Tag Archives: Climate change

Forest restoration for climate change: don’t forget the pollinators and seed dispersers

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There’s been much discussion in the news and online recently about seed collecting, habitat restoration, and tree planting as a way of storing carbon in an effort to reduce the effects of climate change.  This is one of the (many) elements proposed by the recent Drawdown Framework.  In fact their “Table of Solutions” ranks tropical forest restoration in the top 5 to 10 ways of reducing CO2 in the atmosphere, and temperate forest restoration and planting in the top 20.

At one end of the spatial scale, Markus Eichhorn relates the story of his father’s obsession with collecting oak seedlings to reforest the local countryside.  At the other, there’s some very high profile forest restoration schemes going on at the moment; here’s a couple that immediately come to mind:

Grain for Green – China’s attempt to restore vegetation to abandoned farmland to reduce soil erosion and flooding.  According to the Wikipedia entry “Grain for Green has involved 124 million people in 1,897 counties in 25 provinces……. By 2010, around 15 million hectares of farmland and 17 million hectares of barren mountainous wasteland were converted back to natural vegetation”.

Great Green Wall – a multinational initiative in Africa aimed at restoring the vegetation on the southern edge of the Sahara to combat desertification and mitigate climate change.

Several countries have also made a great deal of noise about marshaling huge public efforts to plant hundreds of millions of trees in a single day,  for example India and Ethiopia.

These big schemes are all well and good: they generate a lot of publicity for actions on climate change and a warm, fuzzy feeling that governments and people are Doing Something.  But there’s a couple of problems.  First of all, planting trees is not enough: we could not plant enough trees in the world to reduce CO2 to pre-industrial levels.  Secondly, planted trees require nurturing.  It is not enough just to put in some young plants and hope for the best; a high proportion of trees die even when well looked after.  If they are just planted and ignored, who knows how many will survive?

However habitat restoration is important; it’s not a silver bullet solution to climate change, but it is part of our toolbox of Things We Can Do.  Just as importantly, restoring habitats provides more opportunities for species to move in response to changing climates, and to recolonise areas from where they have been extirpated.  And of course diverse, functioning ecosystems support human societies in ways both tangible and unquantifiable.

With all of this in mind I was interested to read a piece by John Carey in PNAS entitled   “The best strategy for using trees to improve climate and ecosystems? Go natural“. There’s some really inspiring stories in here, it’s well worth taking a look.  The main message of the article is that allowing forest vegetation to naturally regenerate, from seeds, and dormant roots and stumps, is by far the best way to ensure that trees survive and the restoration is successful.  However there’s something fundamental missing from that article: the role of species interactions in determining the survival of these forests over long time scales.

The vast majority of the world’s plants are animal pollinated; this includes trees.  Even in the UK where we often associate trees with wind pollination, about 65% of our native species are insect pollinated.  In the tropics this can rise to 100% of species within a community.  Although many of those trees can engage in some self-pollination, in the long term this is likely to result in genetic problems associated with inbreeding.  Outcrossing sex is common in plants for a good reason.

Similarly many trees require animals to move their offspring away from the parent plant.  This avoids competition between parent and offspring, and the impacts of diseases and pathogens caused by the Janzen-Connell Effect.  I don’t have any comparable statistics on the proportion of trees, regionally and globally, that use animals as seed dispersers (does anyone?  Please comment below if I’ve missed something).  But I’m willing to bet that it’s a high proportion.

Without pollinators and seed dispersers, restored forests will not flourish in the long term.  There seems to be an implicit assumption that once the forests are established, the pollinators and seed dispersers will follow.  That may be true up to a point, but it shouldn’t be taken for granted, particularly for isolated fragments of forest with no ecological connections to more established areas of woodland.  These are the aspects that are missing from John Carey’s (otherwise fine) article, and indeed from wider discussions about forest restoration and tree planting.  As so often when we talk about the conservation of biodiversity we neglect to consider the role of species interactions.  I’ve been trying to press home that point for years, on the blog and in papers, and I was pleased to see an interesting contribution to this topic by Pedro Luna and colleagues from Mexico on “Measuring and Linking the Missing Part of Biodiversity and Ecosystem Function: The Diversity of Biotic Interactions“.

Let’s not forget: species do not occur in isolation, and the biodiversity of species interactions in fundamental to the ecology of the planet.

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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

Climate change, politics and a host of viewpoints: Australia reflections part 5

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It’s impossible to get away from discussions of climate change and its role in the Australian bushfires at the moment. It’s all over the Australian media, at least that part of the media that isn’t controlled by the Murdoch empire.  Politicians of various stripes are falling over themselves to declare their point of view and some careers are (hopefully) being harmed by crass statements that try to belittle expert, informed opinion – the latest example from Twitter is #NotAWeatherGirl, which has been trendingfor a couple of days now.

