Category Archives: Biodiversity

New article just published: ‘Pollinators and pollination: myths, misunderstandings and much more to discover’

My first (and hopefully not my last) article for the magazine British Wildlife has just appeared in the April issue. Entitled ‘Pollinators and pollination: myths, misunderstandings and much more to discover’ you can get a preview here: https://www.britishwildlife.com/article/volume-32-number-5-page-316-323

The article focuses on some of the myths and misunderstandings that I dealt with in my book Pollinators & Pollination: Nature and Society. It also points out that, even in a place like Britain with a long tradition of natural history study, there’s still much for the patient observer to discover. If you’re interested in a PDF, drop me a line via the Contact page.

Protecting British Pollinators event TOMORROW – 25th March

I meant to post about this earlier but it’s been a really busy few weeks, so apologies if this is late in the day for any of you. Tomorrow morning there’s a webinar being run by the Public Policy Exchange entitled: “Protecting British Pollinators”. There’s an interesting set of speakers and I’ve been asked to provide the opening introduction and to chair the event.

Here’s the link for more details and booking information:

https://www.publicpolicyexchange.co.uk/event.php?eventUID=LC25-PPE

It should be a good meeting, hope to see some of you there.

Pollinators are allies in the fight against climate change: a new commentary just published in New Scientist

Over the past few months I’ve been thinking a lot about the relationship between the “Climate Emergency” (CE) and the “Ecological Emergency” (EE), and how they overlap considerably in terms of causes and solutions, but that the priorities of the CE often trump those of the EE. One of the outcomes of this has been a commentary that’s been published in New Scientist this week. It’s free to access – here’s the link:

https://www.newscientist.com/article/mg24933260-100-pollinators-are-our-secret-weapon-in-the-fight-against-global-warming/

It’s extracted from a much longer article that discusses the role of pollinators in relation to climate change. Hopefully that will be published in the not too distant future.

The other thing that’s happened this week is that, in my role as Visiting Professor of Biodiversity at the University of Northampton, I was asked to take part in a webinar that’s one of a series being produced in support of the Levelling Up Goals. The LUGs, modelled on the UN’s Sustainable Development Goals (SDGs) have cross-party support in Parliament and aim to bring economic prosperity to those parts of the country that have lagged behind in recent decades. The “Green Economy” is seen as central to this.

The webinar was recorded and you can view it here: https://www.fit-for-purpose.org/engage/how-to-level-up-harness-the-energy-transition

It was interesting and I learned quite a bit, for example about how the government is investing the state pension pot in sustainable energy projects. The format of the webinar, however, with the chair asking individuals a question and each of us responding, was a little frustrating as there was no real opportunity to counter statements being made, particularly by the MP for Hexham.

Yesterday Karin and I had out first COVID-19 vaccination; today we both feel a little under the weather, but it will pass. It’s certainly better than the alternative!

First, do no harm! The fundamental rule of creating pollinator habitat that you need to know

I had an interesting conversation with a landscape architect on Wednesday who was asking for some advice about creating urban habitat for pollinators. The plan was to strip turf from under the trees in a city greenspace in order to put in some flowering plants as nectar and pollen sources. I often get asked about this, not only by landscape architects, but by professional gardeners, park committees, local residents groups, and so forth. My initial advice, following the Greek physician Hippocrates, is always the same:

“First, do no harm.”

Hippocrates was of course speaking to doctors and saying: before you intervene in a patient’s health, make sure you are not making things worse for them.

So what do I mean by this? Why is it relevant to pollinators?

Well, in the case of the discussion from earlier this week, the team had no idea if there were ground nesting bees such as Andrena spp. in the area where they planned to strip the turf. Stripping the turf would likely have destroyed any nests, or at least prevented the bees from emerging, particularly if a thick mulch was applied to the area. There were also suggestions of using glyphosate to kill off the grass, though I certainly advised against it: by coincidence a meta-analysis by Lucas Battisti and colleagues was published this week showing categorically that glyphosate is toxic to bees. Imagine spraying it over an area that has a colony of one of the ground-nesting solitary species? Or where queen bumblebees might be hibernating? Queen Bombus spp. often hibernate close to the base of trees – see D.V. Alford’s classic 1969 study of bumblebee hibernation.

It’s not only pollinators that could be harmed by starting work without appropriate surveys: even unpromising-looking municipal grassland, for example in parks, can harbour a significant diversity of plants that are being suppressed by too-frequent mowing. Mow less often and they will flower, producing nectar and pollen for pollinators, then later seeds for birds.

Sometimes you can do more by doing less.

