Category Archives: Pollination

A Westminster pollinator seminar and The Great British Big Bee Count

In the run up to Defra’s publication of a National Pollinator Strategy, due for release some time before Christmas, the Parliamentary Office for Science & Technology yesterday ran a two hour seminar at Westminster. It was a full meeting in one of the small rooms, and apparently over-subscribed which doesn’t surprise me: there’s huge interest in pollinator conservation in the UK at the moment. So it would have been better moved to a larger room to allow more scientists, practitioners, MPs, civil servants and other interested parties to attend. In any case it was a useful couple of hours, with some interesting updates on what’s happening in relation to British pollinators.

The event was chaired by Sarah Newton MP and was kicked off by Adam Vanbergen from the Centre for Ecology and Hydrology who got everyone up to speed by giving an overview of the science of pollination, pollinator diversity, and the issues affecting pollinator populations. In the process he cited our “How many flowering plants are animal pollinated?” paper which has fast become the default citation to use as evidence to support the ecological importance of biotic pollen transfer. That’s hugely gratifying and is what it was designed to do. We now have additional data with wider geographical coverage and I hope to update that analysis in the near future. A lot of the information Adam was using can be found on the Insect Pollinators Initiative website.

Adam’s talk was followed by a presentation by Simon Potts from the University of Reading who discussed how we value pollination as an ecosystem service and how we can safeguard pollinator abundance and diversity. There were some stark statistics on the economic contribution of pollinators to crops such as apples, including data from a study by Garratt et al. (2014) which suggests that both quality and quantity of apples could be improved by having more pollinators in British orchards. Perhaps another way of viewing those data is that the UK apple industry is already experiencing the kind of pollinator deficit that conservationists have predicted?

Jane Memmott from Bristol University was next, presenting the preliminary results of the Urban Pollinators Initiative which is the first comprehensive study of the distribution of pollinators in large British cities. The data look really exciting and it will be great to see the results finally published as it will make for an interesting comparison with Muzafar’s data on solitary bees in Northampton, the first manuscript from which has recently been submitted to a journal.

Finally Chris Connolly from Dundee University talked about pesticides in a presentation entitled “Why pick on the neonicotinoids?” and provided some disturbing statistics on how little we really know about what happens when the c. 350 types of pesticides (plus about 700 herbicides and fungicides) that we use in modern British agriculture combine in the environment to produce synergistic effects. It’s also worrying that there is little understanding of the amounts of pesticides being applied because systematic data are not collated. Chris is a neuroscientist working mainly in a medical context and gave the analogy of how combinations of therapeutic drugs can have unforeseen (even deadly) side effects. Chris also used an image of Nigel Farage to illustrate a point which was a brave thing to do in the Houses of Parliament in the current political climate, but which got him a big laugh.

There followed 30 minutes of questions and discussion, and I managed to get in a plug for the Biodiversity Index when making a point of how difficult it is to get business to engage with biodiversity. That led to an interesting conversation afterwards with a consultant that I need to follow up later today.

Out into the unseasonably warm London air by about 6.30pm, there were people standing outside pubs and sitting at cafe tables, as if we were in southern Europe rather than England in late October. It reinforced some of the things I discussed in a post earlier this summer about climate change and current weather patterns.

Coincidentally (or not) Friends of the Earth released the results of their Great British Bee Count, a Citizen Science project designed to augment the monitoring work being done by specialist groups such as the Bees, Ants and Wasps Recording Society (BWARS). I have mixed feelings about the Great British Bee Count. On the one hand it’s great to engage the public in campaigns that raise the awareness of the importance of pollinators, and to get them out looking at bees. But the reality is that the 832,110 records submitted to the count have very limited scientific value, despite what Friends of the Earth might claim. That’s because it is very, very difficult to identify bees to even broad groups unless you’ve had some training, and (apart from some distinctive species) impossible to identify to species level unless you are a specialist. I’ve been studying pollinators for 25 years and there are whole groups within our c. 250 native species that I have great problems identifying, and defer to the opinion of real specialists such as Stuart Roberts, chair of BWARS.

