Tag Archives: Ecology

Don’t forget the blogosphere! A new opinion piece just published

Despite claims to the contrary, the total demise of the ecology blogosphere has not yet occurred. Some of us are still going strong, and others such as Dynamic Ecology and Jabberwocky Ecology have reactivated after a prolonged hiatus. It seems timely, therefore, to revisit the whole notion of ecological blogging, what it’s for, and what bloggers and readers get from it, personally as well as professionally. That’s the purpose of a new opinion piece just published in the Annals of Applied Biology.

The article is part of a special issue of that journal dedicated to the late Prof. Simon Leather, who was both its former Editor-in-Chief and a dedicated blogger. Simon, with his insightful, often very funny, blogging voice on Don’t Forget the Roundabouts, is sorely missed.

The full reference with a link to the journal is below. If anyone needs a PDF, please do ask via my Contact page:

Heinen, R., Duffy, M., Fox, J.W., Heard, S.B., McGlynn, T., Ollerton, J., Rillig, M.C., Saunders, M.E., Millman, C.A. & Azevedo, R.A. (2024) Opinion: Don’t forget the blogosphere. Annals of Applied Biology 185: 124–131

Here’s the abstract:

Communicating results and ideas to a wider audience has been an important, but challenging component of scientists working in an academic environment. Particularly in recent decades, various social media platforms have become increasingly important to facilitate this. In addition, many scientists have used blogging platforms to communicate and discuss their work. Although the online dynamics of science communication are continuously changing, blogging has been used in a remarkably stable form for several decades. For this work, we brought several ecology bloggers to reflect on blogging as a science communication medium. We argue that blogging can be a powerful way to present new ideas and discuss them with a wide audience. Although blogs are not the same as scientific articles, they often serve as the initial brainstorm session. Importantly, we argue that blogs are most effective when bloggers and readers actively engage in conversations. We believe that blogging will be here to stay in science communication because of its unique and independent form of outreach.

Want to keep up with what’s going on in nature conservation and biodiversity? Subscribe to Mike Shanahan’s ‘Nature Beat’!

The hidden potential value of woodland trees for wild bee assemblages – lead author Guthrie Allen introduces his recently published study

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Note: This is a guest blog post by Guthrie Allen who is a PhD candidate at the University of East Anglia.

Though often overlooked, woodlands have great potential to support wild bees in farmed landscapes. Both the understory and canopy can provide large quantities of early-season nectar. The pollen of woodland-tree taxa such as Acer can form a large proportion of the early-season diets of bumblebees and solitary bees. Even the pollen from wind-pollinated trees such as Quercus can form a significant part of the diets of several common solitary bee species. Woodlands are also believed to provide ample nesting opportunities. These factors may explain why several studies have found positive correlations between bee abundance and/or diversity and woodland cover at the landscape scale. Despite this, a large-scale European study has shown that interior woodland understories support very few bees compared to exposed woodland edges.

Sampling the canopy – at heights of up to 20 metres – is not easy, but unlike the understory, this habitat remains sun-exposed after canopy closure and could be favourable for bees. In Europe, however, our knowledge of bee activity in the woodland canopy is very limited. Furthermore, whilst canopy-tree taxa have been identified as suitable food sources for many bees, we have little evidence that these trees are used for forage when located within woodlands. To explore the role of the canopy, we trapped bees in late spring in the understory and canopy – at the exposed edges and in the interiors – of 15 woodland sites across an English agricultural landscape.

A significant proportion of bee abundance was found in the canopy, represented by 23 of the 29 total sampled species. Interior canopy activity was much higher when nectar-producing Sycamore (Acer pseudoplatanus) trees were nearby. Communities differed between the canopy and understory: of the seven most common species sampled, three were more active in the understory, while the opposite was true of one species – Bombus lapidarius. Interestingly, we found the sex ratio of the most abundant species – B. pratorum – to be female-skewed in the canopy. For four of these species, and contrary to expectations, we found no evidence that understory activity was any higher at woodland edges compared to woodland interiors.

Further research is needed to understand community differences between the canopy and understory. Nonetheless, our results suggest that both these habitats have a significant role to play in supporting farmland bees. We demonstrate that a diverse bee community has the potential to exploit canopy resources, with nectar-producing trees in woodland interiors likely to provide forage for many bees. And we show the unexpected potential of interior woodland understories to support bee abundance.

Here’s the full reference with a link to the open access paper:

Allen, G. & Davies, R.G. (2022) Canopy sampling reveals hidden potential value of woodland trees for wild bee assemblages. Insect Conservation and Diversity. Available from: https://doi.org/10.1111/icad.12606

Here’s the abstract:

Woodlands can play an important role in supporting bee abundance and diversity in agricultural landscapes. However, in temperate-region studies, the canopy is rarely sampled, and our understanding of its contribution is limited. To explore this, we sampled bees in late spring with blue vane traps in the understory (n = 30) and crowns of mature Quercus robur (n = 35) at the exposed southern edges and in the interiors (ca. 25–75 m from woodland edges) of 15 woodland sites across an English agricultural landscape. A significant proportion of bee abundance and diversity was found in the canopy: canopy-trap catches were estimated to be a third as large as understory-trap catches, and 23 of the 29 sampled species were present in the canopy. Of the seven most common species sampled, four were equally abundant in woodland edge and interior traps; three were more abundant in understory traps, and a single species—Bombus lapidarius—was more abundant in canopy traps. The sex ratio of the most abundant species, B. pratorum, was female-skewed in the canopy. Additionally, the presence of nearby Acer pseudoplatanus trees in flower greatly increased canopy-trap catches in woodland interiors. These results suggest that both the woodland canopy and understory have a significant role to play in supporting farmland bee communities; they indicate the importance of nectar-producing trees in woodland interiors, opening avenues for canopy-based management; and they demonstrate that a diverse bee community has the potential to exploit canopy floral resources.

Under every stone, an ecosystem: photosynthesis beneath rocks in the Kenyan savanna

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We’re coming to the end of our time here in Kenya and we’ve amassed some amazing memories of the wildlife with great views of large mammals such as giraffe, zebra, elephant, hippos, and a variety of antelopes including the ubiquitous dik-diks. In addition, between us we’ve put together a bird list of about 130 species for the site. But as always it’s the smaller things that have fascinated me the most and some of the student project groups have worked with pollinators, ants, and other invertebrates.

One of those fascinations has been the life that exists beneath some of the rocks that are embedded in the red soils of this part of the savanna. Turn them over and you often find the green growths of what are probably cyanobacteria – so-called “blue-green algae” – which are true bacteria and not at all related to algae, even though they also photosynthesise.

The question arises, of course, of how an organism that requires sunlight to survive is able to grow under a stone? Our investigations have shown that they only live under quartz rocks, mainly those that are lighter in colour. Quartz is of course a crystal and it allows a small amount of sunlight to pass through, typically only one or two percent of the sunshine hitting the rocks. There’s also greater humidity under the stones so it’s a relatively more benign place to grow than the savanna, especially in the dry season.

There’s a great review of these microbial communities, and their ecological importance, by Chan et al. called Hypolithic microbial communities: between a rock and a hard place.

Here’s some photographs that I took of these hypolithic photosynthesisers:

Oh, ok, if you insist: here’s some giraffe:

Published today: a new children’s book about bees and other pollinators!

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One of the projects with which I’ve been involved over the last year has been advising on a new book for children about bees and other pollinators, called Can We Really Help The Bees? Written by Katie Daynes and wonderfully illustrated by Róisín Hahessy, it tells the story of what happens when a swarm of bees comes to the window to let a group of children know that they, and their friends the other pollinators, are in trouble. Can they help? Yes they can!

It’s been a real pleasure working with Katie and Róisín on this project for Usborne Publishing and seeing the ideas, text, and illustrations evolve over time. I’ve written a short post over at the Usborne blog with some ideas about how to get children involved in helping the pollinators, and I think that it’s worth repeating one of the things that I wrote: everyone can make a difference to the wildlife around us and no one is too young to be involved!

Because of my involvement with Can We Really Help The Bees? I wasn’t able to include it on my curated list of the best books about bees and other pollinators at the Shepherd site. But it definitely should be on there and is highly recommended!

