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 »





Avoiding genetic rescue not justified on genetic grounds

12 03 2015
Genetics to the rescue!

Genetics to the rescue!

I had the pleasure today of reading a new paper by one of the greatest living conservation geneticists, Dick Frankham. As some of CB readers might remember, I’ve also published some papers with Dick over the last few years, with the most recent challenging the very basis for the IUCN Red List category thresholds (i.e., in general, they’re too small).

Dick’s latest paper in Molecular Ecology is a meta-analysis designed to test whether there are any genetic grounds for NOT attempting genetic rescue for inbreeding-depressed populations. I suppose a few definitions are in order here. Genetic rescue is the process, either natural or facilitated, where inbred populations (i.e., in a conservation sense, those comprising too many individuals bonking their close relatives because the population in question is small) receive genes from another population such that their overall genetic diversity increases. In the context of conservation genetics, ‘inbreeding depression‘ simply means reduced biological fitness (fertility, survival, longevity, etc.) resulting from parents being too closely related.

Seems like an important thing to avoid, so why not attempt to facilitate gene flow among populations such that those with inbreeding depression can be ‘rescued’? In applied conservation, there are many reasons given for not attempting genetic rescue: Read the rest of this entry »





It’s all about the variation, stupid

12 01 2015

val-1-3It is one of my long-suffering ecological quests to demonstrate to the buffoons in government and industry that you can’t simply offset deforestation by planting another forest elsewhere. While it sounds attractive, like carbon offsetting or even water neutrality, you can’t recreate a perfectly functioning, resilient native forest no matter how hard you try.

I’m not for a moment suggesting that we shouldn’t reforest much of what we’ve already cut down over the last few centuries; reforestation is an essential element of any semblance of meaningful terrestrial ecological restoration. Indeed, without a major commitment to reforestation worldwide, the extinction crisis will continue to spiral out of control.

What I am concerned about, however, is that administrators continue to push for so-called ‘biodiversity offsets’ – clearing a forest patch here for some such development, while reforesting or even afforesting another degraded patch there. However, I’ve blogged before about studies, including some of my own, showing that one simply cannot replace primary forests in terms of biodiversity and long-term carbon storage. Now we can add resilience to that list.

While I came across this paper a while ago, I’ve only found the time to blog about it now. Published in PLoS One in early December, the paper Does forest continuity enhance the resilience of trees to environmental change?1 by von Oheimb and colleagues shows clearly that German oak forests that had been untouched for over 100 years were more resilient to climate variation than forests planted since that time. I’ll let that little fact sink in for a moment … Read the rest of this entry »





We treat our wildlife like vermin

24 09 2014
Just a little of the dog fence's carnage and cruelty at work.

Just a little of the dog fence’s carnage and cruelty at work.

I’ve pointed out in several posts on ConservationBytes.com just how badly Australia is doing in the environmental stakes, with massive deforestation continuing since colonial times, feral predators and herbivores blanketing the continent, inadequate protected areas, piss-weak policies and a government at war with its own environment. Despite a few recent wins in marine conservation, Australia has a dreadful track record.

Now in another monumental demonstration of stupidity, corruption and colonial-era attitudes toward native wildlife, Western Australia has outdone itself by sneaking through legislation to extend its so-called ‘Barrier Fence’ in an effort to isolate its marginal farmland from dingoes, emus and other ‘nuisance’ species.

As I and several others have pointed out before, the mere existence of the record-breaking dingo fence is not only counter-productive, it is expensive and utterly archaic. It should be torn down entirely.

Instead, the Western Australian government wants to extend the national fence, and they’ve approved the plan it without going through any of the appropriate checks in the system. Its environmental impacts have not been adequately assessed, nor has the public been given the opportunity to oppose the plans. In my view, the people responsible for this act should go to gaol.

In a recent paper led by Keith Bradby entitled Ecological connectivity or Barrier Fence? Critical choices on the agricultural margins of Western Australia, we show how the Western Australia state government has not followed any of its own environmental legislation and rushed through these idiotic proposals. If you do not subscribe to Ecological Management and Restoration, you can obtain a copy of the paper by e-mailing Keith or me. 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 »





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 »





More species = more resilience

8 01 2014

reef fishWhile still ostensibly ‘on leave’ (side note: Does any scientist really ever take a proper holiday? Perhaps a subject for a future blog post), I cannot resist the temptation to blog about our lab’s latest paper that just came online today. In particular, I am particularly proud of Dr Camille Mellin, lead author of the study and all-round kick-arse quantitative ecologist, who has outdone herself on this one.

Today’s subject is one I’ve touched on before, but to my knowledge, the relationship between ‘diversity’ (simply put, ‘more species’) and ecosystem resilience (i.e., resisting extinction) has never been demonstrated so elegantly. Not only is the study elegant (admission: I am a co-author and therefore my opinion is likely to be biased toward the positive), it demonstrates the biodiversity-stability hypothesis in a natural setting (not experimental) over a range of thousands of kilometres. Finally, there’s an interesting little twist at the end demonstrating yet again that ecology is more complex than rocket science.

Despite a legacy of debate, the so-called diversity-stability hypothesis is now a widely used rule of thumb, and its even implicit in most conservation planning tools (i.e., set aside areas with more species because we assume more is better). Why should ‘more’ be ‘better’? Well, when a lot of species are interacting and competing in an ecosystem, the ‘average’ interactions that any one species experiences are likely to be weaker than in a simpler, less diverse system. When there are a lot of different niches occupied by different species, we also expect different responses to environmental fluctuations among the community, meaning that some species inherently do better than others depending on the specific disturbance. Species-rich systems also tend to have more of what we call ‘functional redundancy‘, meaning that if one species providing an essential ecosystem function (e.g., like predation) goes extinct, there’s another, similar species ready to take its place. Read the rest of this entry »








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