Stuart has made public his concerns at the quality of the data being submitted to the Great British Bee Count, and the fact that records cannot be checked because no photograph was taken and (worse) there are no specimens to compare. The issues are neatly embodied in the fact that four species which were recorded from Northern Ireland (Tawny mining bee, Hairy-footed flower bee, Red mason bee, and Tree bumblebee) have never previously been seen in Ireland and can all be confused with other similar species. Of particular concern is the fact that Friends of the Earth expects the National Biodiversity Network Gateway to archive the data. If that happens the Great British Bee Count data MUST be kept separate from the high quality, verified data on bee distributions that NBN already possesses, otherwise it will completely devalue the latter. By all means let’s get the public engaged with pollinators and biodiversity more broadly, which is one of the purposes of this blog after all! But let’s also be realistic about what can be achieved by these kinds of campaigns.

Dancing with wolves: more from SCAPE 2014

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Tovetorp Research Station has a small colony of wolves, though we weren’t allowed to visit them as they are being observed as part of a study of canid behaviour. But I did see a White-tailed eagle (Haliaeetus albicilla) which was just as good! And on the last night of the SCAPE meeting there was the usual post-banquet bout of Scando-European dancing by the younger members of the conference, which gave me the idea for the title of this post.

But on to the science! I’ve already talked a little about some of what I learned or was excited about from the Thursday & Friday talks, and Saturday’s sessions continued in the same vein, with interesting and novel research in abundance, including:

species in 166 different plant families lack nectar as a reward, with an estimated 15-20,000 species (from 72 families) utilising buzz pollination (Mario Vallejo-Marin, University of Stirling)
Alocasia sarawakensis employs a brood-site pollination system analogous to figs and yucca moths, but without destroying any ovules (Florian Etl, University of Vienna)
floral scents are more complex in their geographical and anatomical distribution than we realised, and may be used to cheat pollinators into thinking there is a reward in a flower (Magne Friberg, Amy Parachnowitsch & Rosie Burdon, Uppsala University)
exposure to neonicotinoid pesticides can cause very subtle effects on bumblebee behaviour when they forage on apple blossom, which doesn’t seem to translate into an effect on apple pollination (Dara Stanley, Royal Holloway)
it may be possible to assign environmental niches to native and introduced pollinators in order to understand how invasive species out-compete native ones (Jonas Kuppler, University of Salzburg)
functional diversity of floral traits is greater than that of vegetative traits in alpine plant communities (Robert Junker, University of Salzburg)

As I said before, these are just some of the highlights, there were many others. My own talk was about the rate of extinction of bees and flower-visiting wasps in Britain, involving some new analyses I’ve been doing with colleagues over the past 6 months or so. The work seemed to be mostly well received, though there was scepticism from some quarters about the methods we’ve used, and a suggestion that there are better ways to assess extinction which I’m going to follow up.

I returned to the UK at 7pm last night. On the drive home from the airport, Karin asked me what I’d most enjoyed about the conference. The answer was all of it, of course, but what these meetings really provide is an opportunity to discuss science in an informal, friendly (though rigorous and argumentative!) atmosphere, outside the formal talks. Not just the science itself, but also the way we do science, manage our careers, and communicate our findings. I spent some time chatting with Amy Parachnowitsch, who blogs over at Small Pond Science, and her research student Rosie Burdon about the role of blogging in science communication and what we’re aiming to do by releasing these thoughts out onto the internet. Paradoxically these are conversations that are best had face to face I think!

The problem with SCAPE is that it’s over and gone too quickly, but perhaps that’s the point: it leaves us wanting more and looking forward to next year, when it will be in Denmark. Thanks again to the organising committee for a stimulating and enjoyable few days. Any pollination scientists, at all stages of their career, who wish to come along to future SCAPEs would be guaranteed a warm welcome and should drop the organisers a line to be added to the mailing list, or search for the Facebook page of the group and ask to be added.

The bare-foot conference: SCAPE 2014

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Not strictly bare-foot, most of us are wearing socks and padding around the Tovetorp Research Station in Sweden, where outdoor shoes are banned in the building. The Scandinavian Association for Pollination Ecology is holding its 28th annual meeting here, starting Thursday evening with three initial talks, and continuing all today. I’ve posted about SCAPE previously: it’s my favourite conference by a long margin, friendly and informal and attracting some great science. Although I missed it last year due to my trip to Brazil, coming back this year is a little like coming back to a family gathering, where as well as the elder aunts and uncles, there’s also a large group of younger nieces and nephews, and some long-lost cousins – it’s a great mix of older professors, and newer PhD students.

