Penguins cheated by ecosystem change

13 03 2018

Jorge Drexler sings “… I was committed not to see what I saw, but sometimes life is more complex than what it looks like …”*. This excerpt by the Oscar-winning Uruguayan singer seems to foretell the theme of this blog: how the ecological complexity of marine ecosystems can elicit false signals to their predators. Indeed, the fidelity of marine predators to certain feeding areas can turn demographically detrimental to themselves when the amount of available food shrinks. A study of jackass penguins illustrates the phenomenon in a context of overfishing and ocean warming.


Adult of jackass penguin (Spheniscus demersus) from Robben Island (South Africa) — in the inset, one of the first juveniles released with a satellite transmitter on its back. The species is ‘Endangered’ under IUCN’s criteria (28), following a recent halving of the total population currently estimated at ~ 80,000 adults. Jackass penguins are the only penguins living in Africa, and owe their common name to their vocalisations (you can hear their braying sounds here); adults are ~ 50 cm tall and weigh ~ 3 kg. Photos courtesy of Richard Sherley.

Surface temperature, dissolved oxygen, acidity and primary productivity are, by and large, the top four environmental factors driving the functionality of marine ecosystems (1). Growing scientific evidence supports the idea that anthropogenic warming of the atmosphere and the oceans correlates with this quartet (2). For instance, marine primary productivity is enhanced by increased temperatures (3), but a warmer sea surface intensifies stratification, i.e., stacked layers of seawater with contrasting physical and chemical properties.

In coastal areas experiencing ‘upwelling’ (where winds displace surface water, allowing deep water laden with nutrients to reach the euphotic zone where plankton communities feast), stratification weakens upwelling currents and, in turn, limits the growth of plankton (4) that fuels the entire trophic web, including our fisheries. The study of these complex trophic cascades is particularly cumbersome from the perspective of large marine predators because of their capacity to move long distances, from hundreds to thousands of kilometres (5), with strong implications for their conservation (6).

With those caveats in mind, Richard Sherley and colleagues satellite-tracked the movement of 54 post-fledged, juvenile jackass penguins (Spheniscus demersus) for 2-3 years (7). All individuals had been hatched in eight colonies (accounting for 80% of the global population), and were equipped with platform terminal transmitters. Jackass penguins currently nest in 28 island and mainland locations between South Africa and Namibia. Juveniles swim up to 2000 km in search of food and, when approaching adulthood, return to their native colonies where they reproduce and reside for the remainder of their lives (watch individuals swimming here).

The natural history of this species is linked to the Southern Hemisphere’s trade winds (‘alisios’ for Spanish speakers), which blow from the southeast to the tropics. In the South Atlantic, trade winds sustain the Benguela Current, the waters of which surface from some 300 m of depth and fertilise the marine ecosystems stretching from the Western coasts of South Africa to Angola (8). Read the rest of this entry »

Australians: out-of-touch, urban squanderers

23 03 2015

There’s a romantic myth surrounding Australia that is pervasive both overseas and within the national psyche: this sun-scorched continent home to stoic bushmen1 that eek out a frugal, yet satisfying existence in this harsh rural land. Unfortunately that ideal is anathema to almost every Australian alive today.

While some elements of that myth do have a basis in reality – it is indeed a hot, dry, mostly inhospitable place if you count the entire land area (all 7.69 million square kilometres of it), and it does have the dubious honour of being the driest inhabited continent on Earth – most Australians live nowhere near the dry interior or the bush.

Despite our remarkably low average population density (a mere 3.09 people per square kilometre), Australia is in fact one of the most urbanised nations on the planet, with nearly 90% of its citizenry living within a major urban centre. As a result, our largely urban/suburban, latte-sipping, supermarket-shopping population has little, if any, connection to the vast landscape that surrounds its comfortable, built-up environs. There should be little wonder then that Australians are so disconnected from their own ecology, and little surprise that our elected officials (who, after all, represent the values of the majority of the citizens they purport to represent), are doing nothing to slow the rapid flushing of our environment down the toilet. Indeed, the current government is in fact actively encouraging the pace of that destruction. Read the rest of this entry »

Evidence-based conservation advocacy can work

15 09 2014
Colin 'Captain Hook' Barnett

Colin ‘Captain Hook’ Barnett

Just before knock-off time last Friday, I received some inspiring news. It’s not often in conservation science that the news is good, so even small wins are deliciously welcome.

