Why populations can’t be saved by a single breeding pair

3 04 2018

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© Reuters/Thomas Mukoya

I published this last week on The Conversation, and now reproducing it here for CB.com readers.

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Two days ago, the last male northern white rhino (Ceratotherium simum cottoni) died. His passing leaves two surviving members of his subspecies: both females who are unable to bear calves.

Even though it might not be quite the end of the northern white rhino because of the possibility of implanting frozen embryos in their southern cousins (C. simum simum), in practical terms, it nevertheless represents the end of a long decline for the subspecies. It also raises the question: how many individuals does a species need to persist?

Fiction writers have enthusiastically embraced this question, most often in the post-apocalypse genre. It’s a notion with a long past; the Adam and Eve myth is of course based on a single breeding pair populating the entire world, as is the case described in the Ragnarok, the final battle of the gods in Norse mythology.

This idea dovetails neatly with the image of Noah’s animals marching “two by two” into the Ark. But the science of “minimum viable populations” tells us a different story.

No inbreeding, please

The global gold standard used to assess the extinction risk of any species is the International Union for the Conservation of Nature (IUCN) Red List of Threatened Species. Read the rest of this entry »


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Categories : Africa, Allee effect, cloning, conservation, conservation biology, decline, DNA, exploitation, extinction, extinction debt, extinction vortex, genetic diversity, genetics, inbreeding depression, living dead, minimum viable population, mvp, poaching, population dynamics, population viability analysis, PVA, recovery, threatened species

Giving a monkey’s about primate conservation

12 12 2017
Urban monkey living (Macaque, Gibraltar) small

Concrete jungle. A Barbary macaque sits in a human-dominated landscape in Gibraltar. Photo: Silviu Petrovan

Saving primates is a complicated business. Primates are intelligent, social animals that have complex needs. They come into conflict with humans when they raid rubbish bins and crops, chew power cables, and in some cases become aggressive towards people.

Humans, however, have the upper hand. While 60% of non-human primate species are threatened, humans grow in numbers and power, building roads through forests, hunting and trapping primates, and replacing their habitat with farms and houses.

To help primatologists choose the most effective conservation approaches to resolve these problems, researchers in the Conservation Evidence project teamed up with primate researchers to produce a global database on the effectiveness of primate conservation solutions. This free database, which can also be downloaded as a single pdf, summarizes the evidence for 162 conservation interventions — actions that conservationists might take to conserve primates. The data come from searches of over 170 conservation journals and newsletters, and each study is summarized in a single paragraph in plain English, making it possible for conservationists without access to scientific journals to read the key findings.

Front cover primate synopsisSo what works in primate conservation? Well, the picture is rarely straightforward — partly due to the lack of data — but there are some interesting trends. Reducing hunting is one area where there seem to be a range of potentially effective approaches. Community control of patrolling, banning hunting and removing snares was effective in the three studies in which it was tested, all in African countries.

Further emphasizing the importance of involving local communities, implementing no-hunting community policies or traditional hunting bans also appeared helpful in boosting primate numbers. In other places, a more traditional approach of using rangers to protect primates has proved a winning strategy. Training rangers, providing them with arms, and increasing ranger patrols all worked to protect primates from poachers. Identifying the circumstances in which community led approaches or ranger patrols work will be key to implementing the most appropriate response to each conservation challenge. Read the rest of this entry »


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Categories : biodiversity, conservation, conservation biology, decline, deforestation, development, education, environmental policy, exploitation, extinction, habitat loss, harvest, implementation, logging, management, monitoring, planning, research, restoration, software, threatened species, tropical

Microclimates: thermal shields against global warming for small herps

22 11 2017

Thermal microhabitats are often uncoupled from above-ground air temperatures. A study focused on small frogs and lizards from the Philippines demonstrates that the structural complexity of tropical forests hosts a diversity of microhabitats that can reduce the exposure of many cold-blooded animals to anthropogenic climate warming.

