Category Archives: Biodiversity and culture

The explosion in orchids as houseplants: what does it tell us about how flowers evolve?

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One of the major trends in horticulture over the last 20 years or so has been the rise in popularity of orchids as house plants.  Orchids used to have a reputation as being delicate, choosy, costly things that needed expensive glasshouses, heating, and humidity systems to grow.  Some groups of orchids are certainly like that, but many are not (Orchidaceae is one of the two largest families of plants, after all).  These days it’s impossible to walk into any supermarket or department store and not see orchids for sale at a reasonable price, orchids that are tough and can withstand the relatively dry, centrally heated houses in which most of us in Britain live. 

The majority of these orchids are varieties of Phalaenopsis, the moth orchids.  Intensive hybridisation by commercial growers has meant that there is an almost inexhaustible range of flower colours, shapes, sizes and patterning available.  Take a look at this gallery of images and you’ll see what I mean, or go into a shop that sells such orchids and observe that almost no two are alike.

This is the stuff of natural selection: genetic variation in the phenotype that can be acted upon by a selective agent.  In this case it’s the growers of orchids who choose the most attractive types to sell and discard the others.  If this variation emerged in wild populations most of it would disappear over time, but some, just occasionally, would be selected for by a different group of pollinators and go on to form a new species.  This is much more likely to happen if the individuals with this variation are isolated from the rest of the population in time or space, for example if they flower later or have been dispersed to a distant valley or mountaintop (termed allopatric speciation).  But it can also happen within populations – sympatric speciation.

Back in 1996, near the start of this orchid explosion, one of my earliest papers was a speculative commentary in Journal of Ecology called “Reconciling ecological processes with phylogenetic patterns: the apparent paradox of plant-pollinator systems”.  It generated some interest in the field at the time and has picked up >250 citations over the years, mostly other researchers using it as supporting evidence for the discrepancies we see when trying to understand how flowers evolve within a milieu of lots of different types of potential pollinators selecting for possibly diverse and contradictory aspects of floral form.  In that paper I made a passing comment that I expected the reviewers to criticise, which they did not.  Once it was published I thought that perhaps other researchers in the field would critique it or use it as a jumping off point for further study, which has not really happened either.  This is what I wrote:

         “It appears that pollination systems are labile and may evolve quite rapidly….plant breeders can obtain a fantastic range of horticultural novelties through selective breeding over just a few generations.”

This is horticulture holding up a mirror to the natural world and saying: “This is how we do it in the glasshouse, look at the variety we can produce over a short space of time by selecting for flower forms; can nature do it as quickly, and if so what are the mechanisms?”  

I still believe that pollination ecologists could learn a lot from horticulture and there’s some fruitful (flowerful?) lines of enquiry that could be pursued by creative PhD students or postdocs.  Here’s one suggestion: part of the reason why these Phalaenopsis orchids are so popular as house plants is that they have very long individual flower life times, often many weeks.  Now we suspect that floral longevity is under strong selection; see for example research by Tia-Lynn Ashman and Daniel Schoen in the 1990s.  This showed that there is a negative correlation between rate of pollinator visitation and how long flowers stay open.  Plants with flowers that are not visited very frequently stay open much longer, for example the bird-pollinated flowers of the Canary Islands that may only be visited once or twice a day, and which can remain open for more than 20 days.  Is the floral longevity shown by these orchids (or other groups of plants that have been horticulturally selected) beyond the range found in natural populations?  If so, what are the underlying physiological mechanisms that allow such extreme longevity?  If not, does this mean that there is an upper limit to the lifespan of flowers, and if so, why?  

In the mean time I’m going to enjoy the orchids above that sit on our kitchen windowsill.  They actually belong to my wife Karin who has developed something of an interest in them in recent months.  The big spotty one is a late birthday gift for her that I picked up this morning from a local flower shop, and which stimulated this post as I was walking home.  I’d bet that we never see another one like it!

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Filed under Biodiversity, Biodiversity and culture, Birds, British Ecological Society, Evolution, Gardens, Personal biodiversity, Pollination

Why conservation is like paella: thoughts and photos from our Tenerife field trip

 

A couple of days ago I posted a photograph on Facebook with a comment that “after a hot day of collecting data there’s nothing better than a nice big Tenerife paella!”:

Karin and the paella.jpg

My wife Karin and I had ended up in the small town of Candelaria, tired and hungry after sweating our way through the Malpais de Guimar  counting and measuring plants.  Big plates of hot food were just what we needed!

After I posted the image a Spanish colleague commented that the dish was “closer to being an arroz con cosas than a paella”.  The term translates as “rice with things” and is used to convey the fact that the original Valencian dish of paella has been bastardised and changed across the Spanish-speaking world, and no longer reflects its culinary tradition.  Knowing nothing of that culinary tradition I took a look at the Wikipedia entry for paella.  It makes for interesting reading, not least the fact that in the original dish one of the main ingredients was the meat of water voles and that the dish was cooked on an open fire fuelled by wood from orange and pine trees to give a distinctive smoky flavour.  There was also a lot of geographic variation in the dish, so what constitutes an authentic paella is debatable.

Although there was no sign of rodent flesh or naked flames in the dish that we ate, it was certainly delicious!  But the comment about arroz con cosas got me thinking about shifting baselines in cooking and conservation.

The idea of a shifting baseline is that expectations of what is “correct” or “normal” or “natural” change over time depending upon what each generation has experienced.  It’s been mainly applied in conservation; for example, the Lake District of England is seen by many as a “natural” landscape of rolling hills and low mountains, but originally it would have been covered in deciduous forest.  Likewise large parts of Tenerife contain a high proportion of alien plants (such as agave and prickly pear) but local people and visitors see this as natural.  The baseline of “naturalness” has shifted for people.  Returning these landscapes to their original condition would mean a drastic shift in the composition of the vegetation.  And what point do we return that condition to?  One hundred years ago?  One thousand?  Ten thousand?  It’s an issue that is widely debated in the conservation literature, especially in relation to rewilding.

Likewise, over time paella has evolved and been adapted by different chefs, and what is currently cooked in restaurants only partially reflects how the dish was originally cooked.  Other than for epicurean purists, our culinary expectations have changed.  There’s been a shift in the paella baseline.

Anyway, enough metaphorising, here are some photographs from out trip.  To set the context, University of Northampton students and staff, including Pablo Gorostiague who is visiting from Argentina, and colleagues from the University of Sussex (Maria Clara Castellanos and Chris Mackin), were out with us last week.  Then we bade them farewell on Sunday before moving on to do some field work.

Field work on the lava fields at Santiago del Teide:

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The landscape of Malpais de Guimar, which actually probably hasn’t changed much in the last 10,000 years:

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Howe many people can you fit around Pino Gordo, the largest Pinus canariensis on the island:

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The endemic Tenerife Blue Chaffinch:

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The cold, damp laurel forest:

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Team Nicotiana!  Helping Chris with locating Tree Tobacco populations for his PhD work:

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Pablito takes a break:

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Filed under Biodiversity, Biodiversity and culture, Rewilding, Tenerife, University of Northampton

Split the kipper: snowfall thoughts of breakfast, fish and childhood games

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Karin and I had kippers for breakfast this morning, a satisfying and warming treat on this cold Sunday as we watched the snow fall into the garden, softening the edges and hedges:

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I do like a nice kipper!  Smoking fish to make it last longer has been repeatedly discovered and transmitted as an idea across cultures, and represents a fascinating intersection where wild biodiversity meets human ingenuity.  The north east of England, where I grew up, has a great and ancient tradition of smoking herrings to preserve a portion of the catch, a practice that may have originated with the Vikings who colonised that part of the country over one thousand years ago.

Of all of the North Sea’s edible biodiversity I feel most comfortable eating herring; although there were issues with over-fishing in the 1960s and 70s, current stocks look to be being managed sustainably.  The most up to date information I’ve found is in a Norwegian government report from which I took this graph:

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Kippers have had subtle, but interesting, influences on culture, spawning phrases, songs and games. To be “done up like a kipper”* is to be taken advantage of by someone or bamboozled, whilst a “kipper tie” is a fashion hangover from the 60s and 70s, named for its broad proportions.  Of course Supertramp sang about having kippers for breakfast, particularly in Texas “cos everyone’s a millionaire”.  That strikes me as an odd line as herrings (in whatever form) have always been considered a cheap dish. Though I suppose importing them from Craster to Dallas could be quite expensive.

Back to the north east and my childhood, where we played a game called “Split the Kipper”. This involved standing opposite a friend on a grassy field and taking it in turns to throw a knife near to your opponent’s foot.  If it stuck into the ground then your opponent had to slide their foot to that point.  This continued until one of you had your legs so far apart that you fell over – the kipper had been split!  Not the safest game for kids but I never knew anyone to get injured playing it. Like all the best games the point was not just to win but to win beautifully: inching your adversary’s legs apart with accurate knife throws gradually ramped up the tension of the game.  I wonder where the game originated? Is it too fanciful to imagine that it was brought over by the Vikings?

The snow is still falling – wonder what’s for lunch….?

 

*Whatever you do, don’t search the Urban Dictionary for the definition of the word “kippered”….

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Vermicide: how do you deal with earworms?

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Warning: biodiversity content almost nil; bad language content significant.

