Ecosystem functions breaking down from climate change

17 05 2010

I’m particularly proud to present to ConservationBytes.com readers a new paper we’ve just had published online in Journal of Animal Ecology: Mechanisms driving change: altered species interactions and ecosystem function through global warming (Lochran Traill, Matt Lim, Navjot Sodhi and me).

It wasn’t easy to write a review discussing climate change effects on biodiversity, mainly because so many have been written already and we needed to examine the issue from a fresh perspective. The evidence for single species’ responses to rapidly shifting climates around the world is overwhelming (see for a few thousand examples, see the following: Stenseth et al. 2002; Parmesan et al. 2003, 2006; Roessig et al. 2004; Thomas et al. 2004; Poloczanska et al. 2007; Skelly et al. 2004; Dunn et al. 2009). It’s rather remarkable how many things are moving in response, with reduction in range size being more common than expansion.

However, predicting extinction risk from climate change is far more problematic because traditionally there have been too few data on species interactions to make heads or tails of a particular species’ eventual response (e.g., see comment on Chris Thomas’ famous paper regarding this matter). As systems heat up, some species will change in abundance, thereby affecting the abundance of others (think predators and prey, pollinators and their host plants, etc.) – this whole complicated process combined with single-species’ responses makes predicting what a future ecosystem might look like nearly impossible. Add in all the other ecosystem damage we’ve done from forest clearance, invasive species and over-harvesting, it’s a right mess.

It is for this reason we focussed on reviewing the links between species rather than on the species’ responses per se. We looked specifically at ecosystem function, that is, “the processes that facilitate energy transfer along food webs, and the major processes that allow the cycling of carbon, oxygen and nitrogen. ‘Function’ also includes ecosystem services.” Read the rest of this entry »





Classics: Extinction from Climate Change

22 03 2010

© A. Wong

Amidst the mildly annoying, yet functionally irrelevant sensationalism of climate change politics, conservation biologists are taking the problem seriously and attempting to predict (and prevent) extinctions arising from a rapidly heating planet (see BraveNewClimate.com‘s excellent summary here, as well as his general category of ‘ecological impacts of climate change‘).

This week’s Conservation Classic describes the first high-impact paper to signal just how bad it biodiversity could fare from climate change alone (ignoring, for the moment, synergies with other drivers of extinction).

From about the 1990s onward, conservation biologists had been accumulating a large number of case studies quantifying the extent to which species had shifted in their geographic ranges, phenology and behaviour in response to a rapidly warming planet (Parmesan & Yohe 2003). Read the rest of this entry »





Ice: canary in the global coal mine

14 09 2009

An intended pun from James Balog in another classic TED talk. If you thought climate change was merely a prediction from mathematical models, think again. The biodiversity implications are staggering.

“We have a problem of perception… Not enough people really get it yet.” J. Balog

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Charles Darwin, evolution and climate change denial

5 08 2009

DarwinThis week a mate of mine was conferred her degree at the University of Adelaide and she invited me along to the graduation ceremony. Although academic graduation ceremonies can be a bit long and involve a little too much applause (in my opinion), I was fortunate enough to listen to the excellent and inspiring welcoming speech made by the University of Adelaide’s Dean of Science, Professor Bob Hill.

Professor Hill is a world-renown expert in plant evolution, systematics and ecophysiology, and he gave a wonderful outline of the importance of Darwin’s legacy for today’s burgeoning problem solvers. I am reproducing Prof. Hill’s speech here (with his permission) as a gift to readers of ConservationBytes.com. I hope you enjoy it as much as I did.

Chancellor, Vice Chancellor, distinguished guests, members of staff, friends and family of graduates, and, most importantly of all, the new graduates, I am very pleased to have been asked to speak to you today, because 2009 marks one of the great anniversaries that we will see in our lifetimes. 200 years ago, on February 12th 1809, Charles Robert Darwin was born. To add to the auspicious nature of this year, 150 years ago, John Murray published the first edition of Darwin’s most famous book, titled On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life, better known to us all today as The Origin of Species.

I believe that from a modern perspective, Darwin was the most influential person who has ever lived. Darwin’s impact on how we think and work is much more profound than most people realise. He changed the entire way in which we go about living. Today, I want to talk to you briefly about how Darwin had this impact.