This is a quick post before we have dinner and the bar opens. In the last 24 hours I have learned a lot about pollination ecology that I didn’t know before, including:

Vincetoxicum hirundinaria does not vary in its outcrossing rate, regardless of the size of population (Anne Muola, Swedish Agricultural University)
Arum italicum and Arum maculatum hybridise in some populations (Marion Chartier, University of Vienna)
variable weather conditions can result in low bumblebee numbers and increased fly pollination in a north American mountain plant community (Diane Campbell, University of California)
nocturnal pollination by moths is more common than expected in Spanish mountain plant communities (Marcos Mendez, Rey Juan Carlos University)
“double mutualists” that both pollinate plants and disperse their seeds seem to be more common on islands than elsewhere (Jens Olesen, Aarhus University)
colour “purity” is more important than other aspects of flower colouration (Klaus Lunau, Heinrich-Heine University)
there’s very little evidence to support any of the current hypotheses regarding the evolution of andromonoecy (Marcos Mendez, again!)

Those are just a few of the highlights from a conference that’s showcasing some of the best pollination ecology research currently being conducted. Looks like dinner’s ready so I’ll sign off for now. My talk is tomorrow at 4.30pm – wish me luck!

Biodiversity miscellany

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It’s been a few weeks since my last post, not because I’ve had nothing to say, but rather because there’s been too much to say, and too much to do to have time to say it! A lot has been happening personally, professionally and in the wider world that I could have talked about, so I’ve summarised a few things below.

Late September saw the start of a new academic year, with all of the organisation and effort that entails. Recruitment in our Department of Environmental and Geographical Sciences is healthy and the new intake of students are bright and keen. In addition to my usual teaching and research in the Department I’ve been asked to take on the role of Head of Research and Enterprise for the whole School of Science and Technology. Which will be interesting as it covers a vast range of subjects, including computing, leather technology, and engineering, as well as the environmental and geographical area with which I’m more familiar. It’s a two-year post which should be enough time to do some good work.

The Local Nature Partnership annual meeting took place at the university on 25th September. Parliamentary Under Secretary of State for natural environment and science Lord de Mauley popped up again, and gave a better and more focused speech than he did previously at the recent Nature Improvement Area conference in London. It’s a pity he didn’t stay for the afternoon session as there was a very interesting presentation from the company who are developing the Rushden Lakes site in the Nene Valley. Part of the development is a Site of Special Scientific Interest (SSSI) and it’s within the Special Protection Area, designated for over-wintering birds. The Wildlife Trust is working closely with the developers and, if the latter deliver what they say they will deliver, it will enhance and protect the site even further. Time will tell; you can watch a video of the plans here.

Lots of news stories related to biodiversity and conservation have appeared recently, including a scare-mongering piece in the Guardian that “The Earth has lost half its wildlife in the last 40 years” according to a report from WWF. Of course that’s journalistic crap and the report does not say that at all. I can’t sum it up any better than did our former student Ian WIlson, now Reserves Manager at Irthlingborough Lakes and Meadows, who commented (on Facebook) that “There have been terrible losses but this sort of misuse of statistics is unhelpful and misleading. It particularly undermines the ecosystem services arguments which suggest that loss of wildlife will directly affect human populations. You can’t maintain that argument and claim that we’ve lost 50% of wildlife over the last 40 years without having to explain why human populations are still so high. Conservation would be better served by more good science and less journalistic sound bites.” Well said Ian! Fifty percent of wildlife has not be lost; the statistic is actually that “the Living Planet Index (LPI), which measures more than 10,000 representative populations of mammals, birds, reptiles, amphibians and fish, has declined by 52 per cent since 1970”. Those “representative populations” are highly skewed towards large, easily counted species of vertebrates, predominantly in temperate areas, and exclude plants and invertebrates – you can download the full report here. I’m not suggesting that these statistics are anything less than worrying, but the scale of the loss of “wildlife” (in its fullest sense) is not as great as the Guardian’s report suggests.

There’s been huge concern about the disturbing Ebola outbreak in West Africa and beyond, including a statement from IUCN on the links between emergent diseases such as Ebola and loss of biodiversity. In short, deforestation allows humans to hunt animals in previously unexploited areas, increasing the likelihood that rare and novel diseases that use wild animals as a vector (such as Ebola) can pass to humans. Worrying, and yet another reason why we need to slow down, and ultimately stop, such habitat destruction.