Luzon forest frogs

Reproductive pair of the Luzon forest frogs Platymantis luzonensis (upper left), a IUCN near-threatened species restricted to < 5000 km2 of habitat. Lower left: the yellow-stripped slender tree lizard Lipinia pulchella, a IUCN least-concerned species. Both species have body lengths < 6 cm, and are native to the tropical forests of the Philippines. Right panels, top to bottom: four microhabitats monitored by Scheffers et al. (2), namely ground vegetation, bird’s nest ferns, phytotelmata, and fallen leaves above ground level. Photos courtesy of Becca Brunner (Platymantis), Gernot Kunz (Lipinia), Stephen Zozaya (ground vegetation) and Brett Scheffers (remaining habitats).

If you have ever entered a cave or an old church, you will be familiar with its coolness even in the dog days of summer. At much finer scales, from centimetres to millimetres, this ‘cooling effect’ occurs in complex ecosystems such as those embodied by tropical forests. The fact is that the life cycle of many plant and animal species depends on the network of microhabitats (e.g., small crevices, burrows, holes) interwoven by vegetation structures, such as the leaves and roots of an orchid epiphyte hanging from a tree branch or the umbrella of leaves and branches of a thick bush.

Much modern biogeographical research addressing the effects of climate change on biodiversity is based on macroclimatic data of temperature and precipitation. Such approaches mostly ignore that microhabitats can warm up or cool down in a fashion different from that of local or regional climates, and so determine how species, particularly ectotherms, thermoregulate (1). To illustrate this phenomenon, Brett Scheffers et al. (2) measured the upper thermal limits (typically known as ‘critical thermal maxima’ or CTmax) of 15 species of frogs and lizards native to the tropical forest of Mount Banahaw, an active volcano on Luzon (The Philippines). The > 7000 islands of this archipelago harbour > 300 species of amphibians and reptiles (see video here), with > 100 occurring in Luzon (3).

Read the rest of this entry »


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Categories : amphibian, behaviour, biodiversity, carbon, climate change, climate shift, conservation biology, decline, ecology, extinction, frog, function, research, science, threatened species, trophic cascades, tropical

Noses baffled by ocean acidification

18 04 2017

Clown fish couple (Amphiprion percula) among the tentacles of anemone Heteractis magnifica in Kimbe Bay (Papua New Guinea) – courtesy of Mark McCormick. Clownfish protect anemones from predators and parasites in exchange of shelter and food. The fish tolerates the host’s venom because its skin is protected by a mucus layer some 2-3× thicker than phylogenetically related species (12); clownfish fabricate the mucus themselves and seem to obtain anemone antigens through a period of acclimation (13), but whether protection is acquired or innate is still debated. Clownfish are highly social bony fish, forming groups with one reproductive pair (up to 11 cm in length each) and several smaller, non-reproductive males. Reproduction is protandrous (also known as sequential hermaphroditism), so larvae are born male and, as soon as the reproductive female dies, her widower becomes female and the largest of the subsidiary males becomes the alpha male. The IUCN lists clownfish, generically named ‘anemone fish’, as threatened by the pet-trade industry and habitat degradation, although surprisingly, only 1 species has been assessed (A. sandaracinos). The clown anemone fish A. ocellaris is the species that inspired Nemo in the 2003 Academy-Award fiction movie – contrary to the logical expectation that the Oscars Red Carpet would generate support for conservation on behalf of Hollywood, of the 1568 species represented in the movie, only 16 % of those evaluated are threatened (14).

Smell is like noise, the more scents we breathe in one sniff, the more difficult it is to distinguish them to the point of olfactory saturation. Experimental work with clownfish reveals that the increase in dissolved carbon dioxide in seawater, mimicking ocean acidification, alters olfactory physiology, with potential cascading effects on the demography of species.

Places such as a restaurant, a hospital or a library have a characteristic bouquet, and we can guess the emotional state of other people by their scents. Smell is critical between predators and prey of many species because both have evolved to detect each other without the aid of vision. At sea, the smell of predators dissolves in water during detection, attack, capture, and ingestion of prey, and many fishes use this information to assess the risk of ending up crunched by enemy teeth (1, 2). But predator-prey interactions can be modified by changes in the chemical composition of seawater and are therefore highly sensitive to ongoing ocean acidification (see global measuring network here). Experts regard ocean acidification as the ‘other CO2 problem’ of climate change (3) — just to emphasize that anthropogenic climate-change impacts terrestrial and aquatic ecosystems alike. Acidification occurs because the ocean absorbs CO2 at a rate proportional with the concentration of this gas in the atmosphere and, once dissolved, CO2 becomes carbonic acid (H2CO3), which in turn releases protons (H+) — in simple terms, pH is the concentration of protons (see video about ocean acidification): Read the rest of this entry »


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Categories : acidification, behaviour, biodiversity, carbon, climate change, climate shift, conservation biology, decline, demography, development, ecology, extinction, fish, function, marine, ocean, predation, predator, research, threatened species, tropical

Genetic Management of Fragmented Animal and Plant Populations

10 12 2016

logoThat is the title of a new textbook that will be available mid-2017.

