Ice Age? No. Abrupt warmings and hunting together polished off Holarctic megafauna

24 07 2015
Oh shit oh shit oh shit ...

Oh shit oh shit oh shit …

Did ice ages cause the Pleistocene megafauna to go extinct? Contrary to popular opinion, no, they didn’t. But climate change did have something to do with them, only it was global warming events instead.

Just out today in Science, our long-time-coming (9 years in total if you count the time from the original idea to today) paper ‘Abrupt warmings drove Late Pleistocene Holarctic megafaunal turnover‘ led by Alan Cooper of the Australian Centre for Ancient DNA and Chris Turney of the UNSW Climate Change Research Centre demonstrates for the first time that abrupt warming periods over the last 60,000 years were at least partially responsible for the collapse of the megafauna in Eurasia and North America.

You might recall that I’ve been a bit sceptical of claims that climate changes had much to do with megafauna extinctions during the Late Pleistocene and early Holocene, mainly because of the overwhelming evidence that humans had a big part to play in their demise (surprise, surprise). What I’ve rejected though isn’t so much that climate had nothing to do with the extinctions; rather, I took issue with claims that climate change was the dominant driver. I’ve also had problems with blanket claims that it was ‘always this’ or ‘always that’, when the complexity of biogeography and community dynamics means that it was most assuredly more complicated than most people think.

I’m happy to say that our latest paper indeed demonstrates the complexity of megafauna extinctions, and that it took a heap of fairly complex datasets and analyses to demonstrate. Not only were the data varied – the combination of scientists involved was just as eclectic, with ancient DNA specialists, palaeo-climatologists and ecological modellers (including yours truly) assembled to make sense of the complicated story that the data ultimately revealed. Read the rest of this entry »





An appeal to extinction chronologists

2 06 2015

u7Pi3Extinction is forever, right? Yes, it’s true that once the last individual of a species dies (apart from insane notions that de-extinction will do anything to resurrect a species in perpetuity), the species is extinct. However, the answer can also be ‘no’ when you are limited by poor sampling. In other words, when you think something went extinct when in reality you just missed it.

Most of you are familiar with the concept of Lazarus1 species – when we’ve thought of something long extinct that suddenly gets re-discovered by a wandering naturalist or a wayward fisher. In paleontological (and modern conservation biological) terms, the problem is formally described as the ‘Signor-Lipps’ effect, named2 after two American palaeontologists, Phil Signor3 and Jere Lipps. It’s a fairly simple concept, but it’s unfortunately ignored in most palaeontological, and to a lesser extent, conservation studies.

The Signor-Lipps effect arises because the last (or first) evidence (fossil or sighting) of a species presence has a nearly zero chance of heralding its actual timing of extinction (or appearance). In paleontological terms, it’s easy to see why. Fossilisation is in fact a nearly impossible phenomenon – all the right conditions have to be in place for a once-living biological organism to be fossilised: it either has to be buried quickly, in a place where nothing can decompose it (usually, an anoxic environment), and then turned to rock by the process of mineral replacement. It then has to resist transformation by not undergoing metamorphosis (e.g., vulcanism, extensive crushing, etc.). For more recent specimens, preservation can occur without the mineralisation process itself (e.g., bones or flesh in an anoxic bog). Then the bloody things have to be found by a diligent geologist or palaeontologist! In other words, the chances that any one organism is preserved as a fossil after it dies are extremely small. In more modern terms, individuals can go undetected if they are extremely rare or remote, such that sighting records alone are usually insufficient to establish the true timing of extinction. The dodo is a great example of this problem. Remember too that all this works in reverse – the first fossil or observation is very much unlikely to be the first time that the species was there. Read the rest of this entry »





What’s in a name? The dingo’s sorry saga

30 01 2015

bad dingoThe more I delve into the science of predator management, the more I realise that the science itself takes a distant back seat to the politics. It would be naïve to think that the management of dingoes in Australia is any more politically charged than elsewhere, but once you start scratching beneath the surface, you quickly realise that there’s something rotten in Dubbo.

My latest contribution to this saga is a co-authored paper led by Dale Nimmo of Deakin University (along with Simon Watson of La Trobe and Dave Forsyth of Arthur Rylah) that came out just the other day. It was a response to a rather dismissive paper by Matt Hayward and Nicky Marlow claiming that all the accumulated evidence demonstrating that dingoes benefit native biodiversity was somehow incorrect.

Their two arguments were that: (1) dingoes don’t eradicate the main culprits of biodiversity decline in Australia (cats & foxes), so they cannot benefit native species; (2) proxy indices of relative dingo abundance are flawed and not related to actual abundance, so all the previous experiments and surveys are wrong.

