Save a jaguar by eating less meat

8 10 2018
Kaayana

My encounter with Kaayana in Kaa-Iya National Park in the Bolivian Chaco. Her cub was around but cannot be seen in the photo

I was trapped. Or so I thought.

The jaguar came towards me on the dirt road, calmly but attentively in the dusky light, her nearly full grown cub behind her. Nervous and with only a torch as defence, I held the light high above my head as she approached, trying to look taller. But she was merely curious; and, after 20 minutes, they left. I walked home in the thickening darkness, amazed at having come so close to South America’s top predator. We later named this mother jaguar ‘Kaayana’, because she lives inside Kaa-Iya National Park in the Bolivian Chaco. My fascination with jaguars has only grown since then, but the chances of encountering this incredible animal in the wild have shrunk even since that night.

A few years after that encounter, I’m back to study jaguars in the same forest, only now at the scale of the whole South American Gran Chaco. Jaguars are the third largest cats in the world and the top predators across Latin America. This means that they are essential for keeping ecosystems healthy. However, they are disappearing rapidly in parts of their range.

Understanding how and where the jaguar’s main threats — habitat destruction and hunting — affect them is fundamental to set appropriate strategies to save them. These threats are not only damaging on their own, but they sometimes act simultaneously in an area, potentially having impacts that are larger than their simple sum. For instance, a new road doesn’t only promote deforestation, it also increases hunters’ ability to get into previously inaccessible forests. Similarly, when the forest is cut for cattle ranching, ranchers often kill jaguars for fears of stock loss.

Kaayana & kittens

Kaayana was seen years later by Daniel Alarcón, who took much better photos of her and her new cubs

However, the interactions between these threats are still not fully understood. In our new study, just published in the journal Diversity and Distributions, we developed a new framework to quantify how and where habitat destruction and hunting risk acted together over three decades, at the expense of highly suitable jaguar habitat in the Gran Chaco. We also analyzed how well the different Chaco countries — Bolivia, Paraguay and Argentina — and their protected areas maintained key jaguar habitat. Read the rest of this entry »





Sex on the beach

2 10 2018
Female green turtles (Chelonia mydas) spawning (top) and diving (bottom) on Raine Island (Great Barrier Reef, Queensland, Australia) — photos courtesy of Ian Bell. This species is ‘Endangered’ globally since 1982, mainly from egg harvesting (poaching conflict in Mexico for olive ridley Lepidochelys olivacea featured by National Geographic’s video here), despite the success of conservation projects (39). Green turtles inhabit tropical and subtropical seas in all oceans. Adults can grow > 150 kg and live for up to ~ 75 years. Right after birth, juveniles venture into the open sea to recruit ultimately in coastal areas until sexual maturity. They then make their first reproductive migration, often over 1000s of km (see footage of a real dive of a camera-equipped green turtle), to reach their native sandy beaches where pregnant females will lay their eggs. Each female can deposit more than one hundred eggs in her nest, and in several clutches in the same season because they can store the sperm from multiple mating events.

When sex is determined by the thermal environment, males or females might predominate under sustained climatic conditions. A study about marine turtles from the Great Barrier Reef illustrates how feminisation of a population can be partitioned geographically when different reproductive colonies are exposed to contrasting temperatures.

Fortunately, most people in Western societies already perceive that we live in a complex blend of sexual identities, far beyond the kind of genitals we are born with. Those identities start to establish themselves in the embryo before the sixth week of pregnancy. In the commonest scenario, for a human foetus XY with one maternal chromosome (X) and one paternal (Y) chromosome, the activation of the Sry gen (unique to Y) will trigger the differentiation of testicles and, via hormonal pathways, the full set of male characteristics (1).

Absence of that gene in an XX embryo will normally lead to a woman. However, in just one of many exceptions to the rule, Sry-expression failure in XY individuals can result in sterile men or ambiguous genitals — along a full gradient of intermediate sexes and, potentially, gender identities. A 2015 Nature ‘News’ feature echoes two extraordinary cases: (i) a father of four children found to bear a womb during an hernia operation, and (ii) a pregnant mother found to host both XX and XY cells during a genetic test – with her clinical geneticist stating “… that’s the kind of science-fiction material for someone who just came in for an amniocentesis” (2). These real-life stories simply reflect that sex determination is a complex phenomenon.

Three ways of doing it

In nature, there are three main strategies of sex determination (3) — see scheme here: Read the rest of this entry »





The European Union just made bioenergy worse for biodiversity

21 08 2018

bioenergy2While some complain that the European Union (EU) is an enormous, cumbersome beast (just ask the self-harming Brexiteers), it generally has some rather laudable legislative checks and balances for nature conservation. While far from perfect, the rules applying to all Member States have arguably improved the state of both European environments, and those from which Europeans source their materials.

But legislation gets updated from time to time, and not always in the ways that benefit biodiversity (and therefore, us) the most. This is exactly what’s just happened with the new EU Renewable Energy Directive (RED) released in June this year.

Now, this is the point where most readers’ eyes glaze over. EU policy discussions are exceedingly dry and boring (I’ve dabbled a bit in this arena before, and struggled to stay awake myself). But I’ll try to lighten your required concentration load somewhat by being as brief and explanatory as possible, but please stay with me — this shit is important.

In fact, it’s so important that I joined forces with some German colleagues with particular expertise in greenhouse-gas accounting and EU policy — Klaus Hennenberg and Hannes Böttcher1 of Öko-Institut (Institute of Applied Ecology) in Darmstadt — to publish an article available today in Nature Ecology and Evolution.

bioenergy4So back to the RED legislation. The original ‘RED 2009‘ covered reductions of greenhouse-gas emissions and the mitigation of negative impacts on areas of high biodiversity value, such as primary forests, protected areas, and highly biodiverse grasslands, and for areas of high carbon stock like wetlands, forests, and peatlands.

