Category Archives: Climate change

Impact of extreme events on pollinators: download it for free

SHOCKs image

In my last post I highlighted a couple of recent papers on climate change and extreme events, and how they impact pollinators.  The Erenler et al. (2020) mini-review paper that I mentioned has now been published and is available for free download for the next 50 days.  Follow the hot link here:

Erenler, H.E., Gillman, M.P. & Ollerton, J. (2020) Impact of extreme events on pollinator assemblages.  Current Opinion in Insect Science 38: 34-39

This review is one of several from a themed issue of Current Opinion in Insect Science devoted to Ecology.  The issue is edited by Tom Ings from Anglia Ruskin University and Sarah Arnold from University of Greenwich.

 

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Pollinators, climate change, and extreme events: two recent publications

SHOCKs image

Well, we’re back in the UK now and have just about got over the jet lag.  I’ve returned to teaching, admin, and meetings, and both Karin and I are trying to find time to finish our books.  But the persistent backdrop to our stay in Australia – the bushfires and the role of climate change, and the ensuing tensions between scientific evidence and politics – is still fresh in our minds.  It’s timely, then, to highlight two new papers that focus on extreme events, climate change and pollinators.  The first is one of my own, led by Dr Hilary Erenler who carried out her PhD research in my group.  It’s an invited mini-review in the journal Current Opinion in Insect Science entitled “Impact of extreme events on pollinator assemblages” (Erenler et al. 2020).  The review is available as a pre-print on the journal’s website; we’ve not yet even seen the proofs, though the final version should not be too different.  If you want a copy, just ask.

In this essay we focus on what we term SHOCKS: events that provide a Sudden, High-magnitude Opportunity for a Catastrophic ‘Kick’ to the environment that can negatively affect pollinator assemblages in many different ways.  Such events can be natural, human-mediated or human-enhanced, and occur suddenly, at a high-magnitude and with possibly catastrophic outcomes for those pollinators. There are many examples of such SHOCKs, as we illustrate in the figure above which comes from the paper.  However one of our main conclusions is just how little we understand about the outcomes of such events on pollinators.  Ideally we need before, during and after event monitoring to assess how pollinators have been affected and may respond.  But SHOCKs are, by their very nature, infrequent and unpredictable, and often we don’t have the baseline data with which to compare to post-event data.  I know from conversations with Australian pollination ecologists that some have had their field sites burned and they are going to use this as an opportunity to assess how the fires have impacted pollinators.  Field experiments such as the one by Biella et al. (2019) that I discussed last year, in which flowers were removed from a plant community, may also give us some insights into the response of plant-pollinator networks to sudden SHOCKs.  But we need more research focus on this topic, especially consideration of how the impacts of SHOCKs can be reduced and mitigated.

One set of emerging human-enhanced SHOCKs highlighted by Erenler et al. (2020) is extreme weather events that are being exacerbated (in scale or frequency) by anthropogenic climate change.  We cite several papers and reviews that have considered this, but there’s still few empirical studies that have actually looked at how weather SHOCKs might be impacting pollinators.  It’s therefore timely that this week’s Science includes a very impressive study of how climate change has affected populations of bumblebees (Bombus spp.) in Europe and North America (Soroye et al. 2020).

The title of the paper rather gives away its findings:  “Climate change contributes to widespread declines among bumble bees across continents“.  This study shows that, for the 66 species of Bombus studied, there had been a decline in species diversity in 100 km x 100 km quadrats of, on average, 46% in North America and 17% in Europe.  This loss of diversity has occurred in the period 2000–2014, relative to a baseline of 1901–1974.  Using some sophisticated analyses they show that climate change has been the main driver of these losses, and has been more important than factors such as changes in land use, pesticides, etc.  Which is not to discount those other contributors to pollinator loss: they can interact with climate change and are all part of the assault that we are imposing on the environment.

The most significant finding of the Soroye et al. (2020) study, and the reason why I’m discussing Erenler et al. (2020) in the same post, is that it’s extreme heat which seems to be the driving factor in determining Bombus declines.  Bumblebees are large, hairy insects because they are adapted to cooler conditions: they are not, by and large, tropical insects, except in mountainous areas.  Not surprisingly, then, it is the number of days of temperatures higher than those historically encountered by particular bee species that is the main driver of their loss from a region.  In relation to the figure above, this is the result of human-enhanced SHOCKs, and for heat-sensitive species like bumblebees, they are occurring more often than we had imagined when we wrote our review.  I fear that the coming years will see more examples of this as the effects of anthropogenic climate change continue to play out and our world experiences more extremes of weather events that are hotter, wetter, colder, drier, windier, and more combustible than we have previously known.