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Language fascinates me, and one of the things that I find particularly intriguing is the way in which metaphors and analogies from the natural world find their way into our writing and speech.  We talk of a “bird’s eye view” or being as “slow as a snail”; say that “from little acorns large oaks grow”, and we are as “ravenous as wolves”.

Which leads me to earworms.  Nothing to do with real worms of course, but fragments of music that worm their way into your consciousness and stay fixed there, repeating over and over and over and over…….

According to Wikipedia other names include brainworm, sticky music, stuck song syndrome, and Involuntary Musical Imagery, but I’ve always known them as earworms.  And I’ve suffered from them for as long as I can remember; typically every couple of days I’ll have part of a song stuck in my head that I can’t get rid of.  In recent days it’s been “Long-haired Lover From Liverpool” by Little Jimmy Osmond (which I heard on a Top of the Pops Christmas Special); Joni Mitchell’s “River”; and “The Rain Song” by Led Zeppelin that featured on a YouTube playlist on New Year’s Day.

Earworms get worse when I’m stressed or when I have a hangover: indeed if I have drunk too much the night before (a rare occurrence these days) I will wake up with a headache, nauseous, AND SOME FUCKING SONG BOUNCING LOUDLY AROUND IN MY BRAIN LIKE A KANGAROO* ON AMPHETAMINES!

At their worst these earworms can last for days and be very hard to shift.  They can also wake me up in the middle of the night and stop me from getting back to sleep.  The only method that I’ve found that can suppress them is to sing another song to myself that masks the offending song.  After much experimentation I find that “In My Time of Dying”, another Led Zeppelin track, is the most effective, perhaps because it’s slow and not especially catchy.

(Bugger, my son James is tidying his bedroom and playing music and Queen’s “Bohemian Rhapsody” has just come on – almost guaranteed to get stuck in my head!)

If you also suffer badly from earworms I’d be interested to know what methods you use to shift the little blighters: what works for you?

 

*See what I did there?

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The holly, the mistletoe, and the pollinators: an update on an old story

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Holly and mistletoe are two of Europe and Scandinavia’s most iconic plants, steeped in folklore and cultural significance, and redolent of the dark days of mid-winter and its festivities.  Last year, together with my colleagues Jim Rouquette and Tom Breeze, I published a study of the value that pollinators add to the wholesale auction prices of these two plants using data from the UK’s largest holly and mistletoe auction that has been held in the town of Tenbury Wells for 160 years.

Holly and mistletoe are excellent subjects for a study of the added value that pollinators bring to a crop as they are 100% reliant on pollination by a range of wild bees, flies and other insects.  This is because both species are dioecious with separate sex plants, therefore any berries produced on a female plant must be due to the activities of pollinators.

Here’s a link to last year’s blog post about that paper and here’s the reference for the paper itself, with a link to the journal where you can download it for free:

Ollerton, J., Rouquette, J.R. & Breeze, T.D. (2016) Insect pollinators boost the market price of culturally important crops: holly, mistletoe and the spirit of Christmas. Journal of Pollination Ecology 19: 93-97

The data set in that paper only developed the story up to 2015 as the 2016 auctions took place too late to include within our analyses.  However I’ve collected the auction reports for 2016 and 2017 and added them to the data set.  The results are graphed below*.

The auction price for holly with berries is rather volatile, but on average over this time period, berried holly has twice the commercial value of holly without berries.  Indeed in the last auction of 2017, holly without berries failed to sell, hence the value of £0.00.  The very wintry weather on the auction day reduced the number of buyers, but nonetheless, to have no one bidding for the unberried holly was unprecedented.

Holly auction prices plot

The pattern for mistletoe is rather similar, but in this case the value of berried material is less volatile than that of holly, and the average value is around three times greater than for auction lots of unberried plants.

Mistletoe auction plot

This data set offers a unique insight into the value of pollinators for two culturally important crops (all other such studies have focused on food or, rarely, fibre crops).  I’ll continue to archive the auction reports and to update these analyses every few years in the run up to Christmas.  If anyone is interested in accessing the data, please drop me a line.

If you want to learn more about the botany of different types of mistletoe follow this link to Mike Fay’s blog post on the Kew website.

Also worth checking out is Manu Saunders’ recent piece highlighting some old Christmas-themed blog posts.

Yesterday was my last day in the office, I’m now officially on leave and looking forward to a restful Christmas and New Year break.  Season’s greetings to all of my readers and thank you for your continued support and interest in biodiversity!

 

 

*There are three auctions each year and therefore three data points per annum, except for 2016 when only two auction reports were produced.

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Spiral Sunday #33 – an Aeonium from Tenerife (for Karin’s birthday)

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Over the past couple of weeks we’ve been extremely busy doing field work and not had great internet connections, hence no postings on the blog.  But this weekend we are staying in a lovely little hotel in a restored 18th century Canarian house in Icod de los Vinos.  So things have slowed down, though the internet is not much better.