One of the things that I stress in my book Pollinators & Pollination: Nature and Society, is that habitat creation for pollinators is about much more than just planting wild flower meadows and putting up some bee hotels. It needs forethought about what is on a site already, and what may be destroyed by the proposed actions. There also needs to be a consideration of the wider landscape context in which the proposed site is situated, and whether it is providing some of the other things that pollinators need to complete their life cycles each year. The diagram above is from my book and I refer to it as the “Requirements of Pollinators Triangle”. Because pollinators are so diverse in their natural histories, no one site can hope to provide everything that they all need. However there are some general principles that I present in the book.

If you’d like to know more about any of this, or need advice, or to enquire about the training that I offer, please do get in touch via my Contact page.

Online talks and training: here’s a selection of what I offer

Over the past few months I’ve done a large number of online talks for a variety of audiences, including natural history and gardening societies, beekeeping groups, private companies, university estates departments, and ecological consultancies. I thought it would be useful to provide a list of what I offer, with a short description. All talks are accessible and understandable to a broad audience, and can be tailored to the individual needs of the group:

Pollinators & Pollination: Nature and Society is an introduction to the importance of pollinators and the pollination services that they provide to both wild and crop plants. The name, of course, reflects that of my recent book.

The Politics of Pollination is an account of how society (governments, organisations and individuals) has responded to the current “pollination crisis” (if that’s what it actually is…)

Bees in Cities: an Introduction to Urban Pollinators focuses on the positive roles that urban environments can play for pollinators, and the potential threats of city living.

Pollinators in Gardens gives practical advice on how to make your garden “pollinator friendly”.

Pollinator Conservation: Threats and Opportunities describes how and why pollinators are declining and what we can do about it at the individual and societal level.

Habitat Creation and Management for Pollinators gives an introduction to how NGOs, estates departments, consultancies, and so forth, can effectively support pollinators in ways that go beyond just planting flowers and putting up a few “bee hotels”.

To Be a Flower is an introduction to how flowers function and the ways in which they manipulate the behaviour of their pollinators to ensure reproduction.

Darwin’s Unrequited Isle: a Personal Natural History of Tenerife describes some of the field work that we’ve been doing on this most fascinating of the Canary Islands.

Biodiversity: What Is It and Why Should We Care? gives a very general overview of the topic of biodiversity and ecosystem services.

Talks typically last for around 50 minutes, following which I’m happy to answer questions and discuss any issues that have arisen. I also offer a half- or full-day of training for those organisations that need more depth, for example ecological consultancies. Note that I charge for all of my talks and training. If you would like to enquire about any of this, please use the form on the Contact page.

How old are the flowering plants? A new study aims to reconcile the fossil and DNA evidence – but what does it mean for pollinators?

Yesterday I was contacted by a journalist to give a comment on a paper that’s just been published in Nature Ecology and Evolution:

Silvestro, D., Bacon, C.D., Ding, W. et al. (2021) Fossil data support a pre-Cretaceous origin of flowering plants. Nature Ecology and Evolution https://doi.org/10.1038/s41559-020-01387-8

I was happy to do so as it adds a fascinating twist to a long-standing interest of mine: when did the angiosperms evolve and what role did pollinators play in that evolution?

In the end they didn’t use the text that I sent back to them, so I thought that I’d share it on the blog:

The evolution of the angiosperms was arguably one of the most significant events in the history of life on Earth, but the timing of the origin of this group of plants remains a hotly debated topic, with conflicting evidence coming from the fossil record and molecular biology. This important new study has developed a novel statistical approach to reconcile these two lines of evidence, and comes down firmly on the side of the molecular evidence to conclude that angiosperms originated much earlier than the fossil record suggests. This will be sure to stir up further debate that can only be resolved by finding well preserved and accurately interpreted fossils of an appropriate age. In the future I would like to see Silvestro et al.’s technique applied to the major groups of pollinators such as bees and wasps (Hymenoptera) and butterflies and moths (Lepidoptera) where there is likewise a discrepancy between what the fossils and DNA are telling us. Pollinators have had a profound influence on angiosperm evolution and we might expect a close correlation between the origin and subsequent diversification of these different groups of organisms. This would certainly support the findings from Silvestro et al.’s study. It’s an exciting time for researchers in this field: a world without flowers and pollinators would look very different

Climate change history affects contemporary pollination systems – a new study just published

Illustration of Curatella americana and its pollinators by Pedro Lorenzo

The distribution of plants, animals and other organisms that we see around us is clearly influenced by climate: all species have limitations in terms of temperature, rainfall, etc., that affects where they can live and reproduce. As well as these contemporary “climatic niches” however, there are much more subtle effects of historical climate on species, and the ways in which they interact with one another. These are harder to study because it requires us to know about what climatic conditions were like in a particular region thousands or millions of years ago. But as our knowledge of paleoclimates grows, we can apply it to understand how contemporary ecology is shaped by the past. This in turn may tell us how species will react to future climate change.

