Yesterday I was delighted to finally receive an advance copy of my book Pollinators & Pollination: Nature and Society! It’s been over three years in the writing and production, much longer than I had anticipated. But, as I describe in its pages, the book is the culmination of >50 years of experience, study and research. So perhaps three years isn’t so bad…
2 More than just bees: the diversity of pollinators
3 To be a flower
4 Fidelity and promiscuity in Darwin’s entangled bank
5 The evolution of pollination strategies
6 A matter of time: from daily cycles to climate change
7 Agricultural perspectives
8 Urban environments
9 The significance of gardens
10 The shifting fates of pollinators
11 New bees on the block
12 Managing, restoring and connecting habitats
13 The politics of pollination
14 Studying pollinators and pollination
As you can see it’s a very wide-ranging overview of the subject, and written to be accessible to both specialists and non-specialists alike. To quote what I wrote in the Preface:
“While the book is aimed at a very broad audience, and is intended to be comprehensible to anyone with an interest in science and the environment, and their intersection with human societies, I hope it will also be of interest to those dealing professionally with plants and pollinators. The subject is vast, and those working on bee or hoverfly biology, for example, or plant reproductive ecology, may learn something new about topics adjacent to their specialisms. I certainly learned a lot from writing the book.”
The book is about 100,000 words in length, lots of illustrations, and there will be an index. My copy editor reckons there’s 450 references cited, though I haven’t counted. I do know that they run to 28 pages in the manuscript, and that’s with 11pt text. All going well it will be published before Christmas.
As I near completion of the copy-editing phase of my forthcoming book it’s frustrating to see all of the great research that’s been produced in recent weeks that I probably won’t be able to cite! Here’s a few things that caught my eye:
In the journal New Phytologist, Rhiannon Dalrymple and colleagues, including Angela Moles who hosted me during my recent stay in Australia, have a great study entitled Macroecological patterns in ﬂower colour are shaped by both biotic and abiotic factors. The title pretty much sums it up: in order to fully understand how flowers evolve we need to consider more than just their interactions with pollinators. It’s another demonstration of how we must look beyond simplistic ideas about pollination syndromes to fully understand the complexities of the relationship between flowering plants and pollinators…..
…..talking of which, again in New Phytologist, Agnes Dellinger asks: Pollinationsyndromes in the 21st century: where do we stand and where may we go? It’s an insightful and far-reaching review of a topic that has intrigued me for more than 25 years. There are still a lot of questions that need to be asked about a conceptual framework that, up until the 1990s, most people in ecology and biology accepted rather uncritically. One of the main unanswered questions for me is how further study of largely unexplored floras will reveal the existence of new pollination systems/syndromes. Which leads nicely to….
…..an amazing paper in Nature this week by Rodrigo Cámara-Leret etal. showing that New Guinea has the world’s richest island flora. The described flora includes 13,634 plant species, 68% of which are endemic to New Guinea! And the description of new species each year is not leveling off, there’s still more to be discovered. A commentary on the paper by Vojtech Novotny and Kenneth Molem sets some wider context to the work, and quite a number of media outlets have covered the story. Why is this relevant to pollinators and pollination? Well, we actually know very little about this critical aspect of the ecology of the island: there’s only a handful of published studies of plant-pollinator interactions from New Guinea, mostly focused on figs, bird-flower interactions, and a couple of crops. For such a biodiverse part of the world that’s a big gap in our understanding.
Finally, James Reilly, Rachael Winfree and colleagues have a paper in Proceedings of the Royal Society series B showing that: Crop production in the USA is frequently limited by a lack of pollinators. Most significant findings to me were that of the seven crops studied, five of them have their yields limited by lack of pollinators, and that even in areas of highly intensive farming, wild bees provided as much pollination service as honeybees.
That’s a few of the things that I spotted this week; what have you seen that’s excited or intrigued you? Feel free to comment.
In the next few months my new book Pollinators & Pollination: Nature and Society will be published. As you can imagine, I’m very excited! The book is currently available to pre-order: you can find full details here at the Pelagic Publishing website. If you do pre-order it you can claim a 30% discount by using the pre-publication offer code POLLINATOR.