I have managed to capture a few images of spirals along the way that I will use for upcoming Spiral Sunday posts.  As it’s Karin’s birthday today, here’s one of an Aeonium species, the group of plants that’s been the main focus of our recent field work.

Happy Birthday Karin!

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Spiral Sunday #29 – a pair of guest photos

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Spiral Sunday this week features a couple of photographs I’ve been sent recently.  The first is from one of my PhD students, Alex Laws, taken on a trip to Cornwall earlier this year.  The artist is James Eddy, not a name I was familiar with, but definitely worth checking out, especially as he is a land artist too.

Which leads us to the second picture, sent to me by a Polish colleague, Marcin Zych, of a spiral-shaped piece of land art he found near Olomouc, in the Czech Republic.  It reminds me (on a smaller scale) of Robert Smithson’s amazing sculpture Spiral Jetty (of which I was unaware until it was kindly introduced to me by Carrie McLaughlin of the Texas Pollinator Powwow).

Spiral from Marcin Zych

Many thanks to Alex and Marcin, and to Carrie too.

 

 

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Spiral Sunday #28 – hearts and vine

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The sun was illuminating the coloured glass of a window ornament and I noticed two things: (i) the lovely juxtaposition between the metal spirals of the ornament and the spiral tendrils of Cyphostemma simulans, a member of the vine family (Vitaceae) that I grew from seed many years ago; and (ii) the fact that our front windows really need washing….  No time for that this weekend, though, been too busy working in the garden with Karin!  That’s Spiral Sunday, enjoy the weather while you can.

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Celebrating Conrad Gesner Day 2017 (and Spiral Sunday #27)!

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Happy Conrad Gesner Day!  Who is he, you may ask?  And why does he have a day?  Conrad Gesner (sometimes spelled Konrad Gessner) was a Swiss naturalist and polymath, born on this day (26th March) in 1516; he lived much of his life in Zurich, where he died on 13 December 1565.  Gesner was an extremely important figure in Renaissance science and scholarship, and when I visited Zurich in 2008 to give a seminar at the university, a tour of the old town revealed a number of references to the great man, including the memorial stone above.

Gesner’s Historia animalium (“History of Animals”)  is considered one of the founding texts of modern zoology, and for that reason he is memorialised in the name Gesneria Hübner, 1825; this is a genus of moths in the family Crambidae.

However Gesner was also a botanist and wrote a couple of books on the subject, though his Historia plantarum was not published until two centuries after his death.  To celebrate Gesner’s botanical achievements Linnaeus erected the genus Gesneria L. for a group of flowering plants.  Sounds odd to have the same name for two very different types of organism, but this cross-kingdom duplication of genera is allowable under the various codes of taxonomic nomenclature.

Gesneria in turn is the type genus for the family Gesneriaceae.  It’s quite a big family (about 3,450 species in 152 genera) and is ecologically important in the tropics and subtropics, where species may be pollinated by insects and birds, and are often epiphytic on trees.  It’s not a particularly economically important family, though a number of genera are widely grown as ornamentals, and there are specialist gesneriad growers and collectors.  The more familiar plants include those mainstays of Mothering Sunday (which by coincidence is also today) African Violets (Saintpaulia), Cape Primroses (Streptocarpus) and gloxinias (Gloxinia):

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As I was looking through my photographs from the trip to Zurich in 2008 I spotted the following image of some wrought ironwork from the old city which may well be contemporary with Gesner.  This seems a fitting way to celebrate both the great man and this week’s Spiral Sunday:

Spirals in Zurich March 2008 119.png Happy Birthday Dr Gesner!

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Spiral Sunday #26 – a bumper crop from Birmingham Botanical Garden

Today Karin and I took a drive up to Birmingham to visit my daughter Ellen, who is studying applied performance and community theatre at Birmingham School of Acting.  After picking her up we went for lunch at Birmingham Botanical Gardens.  Now, I’m a bit of a botanic gardens collector; I love visiting them, and keep a life list of those I’ve visited and a wish list of those I’d like to visit.  So I was sure I had been to the Botanical Gardens as a PhD student during a British Ecological Society conference at the University of Birmingham.  But when we arrived there I had no recollection of the glasshouses or the layout, it was not familiar at all.  Odd how the memory plays tricks, one way or another.

I can recommend a visit, though – the Gardens looked stunning even this early in the season; lots of plants in flower and even a buzzard circling low overhead.  It being Spiral Sunday, of course, I was seeing spirals everywhere; in the unfurling fronds of a tree fern (Blechnum gibbum):

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On a cast iron garden seat:

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In the flowers of a variety of camellia:

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In the leaves and flower cones of Banksia grandis:

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And in the design of a sun hat in the Gardens shop:

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