Monthly Archives: June 2019

Chequered skippers are back: extinct English butterfly breeds for the first time in over 40 years!

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Last year I wrote about our involvement with the chequered skipper reintroduction project that’s happening in north Northamptonshire, and specifically the work of University of Northampton postgraduate researcher Jamie Wildman.  For the past month we’ve been sitting on some news that we were not allowed reveal: the reintroduction has been a success!  That is to say, adult butterflies emerged in May this year, having overwintered as pupae, and have been seen breeding in Rockingham Forest.  The secrecy was to prevent hordes of butterfly twitchers (buttwitchers?) descending on the site and possibly doing unintentional harm as they searched for the adults.  The population just isn’t large enough to be able to withstand that sort of pressure.

The BBC has run with the story this morning – here’s the link – and we have issued a piece via the university’s press team: the link to that is here.

In a time when the media is dominated by profoundly depressing stories about wildlife and the environment it’s great to be able to end the week with some positive news.  Here’s to the long-term success of this lovely little critter!

 

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Filed under Biodiversity, Butterflies, University of Northampton

Monarchs and Milkweeds Workshop summary, Oak Spring, Virginia, June 2019

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As I recounted in my last post about a train ride through American climate change, my wife Karin and I have been in the USA for the past couple of weeks, visiting colleagues in the west and ultimately heading eastwards to Virginia for a workshop on monarch butterflies and their milkweed hosts.  The meeting was organised by Anurag Agrawal, professor at Cornell University and author of the recent book Monarchs and Milkweed, highly recommended to anyone interested in the natural history of plants and insects.  The monarch (Danaus plexippus) is an iconic migrating  species that travels from Mexico to Canada and back, over the course of a few generations.  This behaviour, and their vast over-wintering assemblages, have become the focus of intense efforts to understand their ecology and biology.  Their caterpillar host plants are mainly milkweeds (Asclepias spp.) and bringing together both plant and animal scientists is important for gaining a fuller over view of the issues facing the monarchs and the milkweeds, and how both can be conserved in a time of anthropogenic change.

The venue for the workshop was Oak Spring, Upperville, the former home of Paul and Rachel (“Bunny”) Mellon which has been turned into the base of operations for a philanthropic foundation specialising in plant science, horticulture, and botanical art.  The Oak Spring Garden Foundation (OSGF) is “dedicated to inspiring and facilitating scholarship and public dialogue on the history and future of plants, including the culture of gardens and landscapes and the importance of plants for human well-being”.  The OSGF generously funded the workshop, including accommodation and travel for participants.  This brought together a small group of scientists from the USA, the UK and Brazil, together with an artist, a milkweed horticulturalist, and two science writers.  Their brief was to discuss the latest developments in our understanding of monarch butterflies, their decline and conservation, and the taxonomy, evolution and ecology of milkweeds and the wider groups of Lepidoptera and the plant family Apocynaceae to which these organisms belong.  My invitation to take part was due to the research on the pollination ecology of this family I’ve conducted, spanning about twenty five years and culminating in a recently published assessment of the diversity of pollination systems in Apocynaceae.

First things first: Oak Spring is one of the most tranquil, beautiful, and inspiring places where it’s ever been my privilege to stay.  Here’s a few photographs, but they really do not do justice to the buildings and garden, their setting, nor to the unique atmosphere of Oak Spring.

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So to the science.  The workshop started with a set of short presentations on our recent research findings and the motivations for our interests in these organisms.  On the second day we then moved on to discussing ideas for future collaborations between the participants and how that work might be funded in the future.  Presentations and discussions were mainly held in the Basket House, named for obvious reasons:

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Each of us was also interviewed on camera to build an online archive of the work we do and why we do it.