As with my blog, the book is aimed at a very broad audience including the interested public, gardeners, conservationists, and scientists working in the various sub-fields of pollinator and pollination research. The chapter titles are as follows:
Preface and Acknowledgements
1. The importance of pollinators and pollination
2. More than just bees: the diversity of pollinators
3. To be a flower
4. Fidelity and promiscuity in Darwin’s entangled bank
5. The evolution of pollination strategies
6. A matter of time: from daily cycles to climate change
7. Agricultural perspectives
8. Urban environments
9. The significance of gardens
10. Shifting fates of pollinators
11. New bees on the block
12. Managing, restoring and connecting habitats
13. The politics of pollination
14. Studying pollinators and pollination
In the past couple of weeks I’ve delivered two presentations at virtual conferences. The first was at a Global Sustainability Summit run by Amity University, one of our partner institutions in India. The second was at the University of Northampton’s own internal research conference. Both of these focused on pollinators, as you might imagine, but they also referred to the United Nations’ Sustainable Development Goals (SDGs). The 17 SDGs are being increasingly used as a framework for promoting the importance of biodiversity to human societies across the globe, and I’m seeing them referred to more and more often in studies and reports about pollinator conservation. That’s great, and I’m all in favour of the SDGs being promoted in this way. However I wanted to highlight a couple of aspects of the SDGs that I think are missing from recent discussions.
The first is that pollinators, and their interactions with plants, are often seen as contributing mainly to those SDGs that are directly related to agriculture and biodiversity. Here’s an example. Last week the European Commission’s Science for Environment Policy released a “Future Brief” report entitled: “Pollinators: importance for nature and human well-being, drivers of decline and the need for monitoring“. It’s a really interesting summary of current threats to pollinator populations, how we can monitor them, and why it’s important. I recommend you follow that link and take a look. However, in the section about relevant, global-level policies, the report highlights “the UN Sustainable Development Goals (SDGs) – especially regarding food security (‘zero hunger’) and biodiversity (‘life on land’).
I think this is under-selling pollinators and pollination, and here’s why. First of all, as we pointed out in our 2011 paper “How many flowering plants are pollinated by animals?”, approaching 90% of terrestrial plants use insects and vertebrates as agents of their reproduction and hence their long-term survival. As we showed in that paper, and a follow up entitled “The macroecology of animal versus wind pollination: ecological factors are more important than historical climate stability“, the proportion of animal-pollinated plants in a community varies predictably with latitude, typically from 40 to 50 % in temperate areas up to 90 to 100% in tropical habitats. Now, flowering plants dominate most terrestrial habitats and form the basis of most terrestrial food chains. So the long-term viability and sustainability of much the Earth’s biodiversity can be linked back, directly or indirectly, to pollinators. That’s even true of coastal marine biomes, which receive a significant input of energy and nutrients from terrestrial habitats.
Biodiversity itself underpins, or directly or indirectly links to, most of the 17 SDGS; those that don’t have an obvious link have been faded out in this graphic:
The underpinning role of biodiversity, and in particular plant-pollinator interactions, on the SDGs needs to be stated more often and with greater emphasis than it is currently.
The second way in which I think that some writers and researchers in this area have misconstrued the SDGs is that they seem to think that it only applies to “developing” countries. But that’s certainly not the way that the UN intended them. ALL countries, everywhere, are (or should be) “developing” and trying to become more sustainable. To quote the UN’s SDG website:
“the 17 Sustainable Development Goals (SDGs)….are an urgent call for action by all countries – developed and developing – in a global partnership.”
“the SDGs are a call for action by all countries – poor, rich and middle-income – to promote prosperity while protecting the environment.”
I interpret this as meaning that “developed” countries need to consider their own future development, not that they only have to give a helping hand to “developing” countries (though that’s important too). Just to drive this home, here’s a recent case study by Elizabeth Nicholls, Dave Goulson and others that uses Brighton and Hove to show how small-scale urban food production can contribute to the SDGs. I like this because it goes beyond just considering the agricultural and food-related SDGs, and also because by any measure, Brighton and Hove is a fairly affluent part of England.
