Tag Archives: Science

8 things I learned from the Parliamentary Pollinators Update seminar – UPDATED

POST event December 2015

As I advertised a couple of weeks ago, last Wednesday I was in London to take part in a Pollinators Update seminar at the Houses of Parliament organised by the Parliamentary Office for Science and Technology (POST). It was a very interesting event and good to catch up with some of the latest ideas about pollinators and their conservation. However it’s been a busy week since then and I’ve not had time to post a full account of the seminar, which was attended by over 40 people. So I’ve decided to write a brief summary of eight things I learned that day from my fellow speakers* and from the day in general; in some cases I’ve linked to the original sources where available:

1. About 46% of Europe’s bumblebees have declining populations (see the European Red List for Bees that I highlighted in an earlier post)

2. Around 2% of the world’s bee species do 80% of the crop pollination (Kleijn et al. (2015) Nature Communications)

3. Pollinators other than bees perform 39% of the flower visits to crops (Rader et al. (2015) Proceedings of the National Academy of Sciences)

4. By 2100 the Red-tailed Bumblebee (Bombus lapidarius), one of the commonest species in Europe, may be extinct across most of the continent due to climate change (Rasmont et al. (2015) Climatic Risk and Distribution Atlas of European Bumblebees)

5. Only 6.6% of Entry Level Stewardship agreements by farmers across England included plans to grow nectar- and pollen-rich flower mixes.

6. Criticism of laboratory studies of the effects of neonicotinoid pesticides are just as illogical as criticisms of field studies: both have their limitations and advantages, and both are needed.

7. A panel of four experts on pollinators and pollination will largely agree about the answers to most questions an audience asks.

8. A Westminster seminar such as this will attract very few MPs if it clashes with an important debate in the House of Commons, in this case about future military action in Syria.

UPDATE: here’s a number 9 suggested by Simon Potts: we all strongly support and encourage the setup of an All Party Parliamentary Group on “Pollinators” not just “honeybees” or “bees”.

*With thanks to my fellow panelists Simon Potts, Claire Carvell and Richard Gill, and to Kirsten Miller and the POST team for organising the event, and for the photograph of the panel in action.

Virtual Conference on Ecology and Climate Change

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Following on from what seemed to be a quite popular Virtual Conference on Pollinators, Pollination and Flowers I thought I’d mark this week’s Paris talks on tackling climate change with a second “virtual conference” on the topic of climate change and how it may affect (and be affected by) natural and agricultural ecological systems.

This is a great set of talks* with some very thought-provoking ideas. Hope you enjoy them.

Douglas Sheil (Norwegian University of Life Sciences)

Do forests attract rain?

Hans Joosten (University of Griefswald)

For peat’s sake – bogs and climate change

Nicola Di Cosmo (Institute for Advanced Study)

Climate, conflict, and historical method

Ben Beard (NCEZID Centers for Disease Control)

Climate change, ecology, and disease emergence

Jennifer Cartwright and Bill Wolfe (USGS Tennessee Water Science Center)

Climate-sensitive, insular ecosystems of the Southeast U.S.

Nabil Nemer (American University of Beirut)

Are changes in insect patterns in the Lebanese Mountains evidence of climate change?

Lini Wollenberg (University of Vermont)

Climate Change Mitigation on Agriculture-Forest Landscapes

Tim Benton (University of Leeds)

Food and the future: climate and resilience

Feel free to discuss the talks in the comments section and to post links to other talks on the same topic.

*I’m assuming that, as all of these videos are in the public domain, none of the presenters or copyright owners objects to them being presented here. If you do, please get in touch and I’ll remove it.

Butterflies and pesticides – a new study and a smoking gun

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Gatekeeper cropped P1010472

Following hot on the trail of the raft of recent papers that I highlighted on the blog last week comes a new study by Andre Gilburn and colleagues entitled “Are neonicotinoid pesticides driving declines of widespread butterflies?“. The paper is open access and published in the journal PeerJ which encourages post-publication comments and review of the work. I see that Tom Oliver of the Centre for Ecology and Hydrology has started the ball rolling with a couple of questions, and hopefully more will follow, with responses from the authors.