After almost 6 years work, authors Dick Frankham, Jonathan Ballou, Katherine Ralls, Mark Eldridge, Michele Dudash, Charles Fenster, Bob Lacy & Paul Sunnucks have produced an advanced textbook/research monograph that aims to provoke a paradigm shift in the management of small, isolated population fragments of animals and plants.

One of the greatest unmet challenges in conservation biology is the genetic management of fragmented populations of threatened animal and plant species. More than a million small, isolated, population fragments of threatened species are likely suffering inbreeding depression, loss of evolutionary potential, and elevated extinction risks (genetic erosion). Re-establishing gene flow between populations is required to reverse these effects, but managers very rarely do this. On the contrary, molecular genetic methods are mainly being used to document genetic differentiation among populations, with most studies concluding that genetically differentiated populations should be managed separately (i.e., kept isolated), thereby dooming many populations to eventual extinction.

The need for a paradigm shift in genetic management of fragmented populations has been highlighted as a major issue in conservation. The rapidly advancing field of molecular genetics is continually providing new tools to measure the extent of population fragmentation and its genetic consequences. However, adequate guidance on how to use these data for effective conservation is still lacking, and many populations are going extinct principally for genetic reasons. Consequently, there is now urgent need for an authoritative textbook on the subject.

Read the rest of this entry »


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Categories : Allee effect, biodiversity, conservation, conservation biology, DNA, extinction, extinction debt, fragmentation, genetic diversity, genetics, threatened species

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). Read the rest of this entry »


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Categories : Africa, anthropocene, Australia, biodiversity, buffalo, bushmeat, conservation, ecology, ecosystem, ecosystem function, exploitation, extinction, fragmentation, habitat loss, living dead, mammal, management, palaeo-ecology, poaching, poverty, protected area, research, South America, threatened species, trophic cascades

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.
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Categories : Australia, biodiversity, biowealth, carbon, climate change, climate shift, conservation, corruption, deforestation, ecology, environmental policy, environmental science, extinction, fragmentation, governance, mammal, management, poverty, protected area, research, science, threatened species, water

Outright bans of trophy hunting could do more harm than good

5 01 2016

In July 2015 an American dentist shot and killed a male lion called ‘Cecil’ with a hunting bow and arrow, an act that sparked a storm of social media outrage. Cecil was a favourite of tourists visiting Hwange National Park in Zimbabwe, and so the allegation that he was lured out of the Park to neighbouring farmland added considerable fuel to the flames of condemnation. Several other aspects of the hunt, such as baiting close to national park boundaries, were allegedly done illegally and against the spirit and ethical norms of a managed trophy hunt.

In May 2015, a Texan legally shot a critically endangered black rhino in Namibia, which also generated considerable online ire. The backlash ensued even though the male rhino was considered ‘surplus’ to Namibia’s black rhino populations, and the US$350,000 generated from the managed hunt was to be re-invested in conservation. Together, these two incidents have triggered vociferous appeals to ban trophy hunting throughout Africa.

These highly politicized events are but a small component of a large industry in Africa worth > US$215 million per year that ‘sells’ iconic animals to (mainly foreign) hunters as a means of generating otherwise scarce funds. While to most people this might seem like an abhorrent way to generate money, we argue in a new paper that sustainable-use activities, such as trophy hunting, can be an important tool in the conservationist’s toolbox. Conserving biodiversity can be expensive, so generating money is a central preoccupation of many environmental NGOs, conservation-minded individuals, government agencies and scientists. Making money for conservation in Africa is even more challenging, and so we argue that trophy hunting should and could fill some of that gap. Read the rest of this entry »