On a happier note, my colleague Duncan McCollin had a paper entitled ‘Reconstructing long-term ecological data from annual census returns: a test for observer bias in counts of bird populations on Skokholm 1928–2002‘ published in the journal Ecological Indicators. It highlights a really nice example of an ecological monitoring scheme that, as Duncan puts it, deserves “the recognition of such long-term data for science in terms of an appropriate conservation designation”.

Finally, here’s a link to an impassioned blog post by my friend and colleague Dave Goulson from the University of Sussex. Dave is a longstanding researcher and campaigner about the adverse effects of neonicotinoid pesticides on pollinators and other biodiversity. Dave’s post originated as a letter in reply to a (misinformed and biased) opinion piece in The Times, which the newspaper saw fit not to print (freedom of the press, eh?) It’s well worth reading and sets out the scientific case for the impact of these pesticides. And if Dave’s blog is not sufficient for you, there’s also been a recent paper from Charles Godfray’s group at Oxford called “A restatement of the natural science evidence base concerning neonicotinoid insecticides and insect pollinators” which received comments and input from many scientists involved in pollinator research (myself included) as well as formal peer review. Hopefully that’s enough rigour for the sceptics.

Bad news for British biodiversity and a comment on ecosystem services

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Two related things have caught my eye this morning that I think deserve a quick blog entry. The first is that Julia Leventon has posted an interesting piece on her frustrations with the ecosystem services concept over on the Ideas for Sustainability blog. Go and read it – Julia raises some important points about the mismatch between our ever-more sophisticated concepts of ecosystem services and what it means to actually manage/support them within our society. One of the things she said really struck me as it chimes with what I feel is a weakness of the current ecosystem services research agenda. Julia says that:

“I feel somewhat as though we are distracting ourselves by creating ever more complex physical constructs that require even more detailed physical understandings, and ever more complex chains of structures, processes, services and benefits.”

This I completely agree with. The underlying science (ecology/biodiversity/natural history/call it what you will) of ecosystem services is hugely complex, even for a reasonably well defined service such as crop pollination. As someone who has studied pollination ecology for 25 years I know how little we truly understand – yet this is supposed to be one of the more “straightforward” ecosystem services!

But to implement the ecosystem services concept within society we don’t need to know the finer details and dynamics of the species/communities/ecosystems involved (as interesting as they are). What we require is as much natural and semi-natural habitat within a landscape as is possible, appropriately managed (or left alone), and with as few anthropogenic stressors on it as possible (e.g. pesticides and other pollutants). And we’ve known that for many years, long before ecosystem services was coined as a term in the 1980s.

Yet governments and agri-business consistently fail to deliver this basic requirement and our natural environment is becoming ever-less diverse and hospitable to the biodiversity that sustains ecosystem services. See for example the latest bit of bad news regarding species-rich meadows in the UK, which are still declining long after it was pointed out that over 90% had disappeared: legislation designed to protect these grasslands seems to have had the opposite effect. These are exactly the same kinds of habitats that are considered most important for the pollinators that agriculture relies upon!

The concept of ecosystem services, in my opinion, is a valuable one for focusing attention on the importance of the natural world, though there are others who disagree. But the concept does not have to become mired down in the “ever more complex physical constructs” that Julia describes in her post. Let’s keep it simple and focus on what’s important rather than disappearing into a conceptual black hole that excludes practitioners, government, business and the public*.

*The photograph above was taken a couple of weeks ago at Northampton’s Umbrella Fair, where I presented an over view of the importance of pollinators, and the idea of ecosystem services, to a small, [ahem] “mixed” audience, which included restless kids and incomprehensible drunks, in a marquee which was too light for the laptop projector to work. But if even one of those who attended “got” the idea of ecosystem services I consider my job well done!

Blackberry Week

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As a kid growing up in the north-east of England in the 1970s, the half-term school holiday that occurred early in October was always referred to as “Blackberry Week”. A quick on-line search suggests that the phrase goes back to at least the 1930s (can anyone trace it earlier than this?) and it refers to the time when blackberries (Rubus fruticosus agg.) were ready for picking. The local kids would spend hours at our favourite blackberry patches, picking bags full of dark, luscious berries to take home for our mothers to cook into pies and crumbles, or stewed to eat with cream. As much fruit was scoffed as was collected (“one for the bag, one for me, one for the bag, one for me…”) and over-ripe ones were pelted at one another until we looked like road casualties.