What happens when pollinators lose their flowers? A new study suggests some answers

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Biella et al image

Pollinators such as bees and butterflies are highly dependent on flowers to provide nectar as food; at the same time, those plants are reliant on the pollinators for reproduction. Over the past few decades, declines in both flower and pollinator diversity and abundance have prompted ecologists to wonder about the consequences of flower loss for pollinator communities and for plant pollination.

In a ground breaking new study, a team from institutions in the Czech Republic and the University of Northampton in the UK have published the results of experiments that seek to answer these questions. Led by PhD researcher Dr Paolo Biella, the team performed experiments in both countries that involved temporarily removing thousands of flower heads from grassland plant communities. They assessed how the pollinator assemblage responded to their removal, and how effectively the remaining flowers were pollinated. The team focused on generalist plant species that support the majority of pollinators within a community because these have traditionally been less well studied than highly specialised relationships.

The results are published today in the open access journal Scientific Reports and provide the first demonstration of the ways in which pollinators flexibly adjust their behaviour when faced with a sequential loss of resources. This flexibility is constrained by the type of flowers they visit, however: pollinators will tend to switch to flowers of a similar shape to the ones that have been lost. From the plant’s perspective, things are less clear: the patterns of pollination for the remaining species were idiosyncratic and not as predictable. Some plants received more pollination during the experiment than before, others less.

For the first time we are seeing the consequences of sudden loss of flowers for both the pollinators and the plants in a habitat. That the pollinators can respond flexibly to this loss is a welcome indication that these insects might be more resilient to sudden changes than we had thought. However, the erratic pollination of the flowers shows that there is a great deal of random chance within these ecological systems that is not easily predictable. In the same week that the UN’s Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) Global Assessment Report on Biodiversity and Ecosystem Services was published, our study reminds us that there is much that we do not currently understand about the consequences of sudden changes in the natural world.

One of the team’s recommendations is that pollination-generalist plant species should be given much more attention in conservation assessments than has previously been the case. These plants are at the core of plant-pollinator communities and without them the rarer and more specialised species could not exist.

Details of the study are as follows:

Biella P., Akter A., Ollerton J., Tarrant S., Janeček Š., Jersáková J. & Klecka J. (2019) Experimental loss of generalist plants reveals alterations in plant-pollinator interactions and a constrained flexibility of foraging. Scientific Reports 9: 1-13

Here’s the abstract:

Species extinctions undermine ecosystem functioning, with the loss of a small subset of functionally important species having a disproportionate impact. However, little is known about the effects of species loss on plant-pollinator interactions. We addressed this issue in a field experiment by removing the plant species with the highest visitation frequency, then measuring the impact of plant removal on flower visitation, pollinator effectiveness and insect foraging in several sites. Our results show that total visitation decreased exponentially after removing 1-4 most visited plants, suggesting that these plants could benefit co-occurring ones by maintaining high flower visitor abundances. Although we found large variation among plant species, the redistribution of the pollinator guild affected mostly the other plants with high visitor richness. Also, the plant traits mediated the effect of removal on flower visitation; while visitation of plants which had smaller inflorescences and more sugar per flower increased after removal, flower visitors did not switch between flower shapes and visitation decreased mostly in plants visited by many morpho-species of flower visitors. Together, these results suggest that the potential adaptive foraging was constrained by flower traits. Moreover, pollinator effectiveness fluctuated but was not directly linked to changes of flower visitation. In conclusion, it seems that the loss of generalist plants alters plant-pollinator interactions by decreasing pollinator abundance with implications for pollination and insect foraging. Therefore, generalist plants have high conservation value because they sustain the complex pattern of plant-pollinator interactions.

Local and regional specialization in plant–pollinator networks: a new study just published

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Euphorbia canariensis pollinators 2016-04-29 17 58 00

A fundamental feature of the natural world is that no species exists in isolation: all organisms interact with other organisms during their lives. These interactions take many forms and the outcome varies with the type of interactions. For example predator-prey interactions are clearly negative for the prey species, but positive for the predator. Other interactions result in positive outcomes for both species, including relationships between pollinators such as bees, birds and flies, and the flowers that they pollinate. An important feature of such interactions is how specialized or generalized it is; that is, how many different pollinators are actually involved in pollinating a particular type of flower, or how many types of flower does a specific pollinator visits.