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Categories : Africa, agriculture, animal welfare, biodiversity, buffalo, conservation, corruption, decline, economics, environmental policy, exploitation, extinction, genetic diversity, governance, habitat loss, harvest, inbreeding depression, management, minimum viable population, mvp, poaching, population viability analysis, poverty, predator, preservationist, protected area, reserve, sustainability, threatened species, tourism

Social and economic value of protected areas

2 03 2015
© P. Crowley/"mokolabs" via Flickr

© P. Crowley/”mokolabs” via Flickr

I’ve just come across an exceptionally important paper published recently in PLoS Biology by a team of venerable conservation biologists led by the eminent Andy Balmford of the University of Cambridge. My first response was ‘Holy shit’, and now that I contemplate the results further, I can now update that sentiment to ‘Holy shit!’.

Most people reading this blog wouldn’t bother questioning the importance of protected areas for the preservation of biodiversity – for them, it’s a given. While the effectiveness of protected areas globally is highly variable in that regard, there’s little contention among conservationists that we do not yet have enough of them to conserve biodiversity effectively, especially in the oceans that cover some 70% of the planet’s surface.

But that justification isn’t good enough for some people – perhaps even the majority. Even our own myopic, anti-environment political bungler Prime Minister has stated publicly that national parks just ‘lock up‘ areas to the exclusion of much more important things like jobs and income generation. He’s even stated that Australia has ‘too many‘ national parks already, and that timber workers are “the ultimate conservationists“. As I type those words, I can feel the bile accumulating in my throat. Read the rest of this entry »


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Categories : conservation, economics, ecosystem services, environmental policy, MPA, protected area, reserve, threatened species

The Abbott-oir survives another day to wreak more environmental havoc

9 02 2015

The Great Red UnderpantsTone Abbott-oir, easily the most environmentally destructive Prime Minister this country has seen in the modern era, has survived the party room spill for a leadership change. Although 39% of his own Fiberal Party MPs voted to dump him, he remains standing (limping) – for now.

I’ve seen rather a lot lately in the Australian media about the impending spill vote, and the potential political repercussions of a change (or not), but there’s been nearly no mention of what it all means for the continually degrading Australian environment.

As is typical in Australian politics, the environment takes a very distant back seat to the those oh-so-important societal issues like knighthoods, paid parental leave and where to put the next road in Melbourne, so I certainly wasn’t hopeful that a leadership change (or not) would have any positive environmental outcomes. This particular latte-snorting, quinoa-flavoured-pinot-grigio-in-the-artisanal-underpants-pouring, erect-nipple-paper-rubbing environmental scientist has nothing at all to celebrate, even if the no-confidence in The Great Red Underpants is potentially a positive sign. Read the rest of this entry »


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Categories : Australia, biodiversity, carbon, climate change, conservation, corruption, ecology, economics, ecosystem services, environmental policy, protected area, reserve, threatened species

When human society breaks down, wildlife suffers

22 01 2015

bearGlobal human society is a massive, consumptive beast that on average degrades its life-support system. As we’ve recently reported, this will only continue to get worse in the decades to centuries to come. Some have argued that as long as we can develop our societies enough, the impact of this massive demographic force can be lessened – a concept described by the environmental Kuznets curve. However, there is little evidence that negative societal impact on the environment is lessened as per capita wealth exceeds some threshold; unfortunately environmental damage tends to, on average, increase as a nation’s net wealth increases. That’s not to say that short-term improvements cannot be achieved through technological innovation – in fact, they will be essential to offset the inexorable growth of the global human population.

So poor nations as well as the wealthy ones are responsible for environmental damage. Poorer nations often have ineffective governance systems so they fail to enforce compliance in environmental regulations, but wealthier nations often exploit a high proportion of their natural resources, with the inevitable environmental damage this entails. In some cases however, biodiversity can temporarily escape some of the ravages of society because humans either perceive the area to be too dangerous, or otherwise have no incentive to go there. There are some good examples of the latter, such as the vicinity around the Chernobyl nuclear reactor that melted down in 1986, or the Korean demilitarised zone.

In this vein, I just stumbled across an extremely interesting paper today published online early in Conservation Biology that describes trends in charismatic wildlife (i.e., big mammals) as the former Soviet Union collapsed in 1991 and societal breakdown ensued. The authors had access to an amazing dataset that spanned the decade prior to the collapse, the decade immediately following, and a subsequent decade of societal renewal. What they found was fascinating. Read the rest of this entry »


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Categories : agriculture, anthropocene, conservation, decline, environmental policy, exploitation, governance, habitat loss, harvest, human overpopulation, mammal, population dynamics, Russia, threatened species

Psychological toll of being a sustainability scientist

8 12 2014

depressed scientistLike many academics, I’m more or less convinced that I am somewhere on the mild end of the autism spectrum. No, I haven’t been diagnosed and I doubt very much that my slight ‘autistic’ tendencies have altered my social capacity, despite my wife claiming that I have only two emotions – angry or happy. Nor have they engendered any sort of idiot savant mathematical capability.

But I’m reasonably comfortable with mathematics, I can do a single task for hours once it consumes my attention, and I’m excited about discovering how things work. And I love to code. Rather than academics having a higher innate likelihood of being ‘autistic’, I just think the job attracts such personalities.

In the past few years though, my psychological state is probably less dictated by the hard-wiring of my ‘autidemic’ mind and more and more influenced by the constant battery of negative information my brain receives.

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Categories : anthropocene, biodiversity, climate change, conservation, conservation biology, corruption, deforestation, ecological literacy, ecology, environmental policy, environmental science, exploitation, extinction, habitat loss, health, human overpopulation, logging, pollution, population dynamics, poverty, research, science, threatened species, toxicology

Human population size: speeding cars can’t stop quickly

28 10 2014

Stop breeding cartoon-Steve Bell 1994Here at ConservationBytes.com, I write about pretty much anything that has anything remotely to do with biodiversity’s prospects. Whether it is something to do with ancient processes, community dynamics or the wider effects of human endeavour, anything is fair game. It’s a little strange then that despite cutting my teeth in population biology, I have never before tackled human demography. Well as of today, I have.

The press embargo has just lifted on our (Barry Brook and my) new paper in PNAS where we examine various future scenarios of the human population trajectory over the coming century. Why is this important? Simple – I’ve argued before that we could essentially stop all conservation research tomorrow and still know enough to deal with most biodiversity problems. If we could only get a handle on the socio-economic components of the threats, then we might be able to make some real progress. In other words, we need to find out how to manage humans much more than we need to know about the particulars of subtle and complex ecological processes to do the most benefit for biodiversity. Ecologists tend to navel-gaze in this arena far too much.

So I called my own bluff and turned my attention to humans. Our question was simple – how quickly could the human population be reduced to a more ‘sustainable’ size (i.e., something substantially smaller than now)? The main reason we posed that simple, yet deceptively loaded question was that both of us have at various times been faced with the question by someone in the audience that we were “ignoring the elephant in the room” of human over-population.

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Categories : anthropocene, Asia, conservation, demography, economics, ecosystem services, endemism, environmental policy, famine, health, human overpopulation, modelling, population dynamics, science, threatened species

Demonising the hellbender

19 09 2014
Not 'Hellraiser', FFS - 'hellbender'

Not ‘Hellraiser’, FFS – ‘hellbender’

Here’s one by my new PhD student, Leah Collett:

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I have never heard of the hellbender before. “Brilliant name”, I thought. Then I saw it mentioned again a few days later, in company with honey badgers and blue-footed boobies, in a recent article on why we need to see nature as useless in order to ‘save’ it.

So what is it? The hellbender is a species of salamander found in eastern North America, the only species of its genus it turns out, and one of only three left in its family (Cryptobranchidae – ‘hidden gills’). It is assessed as Near Threatened with possible extinction in the near future by the IUCN Red List. Along with the, sadly all too often, habitat degradation it is suffering due to it being highly sensitive to environmental change, it is still believed to be poisonous and that it will kill other fish and their eggs with this poison. In this day and age, some people will kill these salamanders when they come across them when they are out fishing, due to inaccurate held beliefs. I think I found it more incredible that this still occurs in a country where people have quick access to research and information denouncing such a myth.

This wonderful document on the biology and ecology of the hellbenders includes a section titled ‘Man and Hellbenders’ and highlights the likely culprit for starting the ‘hellbenders are poisonous – kill them all’ campaign:

“Dr N. Bayard Green (1971) related how a former editor of the Pocahontas Times (Pocahontas, West Virginia) in 1926 continually tried to vilify the hellbender as a destroyer of game fish and their eggs. Throughout West Virginia many sportsmen’s groups attempted to eradicate many of the so-called enemies of fish and game.”

(I could not read the original paper of Dr Green’s, although it might be available in the collections section). Read the rest of this entry »


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Categories : biodiversity, conservation, threatened species, USA

We generally ignore the big issues

11 08 2014

I’ve had a good week at Stanford University with Paul Ehrlich where we’ve been putting the final touches1 on our book. It’s been taking a while to put together, but we’re both pretty happy with the result, which should be published by The University of Chicago Press within the first quarter of 2015.

It has indeed been a pleasure and a privilege to work with one of the greatest thinkers of our age, and let me tell you that at 82, he’s still a force with which to be reckoned. While I won’t divulge much of our discussions here given they’ll appear soon-ish in the book, I did want to raise one subject that I think we all need to think about a little more.

The issue is what we, as ecologists (I’m including conservation scientists here), choose to study and contemplate in our professional life.

I’m just as guilty as most of the rest of you, but I argue that our discipline is caught in a rut of irrelevancy on the grander scale. We spend a lot of time refining the basics of what we essentially already know pretty well. While there will be an eternity of processes to understand, species to describe, and relationships to measure, can our discipline really afford to avoid the biggest issues while biodiversity (and our society included) are flushed down the drain?

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Categories : agriculture, anthropocene, biodiversity, carbon, carbon trading, climate change, conference, conservation, conservation biology, economics, ecosystem, environmental policy, extinction, food, human overpopulation, planning, population viability analysis, protected area, PVA, research, reserve, science, threatened species

50/500 or 100/1000 debate not about time frame

26 06 2014

Not enough individualsAs you might recall, Dick Frankham, Barry Brook and I recently wrote a review in Biological Conservation challenging the status quo regarding the famous 50/500 ‘rule’ in conservation management (effective population size [Ne] = 50 to avoid inbreeding depression in the short-term, and Ne = 500 to retain the ability to evolve in perpetuity). Well, it inevitably led to some comments arising in the same journal, but we were only permitted by Biological Conservation to respond to one of them. In our opinion, the other comment was just as problematic, and only further muddied the waters, so it too required a response. In a first for me, we have therefore decided to publish our response on the arXiv pre-print server as well as here on ConservationBytes.com.

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50/500 or 100/1000 debate is not about the time frame – Reply to Rosenfeld

cite as: Frankham, R, Bradshaw CJA, Brook BW. 2014. 50/500 or 100/1000 debate is not about the time frame – Reply to Rosenfeld. arXiv: 1406.6424 [q-bio.PE] 25 June 2014.

The Letter from Rosenfeld (2014) in response to Jamieson and Allendorf (2012) and Frankham et al. (2014) and related papers is misleading in places and requires clarification and correction, as follows: Read the rest of this entry »


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Categories : biodiversity, conservation, conservation biology, decline, ecological triage, extinction, extinction debt, extinction vortex, genetic diversity, genetics, management, minimum viable population, MPA, population viability analysis, PVA, recovery, restoration, synergies, threatened species

South Australia’s tattered environmental remains

16 04 2014
State budget percentage expenditures for health, education and environment

South Australia State budget percentage expenditures for health, education and environment

Yesterday I gave the second keynote address at the South Australia Natural Resource Management (NRM) Science Conference at the University of Adelaide (see also a brief synopsis of Day 1 here). Unfortunately, I’m missing today’s talks because of an acute case of man cold, but at least I can stay at home and work while sipping cups of hot tea.

Many people came up afterwards and congratulated me for “being brave enough to tell the truth”, which both encouraged and distressed me – I am encouraged by the positive feedback, but distressed by the lack of action on the part of our natural resource management leaders.

The simple truth is that South Australia’s biodiversity and ecosystems are in shambles, yet few seem to appreciate this.