References

Biella P., Akter A., Ollerton J., Tarrant S., Janeček Š., Jersáková J. & Klecka J. (2019) Experimental loss of generalist plants reveals alterations in plant-pollinator interactions and a constrained flexibility of foraging. Scientific Reports 9: 1-13

Erenler, H.E., Gillman, M.P. & Ollerton, J. (2020) Impact of extreme events on pollinator assemblages.  Current Opinion in Insect Science (in press)

Soroye, P., Newbold, T. & Kerr, J. (2020) Climate change contributes to widespread declines among bumble bees across continents. Science 367: 685-688 [see also the commentary by Bridle and van Rensburg pp. 626-627 of the same issue]

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Filed under Australia, Bees, Biodiversity, Climate change

Neither left nor right, but international environmentalism: Australia reflections part 8

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The NASA Earth Observatory reported this week that “explosive fire activity” has caused smoke from the Australian bushfires to enter the stratosphere and be carried half way around the world.  That smoke is currently creating hazy skies and colourful sunrises and sunsets across South America.  In the coming months the smoke will complete a full circuit and arrive back in Australia, and then continue onwards … for who knows how long?

Nothing I’ve read this week sums up better the fact that the world’s environmental challenges, including climate change, are global in scale and scope.  They therefore require global initiatives to solve.  But as I’ll argue below, equating “green” politics with the left and “anti-environmental” policies with the right is an unhelpful characterisation.

Despite the need for global action, the world’s political landscape seems to be going in the opposite direction.  Inward-looking, right-wing populism is on the rise, and governments are hunkering down into a siege mentality of denying that there are any environmental problems that require serious, long-term action.  The Australian government, bolstered by the Murdoch-owned media empire (see Michael Mann’s recent piece on this in Newsweek), sees the bushfire crisis as “business as usual” even though all the evidence is to the contrary – demonstrated in this interesting piece from two Australian climate scientists.

Elsewhere in the world, Presidents Bolsonaro in Brazil and Trump in the USA are tearing up environmental regulations and “green tape” and allowing “the people” (or at least big business interests) to ransack the natural world for their own gain.  At the same time, one of the less-well-reported elements of Boris Johnson’s various speeches over the past few months has been its emphasis on the environment (he even used the word “biodiversity” in one of them) and the pressure he put on the other leaders of the G7 countries at their most recent meeting.  Perhaps that should come as no surprise given that Boris’s father, former Conservative MEP Stanley Johnson, has sound credentials as an environmentalist, particularly during his time with the European Commission. Indeed, in the mid 1980s Stanley Johnson received an award from Greenpeace for “Outstanding Services to the Environment”.  He’s even written for The Guardian, which is not the natural home for a member of the Conservative party.  There are other Conservatives with sincere pro-environmental attitudes (Zac Goldsmith and Rory Stewart come immediately to mind) and whatever you may think about their views on other topics, you can’t doubt their sincere environmental commitments.  And of course there are pro-environmental politicians in the Labour Party, and the Liberals and the SNP and Plaid Cymru and…..well, just about all of them.

Globally, both right- and left-governed states have variable environmental policies. Two countries recently reported that they had made extraordinary progress in tree planting restoration schemes: India (a right-wing, populist government) and Ethiopia (much more left-leaning).  China (communist in name but who knows what we should call it?) has a very mixed record on the environment, with huge investments in both solar power and coal mining.  It’s hard to get firm environmental data out of communist North Korea but the evidence so far suggests that they are not doing well: see this piece from 2009 by journalist Peter Hayes.

Closer to home, in the last few months on Twitter I’ve been called an “eco-loony” by a farmer; told that my objections to the High Speed 2 (HS2) rail infrastructure project were providing support for climate change deniers by a couple of train buffs; and accused of “sleeping with the enemy” by an environmental activist who didn’t like my stance on another large project.  The latter also tweeted a made-up quote from me to emphasise just how morally corrupt I was. Irony was lost on them I think.  I don’t know the political allegiances of those individuals but if I was a betting man I’d be fairly sure of a good return – definitely a mix across the spectrum.