Darwin was a great observer and a great writer, but above all he was a great critical thinker. He became a scientist by a round about route, planning to be a doctor and a minister of religion along the way, although his passion was always natural history. He was not a great undergraduate student, but he benefited enormously from contact he had with University staff outside the formal classroom. His potential must have been obvious, because he was strongly recommended at a relatively young age, to take the position of naturalist and gentleman companion to Captain Robert Fitzroy on his famous five year voyage of the Beagle. Following this voyage, Darwin never physically left Britain again, but intellectually he roamed far and wide. Darwin was one of the great letter writers. He wrote thousands of letters to contacts all over the world, requesting specimens, data and opinions, and he worked relentlessly at analysing what he received back.

Over many years as a practising scientist I have met a lot of people with a passion for natural history, some of them trained scientists like Darwin, some of them gifted amateurs. There is a very obvious distinction between those with and without formal scientific training at a Tertiary level, but it took me a long time to work out what that distinction is. Let me digress slightly before I explain it.

In today’s terminology we talk a lot about graduate attributes. For some graduates, it is reasonably simple to define the kinds of attributes you expect them to have. I prefer engineers whose bridges don’t fall down, lawyers who keep me out of jail unnecessarily, accountants who can add up and doctors who do their best to keep me alive and healthy. However, the key attributes we expect of Science graduates are not so simple to define. You will all have one or more specialities where you have more knowledge than those who did not do the relevant courses, but if you are anything like I was when I was sitting out there waiting to graduate, you probably think you did what you had to do in order to pass your exams and you now think you have forgotten most of what you were taught. I can assure you that you haven’t, but I can also assure you that specific knowledge of a scientific subject is not the most important thing you have been taught here.

So what is that special something that separates out a professional scientist? It is the capacity for critical scientific thinking. You are now ready to work as professionals in many fields, and employers will actively seek to hire you because they know you have been trained here to apply a particular approach to problem solving. That approach is not easily obtained and has been taught to you in the most subtle way over the full breadth of what you have been exposed to during your time here. I suspect most of you don’t even know that you now have this skill, but you do. Darwin had it in the most sublime fashion.

When Darwin published the Origin of Species it was the culmination of decades of data gathering, backed up by meticulous analysis. Darwin never swayed from that rigorous approach, which strongly reflected the training he received as a student.

When you are exposed to a new problem, you will approach the solution in a similar way to Darwin. Let me consider the example of climate change. There is a remarkable parallel between the public reaction to the publication of the Origin of Species and the current public reaction to climate change. Darwin suffered a public backlash from people who were not ready to accept such a radical proposition as evolution by means of natural selection and this was reinforced by a significant number of professional scientists who were willing to speak out against him and his theory. As time went by, professional scientists were gradually won over by the weight of evidence, to the point where mainstream science no longer considers evolution as a theory but as scientific fact.

The reality of climate change and its potential impacts has not had a single champion like Darwin, but it has involved a similar slow accumulation of data and very careful analysis and critical thinking over the implications of what the data tell us. Initially, there were many scientists who spoke against the human-caused impact on climate change, but their number is diminishing. Most significantly, the critical analysis undertaken by thousands of mainstream scientists has gained broad political acceptance, despite the best efforts of special interest lobbyists. I suspect Darwin would be fascinated by the way this debate has developed.

Lobbyists who write stern words about how scientists as a whole are engaged in some conspiracy theory to alarm the general population simply do not understand or choose to ignore how scientists work. The world needs the critical and analytical thinking that scientists bring more than ever before. We live on a wonderful, resilient planet, that will, in the very long run, survive and thrive no matter what we do to it. But we are an extremely vulnerable species, and our survival in a manner we would consider as acceptable, is nowhere near as certain. That is the legacy of my generation to yours. I have faith that your generation will be wiser than mine has been, and I know that good science will lead the charge towards providing that wisdom.

Charles Darwin was the greatest scientist of all, and that is partly because he was a great observer and a great writer. But most of all, Darwin was the consummate critical thinker – he collected masses of data himself and from colleagues all over the world and he fashioned those data into the most relevant and elegant theory of all. I will conclude with a brief and well known passage from the first edition of the Origin of Species, which clearly demonstrates the power of Darwin’s writing:

Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows. There is grandeur in this view of life, with its several powers having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.

I hope that the next Charles Darwin is sitting amongst you today. I know that at the very least I am standing in front of a group of people who have all the attributes necessary to be great contributors to the well-being of society and the planet. Be confident of your training and use your skills well. You have a grand tradition to uphold.

