Singin’ in the heat

9 03 2017
coqui & forest

Common coqui frog male (Eleutherodactylus coqui, snout-to vent length average ~ 3 cm) camouflaged in the fronds of an epiphyte in the El Yunque National Forest (Puerto Rico), along with an image of the enchanted forest of the Sierra de Luquillo where Narins & Meenderink did their study (4) – photos courtesy of Thomas Fletcher. This species can be found from sea level to the top of the highest peak in Puerto Rico (Cerro Punta = 1338 m). Native to mesic ecosystems, common coquis are well adapted to a terrestrial life, e.g., they lack interdigital webbing that support swimming propulsion in many amphibians, and youngsters hatch directly from the egg without transiting a tadpole stage. The IUCN catalogues the species as ‘Least Concern’ though alerts recent declines in high-altitude populations caused by chytrid fungus – lethal to amphibians at a planetary scale (9). Remarkably, the species has been introduced to Florida, Hawaii, the Dominican Republic and the Virgin Islands where it can become a pest due to high fertility rates (several >20 egg clutches/female/year).

Frog songs are species-specific and highly useful for the study of tropical communities, which host the highest amphibian diversities globally. The auditory system of females and the vocal system of males have co-evolved to facilitate reproductive encounters, but global warming might be disrupting the frequency of sound-based encounters in some species..

It is a rainy night, and Don (Gene Kelly) has just left his love, Kathy (Debbie Reynolds), at home, starting one of the most famous musical movie scenes ever: Singin’ in the rain 

Amphibians (see Amphibians for kids by National Geographic) also love to sing in rainy nights when males call for a partner, but now they have to do it in hotter conditions as local climates become warmer. Vocal behaviour is a critical trait in the life history of many frog species because it mediates recognition between individuals, including sexual selection by females (1).

With few exceptions, every species has a different and unique call, so scientists can use call features to identify species, and this trait is particularly useful in the inventory of diverse tropical communities (2). Differences in call frequency, duration and pitch, and in note, number, and repetition pattern, occur from one species to another. And even within species, songs can vary from individual to individual (as much as there are not two people with the same voice), and be tuned according to body size and environmental temperature (3). Read the rest of this entry »

Not all wetlands are created equal

13 02 2017

little-guyLast year I wrote what has become a highly viewed post here at about the plight of the world’s freshwater biodiversity. In a word, it’s ‘buggered’.

But there are steps we can take to avoid losing even more of that precious freshwater biodiversity. The first, of course, is to stop sucking all the water out of our streams and wetlands. With a global population of 7.5 billion people and climbing, the competition for freshwater will usually mean that non-human life forms lose that race. However, the more people (and those making the decisions, in particular) realise that intact wetlands do us more good as wetlands rather than carparks, housing developments, or farmland (via freshwater filtering, species protection, carbon storage, etc.), the more we have a chance to save them.

My former MSc student, the very clever David Deane1, has been working tirelessly to examine different scenarios of wetland plant biodiversity change in South Australia, and is now the proud lead author of a corker of a new paper in Biological Conservation. Having already published one paper about how wetland plant biodiversity patterns are driven by rare terrestrial plants, his latest is a very important contribution about how to manage our precious wetlands. Read the rest of this entry »

Where do citizens stand on climate change?

2 01 2017
Talk to the hand

Talk to the hand

Climate change caused by industrialisation is modifying the structure and function of the Biosphere. As we uncork 2017, our team launches a monthly section on plant and animal responses to modern climate change in the Spanish magazine Quercus – with an English version in Conservation Bytes. The initiative is the outreach component of a research project on the expression and evolution of heat-shock proteins at the thermal limits of Iberian lizards (papers in progress), supported by the British Ecological Society and the Spanish Ministry of Economy, Industry and Competitiveness. The series will feature key papers (linking climate change and biodiversity) that have been published in the primary literature throughout the last decade. To set the scene, we start off putting the emphasis on how people perceive climate change.

