Human population size: speeding cars can’t stop quickly

28 10 2014

Stop breeding cartoon-Steve Bell 1994Here at, I write about pretty much anything that has anything remotely to do with biodiversity’s prospects. Whether it is something to do with ancient processes, community dynamics or the wider effects of human endeavour, anything is fair game. It’s a little strange then that despite cutting my teeth in population biology, I have never before tackled human demography. Well as of today, I have.

The press embargo has just lifted on our (Barry Brook and my) new paper in PNAS where we examine various future scenarios of the human population trajectory over the coming century. Why is this important? Simple – I’ve argued before that we could essentially stop all conservation research tomorrow and still know enough to deal with most biodiversity problems. If we could only get a handle on the socio-economic components of the threats, then we might be able to make some real progress. In other words, we need to find out how to manage humans much more than we need to know about the particulars of subtle and complex ecological processes to do the most benefit for biodiversity. Ecologists tend to navel-gaze in this arena far too much.

So I called my own bluff and turned my attention to humans. Our question was simple – how quickly could the human population be reduced to a more ‘sustainable’ size (i.e., something substantially smaller than now)? The main reason we posed that simple, yet deceptively loaded question was that both of us have at various times been faced with the question by someone in the audience that we were “ignoring the elephant in the room” of human over-population.

Read the rest of this entry »

If biodiversity is so important, why is Europe not languishing?

17 03 2014

collapseI don’t often respond to many comments on this blog unless they are really, really good questions (and if I think I have the answers). Even rarer is devoting an entire post to answering a question. The other day, I received a real cracker, and so I think it deserves a highlighted response.

Two days ago, a certain ‘P. Basu’ asked this in response to my last blog post (Lose biodiversity and you’ll get sick):

I am an Indian who lived in Germany for quite a long period. Now, if I am not grossly mistaken, once upon a time Germany and other west european countries had large tracts of “real” forests with bears, wolves, foxes and other animals (both carnivore and herbivore). Bear has completely disappeared from these countries with the advent of industrialization. A few wolves have been kept in more or less artificially created forests. Foxes, deer and hares, fortunately, do still exist. My question is, how come these countries are still so well off – not only from the point of view of economy but also from the angle of public health despite the loss of large tracts of natural forests? Or is it that modern science and a health conscious society can compensate the loss of biodiversity.

“Well”, I thought to myself, “Bloody good question”.

I have come across this genre of question before, but usually under more hostile circumstances when an overtly right-wing respondent (hell, let’s call a spade a spade – a ‘completely selfish arsehole’) has challenged me on the ‘value of nature’ logic (I’m not for a moment suggesting that P. Basu is this sort of person; on the contrary, he politely asked an extremely important question that requires an answer). The comeback generally goes something like this: “If biodiversity is so important, why aren’t super-developed countries wallowing in economic and social ruin because they’ve degraded their own life-support systems? Clearly you must be wrong, Sir.”

There have been discussions in the ecological and sustainability literature that have attempted to answer this, but I’ll give it a shot here for the benefit of readers. Read the rest of this entry »

Biowealth: all creatures great and small

4 12 2013

Curious Country flyer“So consider the crocodiles, sharks and snakes, the small and the squirmy, the smelly, slimy and scaly. Consider the fanged and the hairy, the ugly and the cute alike. The more we degrade this astonishing diversity of evolved life and all its interactions on our only home, the more we expose ourselves to the ravages of a universe that is inherently hostile to life.”

excerpt from ‘Biowealth: all creatures great and small’ The Curious Country (C.J.A. Bradshaw 2013).

I’ve spent the last few days on the east coast with my science partner-in-crime, Barry Brook, and one of our newest research associates (Marta Rodrigues-Rey Gomez). We first flew into Sydney at sparrow’s on Monday, then drove a hire car down to The ‘Gong to follow up on some Australian megafauna databasing & writing with Bert Roberts & Zenobia Jacobs. On Tuesday morning we then flitted over to Canberra where we had the opportunity to attend the official launch of a new book that Barry and I had co-authored.

The book, The Curious Country, is an interesting experiment in science communication and teaching dreamed up by Australia’s Chief Scientist, Professor Ian Chubb. Realising that the average Aussie has quite a few questions about ‘how stuff works’, but has little idea how to answer those questions, Ian engaged former Quantum star and science editor, Leigh Dayton, to put together a short, punchy, topical and easily understood book about why science is good for the country.

Yes, intuitive for most of you out there reading this, but science appreciation isn’t always as high as it should be amongst the so-called ‘general public’. Ian thought this might be one way to get more people engaged.