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Climate change’s ugly cousin – biodiversity loss

17 05 2009

uglybaby…nobody puts a value on pollination; national accounts do not reflect the value of ecosystem services that stop soil erosion or provide watershed protection.

Barry Gardiner, Labour MP for Brent North (UK), Co-chairman, Global Legislators Organisation‘s International Commission on Land Use Change and Ecosystems

Last week I read with great interest the BBC’s Green Room opinion article by Barry Gardiner, Labour MP in the UK, about how the biodiversity crisis takes very much the back seat to climate change in world media, politics and international agreements.

He couldn’t be more spot-on.

I must stipulate right up front that this post is neither a whinge, rant nor lament; my goal is to highlight what I’ve noticed about the world’s general perception of climate change and biodiversity crisis issues over the last few years, and over the last year in particular since ConservationBytes.com was born.

Case in point: my good friend and colleague, Professor Barry Brook, started his blog BraveNewClimate.com a little over a month (August 2008) after I managed to get ConservationBytes.com up and running (July 2008). His blog tackles issues regarding the science of climate change, and Barry has been very successful at empirically, methodically and patiently tearing down the paper walls of the climate change denialists. A quick glance at the number views of BraveNewClimate.com since inception reveals about an order of magnitude more than for ConservationBytes.com (i.e., ~195000 versus 20000, respectively), and Barry has accumulated a total of around 4500 comments compared to just 231 for ConservationBytes.com. The difference is striking.

Now, I don’t begrudge for one moment this disparity – quite the contrary – I am thrilled that Barry has managed to influence so many people and topple so effectively the faecal spires erected by the myriad self-proclaimed ‘experts’ on climate change (an infamous line to whom I have no idea to attribute states that “opinions are like arseholes – everyone’s got one”). Barry is, via BraveNewClimate.com, doing the world an immense service. What I do find intriguing is that in many ways, the biodiversity crisis is a much, much worse problem that is and will continue to degrade human life for millennia to come. Yet as Barry Gardiner observed, the UK papers mentioned biodiversity only 115 times over the last 3 months compared to 1382 times for climate change – again, that order-of-magnitude disparity.

There is no biodiversity equivalent of the Intergovernmental Panel on Climate Change (although there are a few international organisations tackling the extinction crisis such as the United Nation’s Environment Program, the Millennium Ecosystem Assessment and the International Union for Conservation of Nature), we still have little capacity or idea how to incorporate the trillions of dollars worth of ecosystem services supplied every year to us free of charge, and we have nothing at all equivalent to the Kyoto Protocol for biodiversity preservation. Yet, conservation biologists have for decades demonstrated how human disease prevalence, reduction in pollination, increasing floods, reduced freshwater availability, carbon emissions, loss of fish supplies, weed establishment and spread, etc. are all exacerbated by biodiversity loss. Climate change, as serious and potentially apocalyptic as it is, can be viewed as just another stressor in a system stressed to its limits.

Of course, the lack of ‘interest’ may not be as bleak as indicated by web traffic; I believe the science underpinning our assessment of biodiversity loss is fairly well-accepted by people who care to look into these things, and the evidence spans the gambit of biological diversity and ecosystems. In short, it’s much less controversial a topic than climate change, so it attracts a lot less vitriol and spawns fewer polemics. That said, it is a self-destructive ambivalence that will eventually come to bite humanity on the bum in the most serious of ways, and I truly believe that we’re not far off from major world conflicts over the dwindling pool of resources (food, water, raw materials) we are so effectively destroying. We would be wise to take heed of the warnings.

CJA Bradshaw

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Eastern Seaboard Climate Change Initiative

30 04 2009
© A. Perkins
© A. Perkins

I’ve just spent the last few days in Sydney attending a workshop on the Eastern Seaboard Climate Change Initiative which is trying to come to grips with assessing the rising impact of climate change in the marine environment (both from biodiversity and coastal geomorphology perspectives).

Often these sorts of get-togethers end up doing little more than identifying what we don’t know, but in this case, the ESCCI (love that acronym) participants identified some very good and necessary ways forward in terms of marine research. Being a biologist, and given this is a conservation blog, I’ll focus here on the biological aspects I found interesting.

The first part of the workshop was devoted to kelp. Kelp? Why is this important?