But RED 2009 was far from what we might call ‘ambitious’, because globally mandatory criteria on water, soil and social aspects for agriculture and forestry production were excluded to avoid conflicts with rules of the World Trade Organization.

Nor did RED 2009 apply to all bioenergy types, and only included biofuels used in transport, including gaseous and solid fuels, and bioliquids used for electricity, heating, and cooling. But RED 2009 requirements also applied to all raw materials sourced from agriculture and forestry, especially as forest biomass is explicitly mentioned as a raw material for the production of advanced biofuels in the RED 2009 extension from 2015.

Thus, one could conceivably call RED 2009 criteria ‘minimum safeguards’.

But as of June this year, the EU accepted a 2016 proposal to recast RED 2009 into what is now called ‘RED II’. While the revisions might look good on paper by setting new incentives in transport (advanced biofuels) and in heating and cooling that will likely increase the use of biomass sourced from forests, and by extending the directive on solid and gaseous biomass, the amendments unfortunately take some huge leaps backwards in terms of sustainability requirements.

These include the following stuff-ups: Read the rest of this entry »





Some scary stats about agriculture and biodiversity

20 07 2018

84438Last week we had the pleasure of welcoming the eminent sustainability scientist, Professor Andrew Balmford of the University of Cambridge, to our humble Ecology and Evolution Seminar Series here at Flinders University. While we couldn’t record the seminar he gave because of some of the unpublished and non-proprietary nature of some of his slides, I thought it would be interesting, useful, and thought-provoking to summarise some of the information he gave.

Andrew started off by telling us some of the environmental implications of farming worldwide. Today, existing agriculture covers more than half of ‘useable’ land (i.e., excluding unproductive deserts, etc.), and it has doubled nitrogen fixation rates from a pre-industrial baseline. Globally, agriculture is responsible for between 19 and 35% of all greenhouse gas emissions, and it has caused approximately 40% increase in observed sea-level rise (1961-2003). Not surprisingly, agriculture already occupies the regions of highest biodiversity globally, and is subsequently the greatest source of threat to species.

Read the rest of this entry »





A life of fragmentation

9 05 2018

LauranceWhat do you say to a man whose list of conservation awards reads like a Star Wars film intro, who has introduced terms like the ‘hyperdynamism hypothesis’ to the field of ecology, and whose organisation reaches over one million people each week with updates of the scientific kind?

Interview with Bill Laurance by Joel Howland (originally published in Conjour)


Well, I started by asking what it is that leads him to love the natural world to the extent he does. His answer was disarmingly simple.

“I grew up in the country, on an Oregon cattle ranch, and I think my love of nature just evolved naturally from that. When I was a young kid my dad and I did some fishing and ‘rock-hounding’— searching for rare stones and fossils. As an adolescent and teen I loved heading off into a forest or wilderness, rifle in hand – back in those days you could do that – to see whatever I could find. I watched red foxes hunting, eagles mating, and even heard a mountain lion scream. I got to be a pretty good duck and game-bird hunter.”

He’s quick to point out, however, he realised his taste for guns was not so developed as his love of nature.

“I gave up my rifles for a camera, and enjoyed that even more. I really got into photography for a while. Nature has always just calmed and fascinated me —I guess that’s partly why I became a conservationist.”

Who is Bill Laurance?

William F. Laurance is one of the leading ecology and conservation scientists globally, publishing dozens of papers in journals like Nature and Science, and rewriting the way scientists in the field research the complex interactions between flora and fauna — particularly in rainforests like the Amazon.

He is a Distinguished Research Professor at James Cook University in Australia, a Fellow of the Australian Academy of Science and the American Association for the Advancement of Science, and has received an Australian Laureate Fellowship from the Australian Research Council.

All this for a man from western USA who dreamed of running a zoo. Instead, he has travelled a path of intricate and game-changing research, trailblazing awareness campaigns and inspirational writings that have driven the way many see the environment over the past few decades.

Despite this profile, Laurance gave some time to tell Conjour about his life, his passion and his aims. I asked him what — considering his impressive CV — the future holds.

His response seems a real insight to the man. Read the rest of this entry »





Predicting sustainable shark harvests when stock assessments are lacking

26 03 2018

srb 1

© Andrew Fox

I love it when a good collaboration bears fruit, and our latest paper is a good demonstration of that principle.

It all started a few years ago with an ARC Linkage Project grant we received to examine how the whaler shark fishing industry in Australia might manage its stocks better.

As I’m sure many are aware, sharks around the world aren’t doing terribly well (surprise, surprise — yet another taxon suffering at the hands of humankind). And while some populations (‘stocks’, in the dissociative parlance of the fishing industry) are doing better than others, and some countries have a better track record in managing these stocks than others, the overall outlook is grim.

One of the main reasons sharks tend to fair worse than bony fishes (teleosts) for the same fishing effort is their ‘slow’ life histories. It doesn’t take an advanced quantitative ecology degree to understand that growing slowly, breeding late, and producing few offspring is a good indication that a species can’t handle too much killing before populations start to dwindle. As is the case for most large shark species, I tend to think of them in a life-history sense as similar to large terrestrial mammals.

Now, you’d figure that a taxon with intrinsic susceptibility to fishing would have heaps of good data with which managers could monitor catches and quotas so that declines could be avoided. However, the reality is generally the inverse, with many populations having poor information regarding vital rates (e.g., survival, fertility), age structure, density feedback characteristics, and even simple estimates of abundance. Without such key information, management tends to be ad hoc and often not very effective. Read the rest of this entry »





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.

CB_JackassPenguinsEcologicalTrapPhoto

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 »