Category Archives: Urban biodiversity

Garden pollinators for PAW no. 2 – Marmalade hoverfly (Episyrphus balteatus)

Syrphid on lemon balm 1 cropped - 1P1020548 copyOne of the most frequently encountered of hoverfly species in urban gardens is the beautifully named Marmalade hoverfly (Episyrphus balteatus).  This insect is a “true fly” of the order Diptera that is sometimes confused with superficially similar wasps (order Hymenoptera), though (as the common name suggests) the species is translucent orange and black in colour rather than waspish yellow and black.  It also has a very flat abdomen whereas wasps are rounded, and they certainly don’t sting.

Individual insects are relatively ineffective as pollinators – they are small and not very hairy, so carry little pollen compared to bumblebees for instance.  However they can be extremely abundant and that abundance makes up for any individual ineffectiveness.  It’s a real generalist, visiting lots of different types of flowers, and in my garden they visit radishes (as I noted last year) and raspberries.

I often see individuals patrolling crops such as runner beans, not visiting the flowers but laying eggs on leaves and stems: the larvae of the Marmalade hoverfly is carnivorous and feeds on aphids, so it plays an interesting dual role of both pollinator and pest controller.  Definitely a gardener’s friend!

Syrphid on lemon balm 2 - 1P1020548

Garden pollinators for PAW no. 1 – Patchwork leaf-cutter bee (Megachile centuncularis)

Megachile on lambs ear 2015-06-29 18.16.49

As promised, here’s the first of my posts for Pollinator Awareness Week and I’m going to start with one of my favourite groups of bees – the leaf-cutters of the genus Megachile.  The UK has only nine Megachile species recorded, several of which are quite frequently found in gardens.

In my urban garden in Northampton I’ve often encountered the Patchwork leaf-cutter (Megachile centuncularis) this summer.  As you can see from the link to Steve Falk’s excellent photographs and description of the species, it’s quite distinctive with a brush of orange hairs that extends right to the tip of the abdomen (see the first picture, though the colour of this can fade with age so it’s not always so apparent).  The brush is used for collecting pollen from flowers to take back to provision its nest, which is constructed from leaf segments lining a tubular cavity in old walls, wood or occasionally soil (hence “leaf-cutter” bees).  The leaf-cutters (as with 90% of bee species) are “solitary” in the sense that they don’t have a social structure with a communal nest, a queen, etc.  It’s the female bees that are solely responsible for nest building; the purpose of the males is simply to mate.

I’ve seen this species visiting my runner beans in the garden and, given their size, they probably pollinate that crop, though not as effectively as bumblebees which are much more abundant.

Megachile female 2 - close up July 2015P1020491

In the image above you can clearly see the pollen that’s been collected by this bee under its abdomen.

Megachile female - close up - July 2015 P1020489 copy

In my garden the Patchwork leaf-cutter is very fond of Lamb’s ear (Stachys byzantina), but I’ve seen it collecting nectar and pollen on a wide range of other plants too.

Urban bee diversity – a new study

Bee on apple blossom 2 - 1st May 2015

Over the past couple of years I’ve mentioned urban pollinators, and specifically the work of my PhD student Muzafar Hussain Sirohi, several times; for example here and here.  Muzafar is currently finishing off the writing of his thesis, and during that time he’s also managed to publish the first paper from the study.

We are really pleased with this paper because not only is it the product of a lot of hard work to systematically sample and identify the bees, but the results are really exciting: Muzafar has shown that the centre of Northampton is home to a more diverse set of bee species than expected. In fact at least 50 species of bees are thought to live within a 500m radius of All Saints Church, which is significantly more than are found in the nature reserves at the edge of the town.

Muzafar’s work involved surveying the small gardens, road verges, traffic islands, and other patches of plants in the urban centre of Northampton.  These areas provide important nectar and pollen sources for the bees, whilst old stone walls and bare soil offer opportunities for nesting sites. This community of bees includes one nationally rare Red Data Book species called Coelioxys quadridentata that is known from rather few sites.

Our estimate of about 50 species of bees is certainly too low because we focussed on the more neglected groups of bees and didn’t include the social bumblebees. The true figure is likely to be over 60 species, a remarkable number given the small area surveyed.

As I’ve discussed many times on this blog, pollinators such as bees are hugely important both ecologically (most plants require them for reproduction) and economically (much of our food production relies directly or indirectly on pollination by animals). However a significant proportion of bee species in the UK are declining in abundance, and some have gone extinct. Understanding how these bees are distributed across the landscape, including urban areas, is crucial to the conservation of such pollinators in a rapidly changing world. The project therefore has implications not only for conservation of biodiversity, but also food security, given the number of urban gardeners who grow their own food, and the ability of many bees to travel significant distance from urban to rural areas.

The research is published in the international, peer-reviewed Journal of Insect Conservation. The full reference (with a link to the abstract) is:

Sirohi, M.H., Jackson, J., Edwards, M. & Ollerton, J. (2015) Diversity and abundance of solitary and primitively eusocial bees in an urban centre: a case study from Northampton (England). Journal of Insect Conservation DOI 10.1007/s10841-015-9769-2

If anyone would like to receive a PDF of the paper, please leave a comment below or drop me an email: jeff.ollerton[at]northampton.ac.uk

How do animals respond to solar eclipses? Please share your observations.

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If you have been anywhere in the Palearctic during the past 48 hours then you can’t have missed the fact that we experienced that most rare of astronomical phenomena, a solar eclipse.  The eclipse was total only as far north as the Faroe Islands and Svalbard; further south it was partial and here in Northampton the eclipse was perhaps 80-90% total.

It’s been big news with lots of public interest.  As well as explaining the astronomy of eclipses, various commentators on current affairs and science programmes have talked about how animals respond to eclipses.  This is a topic that’s intrigued me ever since the August 1999 eclipse.  During that event I was carrying out field work in a Northampton grassland and as the eclipse reached its maximum the bumblebees and butterflies on the site stopped flying and foraging, and settled into the grass.  Once the eclipse had passed they carried on as before.  I don’t have any hard data to demonstrate the effect, it was purely an observation of what was happening around me.

Since then I’ve waited over 15 years for the next opportunity to observe how solar eclipses affect animal behaviour.  Unfortunately there are few pollinators flying at the moment so I had to content myself with watching the gulls, woodpigeons, carrion crows and other birds on the Racecourse park adjacent to the university.

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This time I took some video footage before, during and after the eclipse, noted the birds’ behaviour, flying, calls and singing.  And guess what? As far as I could tell the eclipse had no effect on the birds!  They behaved as if nothing was happening.  Even a mistle thrush than had been singing all morning from a perch in one of the boundary lime trees continued its song as the moon passed in front of the sun.

That really surprised me!  I was expecting the birds to at least reduce their activity as has been noted in previous eclipses.  But they didn’t as far as I could tell.  Perhaps it was the type of birds I was observing?  Or the time of year?  Or the fact that the eclipse was only partial?  Lots of questions but it’s difficult to do repeat observations for this kind of science – the next British total eclipse is not until 2090!

What did you see?  Did you notice any effect of the eclipse on animal behaviour?  Or did you, like me, see no effect of the eclipse.  I’d be interested to hear your observations.

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Something for the weekend #4

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

 

  • It’s been a good week for birds: Jerdon’s babbler, a species thought to have been extinct for over 70 years, has been rediscovered in Myanmar, whilst the Blue-bearded helmetcrest, a hummingbird not seen for 69 years, has recently been photographed in Colombia.

 

 

  • Related to this, prominent ecologist Charley Krebs asks why physical sciences take the largest share of science budgets, given the importance (and urgency) of global environmental problems.  Charley’s text books have long been required reading on our undergraduate degrees, including his latest The Ecological World View.

 

 

 

 

  • Finally and close to home, the Northampton Greyfriars Bus Station, widely regarded as one of the ugliest buildings in Britain, was demolished with a set of controlled explosions.  What’s that got to do with biodiversity, I hear you ask?  Well the area of green space visible as a still before the video starts, and shown later at 0:45 and 1:15, was one of the field sites used by my PhD student Muzafar Hussain during his surveys of urban solitary bees, which I’ve talked about previously, e.g. here and here.   That patch of green, a rather neglected area of urban grassland with some scattered trees, was home to at least 17 species of bees.  Will they survive the demolition?  Hopefully, though the future redevelopment of the area may result in their loss.  But that’s been happening to urban bee populations for centuries, and they are adaptable and mobile.  I’ll talk more about Muzafar’s work in a post in the near future as the first manuscript from his PhD research has been accepted for publication.

 

Feel free to recommend links that have caught your eye.