Hopefully these examples make something abundantly clear: the relationship between politics and environmentalism is not straightforward.  That’s been obvious to me, and many others, for a long time.  But I’m not sure how widely understood this is because the impression that is presented to the public by both the right- and left-leaning media, is that “green equals left”.  And whilst there may be some truth to that currently in relation to the political alliances formed between various Green Parties, there is no historical basis for this correlation.  It’s even mixed up in the minds of the modern-day socialists. A few months ago a left-wing journalist opined that the left had “always” been pro-environmental, yet the (supposedly) socialist website Spiked has been publishing pieces arguing that environmentalists are against the working class and that de-carbonisation strategies will cost jobs – see this piece for instance.  Before anyone comments, I’m aware that Spiked has an odd and paradoxical history…..

Historically, both the far left and the far right have a mixed track record on the environment.  I read an appalling story recently about the Soviet Union whaling fleet killing whales simply to meet targets, not because they were of value economically; the author described it as “the most senseless environmental crime of the 20th century“.  However, communist Cuba set aside 10% of its area as national parks and biosphere reserves, and has a strong environmental track record.  In the 1950s, Maoist China had a policy of killing sparrows and other “pests” that was partly the cause of the Great Chinese Famine in which tens of millions of people died of starvation.  The first National Parks in the world were set up in the USA by what we could broadly consider conservative presidents, but the American legacy of nuclear testing and the fossil fuel industry is nothing to be proud of.  Finally, there is a long history of “green” fascism, from the environmental policies of the Nazis (I’ve not read this book but it looks fascinating), to individuals such as Jorian Jenks who was a founding member of the Soil Association, to modern day “eco-fascists” whose justification for carrying out mass-murder and domestic terrorism is rooted in arguments about reducing population growth in order to “save the Earth”.

It’s telling that Big Capitalism is starting to think more seriously about global environmental problems, how they can be solved, and at the same time create jobs and prosperity (and a buck or two for investors – I’m not naive).  Outgoing head of the Bank of England Mark Carney  has argued that firms and banks need to stop investing in fossil-fuels.  Many are following his lead, or are ahead of that curve, including the bank Goldman Sachs and the $7 trillion investment firm BlackRock which has recently stated that “climate change will become the centre of the firm’s investment strategy“.  Nobel Prize-winning economist Paul Krugman  has argued this week that Australia is showing us “the road to hell” and that governments and businesses of all political stripes and inclination better get on board with the environmental agenda.  Soon!

I firmly believe that neither the left nor the right are the friend nor the foe of environmentalism: there are plenty of historical and current examples of rapacious right-wing and left-wing governments, and also examples of such governments being highly pro-active at reducing  their country’s environmental impact.  The one thing that seems to me to be environmentally damaging is a rigid ideology that is followed through regardless of where it is positioned.

The title of this piece is a word play on a slogan adopted by the Socialist Workers Party: “Neither Washington nor Moscow but International Socialism”.  The environmental challenges facing our planet, our species, and the species with which we share this biosphere, are international in scope and it requires international, multi-partisan political action to address.   Whatever your personal political leanings, if you care about the planet, that statement must be blindingly obvious.  That’s why I’m so supportive of organisations like the UN’s IPBES (Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services).  Now, more than ever, the world needs this level of pan-national leadership.

If I’ve learned one thing as an ecologist it’s that the world is a complex, historically contingent and often unpredictable place: simplistic notions of socialism = good/bad and capitalism = good/bad are not going to solve the current crisis of climate change, loss of biodiversity, pollution, and a host of other environmental problems.  Only thinking outside of narrow ideologies is going to do that, and using the tools and strategies that are available to us, including market forces, open democracy, local activism, global movements, and whatever else works.  I’m still optimistic that the world can provide humanity with the kind of  metaphorical “pleasant walks” that Charles Darwin wrote about when he visited the Royal Botanic Gardens, Sydney:

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But we have to act fast.  Otherwise the ruins of civilization, and of the biosphere, may be our species’ legacy: that’s why I chose the image that opens this piece.

