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 »





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.

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 »





Cleaning up the rubbish: Australian megafauna extinctions

15 11 2013

diprotodonA few weeks ago I wrote a post about how to run the perfect scientific workshop, which most of you thought was a good set of tips (bizarrely, one person was quite upset with the message; I saved him the embarrassment of looking stupid online and refrained from publishing his comment).

As I mentioned at the end of post, the stimulus for the topic was a particularly wonderful workshop 12 of us attended at beautiful Linnaeus Estate on the northern coast of New South Wales (see Point 5 in the ‘workshop tips’ post).

But why did a group of ecological modellers (me, Barry Brook, Salvador Herrando-Pérez, Fréd Saltré, Chris Johnson, Nick Beeton), ancient DNA specialists (Alan Cooper), palaeontologists (Gav Prideaux), fossil dating specialists (Dizzy Gillespie, Bert Roberts, Zenobia Jacobs) and palaeo-climatologists (Michael Bird, Chris Turney [in absentia]) get together in the first place? Hint: it wasn’t just the for the beautiful beach and good wine.

I hate to say it – mainly because it deserves as little attention as possible – but the main reason is that we needed to clean up a bit of rubbish. The rubbish in question being the latest bit of excrescence growing on that accumulating heap produced by a certain team of palaeontologists promulgating their ‘it’s all about the climate or nothing’ broken record.

Read the rest of this entry »





Too small to avoid catastrophic biodiversity meltdown

27 09 2013
Chiew Larn

Chiew Larn Reservoir is surrounded by Khlong Saeng Wildlife Sanctuary and Khao Sok National Park, which together make up part of the largest block of rainforest habitat in southern Thailand (> 3500 km2). Photo: Antony Lynam

One of the perennial and probably most controversial topics in conservation ecology is when is something “too small’. By ‘something’ I mean many things, including population abundance and patch size. We’ve certainly written about the former on many occasions (see here, here, here and here for our work on minimum viable population size), with the associated controversy it elicited.

Now I (sadly) report on the tragedy of the second issue – when is a habitat fragment too small to be of much good to biodiversity?

Published today in the journal Science, Luke Gibson (of No substitute for primary forest fame) and a group of us report disturbing results about the ecological meltdown that has occurred on islands created when the Chiew Larn Reservoir of southern Thailand was flooded nearly 30 years ago by a hydroelectric dam.

As is the case in many parts of the world (e.g., Three Gorges Dam, China), hydroelectric dams can cause major ecological problems merely by flooding vast areas. In the case of Charn Liew, co-author Tony Lynam of Wildlife Conservation Society passed along to me a bit of poignant and emotive history about the local struggle to prevent the disaster.

“As the waters behind the dam were rising in 1987, Seub Nakasathien, the Superintendent of the Khlong Saeng Wildlife Sanctuary, his staff and conservationist friends, mounted an operation to capture and release animals that were caught in the flood waters.

It turned out to be distressing experience for all involved as you can see from the clips here, with the rescuers having only nets and longtail boats, and many animals dying. Ultimately most of the larger mammals disappeared quickly from the islands, leaving just the smaller fauna.

Later Seub moved to Huai Kha Khaeng Wildlife Sanctuary and fought an unsuccessful battle with poachers and loggers, which ended in him taking his own life in despair in 1990. A sad story, and his friend, a famous folk singer called Aed Carabao, wrote a song about Seub, the music of which plays in the video. Read the rest of this entry »





Biogeography comes of age

22 08 2013

penguin biogeographyThis week has been all about biogeography for me. While I wouldn’t call myself a ‘biogeographer’, I certainly do apply a lot of the discipline’s techniques.

This week I’m attending the 2013 Association of Ecology’s (INTECOL) and British Ecological Society’s joint Congress of Ecology in London, and I have purposefully sought out more of the biogeographical talks than pretty much anything else because the speakers were engaging and the topics fascinating. As it happens, even my own presentation had a strong biogeographical flavour this year.

Although the species-area relationship (SAR) is only one small aspect of biogeography, I’ve been slightly amazed that after more than 50 years since MacArthur & Wilson’s famous book, our discipline is still obsessed with SAR.