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

Something for the weekend #3

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

 

  • A new report by WWF documents over 1000 new species discovered in Papua New Guinea between 1998 and 2008, and the risks to their survival from logging and other human activities.

 

  • How does history inform ecological restoration?  Ian Lunt has a great post on this topic.

 

 

  • In the latest in a series of high-profile rewilding initiatives, the conservation charity Lynx UK Trust has launched a survey to elicit public views on their proposal to reintroduce these large cats – make your views known here.

 

 

  • The University of Northampton’s annual Images of Research exhibition is available to view online and you can vote for your favourite three images.  Now I’m not saying that you should vote for “An ecosystem in a cup”.  But you could.  If you wanted to.

 

  • Staying with the University of Northampton, the Press Office has made me the first Staff Blogger of the Month.  Which is nice.  Not sure exactly how many other staff blog, but my impression is that it’s not many so it may be only a matter of time before I’m honoured again.  I thought I’d share what I wrote when asked about why I blog:

“Why do I blog? The main aim is to communicate the science relating to the importance of biodiversity and ecosystem services (and therefore why we need to conserve species and habitats) to as wide an audience as possible, including the general public, students, non-governmental organisations, businesses, and policy makers, as well as other academics.  Some of that communication relates to examples from our own research, and I also draw on the work of others in the field.  A secondary aim is to give my students a flavour of what it is that I actually do in the rest of my job: teaching is only part of the story!”

 

  • All of which links nicely to the recent post by Jeremy Fox, and subsequent discussion, over at Dynamic Ecology about whether science blogging (and specifically “ecology” blogs, whatever they might be) is on the decline.  For what it’s worth, I don’t think it is and I also think that the definition of what “ecology” blogging actually covers is much wider than the discussion suggests.

 

Feel free to recommend links that have caught your eye.

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

Monitoring the biodiversity impact of the new Waterside Campus

Waterside winter 2014-15 - 2

All human activities can potentially have an impact on the biodiversity of the local environment in which they occur.  That impact can be positive or negative, depending upon how the activity is managed, how impact is mitigated, and the metrics that we use to measure the effects that are occurring.  This is particularly true of large infrastructure developments such as big buildings,  housing developments, roads, and, a category close to home for me at the moment, new university campuses.

I’ve written before about the University of Northampton’s plans to build the new Waterside Campus on brownfield land close to the River Nene, here and here.  It’s a huge project, likely to cost in excess of £330 million on a site covering about 20 hectares.

As you might imagine, such an ambitious scheme has not been without its controversies and there is much debate within the university about changes to how we work and interact with colleagues and students, provision of teaching and research spaces, etc.  There’s also been much discussion within the town, though the general feeling amongst the public (as far as I perceive it) is that bringing the university closer to the centre of Northampton will provide a much-needed economic boost and add significantly to the town’s life.

But what effect will such a development have on the wildlife in and around this peri-urban site, given that it’s in the middle of the Nene Valley Nature Improvement Area and very close to internationally important bird sites?

Over the past few months, together with my colleague Dr Janet Jackson, I’ve been taking part in meetings with the Waterside project’s landscape architects (LUC), other partners from the NIA project board, and the local Wildlife Trust. We’ve been discussing the current plans for the green infrastructure of the campus and thinking about how these can be enhanced.  It’s been a fascinating process as initial disagreements have been negotiated towards compromises and additions that everyone is happy with, balancing budgetary, function and space restrictions with habitat creation and landscape enhancement.

There’s too much been discussed to give a full account at this stage, and it’s possible that some details will change over time, but  the current Ecology Strategy document produced by LUC shows that there will be more than 10 hectares of habitat creation on the site, including species-rich grassland, woodland patches, brown and green roofs, swales and damp areas, and recreated brownfield habitat.  The latter is particularly exciting and something of an experiment, as much of the (albeit limited) current wildlife interest on the site relates to the brownfield element, including the “urban tundra“.

P1100110

To put the 10 hectares into perspective, the adjacent Wildlife Trust Local Nature Reserve of Barnes Meadow is only 20 hectares in area, so it’s potentially increasing that site by 50%.  It’s rare for academic ecologists such as Janet and myself to be able to influence large building developments, so this has been an exciting opportunity for us to make a contribution that (if all goes to plan) will have a positive effect on biodiversity conservation in the Nene Valley.

But how will we know if the Great Waterside Experiment has been a success and that the biodiversity of the new campus is at least as rich, and preferably richer, in species than it was before building took place?