Some strong accusations, for sure. Unfortunately, they hold no water at all. Read the rest of this entry »





Using ecological theory to make more money

1 12 2014

huge.9.46974Let’s face it: Australia doesn’t have the best international reputation for good ecological management. We’ve been particularly loathsome in our protection of forests, we have an appalling record of mammal extinctions, we’re degenerate water wasters and carbon emitters, our country is overrun with feral animals and weeds, and we have a long-term love affair with archaic, deadly, cruel, counter-productive and xenophobic predator management. To top it all off, we have a government hell-bent on screwing our already screwed environment even more.

Still, we soldier on and try to fix the damages already done or convince people that archaic policies should be scrapped and redrawn. One such policy that I’ve written about extensively is the idiocy and cruelty of the dingo fence.

The ecological evidence that dingoes are good for Australian wildlife and that they pose less threat to livestock than purported by some evidence-less graziers is becoming too big to ignore any longer. Poisoning and fencing are not only counter-productive, they are cruel, ineffective and costly.

So just when ecologists thought that dingoes couldn’t get any cooler, out comes our latest paper demonstrating that letting dingoes do their thing results in a net profit for cattle graziers.

Come again? Read the rest of this entry »





Human population size: speeding cars can’t stop quickly

28 10 2014

Stop breeding cartoon-Steve Bell 1994Here at ConservationBytes.com, 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 »





Western Australia’s moronic shark cull

4 07 2014

another stupid politicianA major media release today coordinated by Jessica Meeuwig in Western Australia makes the (obvious) point that there’s no biological justification to cull sharks.

301 Australian and International Scientists experts have today provided their submission to the Western Australia Environmental Protection Authority (EPA), rejecting the scientific grounds for the proposed three-year drum-line programme.

Coordinating scientist, Professor Jessica Meeuwig from the University of Western Australia said:

“To have over 300 researchers, including some of the world’s top shark specialists and marine ecologists, all strongly agreeing that there is no scientific basis for the lethal drum-line programme, tells you how unjustified the government’s proposal is. If the EPA and the Federal Minister for the Environment are using science for decisions, the drum-line proposal should not be approved.”

The experts agree that the proposal presents no evidence that the lethal drum-line programme, as implemented, will improve ocean safety. It ignores evidence from other hook-based programs in Hawaii and Queensland that have been shown to be ineffective in reducing shark attacks on humans.

Dr. Christopher Neff from the University of Sydney stated:

“There is no evidence that drum lines reduce shark bites. The Western Australia EPA now faces a question of science versus politics with global implications because it is considering establishing a new international norm that would allow for the killing of protected white sharks.”

The drum lines are ineffective and indiscriminate, with 78% of the sharks captured not considered ‘threatening’ to humans. Yet, scientifically supported, non-lethal alternatives such as the South African ‘Shark Spotter’ and Brazil’s ‘Tag and Remove’ programmes are not adequately assessed as viable options for Western Australia. Read the rest of this entry »





School finishers and undergraduates ill-prepared for research careers

22 05 2014

bad mathsHaving been for years now at the pointy end of the educational pathway training the next generation of scientists, I’d like to share some of my observations regarding how well we’re doing. At least in Australia, my realistic assessment of science education is: not well at all.

I’ve been thinking about this for some time, but only now decided to put my thoughts into words as the train wreck of our current government lurches toward a future guaranteeing an even stupider society. Charging postgraduate students to do PhDs for the first time, encouraging a US-style system of wealth-based educational privilege, slashing education budgets and de-investing in science while promoting the belief in invisible spaghetti monsters from space, are all the latest in the Fiberal future nightmare that will change our motto to “Australia – the stupid country”.

As you can appreciate, I’m not filled with a lot of hope that the worrying trends I’ve observed over the past 10 years or so are going to get any better any time soon. To be fair though, the problems go beyond the latest stupidities of the Fiberal government.

My realisation that there was a problem has crystallised only recently as I began to notice that most of my lab members were not Australian. In fact, the percentage of Australian PhD students and post-doctoral fellows in the lab usually hovers around 20%. Another sign of a problem was that even when we advertised for several well-paid postdoctoral positions, not a single Australian made the interview list (in fact, few Australians applied at all). I’ve also talked to many of my colleagues around Australia in the field of quantitative ecology, and many lament the same general trend.

Is it just poor mathematical training? Yes and no. Australian universities have generally lowered their entry-level requirements for basic maths, thereby perpetuating the already poor skill base of school leavers. Why? Bums (that pay) on seats. This means that people like me struggle to find Australian candidates that can do the quantitative research we need done. We are therefore forced to look overseas. Read the rest of this entry »








Follow

Get every new post delivered to your Inbox.

Join 8,319 other followers

%d bloggers like this: