions will be to the work package dedicated to understanding and reacting to the human dimensions of pollinator decline, where I hope to provide a case study that builds on the work I published almost a decade ago on how the auction prices of holly and mistletoe are a reflection of the work of wild pollinators. In the evening we had a “cross-pollination” networking buffet dinner, themed around pollinator-dependent food crops, that provided an opportunity for participants to mix across disciplines, brainstorm, and spark new collaborations in an informal setting.

Laying the Groundwork for Action

Day two shifted toward practicalities—data sharing, financial management, ethics, and stakeholder engagement—as well as discussions about how Butterfly will connect with other major EU-funded projects, including VALOR, which is Butterfly’s partner and with which we will closely collaborate. Thematic sessions continued to dive deep into topics like mainstreaming pollinator stewardship and developing indicators to track the societal impacts of pollinator loss.

Looking Ahead

The meeting wrapped up with a plenary session with the project’s Advisory Board, reinforcing the importance of external perspectives in guiding the project’s evolution. Dinner that evening was an informal affair (not funded by the project!) at a really wonderful, traditionally French restaurant – Le Temps des Cerises – where service was slow, the food and wine were delicious, and the conversations continued to flow.

For those of us who stayed an extra day, a field visit on Saturday offered a first-hand look at urban pollinator research at the Jardin Écologique within the Jardin des Plantes—a fitting reminder of why this work matters! Here’s some photographs from that trip:

My sincere thanks to all of the colleagues who made the Butterfly kick-off meeting such a success: I look forward to working with you all over the next four years! Particular thanks to Paolo Biella who allowed me to use the photo at the top of the post, of a female mason bee outside our venue. We kept an eye on her during the meeting and I’m pleased to report that she successfully sealed up her nest. May her offspring thrive!

If you’d like to delve deeper into Butterfly’s objectives, here’s the project summary from our funding application:

Butterfly aims to significantly enhance society’s capacity to appraise, foresee, and respond to the threats posed by cascading impacts of pollinator decline. To reach that goal it will establish a test system of geographically well spread multi-actor communities across sectors for co-creating proactive pollinator restoration solutions and: (1) collect, integrate, manage and share ecological and spatial information on a wide range of known and lesser known pollinators and pollination services provided for wild and cultivated plants, across Europe and selected overseas territories; (2) advance the monetary and non-monetary valuation of marketed and not marketed direct and indirect ecosystem functions and services provided by pollinators, and advance ecosystem accounting; (3) comprehensively model and quantify the macro-economic implications of pollinator decline and country-specific economic butterfly effects of dependencies on pollinators, and assess policy options and scenarios; (4) assess how five key biomass supply chains (food/micronutrients, pharmaceuticals, cosmetics, biomaterials, biomass energy) depend on pollination and co-create pollinator restoration options that increase resilience of these supply chains; (5) devise, co-create, test and implement transferable tools, interactive atlases and guidelines that enable systematic mainstreaming of proactive pollinator stewardship in vulnerable sectors; (6) conceive indicators for human dimensions and assess and exploit the socio-cultural capacity of the concepts: ‘pollinator stewardship’, ‘ecoliteracy’, ‘historical agency’ and ‘slow hope’ in reversing pollinator decline. It will inform EU policy processes and build strategic alliances for high-level impact. The Butterfly network of Living Labs will accelerate knowledge transfer and uptake of new business models and serve as breeding place for multi-actor co-creation of knowledge and sustainable solutions, paving the way to pollinator stewardship in all sectors.

Is Biodiversity Net Gain a missed opportunity for invertebrate conservation? A new open access study suggest ways to improve it

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The UK has set ambitious targets under the Global Biodiversity Framework 2030, aiming to halt and reverse biodiversity loss. One of the key policies designed to help achieve this is Biodiversity Net Gain (BNG), a requirement in England that ensures new developments (such as housing projects) result in a 10% increase in biodiversity. On the surface, this sounds like a positive step—but is it really working for all species?

In a newly published paper that I co-authored, led by University of Oxford PhD student Natalie Duffus, we suggest that BNG may be falling short for some of the most vital, yet overlooked, members of our ecosystems: invertebrates. This group includes insects, spiders, and other arthropods—organisms that play critical roles in pollination, pest control, and nutrient cycling but are also experiencing dramatic population declines worldwide.

The Problem with a Habitat-Focused Approach

The way BNG is currently applied focuses heavily on habitats rather than species, meaning that while new green spaces may be created, they may not necessarily provide the right conditions for invertebrates to thrive. In some cases, BNG could even make things worse by fragmenting existing habitats or failing to account for the complex ecological needs of different species.

For instance, many invertebrates rely on very specific plants, soil conditions, and microhabitats that a broad-brush approach to habitat restoration may not support. Simply increasing the area of green space does not guarantee it will be suitable for pollinators, decomposers, or predatory insects that help keep ecosystems functioning. It’s an issue that I highlighted in October 2023 when I wrote a report about BNG and pollinators.

How Can BNG Be Improved?

Rather than being a one-size-fits-all approach, BNG could be better aligned with evidence-based conservation strategies, such as the National Pollinator Strategy. By integrating more targeted actions—including planting native wildflowers, preserving deadwood for beetles, or ensuring hedgerows and wetlands remain intact—BNG could deliver real benefits for invertebrates.

Additionally, better monitoring and evaluation are needed to track whether biodiversity is genuinely improving under BNG policies. This would help policymakers refine their approach and ensure conservation efforts support the widest possible range of species, not just the most obvious or easily monitored ones.

Lessons for Global Conservation

With many countries looking to adopt biodiversity offsetting schemes like BNG, England’s experience offers valuable lessons. If BNG is to be truly effective, it must take a more holistic, species-specific approach—one that recognizes the essential role of invertebrates and actively works to protect and enhance their populations.

If done right, BNG could be a game-changer for conservation. But if we fail to consider the full picture, it risks becoming a well-intentioned policy that does little to halt biodiversity loss where it matters most.

Here’s the full reference with a link to the paper – it’s open access and can be downloaded for free:

Duffus, N.E., Lewis, O.T., Grenyer, R., Comont, R.F., Goddard., D., Goulson, D., Ollerton, J., Townsend, M.C., Webb, J.A., Wilson, R.I. & zu Ermgassen, S.O.S.E. (2025) Leveraging Biodiversity Net Gain to address invertebrate declines in England. Insect Conservation and Diversity (in press)