Monitoring of the wildlife is key to this.  Fortunately we have some base-line surveys of birds, plants and invertebrates (including bees and butterflies) from before building started that we can compare with later surveys during and after the campus build.  That process has already started, and with my colleague Dr Duncan McCollin and with two keen second-year students, Jo and Charlie, we have already completed three winter bird surveys to get a sense of how the current site clearance and ground works is affecting the presence of birds in and around the development, including those using the River Nene.  The plan is to continue these surveys up to and after the campus opens in 2018, to give us a data series showing the influence of the campus on bird diversity and numbers.

The initial results are currently being analysed and it appears that the current phase of building has reduced overall bird diversity by about 30%, and that red and amber status birds (of most conservation concern) have been affected more than green status birds, as this figure demonstrates (click on it for a closer view):

Waterside bird surveys

These rough figures hide a lot of detail, however.  For example, there has been some addition of species in 2014-15 that were not recorded in 2012-13, including Coot, Treecreeper and the amber-status Stock dove.  More importantly, some of the amber status birds that we didn’t record on site in 2014-15, we know from additional surveys are still present in habitats within 500 metres of the development, for example Dunnock, Green woodpecker, and Bullfinch.  Similarly, red status birds such as resident Starling, and winter migrant Fieldfare and Redwing occur within at least one kilometre of the site.  Hopefully as the building work progresses towards completion these (and other) species will return, so at the moment we’re not too concerned by their disappearance from the site.

Later in the spring we will conduct a couple of breeding bird surveys, and continue surveying for the next few years until the campus opens in 2018.  Only then will we see exactly how successful our influence has been.  In the mean time I’ll report back as and when we have more data to share.

Waterside winter 2014-15

 

Clever crows!

Clever crows

Back in October I was staring out of the window of the office that I share with my colleagues, something I often do when I’m pondering a question or trying to add a tick to our “Birds Seen Out of the Window” list*, when I spotted something odd.  A pair of crows had focused their attention on a brown patch of lawn and appeared to be eating the grass.  I’m not much of a birder but I do know enough about crows to realise that grass is not a regular feature of their diet.  The same behaviour was observed a few other times after that, and on other occasions magpies were seen doing the same thing.  What could be going on?

Once I’d taken a closer look at the patch of dead grass the explanation was clear.  During our first year undergraduate induction week about a month earlier there had been a barbeque set up on that spot which had leaked hot fat onto the grass.  What the birds were eating was dead grass coated in lard, a useful source of fat to store for the cold conditions of the oncoming winter.

That’s one of things I love about urban birds such as corvids and gulls: they are adaptable and will exploit any resource that becomes available.  But how had they located the patch of fatty grass?  Were they simply exploring the lawn and stumbled across it by accident?  Seems plausible especially as they often feed on earthworms on the adjacent parkland.  Could they smell it?  The acuity of birds’ sense of smell has been the topic of considerable debate, but that’s certainly a possibility.

I was reminded to post this (originally half-written before Christmas) by a story on the BBC news website this morning about a young girl in the USA who receives gifts from the crows in her garden.  If you’ve not read it, please do: it’s a wonderful example of positive interactions between humans and the rest of biodiversity.

Crows (and other corvids) get a bad press, being often described as “evil” (surely a term that only applies to humans) and blamed for the demise of “nicer” birds – a reputation that is not completely justified, as a recent post on Kaeli Swift’s crow research site demonstrates.

So, learn to appreciate (even love) the crows in your local neighborhood; they will reward you with some entertainment as you watch their behaviour, if not necessarily with gifts.

 

*currently standing at 19 species and rising every month.

Evolving a naturalist – happy birthday to me!

Jeff in the tee-pee

Somehow, today is my 50th birthday.  So I thought I’d mark it with a short post about my personal evolution as a naturalist and, ultimately, professional scientist.

One of the great things about the internet and social media such as Facebook is that you can make exciting discoveries on a weekly basis.  Recently I found out something that means a lot to me on a very personal level: I discovered that a family* who lived in the same street when I was growing up in Sunderland in the 60s and 70s have digitised some old home movies and made them available on YouTube.  In our digital age in which every phone and camera can capture and share events as they happen, it’s sometimes easy to forget that owning a movie camera in the 60s was quite a rarity and the majority of kids living at that time were never filmed.   

These movies are exciting not just because one of them shows me aged about 5 years (in the blue shirt) playing with friends (I’m there from 3’53”) but because it documents, in colour and moving pictures, one of the reasons why I became a professional naturalist with a deep fascination for biodiversity. 

The grassland in which we are erecting a tee-pee is not some country meadow, the kind of wild rural landscape cited by so many other naturalists as inspiring their childhood fascination with natural history.  These grasslands had arisen spontaneously on cleared demolition sites, following the removal of Victorian terraced housing and tenement blocks, some of which were slums and others that had suffered bomb damage in the Second World War (now that does make me sound old!)

Up until the 1950s this area had been very built up, with the houses, shops and pubs serving the local families who were employed mainly in the shipyards and coal mines to the north of the town.  You can get a sense of how urban it was from this 1898 map of Southwick; the places I refer to are just south-west of The Green to the left of the map. 

Following demolition the sites were left to their own ends, and were colonised by plants, insects, birds and mammals from patches of habitat closer to the river that had either been cleared of buildings earlier in the century, or which had never been built upon at all.  There are some nice areas of magnesian limestone grassland nearby along the higher banks of the River Wear valley, and typical calcicole plants such as Greater Knapweed (Centaurea scabiosa) could be found on these post-demolition grasslands.  In fact, in the absence of horse chestnut trees, we used to play a version of conkers using the unripe seed heads of Greater Knapweed.  Was that an echo of earlier children’s games in Britain, prior to the introduction of horse chestnuts in the 17th century?  Apparently similar games were played with snail shells and hazelnuts.  

If you watch the opening minute of this piece of footage from the same series, and ignore the girls posing and playing in the foreground, the background reveals a rich flora of plants, with butterflies hopping between flowers.  The first bird species that I can remember identifying, and being fascinated by its bright colours, was Goldfinch (Carduelis carduelis) feeding on the seeds of tall thistles in the very area where this was filmed.   The first butterfly that I could put a name to was the Small Tortoiseshell (Aglais urticae), also feeding on thistles, but this time on the nectar-rich flower heads, as a pollinator.  We’d collect its caterpillars from the nearby nettles and raise them in jars.

So you don’t have to have had a rural upbringing to appreciate and benefit from nature, and to later influence your profession and passions, any piece of land can inspire interest in kids, regardless of its origin, if nature is left to colonise. Unmanaged, semi-wild green space within towns and cities has huge value, both for wildlife and for the culture of childhood.  They need to be protected just as much as rural nature reserves, including the generally disparaged but actually biodiverse “brownfield” sites, as Sarah Arnold has discussed in a recent blog post.

Some of the riverside grasslands still remain and I hope that they are fascinating new generations of kids with their colour and diversity and flouncing butterflies. But the post-industrial grasslands on which I played and looked for bugs and flowers are all gone; they were cleared and built upon in a flurry of housing and retail development in the 1980s.  Perhaps in the future they may return if those buildings are themselves demolished and the land allowed to lie undisturbed for a while.  That is what nature does: it ebbs and flows across our landscapes in response to human, and natural, interventions, endlessly changing and endlessly fascinating to the curious minds of children and scientists, no matter how old they are.

 

*My sincere thanks to the Scrafton family who took the original footage, made it available on YouTube, and gave me permission to use it in this post.

Bumper Big Garden Birdwatch this year!

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As I posted yesterday, this weekend is the RSPB’s Big Garden Birdwatch, the world’s largest wildlife-watching event, and one that’s been running for 36 years.  I completed my hour of surveying between 09:04 and 10:04 this morning, and it’s been a bumper year!  Armed with a notebook, binoculars, and a cup of coffee, I recorded all the different bird species I observed in the field of view from the tall silver birch to the left across to the patch of brambles on the right (my “garden”, as you can see, encompasses parts of my neighbours’ gardens too).

In 2013 (the first year I did the BGBW at this house) I recorded a disappointing 6 species; in 2014 it was 8 species; this year it’s been a whopping 15 species!  They were (in order of first observation, with numbers of birds):

Robin – 1

Collared dove – 3

Chaffinch – 4

Dunnock – 3

Magpie – 1

Blue tit – 4

Coal tit – 1

Lesser redpoll – 4

Blackbird – 4

Greenfinch – 5

Carrion crow – 1

Great tit – 2

Wood pigeon – 2

Goldfinch – 4

Blackcap – 1

Not bad for an urban garden!  Did you do the BGBW this weekend?  How many species did you count? Was it a higher count than last year?