I’m going to be talking about all of this and discussing it with the audience during an online Cafe Scientifique on Thursday 25th June – details are here. I’m also going to be exploring more of these ideas in my forthcoming book Pollinators & Pollination: Nature and Society, which is due for publication later this year. The manuscript is submitted and is about to be copy-edited. The PowerPoint slide which heads this post uses a graphic from that book that sums up how I feel about biodiversity, plant-pollinator interactions, and the UN’s Sustainable Development Goals.
UPDATE: turns out the figure I cited for number of bee species is out of date so I’ve corrected it below. Thanks to John Ascher for pointing this out.
Publication of my book Pollinators & Pollination: Nature and Society by Pelagic Publishing has been pushed back until the end of this year or early in 2021. The current pandemic has created problems for the printing and distribution sectors, as it has for so many industries. Therefore, to celebrate World Bee Day, here’s a preview of the bee section from Chapter 2 which is entitled (ironically enough) “More than just bees – the diversity of pollinators”.
2.3 Bees, wasps and sawflies (Hymenoptera)
The bees and their relatives rank only third in terms of overall pollinator diversity. Within this taxonomic Order, bees are not especially species rich (17,000 or so described species, perhaps 20,000 in total) – over 20,400 (see: https://www.catalogueoflife.org/col/details/database/id/67) compared with the other 50,000 social and solitary wasps, sawflies, and so forth. But what they lack in diversity the bees make up for in importance as pollinators of both wild and agricultural plants, and in their cultural significance. The general notion of what a bee is, and how it behaves, looks to the honeybee (Apis mellifera) as a model: social, with a hierarchy, a queen, and a large nest (termed a hive for colonies in captivity). In fact, this view of bee-ness, though long embedded within our psyche, is far removed from the biology of the average bee: most of them have no social structure at all, and a fair proportion of those are parasitic. In Britain we have about 270 species of bees, give or take (Falk 2015) though there have been extinctions and additions to this fauna (see Chapters 10 and 11). These species provide a reasonable sample of the different lifestyles adopted by bees globally. They can be divided into four broad groups.
Honeybees include several highly social species and subspecies of Apis, of which the ubiquitous western honeybee (A. mellifera) is the most familiar. Most colonies are found in managed hives, though persistent feral colonies can be found in hollow trees, wall cavities, and other suitable spaces. They are widely introduced into parts of the world where they are not native (e.g. the Americas, Australia, New Zealand) and there is some debate as to whether they are truly native to Britain and northern Europe, with supporting evidence and arguments on both sides. Colonies can be enormous and contain thousands of individuals, mostly female workers, with a single queen. Unmated queens and males (drones) are produced by the colony later in the season.
Bumblebees (Bombus spp.) are typically also social, though their nests are much smaller (tens to hundreds of individuals). Depending upon the species these nests can be in long grass, rodent holes, or cavities in buildings and trees. Twenty-seven of the more than 250 species have been recorded in the UK, but six of these are not strictly social; they are parasitic and belong to the subgenus Psithyrus which will be described below.
The so-called solitary bees are by far the largest group in Britain (about 170 species) and worldwide (more than 90% of all species). In the UK they belong to 15 genera, including Andrena, Anthophora, Osmia, Megachile, etc. The females of most of these bees, once they have mated, construct nests that they alone provision with pollen for their developing young. Nesting sites can be genus- or species-specific, and include soil, cavities in stone or wood, and snail shells. Some species are not strictly solitary at all and may produce colonies with varying levels of social structure, though without a queen or a strict caste system; we term them “primitively eusocial”. In fact sociality has evolved and been lost numerous times in the bees and in the rest of the Hymenoptera (Danforth 2002, Hughes et al. 2008, Danforth et al. 2019). It’s also been lost in some groups that have reverted back to a solitary lifestyle, and even within a single genus it can vary; for example in the carpenter bee genus Ceratina (Apidae: Xylocopinae) tropical species are more often social than temperate species (Groom & Rehan 2018).