The advantage of face-to-face meetings such as this, and why Skype and so forth can never fully replace them, is the free-flowing conversations that occur within the formal sessions and outside them.  Among the many things that I learned from presentations and discussions were:

  • The California monarch population has declined by almost 90% this year and there’s an urgent need to understand why this has happened.  Climate change has been implicated, especially in relation to the increased frequency of wildfires in this region.
  • Existing methods of nectar extraction from milkweed flowers may strongly underestimate the volume available to flower visitors, and overestimate the sugar concentration.  Using a small centrifuge to spin out the nectar seems to be the most effective method.
  • Asclepias arrived in the Americas (probably from Africa) some 10 million years ago (mya).  However Danaus only arrived about 3.7 mya, so there was a long period of time in which the plant was not co-evolving with one of its major herbivores.
  • There is strong evidence of migrations along the Andes by a close relative of the monarch, Danaus erippus.  Migrations in this group of butterflies therefore extends beyond the iconic D. plexippus.
  • Sonoran Desert Asclepias are sister group to the rest of the New World Asclepias spp.  The exact route by which the African ancestors made it to the Americas is unknown, it could be via Asia and the Bering Strait, or across the Atlantic by way of island stepping stones.  Either way, the phylogenetic position of the Sonoran milkweeds implies that a lot of Asclepias species have gone extinct over the past 10 million years.
  • Climate change seems to be resulting in more complex and unpredictable windows of opportunity for monarch egg laying and caterpillar development.  The monarchs are most successful in late spring and late summer, but not in all years.
  • Likewise, extreme precipitation of the kind I recently documented in the USA is also likely to have a negative impact on the monarchs and their host plants.
  • There is molecular evidence that monarch butterflies went through a huge genetic bottleneck in the 1960s-1970s, for reasons that are not altogether clear.

All of these findings, and more that there isn’t space to document, point to a need for further research to better understand these organisms if we wish to secure their futures.

By the end of the workshop we had made some concrete decisions on future steps:

  •  The African members of the genus Asclepias, plus about 20 other closely related genera, require more critical taxonomic and phylogenetic assessment in order to understand their systematic relationship to the North and South American Asclepias species.
  • A poster (or possibly series of posters) will be produced that explain the ecology of the monarch, its relationship with milkweeds, the patterns of migration, and the value of milkweeds as nectar sources for a diverse range of pollinators.
  • We will explore a multi-agency grant application to further develop the collaborations between participants.

The final day of the workshop involved a field trip around Virginia to see some of the local milkweed species, many of which live in woodland.  That surprised me: I always envision Asclepias spp. as grassland or desert plants.  The leader of the field trip, Mark Fishbein, had a hit list of 8 species that he wanted us to see and in the end we located all of them, including a rare hybrid population of A. syriaca x A. exaltata, plus the tropical milkweed Asclepias curassavica planted in the OSGF garden, plus the distant relative dogbane Apocynum cannabinum.  Here are some images from that day:

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Searching for milkweeds along Skyline Drive, Shenandoah National Park

 

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Poke milkweed – Asclepias exaltata

 

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Hunting that elusive hybrid milkweed!

 

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Caterpillar of the monarch butterfly feeding on a milkweed

 

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Alessandro Rapini intent on getting a good photo of the A. syriaca x A. exaltata hybrid

 

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A bumblebee and a butterfly visiting A. exaltata

 

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Purple milkweed – Asclepias purpurascens

 

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Common milkweed – Asclepias syriaca – with a visiting skipper butterfly

 

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Climbing milkvine – Matelea obliqua – a member of a largely fly-pollinated group of New World asclepiads

 

Thanks to my fellow workshoppers for such a stimulating and enjoyable meeting, and to all the staff at Oak Spring for making us feel so welcome.  Particular thanks go to Prof. Sir Peter Crane who, as President of the Oak Spring Garden Foundation, was hugely supportive of the workshop, and to Angie Ritterpusch, Head of Events and Guest Services, for logistical and organisational support.

 

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Filed under Biodiversity, Biogeography, Butterflies, Climate change, Evolution

A train ride through American climate change

For the past week Karin and I have been travelling in the USA, starting in Denver, driving to Gunnison, then on to Grand Junction, Colorado, to catch the Amtrak California Zephyr train for a 36 hour trip to Chicago. Our final destination is a workshop on conservation of monarch butterflies and their milkweed host plants near Washington DC next week.

I’ll post something about the Gunnison leg of our journey at a later date, and of course the workshop.  But as I write the first draft of this post, we are passing through flooded Iowa farmland and I wanted to get some thoughts down about a repeating theme of our travels so far: climate change.

Our original destination in Colorado was the Rocky Mountain Biological Laboratory (RMBL), an almost legendary research venue for pollination ecologists. We were meeting up with my long-time friends and colleagues Nick Waser and Mary Price, with whom I’ve collaborated on various papers since the mid-90s. However we never made it to RMBL: unseasonably late snow had not yet been ploughed from the road up to the site and the only way in and out was with skis or snowshoes. Some hardy researchers were already there, but the limited time we had in Colorado made it impractical for us to make the journey:

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Unseasonable snow does not, of course, climate change make; but that was our first hint that there’s something odd about the weather in North America at the moment.

Fast forward a few days and we picked up the Zephyr in Grand Junction, the start of an incredible journey through spectacular Rocky Mountain scenery and then down into the flat agricultural lands of Nebraska and Iowa. We had a sleeping cabin and, following a stop in Denver, we drifted off to the slow chug-a-chug of the Zephyr’s wheels and the occasional distant whistle from the front engine – it’s a loooong train!

The next morning we were still in Nebraska and it was then that things started to get both interesting and worrisome. One of the conductors gave us a running commentary about the heavy rainfall that had caused flooding in this region during May and June – see this recent account from NASA’s Earth Observatory.  As you can see from the images below (snapped from the train as we passed, so excuse the quality), flooding is still an issue along the Platt and Missouri Rivers, both of which had over-topped their adjacent levees at various points. A conservation area, the Fontanelle Forest Preserve, had turned from woodland into wooded swamp:

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This is not the river Missouri – it’s actually about quarter of a mile beyond those trees:

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Adjacent farmland was completely flooded shortly after corn crops had been planted. Farm buildings were washed out and their occupants had been forced to leave with little notice. These are areas that do not normally flood and the impact of this heavy rain has been significant and will last long into the future:2019-06-05 09.51.37

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Infrastructure such as roads and bridges were also damaged.  The Union Pacific rail bridge across the Platt was partly washed away and has had to be rapidly rebuilt, but only after a new access road was established:

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Everywhere we looked there was flooding:

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A nearby industrial estate and trailer park had also been flooded, with a lock-up garage of classic American cars under seven feet of water, and the residents and businesses have been told to leave permanently. This area cannot be guaranteed flood-free in the future and will be leveled and allowed to return to nature:

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A local portaloo company was also flooded out and we observed the plastic toilets washed up along a lakeside that used to be a field of corn.  Superficially amusing, until you realise that this represents the loss of someone’s livelihood:

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Along the train tracks ballast had been piled up to begin a programme of raising the track bed. Residents of the nearby town of Pacific Junction (population about 470) have been told to either sell their homes to the government, and move out, or face ever-rising costs of flood insurance – see this recent local newspaper article. Pacific Junction used to be an important rail terminus and some of the families have been there for generations.   Let’s be clear what this means for these people – they are displaced from their homes, they are climate refugees in their own country.

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After we had passed through this area I chatted with one of the train stewards who mentioned that his Louisiana home had been flooded out in August 2016. He was forced to pay $400 per year flood insurance to protect his belongings and home from future events, in a part of the state that had no prior history of flooding.  “But your President says that climate change is not a problem” I probed.  He gave me a look that said more than words could ever convey. “Don’t get me started on that” he replied. A nearby passenger, a young guy, chimed in: “We’d be here all day!”  Trump’s rhetoric is changing slightly and, if anything, becoming less coherent and more deranged as he talked yesterday of “good climate” and “weather going both ways”.

All along the train route to Chicago we saw the same thing, over hundreds of miles and hour after hour – partially or completely flooded fields, crops washed away or submerged under water.  Large ponds in otherwise pristine, planted fields of parallel lines where the first growth of wheat was showing:

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Karin tells me that the flooding around the Mississippi was even worse, but I’m afraid that I slept through it; long train journeys are wonderful, but tiring!

This is just a snap shot of what climate change is doing to the USA at the moment; it’s creating climate refugees in a number of states – see this article for instance. Wildlife seems to be the only thing that’s benefiting as nature reclaims farmland and urban areas: the flooded fields we passed were full of herons, wildfowl, and other water birds. But in the longer term who knows what these changing weather patterns will bring for biodiversity and human society. The only certainty is that change is coming.

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Filed under Biodiversity, Climate change