The paper focuses on the fact that between 2000 and 2009 there was a 58% decline in butterfly abundance on farmed land in the UK despite a doubling of spending on conservation in the UK over the same period, much of it on agri-environmental schemes on that very same farmed land.

Using a statistical modelling approach the authors conclude that the introduction of neonicotinoid pesticides in the mid-1990s is strongly implicated as a likely driver of those declines. My immediate question on reading the paper was: “What were the trends like before the mid-1990s, and did the rate of decline change significantly after that period?”

The authors don’t directly answer the question but it seems to me to be quite an important one to answer because abrupt changes in rates of decline in the abundance and diversity of species can be linked to broader changes in, for example, land management and agricultural practices, as we showed recently for bee and wasp extinctions in Britain.

So I looked for the data that would tell me whether the trend had changed and found what I needed in the UK Butterfly Monitoring Scheme annual report for 2014. Here’s a screen grab of Figure 3 from the report:

Butterfly abundance indices - November 2015

I’ve marked the point at which neonicotinoid pesticides were starting to be widely used in UK farming with a black line. As you can clearly see this is also roughly the point at which the abundance of the 24 “Species of the wider countryside” begins to trend downwards. In comparison, the 26 “Habitat specialists” show much less of a change, and in fact their initial decline was much earlier (in the 1970s-80s), possibly in response to loss of species rich grassland and ancient woodland.

Of course I’m just eyeballing the data and it needs to be tested statistically to see if there really is a break point in the trend at the mid-1990s, but this ought to be possible for anyone with access to the full data set. Even if this is shown to be the case it’s all correlative (as Gilburn and colleagues acknowledge) and proving causation is difficult. Nonetheless it looks to me like there’s an interesting smoking gun here that deserves further study.

Pollinators seminar at the Houses of Parliament – 2nd December

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Skipper on ragwort - cropped

The Parliamentary Office of Science and Technology (POST) has organised a “Pollinators Update” afternoon seminar in London on Wednesday 2nd December, to discuss recent developments in pollinator conservation research. I’ve been asked to give a 15 minute presentation on the pollinator extinctions research we published in Science last year.

The full programme will be:

2.30pm Sarah Newton MP, Chair’s Welcome
2.40pm Presentations
Professor Simon Potts (Professor of Biodiversity and Ecosystem Services) – Reading University
Professor Jeff Ollerton (Professor of Biodiversity) University of Northampton
Dr Claire Carvell – NERC Centre for Ecology and Hydrology
Dr Richard Gill – Imperial College London
3.40pm Discussion
3.55pm Chair’s closing remarks
4.00pm Refreshments

The seminar is free to attend but you need to book a place: see the POST website for details.

Pesticides and pollinators: some new studies and contrasting conclusions

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The question of whether or not neonicotinoid pesticides are negatively impacting agricultural pollinator abundance, diversity and behaviour continues to focus the minds of researchers. It’s an issue that has been almost constantly in the news since the earliest suggestions that these pesticides were harming pollinators. These concerns have led to temporary EU restrictions on the use of these chemicals, a decision that was partially over turned this year in the UK.

The past two months has seen the publication of at least five papers on the topic, two of them this week alone. In this post I want to highlight those papers and provide some commentary.

The first two studies have shown that neonicotinoid pesticides can affect pollinator behaviour, and specifically the memories of both honey bees and bumblebees:

Wright et al. “Low doses of neonicotinoid pesticides in food rewards impair short-term olfactory memory in foraging-age honeybees”

Stanley et al. “Bumblebee learning and memory is impaired by chronic exposure to a neonicotinoid pesticide“.