Unless you’ve been out bush for the last few days or completely ignored the news services, you would have heard that Western Australia has decided not to go ahead with its moronic shark-culling programme. It all came down to the Western Australia Environmental Protection Authority‘s recommendation to the state government that it should not proceed with the cull because of ‘uncertainties’ in its effectiveness and impacts. While the government could conceivably ignore this recommendation and go ahead with the cull anyway, the right-wing Premier of Western Australia, Colin ‘Captain Hook’ Barnett, stated that while he was “disappointed”, the government was unlikely to appeal the decision, at least this year.

Putting the obvious commentary on his response aside for the moment, this is a rare example where overwhelming evidence actually persuaded a semi-autonomous government agency from going ahead with clearly stupid environmental policies. I can claim a small part in this endeavour, having co-written the synopsis of the scientific consensus statement and co-signed the submission to the Environmental Protection Authority. However, it was mainly down to the hard work and dedication of Professor Jessica Meeuwig of the University of Western Australia that the Western Australia government had little choice to but to heed our condemnation. Without her, I can pretty much guarantee that the shark slaughter would be continuing this year.

As they say in France, “chapeau” to Jessica. Read the rest of this entry »

A fairer way to rank conservation and ecology journals in 2014

1 08 2014

Normally I just report the Thomson-Reuters ISI Web of Knowledge Impact Factors for conservation-orientated journals each year, with some commentary on the rankings of other journals that also publish conservation-related material from time to time (see my lists of the 2008200920102011 and 2012 Impact Factor rankings).

This year, however, I’m doing something different given the growing negativity towards Thomson-Reuters’ secretive behaviour (which they’ve promised this year to rectify by being more transparent) and the generally poor indication of quality that the Impact Factor represents. Although the 2013 Impact Factors have just been released (very late this year, for some reason), I’m going to compare them to the increasingly reputable Google Scholar Journal Metrics, which intuitively make more sense to me, are transparent and turn a little of the rankings dogma on its ear.

In addition to providing both the Google metric as well as the Impact Factor rankings, I’ve come up with a composite (average) rank from the two systems. I think ranks are potentially more useful than raw corrected citation metrics because you must first explicitly set your set of journals to compare. I also go one step further and modify the average ranking with a penalty term that is essentially the addition of the coefficient of variation of rank disparity between the two systems.

Read on for the results.

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 »

MPs’ ignorance puts national parks in peril

30 08 2013

greedyLed by Bill Laurance, our latest opinion editorial in the Higher Education supplement. Interestingly, it has already spawned a bilious and spittle-flecked response by Queensland’s Acting National Parks Minister, Tim Mander. Given the evidence, who’s side do you take? I’m happy that at least one of the worst culprit state governments is at least now paying some attention to the issue.

LAST week the world was appalled when Ecuador decided to open up one of its iconic national parks for petroleum development, with Leonardo di Caprio being among the chorus of dissenting voices. Yet the world should be even more disappointed in Australia, a far wealthier nation whose parks could be facing even worse threats.

Why is Australia going down this reckless path? It’s all down to the state governments – especially in Victoria, Queensland and NSW.

For the conservative politicians currently holding sway in these States, it seems it’s time to generate some quick cash while cutting park budgets – and never mind the impact on Australia’s imperilled ecosystems and biodiversity.

In Victoria, for instance, land developers are now being allowed to build hotels and other ventures in national parks. In NSW, recreational shooting and possibly logging will be allowed in parks if new legislation is passed. In NSW’s marine parks, bans on shore-based recreational fishing are being lifted [see previous post here].

Other parks in NSW and Queensland are being opened up to livestock grazing. In Morrinya National Park in Queensland, a strip of forest 20 km long was recently cleared for fencing, with new stock-watering tanks being established throughout the park. Read the rest of this entry »

Conservation and ecology journal Impact Factors 2012

20 06 2013

smack2It’s the time of year that scientists love to hate – the latest (2012) journal ranking have been released by ISI Web of Knowledge. Many people despise this system, despite its major role in driving publishing trends.

I’ve previously listed the 2008, 2009, 2010 and 2011 IF for major conservation and ecology journals. As before, I’ve included the previous year’s IF alongside the latest values to see how journals have improved or worsened (but take note – journals increase their IF on average anyway merely by the fact that publication frequency is increasing, so small jumps aren’t necessarily meaningful; I suspect that declines are therefore more telling).

Read the rest of this entry »