In a new study that I’ve just published with Brazilian, Danish and American colleagues, we’ve shown that the frequency with which a South American savannah tree self-pollinates is determined mainly by the climatic stability experienced by a population since the Last Glacial Maximum. In contrast, and perhaps surprisingly, the current diversity and abundance of pollinators plays a much smaller role in how often plants self-pollinate.

The work was led by André Rodrigo Rech and formed part of his original PhD research. Here’s the full citation:

Rech, A.R., Ollerton, J., Dalsgaard, B., Jorge, L.R., Sandel, B., Svenning, J.-C., Baronio, G.J. & Sazima, M. (2021) Population-level plant pollination mode is influenced by Quaternary climate and pollinators. Biotropica (in press)

The abstract is below, first in English then in Portuguese. If anyone wants a PDF please add a comment or send me a message via my Contact page.

Abstract:

Patterns in ecology are the products of current factors interacting with history. Nevertheless, few studies have attempted to disentangle the contribution of historical and current factors, such as climate change and pollinator identity and behavior, on plant reproduction. Here, we attempted to separate the relative importance of current and historical processes on geographical patterns of the mating system of the tree species Curatella americana (Dilleniaceae). Specifically, we asked the following: (a) How do Quaternary and current climate affect plant mating system? (b) How does current pollinator abundance and diversity relate to plant mating system? (c) How does mating system relate to fruit/seed quantity and quality in C. americana? We recorded pollinators (richness, frequency, and body size) and performed pollination tests in ten populations of C. americana spread over 3,000 km in the Brazilian savannah. The frequency of self‐pollination in the absence of pollinators was strongly influenced by historical climatic instability and not by present‐day pollinators. In contrast, seed set from hand‐cross and natural pollination were affected by pollinators (especially large bees) and temperature, indicating the importance of current factors on out‐cross pollination. Two populations at the Southern edge of the species’ distribution showed high level of hand‐cross‐pollination and high flower visitation by large bees, but also a high level of autogamy resulting from recent colonization. Our results indicate that historical instability in climate has favored autogamy, most likely as a reproductive insurance strategy facilitating colonization and population maintenance over time, while pollinators are currently modulating the level of cross‐pollination.

Resumo:

Os padrões em ecologia são o produto de fatores contemporâneos interagindo a partir de uma bagagem histórica. Apesar desse reconhecimento, poucos estudos se ativeram em separar as contribuições dos fatores históricos e atuais como o clima, a identidade e comportamento de polinizadores sobre a reprodução de plantas. Neste trabalho nós decompomos a importância relativa dos processos contemporâneos e históricos no padrão geográfico do sistema reprodutivo da árvore comum no Cerrado, Curatella americana (Dilleniaceae). Especificamente nós perguntamos a) como o clima do presente e do quaternário afetam o sistema reprodutivo? b) Como a abundância e diversidade de polinizadores afeta o sistema reprodutivo da planta atualmente. c) Como o sistema reprodutivo se relaciona com a quantidade e qualidade dos frutos produzidos em C. americana? Para responder estas questões, nós registramos os polinizadores (riqueza, frequência e tamanho corporal) e realizamos testes de polinização em 10 populações de C. americana distribuídas em mais de 3.000 km de Cerrado no Brasil. A frutificação com autopolinização foi fortemente influenciada pela instabilidade climática do passado e não teve relação com os polinizadores no presente. Em contraste, a frutificação com polinização cruzada manual e natural foi afetada pelos polinizadores (especialmente abelhas grandes) e pela temperatura atual, revelando o papel de fatores ecológicos sobre a polinização cruzada. Duas populações na borda sul da distribuição de C. americana apresentaram alto nível de frutificação com polinização cruzada manual e altas taxas de visitação floral por abelhas grandes, mas também apresentaram alto nível de autogamia interpretadas como resultado da recente colonização dessas áreas. Nossos resultados indicam que a instabilidade climática do passado promoveu a autogamia como uma estratégia de segurança reprodutiva capaz de facilitar a colonização e manutenção de populações nesses locais com polinizadores imprevisíveis. Em contrapartida, nos locais com disponibilidade de polinizadores a polinização cruzada foi intensificada revelando a como processos históricos e contemporâneos atuam de forma sinérgica sobre o sistema reprodutivo das plantas.

Why did I write the book? An interview with NHBS

The nice people at NHBS recently did a wide-ranging interview with me about my new book Pollinators & Pollination: Nature and Society and what led me to write it. It covers a lot of ground, including climate change, food security, the UK Pollinator Monitoring Scheme, and growing up in Sunderland.