All of this has been brought to mind recently, since we began to pick blackberries in our garden – at the end of July. That’s at least two months earlier than I recall doing as a youngster. Part of this difference can be attributed to latitude; I now live more than 200 miles further south than I did, with a concomitant advance in relative dates of flowering and fruiting, amongst other phenological indicators. But that can’t be the only answer, the difference is too extreme, though I have not (and I doubt if anyone has) assessed it systematically.

The main reason for the difference, it seems to me, is that our seasons are shifting. We know that spring is generally earlier now in the UK than it was 20 years ago, and with that shift, autumn has likewise been brought forward and is lasting longer, as shown by changes in fungi fruiting patterns. There’s a lot of research interest in these changes, for example the Centre for Ecology and Hydrology’s collaborative project. Whilst phenology scientists usually express these changes quantitatively, as number of days difference between events, such as bird migration dates or plant flower times, across a period of years, any person with an interest in the natural world can see these changes for themselves, even in gardens.

Without realising it, as kids we were also making decisions about where to pick blackberries that go directly to the heart of biodiversity, which is essentially about variation and difference in the natural world. As part of our own knowledge of the local (and very personal) biodiversity of the area in which we played and explored, we would know the best bushes from which to pick fruit, and the ones to avoid because the plants produced berries that were small, or had a poor flavour. Blackberries are hugely variable in all manner of ways, including leaf shape, number and size of prickles, flower size and colour and, most importantly for us, characteristics of fruit quality.

Much of this variation is genetic rather than environmental and reflects the complex biology of the species, or should I say group of species. Let’s go back to the scientific name of blackberries: Rubus fruticosus agg. I’ve posted in the past about the formalities of writing scientific names of species, and the “agg.” element is an unusual addition not often seen. It’s an abbreviation of “aggregate”, which in its taxonomic sense means a collection of species that are very similar to, and may even be synonymous with, that species. The plant that we know and love as the blackberry is actually an aggregate of many hundreds of “microspecies”, at least according to some plant taxonomists. This is because of the variable sexual behaviour of blackberries and their tendency to hybridise.

Blackberries are often taken for granted and dismissed as invasive woodland dominators that need to be kept in check. But they are important for their cultural significance, have a fascinating biology, attract a wide range of insects to their flowers, and provide both fruit and habitat for birds and mammals. Blackberries are worth making space for if your garden is large enough.

How do we value nature? Costanza, Monbiot and the clash of concepts

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Is nature something that we should simply value for its own sake? Or should we take account of how nature supports our society and our economy in real financial terms? Back in 1997 Australian academic Robert Costanza and colleagues published a now classic paper in the journal Nature called “The value of the world’s ecosystem services and natural capital” that proved to be hugely influential and has been cited more than 3,500 times by other researchers in ecology, conservation, and ecological economics. Soon after publication I began to use the paper in some of my classes, asking students how they felt about putting a monetary ($) value on how nature supports ecosystem services such as soil formation, pollination, carbon storage, climate regulation, etc. Opinions were mixed, reflecting the fact that economic valuation of nature is controversial in theory, difficult to do in practice, and results in vast estimations of the “worth” of nature that seem to be fantastical. The Costanza et al. study, for example, suggested that ecosystem services were worth $33 trillion per year to the global economy, a figure almost twice as large as the Global GDP at the time!

More than a decade and a half later, Costanza has published a follow up paper that updates the figures in the 1997 paper and arrives at a global valuation of natural capital of between $125 and $145 trillion per year, depending on assumptions made about changes to the area of biomes such as temperate forest, grassland, coral reefs, etc. This last point is critical as loss of biome area due to changes in land use from agriculture and urbanisation has resulted in an estimated loss of ecosystem services of between $4.3 and $20.2 trillion per year between 1997 and 2011. That’s a big change and, if nothing else, gives an indication of how we are altering the face of the planet at an ever faster rate, something I will come back to later in this post.

In this new paper Costanza and colleagues have also responded to some of the criticisms of the earlier work, particularly by journalist and activist George Monbiot who, as I’ve previously discussed on this blog, has a genuine, but I feel misguided, aversion to the whole notion of ecosystem services and natural capital. Monbiot’s been repeating these criticisms in a lecture, a video and text of which is available on the Guardian website. I won’t go into a detailed discussion of his position, some of which I agree with, but I do believe that his major criticisms fail on two points.