The final group is termed the cuckoo bees and, like their avian namesake, they parasitise the nests of both social and solitary bees (though never, interestingly, honeybees). There are about 70 species in 7 genera, including the bumblebee subgenus, Psithyrus. Other genera include Melecta, Nomada and Sphecodes. In some cases the parasitic species are closely related evolutionarily to their hosts and may resemble them, for example some Psithyrus species. In other cases they may be only distantly related and in fact look more like wasps, e.g. Nomada species. Some genera of cuckoo bees are restricted to parasitising only a single genus of bees, others are parasites of a range of genera (Figure 2.4).
Although we often think of bees, overall, as being the most important pollinators, in fact species vary hugely in their importance. Pollinating ability depends upon factors such as abundance, hairiness, behaviour, body size, and visitation rate to flowers (Figure 2.1). Size is especially important for three reasons. First of all, larger animals can pick up more pollen on their bodies, all other things being equal. Secondly, in order to bridge the gap between picking up pollen and depositing it, flower visitors must be at least as large as the distance between anthers and stigma, unless they visit the stigma for other reasons. Finally, larger bee species tend to forage over longer distances on average (Greenleaf et al. 2007) thus increasing the movement of pollen between plants. However, most of the world’s bees are relatively small as we can see from the analysis of British bees in Figure 2.5. Many species have a maximum forewing length of only 4 or 5 mm, and the majority of species are smaller than honeybees. Remember also that these are maximum sizes measured from a sample; individual bees can vary a lot within populations and even (in the case of Bombus spp.) within nests (Goulson et al. 2002). So the assumption that all bees are good pollinators needs to be tempered by an acknowledgement that some are much better than others.
Figure 2.5: The sizes of British bees. Forewing length is a good measure of overall body size and the data are maximum lengths recorded for species, except for the social bumblebees and honeybee I have used maximum size of workers (queens are often much larger). The blue line indicates the honeybee (Apis mellifera). The biggest bee in this data set is the Violet Carpenter Bee (Xylocopa violacea) which, whilst not generally considered a native species (yet), has bred in Britain in the past. Data taken from Falk (2015).
The network of pollination ecologists and insect specialists who have confirmed that they are surveying plant-pollinator networks in their gardens now stands at 50. As the map above shows, most are in the UK, Ireland and mainland Europe, but the Americas are also becoming well represented, we have a couple of people surveying in North Africa, and three in Australia. An x-y plot of the coordinates of the gardens shows the spread a little better:
I’ve managed 13 formal 15 minute surveys so far, plus have a few ad hoc observations that I am keeping separate, and I will be continuing my data collection for the foreseeable future. I’ve started playing with the data as you can see below. This is a plot made using the bipartite package in R, with plants to the left and pollinators to the right. The size of the bars is proportional to the number of pollinators/plants a taxon connects to. In the plants you can immediately see the dominance of apple (Malus domestica) and greengage (Prunus domestica), which attract a wide variety of insects to their flowers. Of the pollinators, the hairy-footed flower bee (Anthophora plumipes) and dark-edged beefly (Bombylius major) are especially common and generalist in their flower visits. It will be really interesting to see how this changes over the season, and how our fruit and vegetables are connected into the wider network via pollinators that they share with the ornamental and native plants.
If you are experienced at surveying pollinators and want to get involved, follow that first link and check out the protocol and FAQs, and please do email me: jeff.ollerton [at] northampton.ac.uk
One of the research projects and collaborations that I’m involved with is a BBSRC-funded project entitled “Modelling landscapes for resilient pollination services in the UK” with colleagues from the University of Reading, the University of Huddersfield, and the Natural Capital Solutions consultancy. As part of that project we are surveying opinions on what people in the UK value as landscapes and how these landscapes contribute to supporting biodiversity.
If you are based in the UK and are interested in taking part in this short survey, please read the following text and click on the link to take the survey:
Bees and other insect pollinators are major contributors to UK agriculture. Despite their importance for crop production, pollinator populations are threatened by many modern land management and agricultural practices. This raises questions about how secure this service may be to future changes: will we have enough pollinators where we need them? Will populations be able to withstand changes to the way we manage land? What might be the costs to us, both financially and socially, if we get it wrong?
Our research aims to address this knowledge gap. Our team of ecologist, economists and social scientists are working together to model the ecological, economic and ‘human’ costs of different land management methods.