So for the benefit of those who couldn’t attend, I’ve uploaded the podcast of my slideshow for general viewing here. I’ve also highlighted some key points from the talk below: Read the rest of this entry »


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Categories : alien species, Australia, biodiversity, carbon, carbon trading, climate change, coasts, conservation, deforestation, ecosystem, ecosystem function, ecosystem services, environmental policy, extinction, fragmentation, function, habitat loss, invasive species, kelp, logging, mammal, management, marine, marine protected area, monitoring, planning, prioritisation, protected area, recovery, reforestation, reserve, restoration, South Australia, The University of Adelaide, threatened species, water

Australia’s (latest) war on the environment

3 03 2014

monkYes, the signs were there, but they weren’t clandestine messages written in the stars or in the chaos of tea-leaf dregs. We saw this one coming, but Australians chose to ignore the warning signs and opt for the American political model of extremism, religiosity, plutocracy and science denial.

Enter the ‘Tea Party’ of Australia – the ‘new’ Coalition where reigning Rex perditor Prime Minister Tony The Monk Abbott1 has, in just a few short months, turned back the clock on Australian environmental protection some 40 years.

Yes, we saw it coming, but it wasn’t a tautological fait accompli just because it concerned a ‘conservative’ government. It’s difficult to remember, I know, that conservative governments of yesteryear implemented some strikingly powerful and effective environmental legislation. Indeed, it was the former incarnation of the Coalition government that implemented the once-formidable Environmental Protection and Biodiversity Conservation (EPBC) Act under the direction of then Environment Minister, Robert Hill. A colossus of sorts, the EPBC suffers from many ailments. While it’s the only really bitey environmental legislation we’ve got, that colossus is a lumbering, limping giant missing more than a few teeth – it needs a complete overhaul.

As most Australians are unfortunately aware, The Monk repeatedly and defiantly promised to repeal the Labor-government carbon price implemented in July 2012, despite the absolute necessity to tax the heaviest polluters. While somewhat sheepish about his recent climate disruption denialism following his election in 2013, a denialist he remains:

Let us re-familiarise ourselves with some of his historical pearlers: Read the rest of this entry »


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Categories : anthropocene, Australia, biodiversity, carbon, carbon trading, climate change, conservation, corruption, decline, deforestation, economics, ecosystem, ecosystem services, environmental policy, exploitation, extinction, governance, habitat loss, logging, marine protected area, protected area, recovery, reserve, restoration, threatened species

We’re sorry, but 50/500 is still too few

28 01 2014

too fewSome of you who are familiar with my colleagues’ and my work will know that we have been investigating the minimum viable population size concept for years (see references at the end of this post). Little did I know when I started this line of scientific inquiry that it would end up creating more than a few adversaries.

It might be a philosophical perspective that people adopt when refusing to believe that there is any such thing as a ‘minimum’ number of individuals in a population required to guarantee a high (i.e., almost assured) probability of persistence. I’m not sure. For whatever reason though, there have been some fierce opponents to the concept, or any application of it.

Yet a sizeable chunk of quantitative conservation ecology develops – in various forms – population viability analyses to estimate the probability that a population (or entire species) will go extinct. When the probability is unacceptably high, then various management approaches can be employed (and modelled) to improve the population’s fate. The flip side of such an analysis is, of course, seeing at what population size the probability of extinction becomes negligible.

‘Negligible’ is a subjective term in itself, just like the word ‘very‘ can mean different things to different people. This is why we looked into standardising the criteria for ‘negligible’ for minimum viable population sizes, almost exactly what the near universally accepted IUCN Red List attempts to do with its various (categorical) extinction risk categories.

But most reasonable people are likely to agree that < 1 % chance of going extinct over many generations (40, in the case of our suggestion) is an acceptable target. I’d feel pretty safe personally if my own family’s probability of surviving was > 99 % over the next 40 generations.

Some people, however, baulk at the notion of making generalisations in ecology (funny – I was always under the impression that was exactly what we were supposed to be doing as scientists – finding how things worked in most situations, such that the mechanisms become clearer and clearer – call me a dreamer).

So when we were attacked in several high-profile journals, it came as something of a surprise. The latest lashing came in the form of a Trends in Ecology and Evolution article. We wrote a (necessarily short) response to that article, identifying its inaccuracies and contradictions, but we were unable to expand completely on the inadequacies of that article. However, I’m happy to say that now we have, and we have expanded our commentary on that paper into a broader review. Read the rest of this entry »


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Categories : conservation, conservation biology, demography, DNA, ecological triage, extinction, genetic diversity, genetics, inbreeding depression, management, modelling, population dynamics, population viability analysis, PVA, threatened species

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