Category Archives: Biodiversity

How do artificial nectar feeders affect hummingbird abundance and pollination of nearby plants? A new study in the Journal of Ornithology

Hummingbirds on feeds in Brazil

Back in November 2013, during my research and teaching trip to Brazil, I discussed an amazing garden that we visited in which the owner had set up around a dozen hummingbird feeders that were attracting hundreds of individual birds from over 20 species.  As I mentioned, one of the owner’s concerns was that by feeding the birds he might be negatively affecting the reproduction of hummingbird-pollinated plants in the surrounding forest.  I thought it unlikely but there have been very few tests of this idea, and none in that part of South America.

After I left, a Master’s student called Jesper Sonne, based at the Center for Macroecology and Climate in Copenhagen, worked with my Brazilian and Danish colleagues on collecting data to address this question.  Between us we analysed and wrote up the results, and have recently published the paper in the Journal of Ornithology under the title “Spatial effects of artificial feeders on hummingbird abundance, floral visitation and pollen deposition“.

The abstract is below and if anyone wants a PDF, please drop me a line.  But the take home message is that although these feeders have a significant local effect on hummingbird abundance, there’s no evidence that they affect plant reproduction in the vicinity.  It’s nice when predictions prove correct….

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Abstract

Providing hummingbirds with artificial feeders containing sugar solution is common practice throughout the Americas. Although feeders can affect hummingbird foraging behavior and abundance, it is poorly understood how far this effect may extend. Moreover, it remains debated whether nectar-feeders have a negative impact on hummingbird-pollinated plants by reducing flower visitation rates and pollen transfer close to the feeders. Here, we investigated the effects of distance to nectar-feeders on a local hummingbird assemblage and the pollination of Psychotria nuda (Rubiaceae), a hummingbird-pollinated plant endemic to the Brazilian Atlantic Rainforest. At increasing distance (0–1000 m) from a feeding-station, where hummingbirds have been fed continuously for the past 13 years, we quantified hummingbird abundance, and rates of flower visitation and pollen deposition on P. nuda. We found that hummingbird abundance was unrelated to distance from the feeders beyond ca. 75 m, but increased steeply closer to the feeders; the only exception was the small hummingbird Phaethornis ruber, which remained absent from the feeders. Plants of P. nuda within ca.125 m from the feeders received increasingly more visits, coinciding with the higher hummingbird abundance, whereas visitation rate beyond 125 m showed no distance-related trend. Despite this, pollen deposition was not associated with distance from the feeders. Our findings illustrate that artificial nectar-feeders may locally increase hummingbird abundance, and possibly affect species composition and pollination redundancy, without necessarily having a disruptive effect on pollination services and plants’ reproductive fitness. This may apply not only to hummingbirds, but also to other animal pollinators.

Hummingbirds on feeds in Brazil 2

BBC Wildlife magazine for October features Northampton harvest mice research

BBC WIldlife Magazine

The October issue of BBC Wildlife has a feature on the research being done by Emily Howard-Williams into the ecology and conservation of one of the UK’s most charismatic mammals, the harvest mouse. Emily is a Lecturer in Countryside Management at Moulton College and a PhD student at the University of Northampton, supervised by my colleagues Dr James Littlemore (at Moulton) and Dr Duncan McCollin (at Northampton).

Well done to Emily!  You can find out more about her research in this press release.

Spiders: a guide for first-year students!

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Yesterday I had a phone call from a colleague in the university’s marketing department.  Apparently there’s been a lot of complaints, and some hysteria on social media, about spiders appearing in the rooms of first year students in our halls of residence.  My colleague asked if I’d write something about spiders, and how they were harmless and nothing to worry about, that they could use to placate the students’ worries.  This is what I wrote and I thought it worth sharing on the blog.

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Spiders! Ugly. Unpleasant. Spooky. Dangerous…..even deadly?! Spiders in Britain are all of these things, right?

No! Absolutely not! Spiders are fascinating, sometimes beautiful, and are an ecologically important groups of animals. Although it’s true that large spiders can sometimes give us the jitters, myself included: I don’t like walking into them in the garden! In fact as a kid I had a real phobia of spiders that I got over by handling increasingly bigger ones until eventually I could pick up even the largest spider we have in this country.