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Filed under Australia, Biodiversity, Charles Darwin, Climate change, IPBES

Just published: Interactions between birds and flowers of Rhododendron spp., and their implications for mountain communities in Nepal – download it for free

Figure 3

Back in April I posted a series of reports on a student field trip that I was involved with in Nepal, supporting our University of Northampton partner college NAMI in Kathmandu; the first one is here.  During that trip, my NAMI colleagues and I made some interesting observations about the role of generalist passerine birds and specialist flower-feeding sunbirds as pollinators of rhododendrons in the Himalayas.  This was subsequently followed up with another set of observations in which I didn’t take part, and then written up as a short research note.  I’m pleased to say that it has now been published in the new, open-access journal Plants, People, Planet.  Here’s a link to the paper which you can download for free:

Ollerton J., Koju N.P., Maharjan S.R. & Bashyal B. (2019) Interactions between birds and flowers of Rhododendron spp., and their implications for mountain communities in Nepal. Plants, People, Planet 00:1–6. https ://doi.org/10.1002/ppp3.10091

The report really asks more questions than it answers.  It points out how important these rhododendron forests are for the people of Nepal but that we know virtually nothing about the pollination biology of the dominant trees and therefore the long-term persistence of Rhododendron species in the face of forest exploitation and climate change.  Our hope is that it stimulates both further research on the topic and increased awareness of how important it is to protect these habitats.

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Filed under Biodiversity, Birds, Climate change, Pollination, University of Northampton

How are the Australian bushfires affecting biodiversity? Australia reflections part 4

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Australia’s vast, unprecedented wildfires are going to have a devastating effect on the biodiversity of the country.  To fully understand why this is the case, you need to know something about where species occur and why.

Australia is a land of lizards.  Karin and I see them everywhere we walk and frequently encounter them in gardens.  Reptiles are the most diverse group of vertebrates in Australia, with more than 1000 described species.  Of these, over half are lizards.  One family alone, the skinks (Scincidae) accounts for almost 440 species, with species new to science being described every year.  Some of these lizards are physically extremely impressive, particularly the dragons (Agamidae – about 90 species) and the monitors or goannas (Varanidae – 30 species).  We encountered lace monitors (Varanus varius) over Christmas at Port Macquarie, in coastal bushland and (very dry) rainforest at Sea Acres National Park (see photos above and below):

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Spot the goanna:

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Growing up to two metres in length, they seem to arrogantly swagger through the bush as though they own it; which of course they sort of do – they were here millions of years before people arrived.  Smaller but still impressive are the Eastern water dragons (Intellagama lesueurii) – here’s male and female checking one another out:

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Much smaller but more charming are the various skinks that seem to inhabit every garden and green space in the city; this one seems to be the Eastern water skink (Eulamprus quoyii):

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And here’s where we get to the main point of this post.  All of the lizards I mentioned above are endemic to Australia, it’s the only place on Earth where they naturally occur.  But they are all widespread species found across a huge area in the east of the country, from Queensland to Victoria, a linear distance of over 2,000 km.  This is unusual for species in Australia, and indeed in the rest of the world; most organisms naturally occur over a much smaller area.  To see what I mean, look at the image below from Steve Wilson & Gerry Swan’s book A Complete Guide to Reptiles of Australia:

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The maps adjacent to each species description illustrate the distribution of these organisms. The garden skink and the grass skink live in suitable habitat over vast areas. But the other two species are much more restricted in their ranges, which are so small that they need to be highlighted with arrows.  The elongate sunskink (Lampropholus elongata) for instance is found only “in the vicinity of Grundy Fire Tower and “The Flags”” at 1180-1455 m in the Great Dividing Range.  This is more typical of species distributions in Australia: most are restricted, and some are extremely restricted.  This is true of other reptiles, plants, birds, insects and fungi, in fact all major groups, not just the lizards.  Such a skewed distribution of species occurrences, with many rare and localised, and a few common and widespread, is natural; it’s an outcome of the processes of natural selection and evolution.  But it’s been exacerbated by habitat loss across the world, including Australia.  According to the Wilderness Society of Australia, the country “has lost 25% of rainforest, 45% of open forest, 32% of woodland forest and 30% of mallee forest in 200 years”.