If you have any interest in global climate change then the name of Prof. Michael E. Mann will be familiar to you, from his famous hockey stick graph, his work with the Intergovernmental Panel on Climate Change, his books on the topic, the RealClimate blog, as well as numerous media interviews and television appearances.  Until yesterday we’d not met.  But by coincidence, like me, Prof. Mann is also on sabbatical in Australia, is also working at UNSW, and is based near to us.  Via Twitter I invited him for a meet up to discuss what’s happening in Australia at the moment and to set it in a global perspective.  Karin and I met with Mike at a local café, along with an Australian journalist who has asked to remain anonymous, and we chatted for a couple of hours.  From the position of outsiders coming from cultures that politically are moving closer together, and with an expert local perspective, it was interesting to consider what the USA, the UK and Australia have in common and what’s different. And of course, Karin’s Danish heritage provided yet another perspective.  What follows is a short summary of our discussion and some additional thoughts.

One thing that’s clearly true is that the climate change deniers have lost.  Period.  There’s no faux science or dodgy statistics that they can fall back on that have any credibility.  Fudging the data, as some have tried to do for Australia, does not work anymore: anyone willing to listen can see through this charade.

The world’s weather systems are changing, and they are changing EXACTLY in line with the predictions based on human-induced climate change. These changes are causing massive disruptions to natural ecosystems and to human societies, from the drought and fires in Australia and California, to the flooding in Jakarta and the American mid-west, and in parts of the UK.  Karin’s been writing about this recently in relation to human stories from the bushfires and I recommend you take a look; as always, her take on such events complements my own.

The misery that these bushfires and floods have produced among citizens has prompted previously skeptical or agnostic politicians to act, or be seen to be acting.  Those that don’t (and we’re looking here at Aussie Prime Minister Scott Morrison and the increasingly desperate Donald Trump – who’d’ve thunk he’d try to start a war in the middle of a personal political crisis….?) are going to find themselves quickly out of office.  In this regard the British government is rather different, and Boris Johnson appears to be on board with the need to act on climate change.  Even Piers Morgan seems to be hurrying to get on to the right side of history.  But the danger is that it will be too little, too late.  Denmark, of course, along with other Scandinavian countries is showing just how much can be done to cut emissions from energy generation, travel and agriculture, and to invest in a more sustainable future.

In the face of such overwhelming scientific evidence, the consortium of right-wing media barons, plus vested business interests and unfriendly foreign agents, have adopted a different tactic. Rather than deny the science they are targeting the individual influencers who they see as a danger to their power. The vile abuse of Greta Thunberg is the most obvious example, but Mike’s come in for his fair share of abuse too.  Anyone with green credentials who flies or has a less than Spartan lifestyle is accused of hypocrisy, and the focus is being turned on to what individuals should be doing rather than what governments and industry can achieve much more easily and with greater impact.  In Australia it seems there is a campaign to down-play the role of natural processes in the bushfire crisis by claiming that it’s mainly due to a spate of arson, and that “Greenies” have made the situation worse – Twitter bots and trolls have been implicated in this conspiracy.

All of this is an effort to undermine sustainability arguments: that we can have a sound economy based on social justice, environmental protection, green jobs, and a transition to a low-carbon economy.  But we need some structural changes to the global economy, including getting away from this obsession with GDP and “growth”.  This doesn’t mean throwing the baby out with the bath water and dismantling capitalism altogether.  We were agreed that we need to build on the best bits of capitalism and open democracy, and move forward with that, rather than tearing down what has been achieved in terms of human progress.  As I’ve mentioned before, Steven Pinker’s recent book Enlightenment Now has some great arguments on this topic.

Related to this is the fact that environmentalism does not have a political home – it is neither left- nor right-wing in focus: there are greens across the spectrum. Karin summed it up neatly this morning when she said: “Perhaps environmentalism is the catalyst to bring us together, no matter what our political beliefs or backgrounds are?”

This is important to appreciate because we all tend to gravitate towards others who share our views.  Meeting face-to-face with people like Mike and the journalist is inspiring but there’s always the danger that we are talking within a bubble, an echo chamber that just reflects backs our own perspectives on the world. The same is true of social media. One of the discussions we had was about who we aim our blogs, books and Twitter messages at: who are we trying to talk to? Those people too entrenched in their views, who will deny the impact of, or solutions to the world’s environmental problems are a lost cause.  Nothing will sway them.  Those who agree with us don’t need any further convincing: they are already strong allies.  But there’s a huge swathe of the population between these two poles that can hopefully be won over and convinced by sound arguments.  That’s who we need to reach out to, that’s who I hope is following the tragic events in Australia and elsewhere in the world, and seeing what is really happening.

Jeff and Mike Mann

 

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