As part of this we have designed a short online survey to capture the ways that people value and use the countryside, what features they prefer and why.
The survey takes less than 10 minutes and asks you to rate a series of images and say what you think about the landscapes that are illustrated. It can be found here:
Fire and water; those opposing elements have been our constant companions during this trip to Australia. All the major international news media have been reporting on how serious the bush fire situation is in the south east of the continent. In East Gippsland, Victoria, tens of thousands of residents and holiday makers have been advised to leave the area. Four thousand of those who haven’t left were forced to spend last night on the beach, as fires got closer to the town of Mallacoota. These are just the latest examples of climate change refugees in their own country, something I highlighted in a post about our visit to the USA earlier this year. Of course, Australia is a continent that is used to bush fires, they are nothing new. But what is new is the scale of these fires and the extended drought and high temperatures that are making the landscape more flammable than ever.
There’s currently a lot of media discussion in Australia about how landscapes were managed historically by Aboriginal peoples, whose selective and regular burning of the bush reduced fuel loads. Karin and I have just returned from Port Macquarie where we enjoyed Christmas with an Australian branch of our family. Several of them have spent a considerable amount of time working with remote Aboriginal communities in the Northern Territory. We were told a story about an Aboriginal elder who asked one of our relatives to drive him out to an area of bush that had not been burned for over a decade. It was that elder’s role to burn this land at regular intervals, a family tradition that went back generations. Having driven for several hours along dirt roads, the elder asked to stop; he hopped out of the vehicle, went up to a patch of dry grass, and casually set fire to it with a small lighter he was carrying. After pausing a few seconds to make sure that the flame had caught he hopped back into the car and said “Let’s get out of here”. An hour back down the road the companions stopped and looked back. The whole landscape was aflame, with a column of black smoke rising, I was told, in a mushroom cloud “like a nuclear explosion”.
This sounds extreme, but these areas are isolated and a long way from any human settlements or infrastructure. Such activities have been part of toolbox of ways in which Aboriginal peoples have managed these landscapes for thousands of years. By burning areas on a regular cycle the negative effects of large, out-of-control fires are reduced, and opportunities for seedling establishment and fresh foliage for animals to browse are created. There’s more information about these practices hereand here.
In the more heavily populated parts of Australia, and in the adjacent national parks, fires have long been suppressed, such that when they do occur they are much more violent conflagrations, over a greater area, than would normally be the case.
On one of our trips near Port Macquarie we came across an area of woodland that had burned recently, separated by a small road from an adjacent block that had not burned. In the following set of images I’ve alternated the two blocks so you can see what the woodland looked like before and after burning. But remember that this was not an especially intense fire; the trees are still living, and there is foliage in their crowns. Once there’s been some rain and a chance for the vegetation to regrow, the previously burned block will look identical to the currently unburned area. Indeed in one shot you can already see some green shoots emerging from the ground:
So fire in itself is not a problem for these natural communities. What is a problem, for nature and for the communities of people who live in and around these woodlands, is the intensity, the scale and the frequency of the fires that are currently occurring. This morning Karin and I watched silently to a news report of yet another volunteer fire fighter who had lost his life overnight. In this case he had been part of a crew whose 10 tonne fire truck had been lifted up and overturned by cyclone-strength winds created by the blaze itself – there’s a BBC news account of the tragedy here. “Unprecedented” is a word we’re hearing a lot on ABC News.