The first is that Monbiot mixes up some very different concepts, bundling ecosystem services (a reasonable way of thinking about nature in relation to society) with biodiversity offsetting (a load of bollocks), green infrastructure (the importance of green space to urban development), carbon trading (dubious in theory and practice), and payments for ecosystem services (PES) schemes (which can work on a regional scale, as in the case of South West Water’s upland catchments project), as if they were all the same thing, which they are not. In the Nene Valley NIA Project, for example, we are using an ecosystem services approach and are trying to develop a PES, but are wholly against biodiversity offsetting.

The second is that Monbiot sees all of this as some kind of neoliberal agenda to sell off the natural world to the highest bidder. That’s really not the case and ecosystem services are being promoted as a concept by conservationists, NGOs and scientists whose motivation is saving the natural world, not selling it. As Costanza et al. (2014) rightly state: “It is a misconception to assume that valuing ecosystem services in monetary units is the same as privatizing them or commodifying them for trade in private markets”

In his lecture Monbiot uses the classic rhetorician’s device of using partial quotes to support his point. For example he quotes Dieter Helm as saying that:

“The environment is part of the economy and needs to be properly integrated into it so that growth opportunities will not be missed”.

Sounds bad, I agree. But the full quote actually gives a very different and more profoundly “green” message:

“Over the coming decades, there will be a major programme to develop the UK’s infrastructure. The National Infrastructure Plan 2013 sets out ambitious plans – for new railways, roads, airport expansions, energy systems, water resources, sewerage investments, flood defences and a major increase in house building …….. In taking forward this major investment, it is important not to lose sight of natural infrastructure and the integral part that natural capital plays in delivering sustainable economic growth. …… the environment is part of the economy and needs to be properly integrated into it so that growth opportunities will not be missed. Integrating the environment into the economy is hampered by the almost complete absence of proper accounting for natural assets. What is not measured is usually ignored.”

Monbiot does make some good points in relation to how power can trump any environmental monetary valuation, and how political influence works, but his solution of “mobilisation”, is most effective at a relatively small scale, for example the defeat of Derby Council over plans to develop a nature reserve. Mobilisation by passionate environmentalists has failed to protect large swathes of Brazil’s natural environment, but arguments about the link between vegetation and rainfall, underscored by financial assessments of agricultural crop reductions, just might.

What is interesting about the lecture (which I encourage you to watch, Monbiot is a great speaker and it’s more entertaining than the transcript) is that not one of the audience questions afterwards actually dealt with the main topic of the lecture, namely the pricing of nature. Is that because he won over the audience completely with his arguments? Or is it because the ecosystem services approach to nature conservation is too recent a concept for its technicalities to have embedded themselves within public consciousness, and a general audience such as this might not feel confident enough to make challenging comments? I suspect the latter because whenever I give public lectures to gardening and wildlife groups, for instance, I always ask who has heard of “ecosystem services”, and invariably it’s a minority of the audience.

If Monbiot was correct and it’s possible to sell off natural capital in the way he describes, then we would expect the coalition UK government, for one, as well as big business, to buy into the concept wholeheartedly and to invest much more than they currently do in order to make a quick buck out of biodiversity. But they aren’t, and in fact this government has a track record that shows it has only the most cursory of interests in the UK’s natural ecosystems, and is willing to ignore scientific evidence to placate special interest groups who happen to be Conservative Party supporters (witness the recent badger cull debacle and the lack of action over illegal activity on grouse moors).

This is no doubt a debate that will continue but time is running out for the natural world and we don’t have many options: in Table 3 of Costanza et al. (2014) the authors present worrying data on how some biomes have greatly reduced in area since 1997 (e.g. coral reefs, wetlands) whilst croplands and urban settlement has increased. That can’t go on: the natural world is too valuable, in all senses of that world, to lose, something I’m sure George Monbiot would agree with even if he doesn’t believe that monetary valuation is the way to do it.

7 minutes is a long time in science, 7 goals is a big win in football (BES Macroecology meeting day 2)

All pollinators are equal, but some pollinators are more equal than others

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The infamous line from George Orwell’s Animal Farm asserting that “All animals are equal, but some animals are more equal than others” nicely captures an ecological view of pollinators and their relationships with plants. “Pollinators” by definition move pollen between flowers, but not all pollinators are equally good at transferring pollen of any particular plant: some are more effective than others. I’ll illustrate this with examples from the urban garden that Karin and I are developing, which I’ve discussed before.