Subtle behavioural changes such as those documented here are not generally assessed in standard toxicological safety assessments for pesticides, which are mainly focused on whether or not the chemicals kill non-target animals, and at what dosage. But for plant-pollinator interactions (including agricultural pollination) such changes in pollinator behaviour could be crucial to the effectiveness of the pollinators. How crucial? Well up until today we didn’t know; but with the publication of another paper by Stanley and colleagues we now have evidence that the sub-lethal effects on pollinator behaviour can actually translate into an effect on pollination of apple crops:

Stanley et al. “Neonicotinoid pesticide exposure impairs crop pollination services provided by bumblebees“.

The study is the first one to my knowledge that tests the effects of field-relevant doses of pesticides on pollinator performance and subsequent pollination services in a commercial farm crop, and adds some valuable hard data to an already heated debate. The story, embargoed until this evening, has already been picked up by media, including the BBC News website.

To summarise the study: using artificial bumblebee colonies and caged apple trees Stanley and colleagues implemented an experiment in which they tested the effect of two different levels of exposure to a neonicotinoid pesticide on pollinator behaviour and subsequent pollination services to the fruit trees. They found a clear effect of exposure to the higher level of pesticide, resulting in a change in bee behaviour and a subsequent reduction in apple quality.

By way of a contrast, another study this week has focused on the lethal effects of these pesticides. Henry et al. “Reconciling laboratory and field assessments of neonicotinoid toxicity to honeybees” has shown that although the chemicals are lethal to individual honey bees, the overall impact of the loss of the bees is buffered by the fact that the colonies can simply produce more worker bees to compensate for the losses. This is interesting but needs to be judged in the context of the fact that honey bees are very unusual and atypical compared to most other pollinators, and indeed most other bees. They produce very, very large colonies with a unique social structure, and so this compensation might be expected. These caveats were echoed by some of the scientists asked to comment on the study in media stories such as the one on the BBC News website.

Finally, Godfray et al. have updated their earlier review of the environmental effects of these pesticides with “A restatement of recent advances in the natural science evidence base concerning neonicotinoid insecticides and insect pollinators“. Given the rate at which new studies are coming out, it won’t be long before a second restatement is required!

Where does this leave the whole debate around pesticides? Still with firmly entrenched views on both sides I would have imagined. No doubt the debate will run and run.

Meanwhile, important as it is, the focus on pesticides is in danger of over-shadowing other really interesting studies that might affect how we manage our agro-ecosystems in the UK. For example, I’d completely missed a paper from the end of September by Pywell et al. entitled “Wildlife-friendly farming increases crop yield: evidence for ecological intensification“. As far as I can judge from the Altmetric information for the paper, so too had the media: it received no coverage on any of the usual outlets. But this is important stuff that deserves wider publicity: it’s going to take more than a ban on pesticides to recover some of the biodiversity (at both a species and a habitat level) that we’ve lost due to intensive farming over the last 100 years or so.

Pollination syndromes: a brief update on recent developments, and news that Stefan Vogel has passed away

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In a recent post I discussed the current debates about “pollination syndromes”, which I described as “sets of flower characteristics that have repeatedly evolved in different plant families due to the convergent selection pressures applied by some groups of pollinators”.

The authors of the Ecology Letters paper that I discussed (Rosas-Guerrero et al. 2014) have now replied to our original critique of their approach and you can read that reply (Aguilar et al. 2015) in Journal of Pollination Ecology by following this link. Readers can make up their own minds as to whether the authors have responded adequately to our concerns, but I just briefly wanted to raise three points.

The first is that much of these authors’ response is focused on an earlier paper of ours (Ollerton et al. 2009) rather than on our critique per se. Nick Waser, Mary Price and myself have therefore written a second response that deals with some of the misunderstandings apparent in that piece; it’s available to download here.

The second point relates to the existing literature on pollination syndromes and pollinator effectiveness used by Rosas-Guerrero et al. (2014); as we demonstrated in our critique this is clearly a biased data set that is skewed towards groups of plants with relatively large flowers, “interesting” pollination systems, and text book examples of classical pollination syndromes such as bird and bat pollination. Researchers who study flowers and their pollinators choose their subjects based on a whole set of criteria, but random selection is not one of them. However as far as we can judge, Aguilar et al. (2015) seem to be arguing that drawing strong, “universal” conclusions about syndromes from this highly biased data set is perfectly acceptable because of the statistical rigour of formal meta-analysis. I’d re-iterate our main point that no amount of statistical rigour and exhaustive literature searching can take into account inherent biases within the primary data (i.e. the literature itself).

