Monthly Archives: May 2018

Hunting the Chequered Skipper: an encounter with England’s latest species reintroduction project

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If you have been following recent conservation news on social media you’ll know that this week was an important one for invertebrates.  The Chequered Skipper, a butterfly last seen in England in 1976, has been reintroduced to the country as part of the Back From the Brink initiative.  The Chequered Skipper project is led by Butterfly Conservation and a team travelled to a site in Belgium earlier in the week where about 40 skippers were captured.  These insects were transported back to the UK where they were held overnight in mesh cages at a secret location in order to acclimatise them, then released into the wild.  The release was filmed as part of next week’s BBC Springwatch series – look out for it.

The exact location of the reintroduction is secret.  However I can tell you that it’s occurred in the Rockingham Forest area of north Northamptonshire, in habitat that (over the past couple of years) has been managed specifically for this reintroduction, in order to create a network of sites across which the species could disperse in the future.  This area was the last stronghold of the species in England prior to its extirpation.  No one knows why it went extinct here, but hung on and did well in Scotland, but it may relate to climate: 1976, as many of the middle-aged will remember, was a very hot, dry summer, and this butterfly likes it warm and humid.

Yesterday I had the privilege of seeing this reintroduction first hand when I visited the site with my colleague Dr Duncan McCollin.  Duncan and I are supervising a PhD student, Jamie Wildman, along with Prof. Tom Brereton, Head of Monitoring at Butterfly Conservation (BC), and the University of Northampton’s Visiting Professor in Conservation Science.  Jamie’s project will focus on understanding the habitat requirements for Chequered Skipper, and monitoring the success of the reintroduction.  I’m also hoping that it might be possible for Jamie to assess the role of this species as a pollinator of the plants it visits.  Butterflies as pollinators is a very under-researched area.

Here’s a shot of the Four Mus-skipper-teers* just before we set off to help BC volunteers to locate the skippers and record their behaviour:

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The day started unpromisingly.  It was cool and overcast, and little was flying except some hardy Common Carder Bees.  But around lunchtime things began to warm up and gradually the sun broke through and we started to see flying Lepidoptera that we excitedly chased, only to be disappointed by yet another Mother Shipton or Silver Y.  But no skippers.

As we encountered some of the BC volunteers who were also tracking the insects we were told that we had “just missed one” or that they “saw one down that ride, we marked the spot”.  One volunteer wanted to show me a photo of a Chequered Skipper that he’d just taken “so I could get my eye in”.  I politely refused; I wanted to see the real thing and didn’t want to jinx it with a digital preview.

Finally, our efforts were rewarded and we found the first skipper of several we later encountered.  The image at the head of this post is that butterfly, a sight that has not been seen in England in more than 40 years.  An exciting and privileged encounter.  The county Butterfly Recorder, David James (on the right in this next shot), is ecstatic that the reintroduction has occurred “on his patch” but also nervous at the responsibility it represents:

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Later we spent time helping Jamie follow a female skipper who was showing egg-laying behaviour, moving slowly for short distances along a shrubby edge, occasionally nectaring on Bugle, and diving deep into the vegetation to (we hope) oviposit on grass leaves:

 

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Although I’ve over-cropped this next image of the skipper on Bugle, I thought I’d leave it as I like the different textures and patterns, and the slightly blurry ambience:

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The primary aim of Butterfly Conservation’s project is to return a small part of England’s lost biological heritage.  But it’s about more than just the Chequered Skipper.  It’s also about understanding how managing a network of sites for this flagship species can benefit other organisms.  The wide woodland rides that have been created are packed with plant species, amongst them at least five grasses that could be used as caterpillar food sources for the skippers, plus more than 20 nectar sources were flowering that they (and other flower visiting insects) could use.  Those other insects were plentiful too: over the day I spotted five species of bumblebees, several different day flying moths, lots of Dark-edged Bee Flies, and a few different solitary bees and syrphids flies.  We heard calling cuckoos, and four different warblers: chiffchaffs, garden warbler, whitethroats, and blackcaps.  Red kites (another incredibly successful species reintroduction) floated overhead skimming the treetops as they their cried to one another.

Rockingham Forest is a lovely part of Northamptonshire, well worth a visit.  The Chequered Skipper will be a wonderful addition to its biodiversity.  Of course there are no guarantees that the reintroduction part of the project will be a success, but if it isn’t it won’t be because of a lack of commitment from the people involved.  If the population does become established then in the future the location will be made public and butterfly enthusiasts will be able to come and pay homage to one of the few butterflies with a pub named after it.

 

*You get the puns you deserve on this blog…..

 

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Filed under Bees, Biodiversity, Birds, Butterflies, Pollination, University of Northampton

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

Speaking about plant-pollinator research and science blogging in Wageningen in May

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If any of you are near Wageningen University on 31st May I’m giving a talk about some of our recent research called “The macroecology and macroevolution of plant-pollinator interactions”.  It’s preceded by a workshop on the whys and hows of science blogging.  Details are in the poster.

Here are the abstracts for the talk and the workshop:

Macroecology and macroevolution of plant-pollinator interactions

Plant-pollinator relationships are an ecologically critical form of interaction that ensures the long-term survival of the majority of the world’s plants species, and contribute to a large fraction of global agricultural output.  In additiondiversity and abundance of biotically pollinated plant species can be an important determinant of the diversity of animals at higher trophic levels.

Despite that global significance, most studies of plant-pollinator interactions are done at a local level, involving populations and communities of species, over modest time scales.  The ways in which these local sets of interactions scale up to produce global macroecological and macroevolutionary patterns, and the processes underpinning them, will be explored using two case studies.

The first is a data set of 67 plant communities, ranging from 70ºN to 34ºS, with which we investigated the roles of biotic and abiotic factors as determinants of the global variation in animal versus wind pollination.  Factors such as habitat type, species richness, insularity, topographic heterogeneity, current climate and late-Quaternary climate change were investigated. The predictive effects of these factors on the proportion of wind- and animal-pollinated plants were examined (see: Rech et al. 2016 – Plant Ecology & Diversity 9: 253-262).

Since these results were published  we have increased the number of plant communities in our database to >90, and our findings seem to be robust to these additional data.  The dominant influence of contemporary climate on the relative importance of wind-pollinated species suggests that communities may be sensitive to future climate change.  Communities in areas that are predicted to become drier may in time contain more wind-pollinated plants which may in turn reduce the diversity of pollinator species that are present.  There may also be implications for the prevalence of human pollen allergies.  Future work will focus on these two areas.

The second case study uses a newly assembled database of pollinators of the family Apocynaceae (one of the ten largest families of flowering plants), supported by a molecular phylogeny of the major clades.  This database has been used to explore phylogenetic and biogeographic patterns of pollinator exploitation (Ollerton et al. in review).  The findings from this study challenge some long-held assumptions about convergent evolution, the role of rewards such as nectar, and the notion that some specialised pollination systems are evolutionary “dead ends”.  It also highlights the function of novel floral features in determining pollinator type and behaviour, such as the fused gynostegium and pollinia found in the subfamily Asclepiadoideae.  In summary, Apocynaceae is emerging as an important model family for understanding the ecology and evolution of plant-pollinator interactions.

 

Blogging for EEB: why bother?

A growing number of scientists in Ecology and Evolutionary Biology (EEB) have their own blogs or post as guests on others’ blogs.  In this workshop we will explore motivations and strategies for blogging, and its advantages for early career researchers.  Why blog?  What does it do for one’s career?  Is it a distraction from actually doing science?  How does one build a blog readership?  We will also focus on two aspects that are sometimes seen as mutually exclusive: blogging as science outreach to the general public (sci-communication), versus blogging with other professional scientists in mind (sci-community).  As preparation for the seminar please read Saunders et al. (2017) Bringing ecology blogging into the scientific fold: measuring reach and impact of science community blogs

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Filed under Biodiversity, Biogeography, Macroecology, 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!”:

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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