But even these figures do not reflect the full scale of the loss: I’ve seen estimates that more than 90% of the temperate rainforest exemplified by Sea Acres National Park has been destroyed.  Given what I’ve said about the limited distribution of many species, that must mean that locally endemic species have gone extinct in the past.  The huge extent of some of the Australian bushfires, individually covering tens of thousands of hectares and collectively around 6 million hectares, means that most or all of a species’ population could be wiped out.  To give just one example, a small marsupial mammal, the Kangaroo Island dunnart (Sminthopsis aitkeni), is found only on Kangaroo Island.  Indeed, it’s restricted to the western part of the island, where a large bushfire has been raging out of control in recent days.  We will only know whether this species has survived, and in what numbers, once ecologists are able to survey the area once the danger is over.

However even for widespread species the fires can have a massive effect on their genetic diversity, which is an important component of biodiversity.  When we lose individuals from a population we lose genetic variants too.  A recent assessment by ecologists at the University of Sydney has suggested that almost half a billion reptiles, mammals and birds have been killed so far by the fires.  Losses of trees and other flowering plants, as well as insects, spiders and so forth, will be much, much greater of course.

This destruction of biodiversity has a human impact too.  On television news reports we’ve heard farmers and fire fighters describing the emotional trauma of seeing animals on fire and hearing the screams of koalas as they burn in the tree tops.  All of this biodiversity serves to ensure that Australian ecosystems function effectively and sustainably now and in the future. Ecosystems which are crucial for reducing the future effects of climate change, for ensuring supplies of fresh water, supporting agriculturally-important pollinators and predators of pests, and bringing in billions of tourist dollars.  All in all these fires are a tragedy for Australian biodiversity, as well as for the human population of this fabulous country.

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Filed under Australia, Biodiversity, Biogeography, Climate change, Mammals

A land of fire and water: Australia reflections part 3

Fire and water; those opposing elements have been our constant companions during this trip to Australia.  All the major international news media have been reporting on how serious the bush fire situation is in the south east of the continent.  In East Gippsland, Victoria, tens of thousands of residents and holiday makers have been advised to leave the area.  Four thousand of those who haven’t left were forced to spend last night on the beach, as fires got closer to the town of Mallacoota.  These are just the latest examples of climate change refugees in their own country, something I highlighted in a post about our visit to the USA earlier this year.  Of course, Australia is a continent that is used to bush fires, they are nothing new.  But what is new is the scale of these fires and the extended drought and high temperatures that are making the landscape more flammable than ever.

There’s currently a lot of media discussion in Australia about how landscapes were managed historically by Aboriginal peoples, whose selective and regular burning of the bush reduced fuel loads.  Karin and I have just returned from Port Macquarie where we enjoyed Christmas with an Australian branch of our family.  Several of them have spent a considerable amount of time working with remote Aboriginal communities in the Northern Territory.  We were told a story about an Aboriginal elder who asked one of our relatives to drive him out to an area of bush that had not been burned for over a decade.  It was that elder’s role to burn this land at regular intervals, a family tradition that went back generations.  Having driven for several hours along dirt roads, the elder asked to stop; he hopped out of the vehicle, went up to a patch of dry grass, and casually set fire to it with a small lighter he was carrying.  After pausing a few seconds to make sure that the flame had caught he hopped back into the car and said “Let’s get out of here”.  An hour back down the road the companions stopped and looked back.  The whole landscape was aflame, with a column of black smoke rising, I was told, in a mushroom cloud “like a nuclear explosion”.

This sounds extreme, but these areas are isolated and a long way from any human settlements or infrastructure.  Such activities have been part of toolbox of ways in which Aboriginal peoples have managed these landscapes for thousands of years.  By burning areas on a regular cycle the negative effects of large, out-of-control fires are reduced, and opportunities for seedling establishment and fresh foliage for animals to browse are created.  There’s more information about these practices here and here.

In the more heavily populated parts of Australia, and in the adjacent national parks, fires have long been suppressed, such that when they do occur they are much more violent conflagrations, over a greater area, than would normally be the case.