When honoured with the request to write an interesting chapter on biodiversity for the book, I naturally accepted. It turns out Barry was asked to do one on energy provision at the same time (but we didn’t know we had both been asked at the time). Our former lab head, Professor David Bowman, was also asked to write a chapter about fire risk, so it was like a mini-reunion yesterday for the three of us.

Read the rest of this entry »

Ecology: the most important science of our times

12 07 2013

rocket-scienceThe title of this post is deliberately intended to be provocative, but stay with me – I do have an important point to make.

I’m sure most every scientist in almost any discipline feels that her or his particular knowledge quest is “the most important”. Admittedly, there are some branches of science that are more applied than others – I have yet to be convinced, for example, that string theory has an immediate human application, whereas medical science certainly does provide answers to useful questions regarding human health. But the passion for one’s own particular science discipline likely engenders a sort of tunnel vision about its intrinsic importance.

So it comes down to how one defines ‘important’. I’m not advocating in any way that application or practicality should be the only yardstick to ascertain importance. I think superficially impractical, ‘blue-skies’ theoretical endeavours are essential precursors to all so-called applied sciences. I’ll even go so far as to say that there is fundamentally no such thing as a completely unapplied science discipline or question. As I’ve said many times before, ‘science’ is a brick wall of evidence, where individual studies increase the strength of the wall to a point where we can call it a ‘theory’. Occasionally a study comes along and smashes the wall (paradigm shift), at which point we begin to build a new one. Read the rest of this entry »

Global Ecology postgraduate opportunities

12 08 2012

I should have published these ages ago, but like many things I have should have done earlier, I didn’t.

I also apologise for a bit of silence over the past week. After coming back from the ESP Conference in Portland, I’m now back at Stanford University working with Paul Ehrlich trying to finish our book (no sneak peaks yet, I’m afraid). I have to report that we’ve completed about about 75 % it, and I’m starting to feel like the end is in sight. We hope to have it published early in 2013.

So here they are – the latest 9 PhD offerings from us at the Global Ecology Laboratory. If you want to get more information, contact the first person listed as the first supervisor at the end of each project’s description.

1. Optimal survey and harvest models for South Australian macropods (I’ve advertised this before, but so far, no takers):

The South Australia Department of Environment, Water and Natural Resources (DEWNR) is custodian of a long-term macropod database derived from the State’s management of the commercial kangaroo harvest industry. The dataset entails aerial survey data for most of the State from 1978 to present, annual population estimates, quotas and harvests for three species: red kangaroo (Macropus rufus), western grey kangaroo (Macropus fuliginosus), and the euro (Macropus robustus erubescens).

DEWNR wishes to improve the efficiency of surveys and increase the precision of population estimates, as well as provide a more quantitative basis for setting harvest quotas.

We envisage that the PhD candidate will design and construct population models:

  • to predict population size/densities with associated uncertainty, linking fluctuations to environmental variability (including future climate change projections)
  • to evaluate the efficiency of spatially explicit aerial surveys
  • to estimate demographic parameters (e.g., survival rate) from life tables and
  • to estimate spatially explicit sustainable harvest quotas

 Supervisors: me, A/Prof. Phill Cassey, Dr Damien Fordham, Dr Brad Page (DEWNR), Professor Michelle Waycott (DEWNR).

2. Correcting for the Signor-Lipps effect

The ‘Signor-Lipps effect’ in palaeontology is the notion that the last organism of a given species will never be recorded as a fossil given the incomplete nature of the fossil record (the mirror problem is the ‘Jaanusson effect’, where the first occurrence is delayed past the true time of origination). This problem makes inference about the timing and speed of mass extinctions (and evolutionary diversification events) elusive. The problem is further complicated by the concept known as the ‘pull of the recent’, which states that the more time since an event occurred, the greater the probability that evidence of that event will have disappeared (e.g., erased by erosion, hidden by deep burial, etc.).

In a deep-time context, these problems confound the patterns of mass extinctions – i.e., the abruptness of extinction and the dynamics of recovery and speciation. This PhD project will apply a simulation approach to marine fossil time series (for genera and families, and some individual species) covering the Phanerozoic Aeon, as well as other taxa straddling the K-T boundary (Cretaceous mass extinction). The project will seek to correct for taphonomic biases and assess the degree to which extinction events for different major taxa were synchronous.