I’ve blogged about SAR issues before – what makes it so engaging and controversial is that SAR is the principal tool to estimate overall extinction rates, even though it is perhaps one of the bluntest tools in the ecological toolbox. I suppose its popularity stems from its superficial simplicity – as the area of an (classically oceanic) island increases, so too does the total number of species it can hold. The controversies surrounding such as basic relationship centre on describing the rate of that species richness increase with area – in other words, just how nonlinear the SAR itself is.

Even a cursory understanding of maths reveals the importance of estimating this curve correctly. As the area of an ‘island’ (habitat fragment) decreases due to human disturbance, estimating how many species end up going extinct as a result depends entirely on the shape of the SAR. Get the SAR wrong, and you can over- or under-estimate the extinction rate. This was the crux of the palaver over Fangliang He (not attending INTECOL) & Stephen Hubbell’s (attending INTECOL) paper in Nature in 2011.

The first real engagement of SAR happened with John Harte’s maximum entropy talk in the process macroecology session on Tuesday. What was notable to me was his adamant claim that the power-law form of SAR should never be used, despite its commonness in the literature. I took this with a grain of salt because I know all about how messy area-richness data can be, and why one needs to consider alternate models (see an example here). But then yesterday I listened to one of the greats of biogeography – Robert Whittaker – who said pretty much the complete opposite of Harte’s contention. Whittaker showed results from one of his papers last year that the power law was in fact the most commonly supported SAR among many datasets (granted, there was substantial variability in overall model performance). My conclusion remains firm – make sure you use multiple models for each individual dataset and try to infer the SAR from model-averaging. Read the rest of this entry »





Software tools for conservation biologists

8 04 2013

computer-programmingGiven the popularity of certain prescriptive posts on ConservationBytes.com, I thought it prudent to compile a list of software that my lab and I have found particularly useful over the years. This list is not meant to be comprehensive, but it will give you a taste for what’s out there. I don’t list the plethora of conservation genetics software that is available (generally given my lack of experience with it), but if this is your chosen area, I’d suggest starting with Dick Frankham‘s excellent book, An Introduction to Conservation Genetics.

1. R: If you haven’t yet loaded the open-source R programming language on your machine, do it now. It is the single-most-useful bit of statistical and programming software available to anyone anywhere in the sciences. Don’t worry if you’re not a fully fledged programmer – there are now enough people using and developing sophisticated ‘libraries’ (packages of functions) that there’s pretty much an application for everything these days. We tend to use R to the exclusion of almost any other statistical software because it makes you learn the technique rather than just blindly pressing the ‘go’ button. You could also stop right here – with R, you can do pretty much everything else that the software listed below does; however, you have to be an exceedingly clever programmer and have a lot of spare time. R can also sometimes get bogged down with too much filled RAM, in which case other, compiled languages such as PYTHON and C# are useful.

2. VORTEX/OUTBREAK/META-MODEL MANAGER, etc.: This suite of individual-based projection software was designed by Bob Lacy & Phil Miller initially to determine the viability of small (usually captive) populations. The original VORTEX has grown into a multi-purpose, powerful and sophisticated population viability analysis package that now links to its cousin applications like OUTBREAK (the only off-the-shelf epidemiological software in existence) via the ‘command centre’ META-MODEL MANAGER (see an examples here and here from our lab). There are other add-ons that make almost any population projection and hindcasting application possible. And it’s all free! (warning: currently unavailable for Mac, although I’ve been pestering Bob to do a Mac version).

3. RAMAS: RAMAS is the go-to application for spatial population modelling. Developed by the extremely clever Resit Akçakaya, this is one of the only tools that incorporates spatial meta-population aspects with formal, cohort-based demographic models. It’s also very useful in a climate-change context when you have projections of changing habitat suitability as the base layer onto which meta-population dynamics can be modelled. It’s not free, but it’s worth purchasing. Read the rest of this entry »





De-extinction is about as sensible as de-death

15 03 2013

Published simultaneously in The Conversation.


On Friday, March 15 in Washington DC, National Geographic and TEDx are hosting a day-long conference on species-revival science and ethics. In other words, they will be debating whether we can, and should, attempt to bring extinct animals back to life – a concept some call “de-extinction”.

The debate has an interesting line-up of ecologists, geneticists, palaeontologists (including Australia’s own Mike Archer), developmental biologists, journalists, lawyers, ethicists and even artists. I have no doubt it will be very entertaining.

But let’s not mistake entertainment for reality. It disappoints me, a conservation scientist, that this tired fantasy still manages to generate serious interest. I have little doubt what the ecologists at the debate will conclude.

Once again, it’s important to discuss the principal flaws in such proposals.

Put aside for the moment the astounding inefficiency, the lack of success to date and the welfare issues of bringing something into existence only to suffer a short and likely painful life. The principal reason we should not even consider the technology from a conservation perspective is that it does not address the real problem – mainly, the reason for extinction in the first place.

Even if we could solve all the other problems, if there is no place to put these new individuals, the effort and money expended is a complete waste. Habitat loss is the principal driver of species extinction and endangerment. If we don’t stop and reverse this now, all other avenues are effectively closed. Cloning will not create new forests or coral reefs, for example. Read the rest of this entry »





Translocations: the genetic rescue paradox

14 01 2013

helphindranceHarvesting and habitat alteration reduce many populations to just a few individuals, and then often extinction. A widely recommended conservation action is to supplement those populations with new individuals translocated from other regions. However, crossing local and foreign genes can worsen the prospects of recovery.

We are all hybrids or combinations of other people, experiences and things. Let’s think of teams (e.g., engineers, athletes, mushroom collectors). In team work, isolation from other team members might limit the appearance of innovative ideas, but the arrival of new (conflictive) individuals might in fact destroy group dynamics altogether. Chromosomes work much like this – too little or too much genetic variability among parents can break down the fitness of their descendants. These pernicious effects are known as ‘inbreeding depression‘ when they result from reproduction among related individuals, and ‘outbreeding depression‘ when parents are too genetically distant.

CB_OutbreedingDepression Photo
Location of the two USA sites providing spawners of largemouth bass for the experiments by Goldberg et al. (3): the Kaskaskia River (Mississipi Basin, Illinois) and the Big Cedar Lake (Great Lakes Basin, Wisconsin). Next to the map is shown an array of three of the 72-litre aquaria in an indoor environment under constant ambient temperature (25 ◦C), humidity (60%), and photoperiod (alternate 12 hours of light and darkness). Photo courtesy of T. Goldberg.

Recent studies have revised outbreeding depression in a variety of plants, invertebrates and vertebrates (1, 2). An example is Tony Goldberg’s experiments on largemouth bass (Micropterus salmoides), a freshwater fish native to North America. Since the 1990s, the USA populations have been hit by disease from a Ranavirus. Goldberg et al. (3) sampled healthy individuals from two freshwater bodies: the Mississipi River and the Great Lakes, and created two genetic lineages by having both populations isolated and reproducing in experimental ponds. Then, they inoculated the Ranavirus in a group of parents from each freshwater basin (generation P), and in the first (G1) and second (G2) generations of hybrids crossed from both basins. After 3 weeks in experimental aquaria, the proportion of survivors declined to nearly 30% in G2, and exceeded 80% in G1 and P. Clearly, crossing of different genetic lineages increased the susceptibility of this species to a pathogen, and the impact was most deleterious in G2. This investigation indicates that translocation of foreign individuals into a self-reproducing population can not only import diseases, but also weaken its descendants’ resistance to future epidemics.

A mechanism causing outbreeding depression occurs when hybridisation alters a gene that is only functional in combination with other genes. Immune systems are often regulated by these complexes of co-adapted genes (‘supergenes’) and their disruption is a potential candidate for the outbreeding depression reported by Goldberg et al. (3). Along with accentuating susceptibility to disease, outbreeding depression in animals and plants can cause a variety of deleterious effects such as dwarfism, low fertility, or shortened life span. Dick Frankham (one of our collaborators) has quantified that the probability of outbreeding depression increases when mixing takes place between (i) different species, (ii) conspecifics adapted to different habitats, (iii) conspecifics with fixed chromosomal differences, and (iv) populations free of genetic flow with other populations for more than 500 years (2).