As it turns out, kelp forests (e.g., species such as Ecklonia, Macrocystis, Durvillaea and Phyllospora) are possibly THE most important habitat-forming group of species in temperate Australia (corals and calcareous macroalgae being more important in the tropics). Without kelp, there are a whole host of species (invertebrates and fish) that cannot persist. The Australian marine environment is worth something in the vicinity of $26.8 billion to our economy each year, so it’s pretty important we maintain our major habitats. Unfortunately, kelp is starting to disappear around the country, with southern contractions of Durvillaea, Ecklonia and Hormosira on the east coast linked to the increasing southward penetration of the East Australia Current (i.e., the big current that brings warm tropical water south from Queensland to NSW, Victoria and now, Tasmania). Pollution around the country at major urban centres is also causing the loss or degradation of Phyllospora and Ecklonia (e.g., see recent paper by Connell et al. in Marine Ecology Progress Series). There is even some evidence that disease causing bleaching in some species is exacerbated by rising temperatures.

Some of the key kelp research recommendations coming out of the workshop were:

  1. Estimating the value of kelp to Australians (direct harvesting; fishing; diving)
  2. Physical drivers of change: understanding how variation in the East Australian Current (temperature, nutrients) affects kelp distribution; understanding how urban and agricultural run-off (nutrients, pollutants, sedimentation) affects distribution and health; understanding how major storm events (e.g., East Coast Lows and El Niño-Southern Oscillation) affects long-term persistence
  3. Monitoring: what is the distribution and physical limits of kelp species?; how do we detect declines in ‘health’?; what is the associated biodiversity in kelp forests?
  4. Experimental: manipulations of temperature/nutrients/pathogens in the lab and in situ to determine sensitivities; sensitivity of different life stages; latitudinal transplants to determine localised adaption
  5. Adaptation (management): reseeding; managing run-off; managing fisheries to maintain a good balance of grazers and predators; inform marine protected area zoning; understanding trophic cascades

The second part of the discussion centred on ocean acidification and increasing CO2 content in the marine environment. As you might know, increasing atmospheric CO2 is taken up partially by ocean water, which lowers the availability of carbonate and increases the concentration of hydrogen ions (thus lowering pH or ‘acidifying’). It’s a pretty worrying trend – we’ve seen a drop in pH already, with conservative predictions of another 0.3 pH drop by the end of this century (equating to a doubling of hydrogen ions in the water). What does all this mean for marine biodiversity? Well, many species will simply not be able to maintain carbonate shells (e.g., coccolithophore phytoplankton, corals, echinoderms, etc.), many will suffer reproductive failure through physiological stress and embryological malfunction, and still many more will be physiologically stressed via hypercapnia (overdose of CO2, the waste product of animal respiration).

Many good studies have come out in the last few years demonstrating the sensitivity of certain species to reductions in pH (some simultaneous with increases in temperature), but some big gaps remain in our understanding of what higher CO2 content in the marine environment will mean for biota. Some of the key research questions in this area identified were therefore:

  1. What is the adaptation (evolutionary) potential of sensitive species? Will many (any) be able to evolve higher resistance quickly enough?
  2. In situ experiments outside the lab that mimic pH and pCO2 variation in space and time are needed to expose species to more realistic conditions.
  3. What are the population consequences (e.g., change in extinction risk) of higher individual susceptibility?
  4. Which species are most at risk, and what does this mean for ecosystem function (e.g., trophic cascades)?

As you can imagine, the conversation was complex, varied and stimulating. I thank the people at the Sydney Institute of Marine Science for hosting the fascinating discussion and I sincerely hope that even a fraction of the research identified gets realised. We need to know how our marine systems will respond – the possibilities are indeed frightening. Ignorance will leave us ill-prepared.

CJA Bradshaw

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Wake Up, Freak Out

9 10 2008
© Leo Murray

© Leo Murray

An excellent, short animated film about the perils of climate change and its implications for biodiversity (including humans). Highly recommended.

This really isn’t about polar bears any more. At this very moment, the fate of civilization itself hangs in the balance.

It turns out that the way we have been calculating the future impacts of climate change up to now has been missing a really important piece of the picture. It seems we are now dangerously close to the tipping point in the world’s climate system; this is the point of no return, after which truly catastrophic changes become inevitable.

Wake Up, Freak Out – then Get a Grip is a short, animated film about climate change by Leo Murray.





Global warming and biodiversity extinction

14 08 2008

My colleague Barry Brook recently posted a discussion on the impacts of climate change on biodiversity extinction rates and patterns. A very good introduction to the subject.

CJA Bradshaw