Finally, Aguilar et al. (2015) claim that “human disturbance of natural habitats has caused disruptions in patterns of mutualistic interactions that may partly explain the presence of the diverse pollinator assemblages that are frequently found in pollination studies”. It seems to us to be disingenuous to argue that pollination syndromes are universally valid and then to essentially concede that there are lots of wrong visitors (“secondary” pollinators), and to explain that with the idea that everything is disturbed in the Anthropocene. If this is really the case then we probably need to throw out a lot of our understanding of evolutionary ecology as a whole, not just studies of plant-pollinator interactions.

Clearly we don’t accept this argument and in fact it has echoes of arguments that have been going on since the 19th century (Waser et al. 2011): more than 130 years ago the Darwinian biologist Hermann Muller was criticising Federico Delpino (one of the original architects of the idea of pollination syndromes) for ignoring the “wrong” flower visitors. Interestingly, Delpino was a fundamentally a teleologist who saw purpose in nature, expressed through (as he perceived them) the highly ordered relationships between flowers and pollinators.

As we discuss in the Waser et al. (2011) paper, Stefan Vogel was another prominent pollination biologist, and advocate of the importance of pollination syndromes, who was also fundamentally teleological in his thinking. I was sad to learn that Stefan passed away very recently, in what I believe is his 90th year. I was fortunate enough to meet Stefan at a symposium in honour of his 80th birthday at the International Botanical Congress in Vienna in 2005. He graciously signed my copy of The Role of Scent Glands in Pollination and said, with a twinkle in his eye, “you and I have probably got a lot to discuss”. Unfortunately we never got the opportunity, but later I dedicated our 2009 paper on Ceropegia pollination to him “in honour of his pioneering work on pollination” in the genus. Stefan’s legacy of research, particularly in the tropical regions of South America, is a fitting tribute to his memory.

Pollination syndromes clearly continue to attract much interest in the scientific literature, and just this week I was intrigued to see a paper by John Benning showing that a species of Ericaceae that looks as though it “should” be pollinated by bees is actually moth pollinated. No doubt the discussion of the evolutionary extent and predictability of pollination syndromes will continue for some time to come.

SCAPE day 3 – science on a Sunday

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Last night I added a new edible plant family to my life list – Cornaceae – courtesy of the ever-hospitable Marcin Zych and his home-made fruit liqueurs. The one he opened after dinner was made from the fruit of edible dogwood (Cornus mas) and had been maturing for five years. It was sour but delicious, and very, very strong. That’s my first new addition to the list since my Brazil trip back in in November 2013. One day I will post an annotated list of the biodiversity of plant families I’ve consumed….but not tonight, it’s the end of a tiring final day of the SCAPE conference.

To end the meeting this morning there was a short session of three talks from Klaus Lunau’s sensory ecology group. Klaus started the proceedings with a talk about the role of UV-absorbent dark central “bull’s eyes” in the middle of flowers and compound inflorescences. He concluded that, despite their near mythological status, UV patterns were perhaps no more important than patterns absorbing at other wavelengths and presented some interesting experimental data to support the argument. Over breakfast Klaus and I had discussed the absence of difficult questions at the conference; he felt people were being a little too polite. So I asked him a hard one – whether his findings held up for male bees which don’t collect pollen. He confessed that he’d not tested them and agreed that it would be worth doing: hope he does, will be an interesting test.

Klaus was followed by Saskia Wilmsen who showed us the results of some elegant experiments using artificial “flowers” with different shaped epidermal cells (flat, conical, etc.) These different surfaces have distinctive optical properties in different light conditions, and bees behave in slightly different ways, accordingly. A very cool reminder that as we move to ever finer scales in pollination ecology, from macro biogeographical and community questions, to micro surveys, the layers of complexity just go on increasing.