Evidence for the number and size of the fires was everywhere in and around Port Macquarie, as we observed when we took a drive up to the peak of North Brother Mountain in Doorgan National Park. From a height of about 470 m (1500 ft) we could see some amazing panoramic views of the region that also showed black fire scars on the landscape – this is looking south:
Looking north there’s little evidence of the fires – some have occurred there but much smaller in scale. But there is a lot of that second element, water. We were able to explore some shallow coastal lagoons fringed with grey mangroves (Avicennia marina):
Mangrove habitats are fascinating places that are ecologically important as nurseries for marine fish and invertebrates. They also provide physical protection to coastlines, acting as a buffer to storm surges that would erode the land. In recognition of this, a recent project around Port Macquarie has involved restoration of these mangrove areas and was instigated by commercial oyster farmers and a local fishing society. I’m particularly intrigued by the upward-pointing aerial roots of mangroves; termed pneumatophores, they function to provide oxygen to the trees, but also increase the physical complexity of the floor of the lagoon, providing habitats for small animals:
But evidence of the drought in this part of the world is never far away. On our seven-hour train trip back to Sydney we passed mile after mile of parched farmland, with dried-up waterholes and dust-filled streams. The only thing stopping it from burning is the absence of vegetation:
As I complete this blog post, it’s 31st December and we’re back in Coogee Bay, ensconced in the apartment of my colleagues Angela and Stephen. They have headed to Stephen’s native Canada to visit family. It’s going to be cold! We’re very happy to house sit and see in the New Year in warmer climes. Best wishes for 2020 to all of my readers: let’s hope that it’s the start of an environmentally more enlightened decade.
The related issues of how to conserve biodiversity and reduce the impacts of climate change have never had such a high public profile as they do at the moment. The activities of Extinction Rebellion caught the attention of the media around the world, for example here in London. Numerous organisations, cities, regions and countries have declared a Climate Emergency. And IPBES – the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services – has released a summary of its first global assessment with the full report due later this year, and explicitly makes the link between conservation of biodiversity and reducing the effects of climate change.
Timed to coincide with all of this, the University of Cambridge has announced that it is setting up a Centre for Climate Repair in order to explore hi-tech “fixes” to climate change, such as spraying sea water into the atmosphere in order to reduce warming at the poles, and sucking CO2 out of the air using large machines. I think it’s fair to say that this was met with some scepticism on social media; here’s some examples:
To be clear, these approaches do not 'solve the climate problem' or 'repair the climate'. At best they might just reduce some effects of climate change for as long as they are used.
Other people have pointed out that nature-based solutions are the most likely to be successful, and provide a boost for biodiversity at the same time:
Nature provides some of the cheapest solutions for solving the climate crisis as @BrenWintle says. Step one – stop destroying natural habitats. Clearing vegetation is lose-lose-lose. We can feed more people using less land. Step 2 – large scale habitat restoration. https://t.co/LQy824cqlK
All of this reminds me of the Waste Hierarchy in its various iterations – you know the sort of thing – “Reduce > Reuse > Recycle”, where reduction in waste produced is best, followed by reuse of waste resources, with recycling being the least good option (but still better than just land-filling the waste). As far as the link between conservation of biodiversity and reduction of the effects of climate change goes, there’s a parallel hierarchy – see the image at the top of this post – that sets out the order of priorities:
PROTECTION of ecosystems using the full force of national and international laws and conventions has got to be the top priority. Otherwise any of the other activities will result in, at best, humanity running to catch up with what the world is losing. Let’s stop cutting down ancient forests and degrading peatlands that have accumulated millions of tons of carbon over thousands of years!
FIX – by which I mean the kind of hi-tech solutions proposed above – should be the lowest priority: they do little or nothing directly for biodiversity and there is no compelling evidence that they will even work as intended.
Between these two are RESTORATION of currently degraded habitats (such as re-wetting peatlands as in the Great Fen Project) and PLANTING of trees, which can be a form of habitat restoration under some circumstances. Large scale examples of this include
Grain for Green – China’s attempt to restore vegetation to abandoned farmland to reduce soil erosion and flooding.
Great Green Wall – a multinational initiative in Africa aimed at restoring the vegetation on the southern edge of the Sahara to combat desertification and mitigate climate change.
While doing a bit of research for this blog post* I became aware that a Conservation Hierarchy has already been developedby the Convention on Biological Diversity but that really only deals with habitat destruction, mitigation of destructive activities, etc. What I’m suggesting is related more to the direct link between conservation of biodiversity and mitigation of climate change. So what to call this particular hierarchy? Perhaps the BioCC Hierarchy? Can anyone suggest a better name? Maybe it doesn’t need a name at all, it just needs people to be aware of it and for governments to act logically.
*I googled the term “Conservation Hierarchy” – you get the quality of research you pay for on this blog….