Most of the fear of spiders is based on myths and misconceptions, rather than reality. Ignore the DRAMATIC HEADLINES about False Widow Spiders – it’s an uncommon species and it’s extremely rare to encounter one of these, never mind be bitten. They make their webs near rocks where there are deep cracks into which they can hide. So you’re not likely to find them in your room!

Spiders play a really important role in the environment by eating large numbers of flies, including some that bite or carry disease or that might otherwise be much more harmful to humans than spiders. Spiders in turn are a food source for many of our birds, and in the spring some birds also use spider webs to construct their nests. If we had no spiders then we’d lose a lot of the birds that are so familiar in our gardens, such as Blue Tits and Blackbirds.

At this time of the year spiders are more apparent than ever, and the one you are most likely to see is a large, beautifully patterned species know as the European Garden Spider. The big ones are the females; males are much smaller. They sometimes make their way into houses and can construct large webs. But they are harmless and would only bite if held tightly in the hand, and they are much happier outside than in your room. They can’t jump on you and they do not attack!

What to do if you find a spider in your room and you want to get it out but can’t bear to go near? Find a friend who is not so squeamish and ask them to use a glass and a book or piece of cardboard to gently capture the spider and take it outside. Don’t worry, it won’t find its way back! Before you release it, though, try to find the courage to look really closely at this creature: they are attractively speckled and really very pretty!

The other thing you can do is find some conkers from the Horse Chestnut trees on campus and put them on your windowsill. It’s an old folk tradition that spiders don’t like the smell of conkers and there is some evidence that it keeps them out of the house.

I’ll let you into a secret. As Professor of Biodiversity I’ve done ecological field work all over the world, including the rainforests of Africa and the savannahs of South America. Every now and again I come across spiders that are much larger, and potentially more dangerous, than anything we find in Britain. Initially they still give me a shiver; but once I’ve spotted them I can take time to study their colours and forms and beautiful webs, and appreciate just how amazing and important spiders really are.

Have a great year at university and don’t worry about the spiders!

Are tropical plants and animals more colourful? Not according to a new study!

Cinnabar caterpillars 1 P1020535

The notion that tropical ecosystems are somehow “different” to those at higher latitudes is a pervasive one in ecology and biogeography, that has its roots in the explorations of 18th and 19th century Europeans such as von Humboldt, Darwin, Wallace, and Belt.  All of these authors expressed their amazement at the biological riches they observed in their tropical explorations, and how different these habitats were to those they knew from home.

In many ways the tropics are special, of course and we know that they contain many more species than most other parts of the world; indeed my own work has shown that the tropics have significantly more types of functionally specialised pollination systems, and that the proportion of wind pollinated species is lower in tropical communities.  However tropical plants are not, on average, more ecologically specialised (that is, they do not use few species of pollinator) and, as the recent guest blog on Dynamic Ecology argued, there is a growing body of evidence to say that overall tropical interactions between species are not stronger and more specialised than those in the temperate zone (though there are others who dispute this and it’s an ongoing debate).

One of the central tenets of the “tropics are special” idea is that the tropics are more colourful; or rather that the biodiversity of the tropics tends to be more garish, gorgeous, and spectrally exuberant, than that of other parts of the globe.   Now a new study by Rhiannon Dalrymple, Angela Moles and colleagues, published in the journal Global Ecology and Biogeography, has challenged this idea for flowering plants, birds, and butterflies in Australia, using sophisticated colour analysis rather than relying on human impressions. Following that link will take you to the abstract and you can read it yourself; however I wanted to summarise their findings by quoting from the first section of the discussion in the paper:

“Contrary to predictions…[our]…results have shown that tropical species of birds, butterflies and flowers are not more colourful than their temperate counterparts. In fact…species further away from the equator on average possess a greater diversity of colours, and their colours are more contrasting and more saturated than those seen in tropical species.”

It’s a really, really interesting study that, as the authors say, runs counter to all of our expectations.  Gradually ecologists and evolutionary biologists are testing some long-standing assumptions about the tropics and the results are proving to be a challenge to preconceived ideas about patterns in the Earth’s biodiversity.