Here’s the link:
https://www.nhbs.com/blog/jeff-ollerton-pollinators-pollination

Flowers can be assholes – quite literally!

2003-572 s G Bochum

WARNING: There’s a high yuck factor to this post, it’s not for the squeamish or easily offended!

One of my Twitter contacts, Traci Birge in Finland, has been reading Pollinators & Pollination: Nature and Society, and making some very nice comments about it. I had to laugh at this one in which she describes some plants as “assholes” because of the way in which they deceive pollinators into visiting their flowers but offer no reward in return:

If you follow that thread you can see that Traci was closer to the truth than perhaps she realised: there are some plants with flowers that appear to mimic the anuses of dead mammals, particularly in the families Apocynaceae and Araceae. By their smell, texture, colour and hairiness they are fooling flies into visiting the flowers, because assholes, like any mammalian orifice, provide an entry point for maggots of carrion-feeding flies. Sometimes the deception is so great that the flies lay their eggs on these blooms, though of course the maggots starve.

A great example of an anus-mimicking bloom is the Dead Horse Arum (Helicodiceros muscivorus). Check out the image above: if that doesn’t look like a horse’s ass, I don’t know what does!

Other examples might be found within the stapeliads, especially the genus Huernia which often have a thickened annulus to the centre of the flower. However that could also be interpreted as mimicking an open, inflamed wound on the side of an animal:

As I point out in the book, you might imagine that there would be strong natural selection against flies visiting these flowers if they lose fitness by laying eggs on such an unsuitable substrate. But the flowers are tapping into really deep-seated behaviours and clearly the flies can’t distinguish the flowers from the real thing.

This is flower pollination that is far removed from the deliciously perfumed, cute-and-cuddly, heart-warming world of bees and flowers. Isn’t nature wonderful?

All photos from Wikipedia, as follows:

Helicodiceros muscivorus: Göteborgs botaniska trädgård (photographer: Ingemar Johansson) – http://www.mynewsdesk.com/se/pressroom/goteborgs_botaniska_tradgard/image/view/dracunculus-muscivorus-128973, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=19265330

Huernia zebrina: Enzo^ – Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=10963668

Huernia schneideriana: Juan Carlos Fonseca Mata – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=94705877

Plant-pollinator networks in Australian urban bushland remnants are not structurally equivalent to those in residential gardens – a new study just published

Towns and cities are ecologically complex environments where nature finds a home in all sorts of places, including both highly artificial gardens created by people, and the fragments of natural environment left behind when developments are built. In a new study that I’ve co-authored with Australian researcher Kit Prendergast we’ve for the first time compared and contrasted the pollinators, and the plants that they visit, in urban settings in the the biodiversity hotspot of Western Australia. Full disclosure: the field work was all done by Kit as part of her PhD. I just acted as an “adopted supervisor” (her words!) to help with data analysis and writing up of the work.

I think that it’s a great study, not least because it really highlights just how different gardens are to remnant natural vegetation. If we are to maintain the maximum possible pollinator diversity, and associated pollination services, we need to retain as much remnant vegetation as possible when designing and building new developments. Gardens alone are not enough.

The study details are:

Prendergast, K.S. & Ollerton, J. (2021) Plant-pollinator networks in Australian urban bushland remnants are not structurally equivalent to those in residential gardens. Urban Ecosystems https://doi.org/10.1007/s11252-020-01089-w

The abstract is below; if you’d like a PDF of the paper please use the form on the Contact page.

Abstract

Urbanisation is a prominent and increasing form of land-use change, with the potential to disrupt the interactions between pollinators such as bees and the flowering plants that they visit. This in turn may cause cascading local extinctions and have consequences for pollination services. Network approaches go beyond simple metrics of abundance and species richness, enabling understanding of how the structure of plant-pollinator communities are affected by urbanisation. Here we compared pollination networks between native vegetation (bushland) remnants and residential gardens in the urbanised region of the southwest Australian biodiversity hotspot. Across fourteen sites, seven per habitat, plant-bee visitor networks were created from surveys conducted monthly during the spring-summer period over two years. Extinction slope (a measure of how extinctions cascade through the network), and network robustness and nestedness were higher for bushland remnants, suggesting that networks in bushland remnants had greater functional integrity, but if disrupted, more cascading extinctions could occur. In contrast, niche overlap between pollinators was higher in residential gardens, suggesting greater competition for resources. Most species-level properties did not differ between habitats, except for normalised degree, which was higher in bushland remnants. In conclusion, it appears that pollination networks in managed residential gardens are not structurally equivalent with those in bushland remnants. This has implications for conservation of wild bee assemblages in this biodiversity hotspot, and suggests removal of remnant native vegetation for residential development could disrupt the integrity of plant-pollinator assemblages.