This latter point was reinforced by the final presentation of the meeting, which was Sebastien Kothe discussing the functional role of the spines possessed by pollen in some plant families, especially Malvaceae. He presented compelling evidence that these spines have evolved in order to reduce their attractiveness to pollen collecting bees. The spines render the pollen hydrophobic meaning that the bees have to use much more nectar to bind it into the pollen baskets. It would be interesting to track the evolution of this echinaceous pollen through the fossil record and to assess whether its appearance coincides with the evolution of particular bee groups.

And with that, the 29th SCAPE meeting was finished except for the usual hugs and goodbyes and promises to meet up again in 12 months time, probably inside the Arctic Circle: it looks as though the 30th meeting will be held at the field station at Abisko.

The rest of Sunday was spent visiting the botanic garden and the art museum in Aarhus, both to be recommended if you have a chance to visit. It’s now 8.15pm and I’m sat at Billund Airport with a large glass of Carlsberg, my first of the trip. It’s been a great meeting and I look forward to repeating it next year, and interacting with such a passionate group of scientists. Over and out from SCAPE.

SCAPE conference 2015 – day 2 – probably the best pollination ecology meeting in the world

SCAPE conference 2015 – day 1 – welcome to the sanatorium

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The first day of the 29^th SCAPE conference drew to a close and as I started to draft this post I could hear around me some intense discussions of Amy Parachnowitsch’s “crazy idea” (her words!) that flowers may be able to “eavesdrop” on one another via their floral scents. It was a very thought provoking way to end a stimulating day. And I look forward to reading the discussion paper on which the talk was based, in Trends in Plant Sciences.

What else did I learn on the first day? Here’s a few things I noted, with a link to the programme, but certainly not an exhaustive list:

Paul CaraDonna told us about the way that interactions between plants and pollinators have a faster turnover early in the season than later in the season. We discussed this afterwards and it could be because of newly emerged, naïve individual pollinators encountering and exploring flowers they’ve not previously seen.

Jane Stout described the history and future of the All-Ireland Pollinator Plan, and how it was driven from bottom-up by two scientists (Jane herself and Una Fitzpatrick) – a salutary tale of what can happen when passionate scientists become advocates for change.

Markus Sydenham discussed his work on power line corridors in Norway and the fact that these linear landscape elements, though artificial, can be good for solitary bees in appropriately managed by cutting and removal of woody vegetation.

A project encouraging organic Danish farmers to assess the quality of their own land for pollinating bees was described by Vibeke Langer. Interesting example of “citizen science” that goes directly to those who might benefit most from larger and more stable pollinator populations.

In Hawaii, Robert Junker and colleagues have found evidence that the flowers of the endemic plant Metrosideros polymorpha have evolved in less than 150 years to be more effectively pollinated by introduced honey bees rather than its native bird pollinators, which have declined substantially. Some individuals of this species seem to be pre-adapted for bee pollination; is this evidence that a larger bee species once existed on Hawaii but is now extinct?

The “complex, messy” ecology behind the co-existence of different Medicago species (facilitated by the interaction of plant genotypic kinship and allelopathic chemicals produced by Thymus species, was the focus of Bodil Ehlers work.

Judith Trunschke showed how ecotype morphology in hawkmoth-pollinated orchid Platanthera bifolia seems to be driven by different pollinators in grassland and woodland habitats. Are we seeing the early stages of the evolution of two new species here?

I had the honour of being the first speaker yesterday morning, talking about the macroecology of wind versus animal pollination, and the University of Northampton was further represented by Kat Harrold, who is working on her PhD as part of the Nene Valley Nature Improvement Area project. Kat presented a short over view of her work during the poster session.

There was much more, of course, and all of it stimulating and interesting, but that’s at least a taster. The conference is taking place in a fascinating conference facility that was a former TB sanatorium. It’s a step up from the ex-leper colony that SCAPE used in Finland a few years ago….

BBC Wildlife magazine for October features Northampton harvest mice research