As you can see from that link, the garden is modest in size, but nonetheless this year it contains a significant biodiversity of edible plants that require pollinators for some or all of the fruit and seed set, including: strawberries, apples, greengages, cherries, blackcurrants, squashes, courgettes, blackberries, fennel, runner beans, french beans, passion fruit, tomatoes, raspberries, and radishes.

“Radishes?!” I hear you ask. “But they are grown for their edible swollen roots which don’t require pollination!” True, usually. But we let our radishes flower because we mainly grow them for their seed pods which, picked young, are delicious in salads and stir fries, like mustardy mange tout. They look like this:

The radish flowers are pollinated by a diversity of insects including butterflies, bees, and small flies:

These insects will vary in their effectiveness as pollinators of radish, depending on the frequency of visits, how often they move between flowers, and the amount of pollen on their bodies. This last factor is largely a function of size and hairiness (bigger, hairier insects carry more pollen as a rule), though cleanliness also plays a part: insects often groom the pollen from their bodies and, in the case of bees, may pack it into their pollen baskets where it’s not available for pollination.

The size and behaviour aspect is best illustrated by some recent photos that I took of visitors to the flowers of passion fruit (Passiflora caerulea var.). We have a large, sprawling plant growing up a fence which is currently being visited by honey bees, hoverflies, solitary bees and bumblebees. In comparison to the size of the flower and the position of the anthers (male, pollen producing parts) and stigmas (female, pollen receiving parts), the hoverflies, honey bees and solitary bees are relatively small. These two images are of honey bees (Apis mellifera):

Here’s an unidentified solitary bee:

These bees were occasionally touching the anthers, mainly with their wings, so some pollen will be moved around. But from what I observed it’s likely to be a relatively small amount in comparison to bumblebees, which are usually much larger and hairier, and don’t groom themselves as often as honey bees. Here’s a Buff-tailed bumblebee (Bombus terrestris):

They were actively collecting pollen as well as nectar. Much of this pollen is packed into the pollen baskets on the rear legs and will go back to the nest to feed the developing larvae, but some will be involved in pollination:

So it seems to be the bumblebees we have to mainly thank for the deliciously sweet-sour fruit we will enjoy later in the season. Of course to test this properly we would need to set up an experiment in which we excluded larger bumblebees from the flowers and only allowed smaller bees to forage, with appropriate experimental controls. Would make a great project if any of my students are interested! But it should give you a sense of just how complex the interactions between flowers and their pollinators are: the ecology of pollination is far from simple, despite what some would have us believe.

From Chester to Copenhagen

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P1110838

It is 6.30am on Sunday morning but I’m wide awake and can hear the hotel in which we are staying stirring into life. Time to reflect on what has been a long and busy week, rather than the start of a long and relaxing summer holiday as some assume academics enjoy. That’s a myth: summers for many of us are at least as busy as the main teaching part of the year, though that’s not to say we don’t teach in the summer – I have final year project students to advise, and for students who did not pass first time round there’s still re-sit exams and assignments to be undertaken.

Of course I’m not complaining and the busyness is part of the fun of my job, which includes opportunities to travel, as I’ve previously described on this blog. Before any travelling this week, however, Monday was taken up listening to my PhD student Kat Harrold give a seminar about the progress of her research on pollinator mapping and habitat modelling in the Nene Valley Nature Improvement Area. This was followed by an hour’s grilling from the supervisory team and an independent colleague, as we drilled down into the research and suggested ways in which Kat could improve on the already excellent work that she’s doing. All of this is a formal part of our PhD programme and Kat aquitted herself very well indeed.

Tuesday was the start of the travelling, and was spent in Chester helping with filming for an episode of a new four-part BBC2 series provisionally called Plant Odyssey, fronted by Carol Klein, Gardener’s World presenter and Honorary Fellow of the University. The series is being produced by Oxford Scientific Films and will be broadcast in the spring. In the following scene we were making a rose perfume based on an ancient Roman recipe from the writings of Pliny the Elder.

Now, I know very little about how to make perfume, but I do know a bit about flower scents and how they attract pollinators, so my role was to act as both a foil for Carol’s scent experiment and to add some science to the mix. This is not the first filming I’ve done with Carol, having also helped out with her Science in the Garden special edition of Gardener’s World a few years ago. While looking for that last link I discovered that all three episodes of Bees, Butterflies and Blooms is also available on YouTube, which is great to see as the BBC didn’t repeat the series or produce a DVD. I was involved in the making of episode 2, which helped to kick-start the RHS’s Perfect for Pollinators plant labelling campaign. Television work is fun and brings science, and the scientists who do it, to a much wider audience.

Wednesday I prepared my talk for Friday’s lecture in Copenhagen (more of which later) and Thursday involved attending the University of Northampton’s annual postgraduate research conference. This is a highlight of the year for me as it’s an opportunity to see the breadth of postgraduate research going on across the university, something that would be impossible in a larger and more research intensive institution. I was only able to attend the first session, but that alone covered research on the research process itself; feminist cyborg literature; the legality of the World Bank’s scrutiny panel; pollinator conservation (Kat Harrold again); and the experiences of families with children who have difficulties communicating. Questions from the audience tended to be broad and non-specialist, and all the better for that: often it’s the straightforward, naive questions which test specialist knowledge.

The rest of Thursday Karin and I packed and then travelled up to Birmingham International for an early evening flight to Denmark. I’d been invited by my colleague Bo Dalsgaard to present a research seminar at the University of Copenhagen’s Center for Macroecology, Evolution and Climate. Coming from a small and very diverse department, it was great to visit such a large and specialised group of researchers, though over lunch the Center’s Director Carsten Rahbek told me that a common complaint from his staff was: “Why can’t we employ more people doing what I’m going?” Everything’s relative I suppose.

The title of my talk was “Pattern and process in pollination at large geographic scales”, which gave an overview of some of the research I’ve published over the last decade or so, framed around the following questions:

Globally, how many plant species are animal pollinated?
Are plant-pollinator interactions more ecologically specialized in the tropics?
How predictable are pollination syndromes in different parts of the world?
What are the historical and contemporary drivers of the relative importance of animal versus wind pollination? [No link here as that manuscript is currently in review!]

Quite a number of people in the Center were out doing field work or were otherwise engaged so I spoke to a modest-sized audience of some 30 people: certainly not the smallest audience I’ve ever presented to – that was three people, including the two who had invited me to give the talk!

The lecture seemed to be well received and there were some stimulating questions afterwards, though also a couple of challenging ones about statistical analysis. One of these I couldn’t answer until afterwards because I’d forgotten the details of the methods we’d used (note to self: re-read old papers before you present their findings). In answering the other I agreed with the questioner that the data could now be analysed in a more sophisticated way (future task, if I ever get the time). If Kat’s reading this, I hope she takes satisfaction in not being the only person to be asked difficult questions about their research this week!

Afterwards I chatted with Bo and Carsten about the limitations of the current and paleo-climate data sets we’ve been using in some studies, which are indeed very limited. But there are only two options. Do we work with data sets that are flawed, whilst acknowledging that any conclusions are tentative? Or wait until better data become available, which could be a decade in the future? My choice is definitely to go with the former, otherwise we’d never publish anything because there are always limitations to data used in studies of ecology and biodiversity. Personal and public honesty about such limitations, and ideas as to how they can be overcome in the future, are surely preferable to stalling research.

Later that afternoon I discussed science with two of Bo’s collaborators, Pietro Maruyama a Brazilian PhD student whom I’d met last November, and Peter, a Danish undergraduate. Both are doing excellent work on that most charismatic group of pollinators, the hummingbirds.

Friday evening I was exhausted, and Karin and I opted for dinner in the hotel restaurant and an early night, as Saturday was to be spent exploring Copenhagen. It’s a great city for wandering around, with fascinating architecture and unexpected additions to buildings, such as bronze dragons:

And parks with statues of artists and writers, such as Hans Christian Andersen:

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After a roundabout wander, via a gallery selling African tribal art (which we couldn’t afford) and a small lunch (which we could only just afford – Copenhagen’s an expensive city!) we eventually ended up at the University’s Botanical Garden, which has a superb living collection of cacti and succulents, orchids and other epiphytes, and alpine plants.

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It beautifully illustrates the huge morphological diversity encompassed within the 352,000 or so species of flowering plants, one of the many reasons why I love visiting botanical gardens: I always see something new. This included two species of bumblebees (Bombus) which I’m sure don’t occur in Britain. I’ll have to look them up when I get back: from Chester to Copenhagen and, tomorrow, back to Northampton.