In a newly published study, I have collaborated with colleagues from Denmark and Brazil to assess how local specialization (within a community) relates to regional specialization (across communities) using two separate data sets from the Brazilian rupestrian grasslands and Canary Island/North African succulent scrub vegetation.

Here’s the citation with a link to the paper (drop me a line if you can’t access it and need a PDF):

Carstensen, D.W., Trøjelsgaard, K., Ollerton, J. and Morellato, L.P.C. (2017) Local and regional specialization in plant–pollinator networks. Oikos (in press) doi:10.1111/oik.04436

The abstract is as follows:

“Specialization of species is often studied in ecology but its quantification and meaning is disputed. More recently, ecological network analysis has been widely used as a tool to quantify specialization, but here its true meaning is also debated. However, irrespective of the tool used, the geographic scale at which specialization is measured remains central. Consequently, we use data sets of plant–pollinator networks from Brazil and the Canary Islands to explore specialization at local and regional scales. We ask how local specialization of a species is related to its regional specialization, and whether or not species tend to interact with a non-random set of partners in local communities. Local and regional specialization were strongly correlated around the 1:1 line, indicating that species conserve their specialization levels across spatial scales. Furthermore, most plants and pollinators also showed link conservatism repeatedly across local communities, and thus seem to be constrained in their fundamental niche. However, some species are more constrained than others, indicating true specialists. We argue that several geographically separated populations should be evaluated in order to provide a robust evaluation of species specialization.”

This is what those two different habitats look like:

If you would like more information on plant-pollinator networks, including details of an edible game for Christmas (!), follow this link to the standingoutinmyfield blog.

Saved by a bee: a true story, with reflections and photos from PopBio2017

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The blog has been a bit quiet of late, due to a lot of traveling on my part, starting with field work in Tenerife, then a weekend away with friends on the Isle of Wight, followed by the topic of this post: PopBio2017 – the 30th Conference of the Plant Population Biology Section of the Ecological Society of Germany, Austria and Switzerland in Halle, Germany. And I’d like to begin with a story….

The organisers of PopBio2017 had invited me to be one of five keynote speakers at the conference and I was due to deliver a talk on “The macroecology of wind and animal pollination” first thing (09:00) on Thursday morning. So the night before I duly set my phone’s alarm for 07:00, thinking I’d have enough time to get ready, have breakfast, then take the tram to the venue (a 15 minute ride/walk).

It was a very hot night and I left the windows open, but my mind was restless with thoughts of how to deliver the talk most effectively. So I kept waking up during the night, and actually slept through the alarm. The next thing I know it is 07:45 and I am being woken up by an urgent buzzing noise….from a bee!

I swear this is true: a bee had flown in through the window, buzzed for a few seconds right in front of my face, and woke me up in time to deliver my talk on pollinators! It then turned around and flew straight back out of the window.

It actually wasn’t until I’d jumped out of bed and into the shower that I’d woken up sufficiently to appreciate what had happened…and wondered if anyone would actually believe me! Anyway, I got to the venue with 15 minutes to spare, the talk seemed to go well, and it’s a story I think I’ll enjoy telling for some time to come.

The conference was really fabulous, with some very impressive science on show. It was a good mix of postdocs, PhD students, and established researchers talking on a diverse range of plant ecology topics, not just “plant population biology” (whatever that really is – there was some discussion on that score). The organisers had arranged the programme so that the keynotes in each session were followed by shorter talks broadly related to that topic, so I was followed by a series of presentations on pollination biology. And very good they were too.

Here’s some photos from the week:

A slightly blurry audience waiting for my talk to begin (not as blurry as me after the dash to the venue however…):

I was fascinated by the coypu that are common in the River Salle which flows through the city of Halle. They are classed as an invasive species, but are very, very cute:

Indeed so cute I couldn’t resist taking a selfie…

Some interesting urban greenery including swales for flood defence:

Wall plants surviving the graffiti:

Halle’s most famous resident, Handel:

There’s a Harry Potter feel to some parts of the town:

The fabulous double-double-spired cathedral:

There had to be a spiral or two, of course:

On the Saturday after the talks had finished we took an excursion to the fascinating “Porphyry Hills” dry grasslands – unique western extensions of plant communities and species normally found in the east, including many plants of the steppe:

These rocky outcrops have become exposed as agricultural ploughing caused the surrounding soil level to drop:

Some of the grassland areas have very thin soils with resultant high plant diversity:

Lots in flower, though not as many pollinators as I would have liked:

On the last evening a couple of us had a private tour of the university’s botanic garden, and well worth a visit it is too:

It was a thirsty conference – “To beer or not to beer….”?

Finally thanks to the organisers of PopBio2017 for the invitation to speak, and to all of the conference attendees who made it such a special meeting.

Why has a 102 year old ecologist been asked to vacate his university office?

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David W. Goodall is an Australian ecologist with an outstandingly long career – he received his PhD 75 years ago! Over that period he has produced some seminal works in the field of vegetation analysis, and acted as Editor-in-Chief of the 36 volume, highly influential Ecosystems of the World series.

Until recently David had been allocated office space at Edith Cowan University in Perth, and commuted into campus by bus and train at least four days a week. As reported in the Australian media, however, David has now been asked to give up his office and only come on to campus, accompanied, for pre-arranged meetings.

The university claims that it made the decision in David’s own interest, but his own daughter (who surely knows him and his capabilities better than the university authorities) says it’s the “the worst thing …[they]… could possibly do, I don’t know if he would survive it”.

I really hope Edith Cowan University reconsiders this, it seems a very shabby way to treat a distinguished researcher with such a long working history, who is still active (his most recent paper is from 2014!) and contributing to the scholarly life of his department.

Please read the original story and, if you feel so inclined, tweet your reaction to @EdithCowanUni

Polinode – a user-friendly tool for visualising ecological networks

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Birds mixed flocks (2) - curved It is a general ecological rule that no species exists in isolation; all species interact with other organisms within the communities to which they belong. The collection and analysis of ecological interaction data has burgeoned over the past couple of decades, particularly in my own area of (largely) mutualistic species interactions such as plant-pollinator relationships – see for example this recent post on hummingbird-plant networks.

There are a number of software packages available for analysing and visualising this type of data, including bipartite and foodweb in R, Food Web Designer, and Gephi. Tools such as this vary in their flexibility and in the investment of time required to produce good quality graphics, and ultimately it’s down to personal preferences which you use.

Recently I discovered some very user-friendly network visualisation software that is browser/cloud based, free to use (at least the basic version), very flexible, intuitive and quick to learn. Ideal if you are pressed for time and want to generate some quick food webs.

The system is called Polinode and was developed primarily to visualise business and social science data (the “poli” part is nothing to do with pollination, that’s purely coincidental). However there’s no reason why it can’t be used for ecological data, as the image above demonstrates. This is a visualisation of mixed-species flocks of birds feeding together and alone on a local urban park that I’ve discussed previously. The thickness of the line is proportional to number of interactions observed, and the size of each node is proportional to the number of birds. Both are scalable in Polinode.

One could also present these data as a straight-line graph, without the loops to indicate single-species feeding:

Birds mixed flocks (5)

As well as these types of networks it’s also possible to produce bipartite (what Polinode terms “hierarchical”) graphs, for example this network of bumblebees feeding on different plant families in a British grassland (click for a closer view – I realised afterwards that I downloaded a rather small version):

Bombus hypnorum with plant families

The system is very flexible and nodes can be grabbed and moved around (as I did above to offset the plant family nodes), recoloured, resized, text resized, etc.

Polinode also calculates a range of network metrics such as degree and Louvain communities (a measure of modularity) which is more limited than some ecologists might require, but which is a good starting point for those new to ecological network statistics.

Data files can be uploaded directly from Excel, and there are example templates showing how to lay out the data. There is also ample online support including written guidance, videos, and a regular blog. Even in the few months I’ve been playing with the system the developers have added more features, including a graphing facility that generates column and scatter plots from your networks.

There you go, that’s an introduction to Polinode for ecologists; hope it’s useful for your work.