Salvador Herrando-Pérez, David R. Vieites & Miguel B. Araújo

“I would like to mention a cousin of mine, who is a Professor in Physics at the University of Seville – and asked about this matter [climate change], he stated: listen, I have gathered ten of the top scientists worldwide, and none has guaranteed what the weather will be like tomorrow in Seville, so how could anyone predict what is going to occur in the world 300 years ahead?”

Mariano Rajoy (Spanish President from 2011 to date) in a public speech on 22 October 2007

Weather (studied by meteorology) behaves like a chaotic system, so a little variation in the atmosphere can trigger large meteorological changes in the short term that are hard to predict. On the contrary, climate (studied by climatology) is a measure of average conditions in the long term and thus far more predictable than weather. There is less uncertainty in a climate prediction for the next century than in a weather prediction for the next month. The incorrect statement made by the Spanish President reflects harsh misinformation and/or lack of environment-related knowledge among our politicians.

Climate has changed consistently from the onset of the Industrial Revolution. The IPCC’s latest report stablishes with 95 to 100% certainty (solid evidence and high consensus given published research) that greenhouse gases from human activities are the main drivers of global warming since the second half of the 20th Century (1,2). The IPCC also flags that current concentrations of those gases have no parallel in the last 800,000 years, and that climate predictions for the 21st Century vary mostly according to how we manage our greenhouse emissions (1,3). Read the rest of this entry »

More things stay the same, more we retrogress

20 07 2016

obrazek_1idiommmmsmmWithin six months of Abbott and the Coalition seizing power in the 2013 Australian election, decades—if not centuries—of environmental damage and retrograde policies unfolded. But this was no run-of-the-mill incompetence and neglect by government—this was an all-out attack on anything with the merest whiff of environmental protection. The travesty is well-documented, from infamously axing both the carbon-pricing scheme and climate commission, eradicating Labor’s 80% emissions-reduction target by 2050, diluting the Renewable Energy Target, refusing to commit to enforcing the Illegal Logging Prohibition Act (fortunately, this is now law), defunding the only independent legal entity available to limit environmentally destructive development (Environmental Defenders Office), to even attempting to remove the rights of environmental groups to challenge development proposals (thankfully, that failed).

The Coalition’s backward and ineffectual climate change-mitigation policies alone are evidence enough for long-term damage, but their war on the environment in general means that even the future election of a more environmentally responsible government will not undo the damage quickly, if at all. As a result of these and other nearsighted policies, Australia remains one of the highest per-capita greenhouse-gas emitters on the planet, has one of the highest per-capita water uses of any nation, leads the world in mammal extinctions, continues to deforest its already forest-poor landscape, and is a society utterly unprepared to deal with the future challenges of a degraded planet.
Read the rest of this entry »

Buying time

27 06 2016

farmOriginally published in the Otago Daily Times by Tom McKinlay

If we don’t act soon, the world we leave our children will be in a sorry state indeed, leading Australian scientist Prof Corey Bradshaw tells Tom McKinlay.

Prof Corey Bradshaw’s 9-year-old daughter lives what sounds an idyllic existence. On their small farm outside Adelaide in South Australia, she has her chickens and her dogs and her cats, her goats and her sheep.

She’s an only child, but is not short of attention from adults and reads voraciously.

She has big plans; there are at least 25 careers she likes the look of, that she’ll undertake simultaneously: farmer, wildlife rescuer, self-sufficient bush dweller – feeding herself by shooting arrows at fish – scientist and more.

She is optimistic about the future. As she should be. A 9-year-old girl living in Australia in 2016 should regard the sky as no limit at all.

All this I learn from her father, ecologist Prof Bradshaw, who talks of his daughter with an enthusiasm unbounded.

It is fair to assume she has picked up some of her interest in the natural world from him.

He holds the Sir Hubert Wilkins Chair of Climate Change in the School of Biological Sciences at the University of Adelaide.

And the ecologist, conservation biologist and systems modeller – with a University of Otago degree – has shared a great deal of his work with his daughter.

“She’s very much a farm kid, but because of who I am she gets to hear a lot about animal and plant systems around the world, and she’s travelled a lot with me and she’s a complete fanatic of David Attenborough,” the professor says.

So far, still so idyllic. But Prof Bradshaw’s work means he is at the forefront of alerting the world to what is not right with it.

Pollution, climate change, habitat loss, extinction.

His daughter has travelled with him to see species that might not be with us by the time she grows up.

“She’s hyper-aware of extinctions, in particular, and how climate change is contributing to that,” Prof Bradshaw says.

“I don’t pull any punches with her.”

In fact, he made her cry when she was 5 explaining climate change. She hasn’t needed to travel to know the pot is on the boil. Fires have forced the family to flee its South Australian property several times, not just at the height of summer.

One of the worst fires in the region struck in May a couple of years back.

“We were on the doorstep of winter and we had one of our worst fires in 20 years.”

So even without a scientist in the family, there are certain unavoidable truths for a child growing up in 21st-century Australia.

Prof Bradshaw is coming to Dunedin next month as part of the New Zealand International Science Festival to talk on climate change, looking at it from his daughter’s perspective. Read the rest of this entry »

Extinction synergy: deadly combination of human hunting & climate change wrote off Patagonian giants

20 06 2016

MegatheriumHere’s a paper we’ve just had published in Science Advances (Synergistic roles of climate warming and human occupation in Patagonian megafaunal extinctions during the Last Deglaciation). It’s an excellent demonstration of our concept of extinction synergies that we published back in 2008.

Giant Ice Age species including elephant-sized sloths and powerful sabre-toothed cats that once roamed the windswept plains of Patagonia, southern South America, were finally felled by a perfect storm of a rapidly warming climate and humans, a new study has shown.

Research led by the Australian Centre for Ancient DNA (ACAD) at the University of Adelaide, published on Saturday in Science Advances, has revealed that it was only when the climate warmed, long after humans first arrived in Patagonia, did the megafauna suddenly die off around 12,300 years ago.

The timing and cause of rapid extinctions of the megafauna has remained a mystery for centuries.

“Patagonia turns out to be the Rosetta Stone – it shows that human colonisation didn’t immediately result in extinctions, but only as long as it stayed cold,” says study leader Professor Alan Cooper, ACAD Director. “Instead, more than 1000 years of human occupation passed before a rapid warming event occurred, and then the megafauna were extinct within a hundred years.”

The researchers, including from the University of Colorado Boulder, University of New South Wales and University of Magallanes in Patagonia, studied ancient DNA extracted from radiocarbon-dated bones and teeth found in caves across Patagonia, and Tierra del Fuego, to trace the genetic history of the populations. Species such as the South American horse, giant jaguar and sabre-toothed cat, and the enormous one-tonne short-faced bear (the largest land-based mammalian carnivore) were found widely across Patagonia, but seemed to disappear shortly after humans arrived. Read the rest of this entry »

What immigration means for Australia’s climate-change policies

12 06 2016

After dipping my foot into the murky waters of human population demography a few years ago, I’m a little surprised that I find myself here again. But this time I’m not examining what the future of the global human population might be and what it could mean for our environment; instead, I’m focussing on Australia’s population future and its implications for our greenhouse-gas emissions trajectories.

Just published in Asia and the Pacific Policy Forum1, my paper with long-time co-author Barry Brook is entitled Implications of Australia’s population policy for future greenhouse gas emissions targets. It deals with the sticky question of just how many people Australia can ‘afford’ to house. By ‘afford’ I mean several things, but most specifically in the context of this paper is by how much we need to reduce our per capita emissions to achieve future reduction targets under various immigration-rate scenarios.

In many ways Australia’s population is typical of other developed nations in that its intrinsic fertility (1.78 children/woman) is below replacement (which is itself ~ 2.1 children/female). Yet Australia’s population grew nearly twice (1.88×) as large from 1971 to 2014. It doesn’t take a genius to figure out that most of our population growth is due to net immigration.

In fact, between 2006 and 2014, Australia welcomed a net of 215,000 new people per year (this means that of all the permanent immigrants and emigrants, a ‘net’ of approximately 215,000 stayed each year), which represents about 1% of our total population size (that latter most likely just ticked over 24 million). Read the rest of this entry »