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Full disclosure: senior author on the paper Angela Moles was my co-author on that Dynamic Ecology blog, based on which we’ve written a short review article that (hopefully) will be published soon.  Other than that I have no vested interest in the study.

The All-Ireland Pollinator Plan 2015-2020

B pasc on sunflower

In the last 12 months we’ve seen the release of the National Pollinator Strategy for England and the USA’s Strategy to Promote the Health of Honeybees and Other Pollinators.  Now the Republic of Ireland and Northern Ireland have joined forces to produce the All-Ireland Pollinator Plan, a strategy for 2015-2020 that has been released today.  Follow that link and you can download a copy.

This appears to be the first cross-jurisdiction pollinator plan in the world and, as such, is to be welcomed; as I said in my reflections on the National Pollinator Strategy, biodiversity does not respect political boundaries.

That “love wasps” article – this is how Friends of the Earth responded

Clearly my quick post this morning got through to Friends of the Earth at some level (thanks to everyone who tweeted it).  Here’s what they have done to the article in response:

  • Removed the not-a-wasp photograph (good)
  • Added some text about other things that wasps pollinate (good) but left in the text about figs (bad)
  • Under the “garden pests” section they have add some text, as follows (bad):

The University of Northampton’s Dr Jeff Ollerton says: “Wasps are part of a whole ecological guild of scavenging animals that includes ants, various birds, etc, which plays a valuable role by removing vast amounts of waste organic material from our towns and cities every year.”

Huh?  What I said had nothing at all to do with eating pests.  Was that not clear when I talked about “waste organic material” rather than “pests”?

Incidentally, and for the record, I’ve had no contact from anyone at Friends of the Earth asking if it was ok to quote me, or check text, or anything.

So, not a complete success then.  Once again, feel free to tweet this at FoE

More poor quality information: Friends of the Earth’s “Love Wasps” campaign

Despite some recent posts in that vein, I don’t want to turn this blog into just an outlet for my frustrations about the lack of science/evidence in otherwise well-meaning conservation initiatives.  However something caught my eye at the weekend that I feel I have to comment on.

Friends of the Earth has recently posted a very well-meaning piece about why we should stop hating wasps and learn to appreciate them.  I whole-heartedly support this: wasps are one of the least understood and most under-valued aspects of local biodiversity, and the article makes some very good points.

But there are also some aspects to the article that make me cringe and add a new layer of inaccuracy to a subject already flooded with crass statements such as “what use are wasps”:

  • The first photograph in the article does not show a wasp: it’s a syrphid fly, specifically a species that mimics wasps but is other wise harmless.  These flies do not sting or bite.
  • “Wasps pollinate figs” – yes they do, but fig pollinating “wasps” are tiny and only distantly related to the kinds of wasps you’re going to see in a British garden.  In any case they do not pollinate commercial edible figs: these wasps spend much of their life-cycle within the fig and who wants to eat a fig full of insects?
  • Having said that, the sorts of wasps the article is referring to ARE important pollinators of a whole range of plants, including some orchids, umbellifers, ivy, etc.  That’s not mentioned at all.
  • The piece misses out the fact that wasps are part of a whole ecological guild of scavenging animals that includes ants, various birds, etc., which plays a valuable role by removing vast amounts of waste organic material from our towns and cities every year.  They also perform a similar function in natural ecosystems.

What’s frustrating about Friends of the Earth’s article is that there are any number of individuals and organisations out there who would be happy to fact-check such a piece, including Buglife, BWARS, and a range of scientists and well-informed specialists in natural history.  Why doesn’t Friends of the Earth make use of them?

As I’ve said before I don’t use Twitter, so if anyone wishes to tweet this at Friends of the Earth, please go ahead.

The biodiversity of the human family tree just got bigger

Tring 8

Today’s announcement of the discovery in South Africa of a new extinct species in the genus Homo, named Homo naledi, is a major scientific discovery that may prove to be one of the findings of the year, if not the decade.  As I’ve mentioned previously, human evolution fascinates me and I could easily have been sucked into the frustrating, controversial and important world of the professional hominid hunter.  But I’m content to view and appreciate from a distance as palaeo-anthropologists make their amazing discoveries about human ancestral biodiversity, and I thought I’d collate the links to some of the main stories and items relating to today’s events:

The scientific paper describing Homo naledi has been published in the open-access online journal eLife, rather than a journal such as Nature or Science, the more usual outlet for such discoveries, presumably because the importance of the find certainly demands rapid publication.  Interestingly its Altmetric score is already 281, having been picked up by numerous news outlets, tweeted, blogged about, etc.

I first saw the story earlier today on the BBC News website; the long article has a video interview with Professor Lee Berger, lead author of the paper.  There is also video footage from today’s press conference in South Africa, presented by Professor John Hawks, in which he describes in more detail the significance of this fossil, with its mix of both primitive and more derived anatomical features.

The Guardian also ran the story, this time with some different video footage, including a view inside the cave where the fossils were found, and there’s a 40 minute podcast.

Finally, National Geographic, which funded the study, has some videos on YouTube, including a fascinating account of the workshop that was convened to study the fossils and more discussion of its significance and amazing footage of how the fossils were recovered from the cave, and how the species was reconstructed.

This is a story that will run and run: we don’t know how old the species is and there’s lots of speculation about the significance of finding such a large number of individuals all together in what appears to be a burial chamber.  It’s an exciting time to be interested in human evolution.

Something for the weekend #8 – the microclimatic value of planting our cities, one Buddhist view of environmentalism, and orchids. Oh, and we got married.

The latest in a regular series of posts to biodiversity-related* items that have caught my attention recently:

  • One of the best environmental writers around at the moment, Paul Kingsnorth, had an interesting essay on how Buddhism is helping him to come to terms with the current environmental crisis.  It was published earlier this year but I’ve only just seen it.  Paul is one of the founders of the Dark Mountain project, which I’ve mentioned before.
  • Here’s a piece about a fascinating study of how different types of vegetation can alter the average temperatures of our cities.
  • Finally, regular readers of this blog know that I often mix some personal stories with my professional reflections, so the Big News of Summer 2015 is that, on the 15th of August, Karin and I were married at The Guildhall, Northampton, accompanied by our family and friends.  We had an incredibly happy day, and I wore a very biodiverse shirt, as you can see:

Karin&Jeff (73 of 477)

Feel free to recommend links that have caught your eye.

*Disclaimer: may sometimes contain non-biodiversity-related items.

The organisers’ positive response to criticisms of the “honey bee decline” conference

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Three days ago I wrote a short, fast post expressing my unease (in robust terms) about a forthcoming conference entitled “Biodiversity and Local Partnerships: Halting the Decline of the Honey Bee in the UK”.  I had not anticipated that the post would generate quite as much interest as it did:  2007 views, 16 likes, and 28 comments (including my responses) as of 10am today.

There were also a lot of comments and likes on Facebook, most of it positive and agreeing with my sentiments, though some have suggested that I’m over-reacting, that I may be paranoid, and questioned what my “hidden agenda” is and whether I might be funded by an agrochemical firm (!)  Thanks to everyone who took the time to read the post and/or to respond*, to tweet the post, and even, in one case, phone up the conference organisers.

So it was with some satisfaction that yesterday I received the following email from the conference organisers, Public Policy Exchange (PPE), in response to my initial reply to their invitation:

Thank you for your response to our event, we always appreciate any
feedback from experts such as yourself. Your comments have been passed
on to our researchers and they are currently reviewing this event.

Our researchers do use a variety of sources, though on this occasion it
does appear that some have made sweeping generalisations and
over simplified statements, and ultimately have been unreliable. Clearly
our previous marketing mistakenly overplayed the role of the honey bee
in pollination processes. We certainly don’t want to contribute to a
misinformed narrative around bees and other pollinators; that was never
our intention and so we are looking at how we can improve this event.

Biodiversity is an area which we are very keen to develop further and
your feedback is therefore very helpful to us.

Kind regards,

The Conferences Team

They have also changed the title of the conference to “Biodiversity and Local Partnerships: Halting the Decline of Bees and Other Pollinators in the UK“.

So kudos to PPE for their fast response.  That’s a good outcome as far as I’m concerned and I may consider attending the conference; hell I’d even consider speaking at it if i was asked!

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*Yes, that’s deliberate – I got the impression that some on Facebook were responding without reading it…