The results will also have implications for the famous Sepkoski curve, which describes the apparent logistic increase in marine species diversity over geological time with an approximate ‘carrying capacity’ reached during the Cenozoic. Despite recent demonstration that this increase is partially a taphonomic artefact, a far greater development and validation/sensitivity analysis of underlying statistical models is needed to resolve the true patterns of extinction and speciation over this period.

The approach will be to develop a series of models describing the interaction of the processes of speciation, local extinction and taphonomic ‘erasure’ (pull of the recent) to simulate how these processes interact to create the appearance of growth in numbers of taxa over time (Sepkoski curve) and the abruptness of mass extinction events. The candidate will estimate key parameters in the model to test whether the taphonomic effect is strong enough to be the sole explanation of the apparent temporal increase in species diversity, or whether true diversification accounts for this.

Supervisors: me, Prof. Barry Brook

3. Genotypic relationships of Australian rabbit populations and consequences for disease dynamics

Historical evidence suggests that there were multiple introduction events of European rabbits into Australia. In non-animal model weed systems it is clear that biocontrol efficacy is strongly influenced by the degree of genetic diversity and number of breed variants in the population.

The PhD candidate will build phylogenetic relationships for Australian rabbit populations and develop landscape genetic models for exploring the influence of myxomatosis and rabbit haemorrhagic disease virus (RHDV) on rabbit vital rates (survival, reproduction and dispersal) at regional and local scales. Multi-model synthesis will be used to quantify the relative roles of environment (including climate) and genotype on disease prevalence and virulence in rabbit populations.

Supervisors: A/Prof Phill Cassey, Dr Damien Fordham, Prof Barry Brook Read the rest of this entry »

The invisible hand of ecosystem services

4 08 2012

I’ve just spent nearly an entire week trying to get my head around ecosystem services (ES).

You’d think that would have been a given based on my experience, my research, my writings and the fact that I’ve just spent the last week with 400 ES specialists from around the world at the 5th international Ecosystem Services Partnership (ESP) Conference in Portland, Oregon, USA.

Well, prior to this week I thought I knew what ES were, but now I think I’m just a little more confused.

Of course, I’m not talking about the concept of ES or what they are (hell, I’ve written enough about them on this blog and in my papers); my problem is understanding how we as society end up valuing them in a practical, sensible and feasible way.

So I’m going to describe the ESP Conference as I saw it, and not necessarily in chronological order.

First up is the term ‘ecosystem services’ itself – horrible name, and something rammed home again after attending the conference. Most people on the planet that are not scientists (that would be nearly everyone) just might have the most tenuous and ethereal of grasps of ‘ecosystem’ in the first place, and I’d bet that 99 % of most undergraduate students couldn’t provide a comprehensive description. This is because ecosystems are mind-bogglingly, chaotically and awesomely complex. Just ask any ecosystem ecologist.

The second part of the term – services – is particularly offensive in its presumption and arrogance. It’s not like you ring up an ecosystem and get it to clean your carpets, or fill your water tank or gas cylinder. No, the natural world did not evolve to pamper humanity; we are merely part of it (and bloody efficient at modifying it, I might add).

So try to sell this ‘incredibly complex thingy’ that is ‘there to do some (intangible) shit for us’ to the public, policy makers and politicians, and you mostly get a dog’s regurgitated breakfast and some blank, slack-jawed stares. Read the rest of this entry »

When the cure becomes the disease

6 02 2012

I’ve always barracked for Peter Kareiva‘s views and work; I particularly enjoy his no-bullshit, take-no-prisoners approach to conservation. Sure, he’s said some fairly radical things over the years, and has pissed off more than one conservationist in the process. But I think this is a good thing.

His main point (as is mine, and that of a growing number of conservation scientists) is that we’ve already failed biodiversity, so it’s time to move into the next phase of disaster mitigation. By ‘failing’ I mean that, love it or loathe it, extinction rates are higher now than they have been for millennia, and we have very little to blame but ourselves. Apart from killing 9 out of 10 people on the planet (something no war or disease will ever be able to do), we’re stuck with the rude realism that it’s going to get a lot worse before it gets better.

This post acts mostly an introduction to Peter Kareiva & collaborators’ latest essay on the future of conservation science published in the Breakthrough Institute‘s new journal. While I cannot say I agree with all components (especially the cherry-picked resilience examples), I fundamentally support the central tenet that we have to move on with a new state of play.

In other words, humans aren’t going to go away, ‘pristine’ is as unattainable as ‘infinity’, and reserves alone just aren’t going to cut it. Read the rest of this entry »


Get every new post delivered to your Inbox.

Join 6,536 other followers

%d bloggers like this: