Transition from the Anthropocene to the Minicene

24 09 2016
Going, going ...

Going, going … © CJA Bradshaw

I’ve just returned from a life-changing trip to South Africa, not just because it was my first time to the continent, but also because it has redefined my perspective on the megafauna extinctions of the late Quaternary. I was there primarily to attend the University of Pretoria’s Mammal Research Institute 50thAnniversary Celebration conference.

As I reported in my last post, the poaching rates in one of the larger, best-funded national parks in southern Africa (the Kruger) are inconceivably high, such that for at least the two species of rhino there (black and white), their future persistence probability is dwindling with each passing week. African elephants are probably not far behind.

As one who has studied the megafauna extinctions in the Holarctic, Australia and South America over the last 50,000 years, the trip to Kruger was like stepping back into the Pleistocene. I’ve always dreamed of walking up to a grazing herd of mammoths, woolly rhinos or Diprotodon, but of course, that’s impossible. What is entirely possible though is driving up to a herd of 6-tonne elephants and watching them behave naturally. In the Kruger anyway, you become almost blasé about seeing yet another group of these impressive beasts as you try to get that rare glimpse of a leopard, wild dogs or sable antelope (missed the two former, but saw the latter).

Oh, it's just another elephant

Yawn. It’s just another elephant © CJA Bradshaw

Let’s just let that digest for a moment.

If you have seen elephants in the wild, and you have had that ‘oh, it’s just another elephant’ feeling, I challenge you to think about it from the perspective that in every other continent, the megafauna assemblage is long gone. Africa is the last setting on Earth where humans can interact with them (both positively and negatively).

When you think about it like that, I doubt you’ll ever be blasé again about such future interactions.

But human pressures in Africa are growing, meaning that despite largely squeaking through the megafauna-extinction period that happened elsewhere untainted, we may very well be witnessing the final days of Africa’s megabeasts too. I hope to hell that I am wrong, but we don’t have a great track record in this area. I remain largely pessimistic.

This was one of the principal reasons I coughed up to bring my nine-year old with me because I really don’t think she’ll have the opportunity to see a rhino in the wild when she’s my age.

The elusive and impressive sable antelope (Hippotragus niger)

The elusive and impressive sable antelope (Hippotragus niger) © CJA Bradshaw

Seeing these animals in a wild state also gave me a new perspective on interpreting the ecological patterns of megafaunal communities elsewhere during the Pleistocene. We can debate long and hard about the complex climate-vegetation-consumption interactions that occurred when the megafauna was teaming in Eurasia or Australia, but we need only look to Africa to see how it really worked. One thing that struck me was just how nearly every square metre of the ground, and nearly every plant, was influenced to some degree by these herbivores (acknowledging of course that densities of many species, like elephants and many antelope are probably unnaturally high in places like the Kruger). The megafauna is (and was) a superlative ecoengineering unit that altered entire continents, allowing other species to exist in the niches they created.

Plants take quite the beating from megaherbivores

Plants take quite the beating from megaherbivores

While some of this inference has already been pointed out by much of the ground-breaking ecological research that African and other ecologists have done over the last century, I think we need to bring this ecoengineering component into tighter hypothetical focus for the next phase of African ecology. This was indeed one of the things we discussed at the conference I attended, and something that will be brought to light soon with the publications arising from this paradigm-shifting meeting.

All this brings me to my last point. You might have been following the debates surrounding the definition, onset and existence of the Anthropocene — the ‘geological’ era defined by humans. I am of the opinion that the debates are more or less meaningless anyway because even if we are now laying the foundations for an actual geological layer of fossils arising from our current destruction of life on Earth, the plausibility that anything sentient will be able to view and interpret this layer many millions of years from now is vanishingly remote.

Whether the Anthropocene started 50,000 years ago in Australia and Europe, or whether it started in 1640 is also largely irrelevant — there is no question that extinctions are happening by our hand at elevated rates (relative to inter-mass-extinction intervals).

My daughter and I had the marvellous opportunity to interact with live elephants at Elephant Whispers (https://goo.gl/zMHteQ)

My daughter and I had the marvellous opportunity to interact with live elephants at Elephant Whispers (https://goo.gl/zMHteQ)

So my proposition is that when we wake up one day with the realisation that elephants, rhinos, giraffe, hippopotamus and perhaps a few more species are no longer living in a wild state, the Anthropocene should be considered to have ended. I further propose that we call the following era the Minicene, because all that will likely remain on the planet as long as human beings number in the billions will be the smaller species that can persist despite our consumption.

I dare say that my daughter will witness the onset of the Minicene, and I might even survive long enough to see it too. I’m not looking forward to that day.

CJA Bradshaw





One-two carbon punch of defaunation

30 04 2016

1-2 punchI’ve just read a well-planned and lateral-thinking paper in Nature Communications that I think readers of CB.com ought to appreciate. The study is a simulation of a complex ecosystem service that would be nigh impossible to examine experimentally. Being a self-diagnosed fanatic of simulation studies for just such purposes, I took particular delight in the results.

In many ways, the results of the paper by Osuri and colleagues are intuitive, but that should never be a reason to avoid empirical demonstration of a suspected phenomenon because intuition rarely equals fact. The idea itself is straightforward, but takes more than a few logical steps to describe: Read the rest of this entry »





Eye on the taiga

24 03 2014

boreal damageDun! Dun, dun, dun! Dun, dun, dun! Dun, dun, daaaaah!

I’ve waited nearly two years to do that, with possibly our best title yet for a peer-reviewed paper: Eye on the taiga: removing global policy impediments to safeguard the boreal forest (recently published online in Conservation Letters).

Of course, the paper has nothing to do with cheesy Eighties music, underdog boxers or even tigers, but it does highlight an important oversight in world carbon politics. The boreal forest (also known as taiga from the Russian) spans much of the land mass of the Northern Hemisphere and represents approximately one quarter of the entire planet’s forests. As a result, this massive forest contains more than 35% of all terrestrially bound carbon (below and above ground). One doesn’t require much more information to come to the conclusion that this massive second lung of the planet (considering the Amazon the first lung) is a vital component of the world’s carbon cycle, and temperate biodiversity.

The boreal forest has been largely expanding since the retreat of the glaciers following the Last Glacial Maximum about 20,000 years ago, which means that its slow progression northward has produced a net carbon sink (i.e., it takes up more atmospheric carbon that it releases from decomposition). However, recent evidence suggests that due to a combination of increased deforestation, fire from both human encroachment and climate change, mass outbreaks of tree-killing insects and permafrost melting, the boreal forest is tipping towards becoming a net carbon source (i.e., emitting more carbon into the atmosphere than it takes up from photosynthesis). This is not a good thing for the world’s carbon cycle, because it means yet another positive feedback that will exacerbate the rapid warming of the planet. Read the rest of this entry »





Tropical protected areas still in trouble

8 10 2012

© P. Harris

There’s nothing like a bit of good, intelligent and respectful debate in science.

After the publication in Nature of our paper on tropical protected areas (Averting biodiversity collapse in tropical forest protected areas), some interesting discussion has ensued regarding some of our assumptions and validations.

As is their wont, Nature declined to publish these comments (and our responses) in the journal itself, but the new commenting feature at Nature.com allowed the exchange to be published online with the paper. Cognisant that probably few people will read this exchange, Bill Laurance and I decided to reproduce them here in full for your intellectual pleasure. Any further comments? We’d be keen to hear them.

COMMENT #1 (by Hari Sridhar of the Centre for Ecological Sciences at the Indian Institute of Science in Bangalore)

In this paper, Laurance and co-authors have tapped the expert opinions of ‘veteran field biologists and environmental scientists’ to understand the health of protected areas in the tropics worldwide. This is a novel and interesting approach and the dataset they have gathered is very impressive. Given that expert opinion can be subject to all kinds of biases and errors, it is crucial to demonstrate that expert opinion matches empirical reality. While the authors have tried to do this by comparing their results with empirical time-series datasets, I argue that their comparison does not serve the purpose of an independent validation.

Using 59 available time-series datasets from 37 sources (journal papers, books, reports etc.), the authors find a fairly good match between expert opinion and empirical data (in 51/59 cases, expert opinion matched empirically-derived trend). For this comparison to serve as an independent validation, it is crucial that the experts were unaware of the empirical trends at the time of the interviews. However, this is unlikely to be true because, in most cases, the experts themselves were involved in the collection of the time-series datasets (at least 43/59 to my knowledge, from a scan of references in Supplementary Table 1). In other words, the same experts whose opinions were being validated were involved in collection of the data used for validation.

OUR RESPONSE (William F. Laurance, Corey J. A. Bradshaw, Susan G. Laurance)

Sridhar raises a relevant point but one that, on careful examination, does not weaken our validation analysis. Read the rest of this entry »





It couldn’t have been us!

29 05 2012

A few months ago I asked Chris Johnson of the University of Tasmania to put together a post on his recent Science paper regarding Australian megafaunal extinctions. It seems that it stirred, yet again, some controversy among those who refuse to accept (mainly archaeologists) that humans could have had anything to do with pre-European extinctions. Indeed, how could humans possibly have anything to do with extinctions?!

Like Corey, I am mainly interested in current environmental problems. But now and then I wade into the debate over the extinction of Australia’s Pleistocene megafauna [editor’s note: Chris literally wrote the book on Australian mammal extinctions over the last 50,000 years], those huge animals that wandered over the Australian landscape until about 40,000 years ago.

This is an endlessly fascinating topic. The creatures were wonderful and bizarre – it’s great fun doing work that lets you think about marsupial lions, giant kangaroos, geese bigger than emus, echidnas the size of wombats, and the rest. The cause of their extinction is perhaps the biggest mystery, and the most vexed controversy, in the environmental history of Australia. And for reasons that I will explain in a minute, solving this mystery is profoundly important for our understanding of contemporary Australian ecology.

The latest bit of work on this is a paper that a group of us (including Corey’s close colleague, Barry Brook) published in Science. You can see it here (if you don’t have access to Science, email me for a copy). So far, research on this problem has concentrated on dating fossils to find out when megafauna species went extinct. Several recent studies have found evidence for extinction between 40,000 and 50,000 years ago, which is about when people first came to Australia. But the conclusion that people caused a mass extinction of megafauna has been strenuously criticised, because so far it is based on only a few species with good collections of dates. The critics argue that other species disappeared before humans arrived, maybe in an extended series of extinctions caused by something else, like a deteriorating climate.

This argument over fossils will be with us for a long time. Because finding and dating fossils is such hard, slow work, the fossil record will inevitably give a seriously incomplete picture of what happened. One way around this problem would be to analyse the fossil record using mathematical approaches that take into account the problem of incomplete sampling. Corey is lead author of a recent paper that introduced a great new set of tools for this, and we are part of a group that is currently assembling a complete database of all recent dates on Australian fossils so that we can analyse them using these tools. Stay tuned for the result. Read the rest of this entry »





Eat a feral a week

22 03 2012

© Y. Sugiura

Just a quick post this week about something I’ve been contemplating for a while.

What if every Australian pledged to eat a feral animal a week?

Yes, I know that it’s a bit out of the pitch, and I’m sure not everyone would do it. Nor would it be physically possible for one person to eat an entire camel, buffalo or deer in a week – but hopefully you get the picture.

Why propose this? Australia is quite over-run with feral animals. Some quick stats:

Now we have, of course, many other ferals (cats, rats, foxes, mice), but I don’t think too many people would want to eat them. I have personally eaten feral pigs, camels, buffalo, goats, and red, fallow and sambar deer, mostly from my own research trips or from friends who hunt. Read the rest of this entry »





The evil sextet

18 05 2011

This post doubles as a Conservation Classic and a new take on an old concept. It’s new in the sense that it updates what we believe is an advance on a major milestone in conservation biology, even though some of the add-on concepts themselves have been around for a while.

First, the classic.

The ‘evil quartet’, or ‘four horsemen of the ecological apocalypse’, was probably the first treatment of extinction dynamics as a biological discipline in its own right. Jarod Diamond (1984) took a sweeping historical and contemporary view of extinction, then simplified the problem to four principal mechanisms:

  1. overhunting (or overexploitation),
  2. introduced species,
  3. habitat destruction and
  4. chains of linked extinctions (trophic cascades, or co-extinctions).

Far from a mere review or list of unrelated mechanisms, Diamond’s evil quartet crystallized conservation biologists’ thinking about key mechanisms and, more importantly, directed attention towards those factors likely to drive extinctions in the future. The unique combination of prehistorical through to modern examples gave conservation biologists a holistic view of extinction dynamics and helped spawn many of the papers described hereafter. Read the rest of this entry »








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