On one of our trips near Port Macquarie we came across an area of woodland that had burned recently, separated by a small road from an adjacent block that had not burned.  In the following set of images I’ve alternated the two blocks so you can see what the woodland looked like before and after burning.  But remember that this was not an especially intense fire; the trees are still living, and there is foliage in their crowns.  Once there’s been some rain and a chance for the vegetation to regrow, the previously burned block will look identical to the currently unburned area.  Indeed in one shot you can already see some green shoots emerging from the ground:

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So fire in itself is not a problem for these natural communities.  What is a problem, for nature and for the communities of people who live in and around these woodlands, is the intensity, the scale and the frequency of the fires that are currently occurring.  This morning Karin and I watched silently to a news report of yet another volunteer fire fighter who had lost his life overnight.  In this case he had been part of a crew whose 10 tonne fire truck had been lifted up and overturned by cyclone-strength winds created by the blaze itself – there’s a BBC news account of the tragedy here.  “Unprecedented” is a word we’re hearing a lot on ABC News.

Evidence for the number and size of the fires was everywhere in and around Port Macquarie, as we observed when we took a drive up to the peak of North Brother Mountain in Doorgan National Park.  From a height of about 470 m (1500 ft) we could see some amazing panoramic views of the region that also showed black fire scars on the landscape – this is looking south:

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Looking north there’s little evidence of the fires – some have occurred there but much smaller in scale.  But there is a lot of that second element, water.  We were able to explore some shallow coastal lagoons fringed with grey mangroves (Avicennia marina):

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Mangrove habitats are fascinating places that are ecologically important as nurseries for marine fish and invertebrates.  They also provide physical protection to coastlines, acting as a buffer to storm surges that would erode the land.  In recognition of this, a recent project around Port Macquarie has involved restoration of these mangrove areas and was instigated by commercial oyster farmers and a local fishing  society.  I’m particularly intrigued by the upward-pointing aerial roots of mangroves; termed pneumatophores, they function to provide oxygen to the trees, but also increase the physical complexity of the floor of the lagoon, providing habitats for small animals:

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But evidence of the drought in this part of the world is never far away.  On our seven-hour train trip back to Sydney we passed mile after mile of parched farmland, with dried-up waterholes and dust-filled streams.  The only thing stopping it from burning is the absence of vegetation:

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As I complete this blog post, it’s 31st December and we’re back in Coogee Bay, ensconced in the apartment of my colleagues Angela and Stephen.  They have headed to Stephen’s native Canada to visit family.  It’s going to be cold!  We’re very happy to house sit and see in the New Year in warmer climes.  Best wishes for 2020 to all of my readers: let’s hope that it’s the start of an environmentally more enlightened decade.

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Filed under Australia, Biodiversity, Climate change, Ecosystem services

Ash on the beach, fire in the bush: Australia reflections part 1

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Although we’ve only been in Australia for less that two weeks, it feels as if we’ve been here forever; once we got over the jetlag and the weird sleeping patterns, Karin and I have easily settled into the life of a Southern Hemisphere summer.  It’s hard to believe that back home in the UK it’s cold, wet and (politically) miserable….

We’re based at Coogee Beach in the eastern suburbs of sprawling Sydney, just a short walk from the University of New South Wales (UNSW) where I’ve spent most of my time, and an even shorter walk from sand and surf.  It sounds idyllic but one of the recurring features of the past week has been the amount of ash and charred leaves washing up on the beaches from the bush fires that surround Sydney at the moment:

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The region is in the midst of an extended drought and this has worsened the fire season.  The Australian Government seems intent on denying that it’s anything to do with climate change, though recently one of the state ministers has broken ranks.  That’s going to be little consolation this year but may mark the start of some changes in policies.  Let’s see.

During our time here Karin and I have facilitated a workshop on “Writing for a non-academic audience” which was attended by 17 UNSW postgraduate researchers.  I’ve presented a lecture on “Macroecology and macroevolution of plant-pollinator interactions: pattern and process at large geographical and temporal scales”…..

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….and spent a lot of time chatting with staff and postgrads at UNSW.  In addition, Angela Moles, Stephen Bonser and I have made initial progress with a short paper that I’m hoping will be ready to submit before we head back to the UK in early February.

Time to actually get out and see some of the habitats and biodiversity of this part of Australia has been limited.  But we’ve done a couple of hikes north and south of Coogee Beach, along cliff-top trails and boardwalks through remnant coastal heathland habitat, enjoying the novelty of watching rainbow lorikeets visiting the inflorescences of native Banksia trees:

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Yesterday we went further afield with a bird watching trip down to the Royal National Park (RNP) with Kew/NRI scientist Phil Stevenson (who is in the country for a couple of weeks on a flying visiting to speak at a conference and meet with colleagues); and Graham Pyke from Macquarie University, whose work on foraging behaviour of pollinators I’ve known for many years, but whom I’d never met.  Leading our trip was Steve Anyon-Smith, a professional bird guide who literally wrote the book on birding in the RNP.  Steve was great, highly knowledgeable, and a mine of information about the Australian environment.  As well as seeing about 67 bird species we encountered a host of other wildlife, and I collected data on wind and animal pollination for another set of species.  Here’s some images from that day:

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An orchid – Dipodium punctatum.

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The bower of a male satin bower bird.

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Not a great shot – it’s an Eastern dwarf tree frog.

2019-12-13 13.14.41 This is better – a very confiding Eastern water dragon along a well-used coastal trail.

Along that trail we also saw two forms of Banksia serrata – an upright one and a prostrate form – growing quite close together:

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I’ve seen a lot of birds visiting the inflorescences of this species but it’s suggested that mammals might be the main pollinators – the flowers have a very thick, yeasty smell.  Perhaps it’s both?

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An Australian fringe-lily.

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This is Epacris longiflora – thanks to Ryan O’Donnell for the identification.

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And of course we saw a lot of the iconic laughing kookaburras.

Steve was really concerned that much of the forest and wildlife in the NPR may be destroyed over the summer.  None of it has yet burned and, with temperatures due to rise enormously by next week, much of this habitat could be lost to fire by summer’s end.  I sincerely hope not, it’s too precious and beautiful to lose.  Vegetation in relatively light burns can reestablish itself given time, as we encountered in one of the Coogee remnants that burned a few years ago:

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But the bigger, hotter, more intense fires that are currently sweeping the state are something else entirely, and are alien to these forests.  Aboriginal Australians carefully managed their environment using regular, small burns, a practice that has been lost in most areas.

Fire in Australia is a theme that I keep coming back to.  A few weeks ago, during one of my second-year undergraduate grassland ecology lectures, I was  discussing fire as a threat and a management tool in grasslands.  I mentioned the situation in Australia with respect to Aboriginal use of fire and I asked my students what the purpose of their burning the grasslands was.  Someone suggested that it might relate to their agriculture.  My response then was “no” because Australian Aborigines were nomadic hunter-gatherers who never developed agriculture, which is what the received wisdom has been for decades.  The answer I’d give now is: “yes, quite probably”.  As so often is the case in science, the received wisdom was wrong.

My colleague at the University of New South Wales, Angela Moles, has loaned me a book called Dark Emu which draws on early European settler accounts, Aboriginal oral tradition, and recent archaeological discoveries to turn our understanding of the ecology of pre-European Australia on its head.  In particular, it seems as though the (then) very large Aboriginal population was much more settled and had developed a sophisticated form of agriculture that included the creation and exploitation of huge areas of native grasses for their grains.  This was all destroyed by colonial European agriculture within a short time period, before it was fully understood.  One of the arguments in Dark Emu is that these native grasses are much more suitable to the Australian climate than wheat and may allow more sustainable agriculture in the future.

If you want to know more, here’s a link to a recent review and interview with the author, Bruce Pascoe:

https://www.theguardian.com/books/2019/may/24/dark-emus-infinite-potential-our-kids-have-grown-up-in-a-fog-about-the-history-of-the-land

Strange as it might sound for a professor to say, I was happy to be wrong on this (or indeed any) occasion: scientific understanding only progresses by people being wrong and incorrect ideas being superseded by new knowledge.  I made a point of sending my students an email telling them about what I’d discovered.  It may well form a question on the test they have to take next term…..

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Filed under Australia, Biodiversity, Birds, Climate change, Pollination

A Climate Change Tourist in America

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Following on from my recent post about A train ride through American climate change, my wife Karin has extended this and written a great piece called A Climate Change Tourist in America for Medium.

It’s a really beautifully observed and thoughtful piece of writing that weaves together themes that I would never have considered dealing with: aspects of life, love, tourism, poverty, suicide and desperation, all linked by climate change.  It’s only a 10 minute read: do yourself a favour and take a look.

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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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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