A striking example supporting (some of) those criteria is the pink salmon (Oncorhynchus gorbuscha) from Auke Creek near Juneau (Alaska). The adults migrate from the Pacific to their native river where they spawn two years after birth, with the particularity that there are two strict broodlines that spawn in either even or odd year – that is, the same species in the same river, but with a lack of genetic flow between populations. In vitro mixture of the two broodlines and later release of hybrids in the wild have shown that the second generation of hybrids had nearly 50% higher mortality rates (i.e., failure to return to spawn following release) when born from crossings of parents from different broodlines than when broodlines were not mixed (4).

Read the rest of this entry »





Rocking the scientific boat

14 12 2012
© C. Simpson

© C. Simpson

One thing that has simultaneously amused, disheartened, angered and outraged me over the past decade or so is how anyone in their right mind could even suggest that scientists band together into some sort of conspiracy to dupe the masses. While this tired accusation is most commonly made about climate scientists, it applies across nearly every facet of the environmental sciences whenever someone doesn’t like what one of us says.

First, it is essential to recognise that we’re just not that organised. While I have yet to forget to wear my trousers to work (I’m inclined to think that it will happen eventually), I’m still far, far away from anything that could be described as ‘efficient’ and ‘organised’. I can barely keep it together as it is. Such is the life of the academic.

More importantly, the idea that a conspiracy could form among scientists ignores one of the most fundamental components of scientific progress – dissension. And hell, can we dissent!

Yes, the scientific approach is one where successive lines of evidence testing hypotheses are eventually amassed into a concept, then perhaps a rule of thumb. If the rule of thumb stands against the scrutiny of countless studies (i.e., ‘challenges’ in the form of poison-tipped, flaming literary arrows), then it might eventually become a ‘theory’. Some theories even make it to become the hallowed ‘law’, but that is very rare indeed. In the environmental sciences (I’m including ecology here), one could argue that there is no such thing as a ‘law’.

Well-informed non-scientists might understand, or at least, appreciate that process. But few people outside the sciences have even the remotest clue about what a real pack of bastards we can be to each other. Use any cliché or descriptor you want – it applies: dog-eat-dog, survival of the fittest, jugular-slicing ninjas, or brain-eating zombies in lab coats.

Read the rest of this entry »





To corridor, or not to corridor: size is the question

24 04 2012

I’ve just read a really interesting post by David Pannell from the University of Western Australia discussing the benefits (or lack thereof) of wildlife ‘corridors’. I’d like to elaborate on a few key issues, and introduce the most important aspect that really hasn’t been mentioned.

Some of you might be aware that the Australian Commonwealth Government has just released its Draft National Wildlife Corridors Plan for public comment, but many of you might not really know what a ‘corridor’ constitutes.

Wildlife or biodiversity ‘corridors’ have been around for a long time, at least in terms of proposals. The idea is fairly simple to conceive, but very difficult to implement in practice.

At least for as long as I’ve been in the conservation biology biz, ‘corridors’ have been proffered as one really good way to make broad-scale landscape restoration plausible and effective for (mainly) forest-dwelling species which have copped the worst of deforestation trends around Australia and the world. The idea is that because of intense habitat fragmentation, isolated patches of primary (or at least, reasonably intact secondary) forest can be linked by planting some sort of long corridor of similar habitat between them. Then, all the little creatures can merrily make their way back and forth between the patches, thus rescuing each other from extinction via migration. Read the rest of this entry »





Conservation catastrophes

22 02 2012

David Reed

The title of this post serves two functions: (1) to introduce the concept of ecological catastrophes in population viability modelling, and (2) to acknowledge the passing of the bloke who came up with a clever way of dealing with that uncertainty.

I’ll start with latter first. It came to my attention late last year that a fellow conservation biologist colleague, Dr. David Reed, died unexpectedly from congestive heart failure. I did not really mourn his passing, for I had never met him in person (I believe it is disingenuous, discourteous, and slightly egocentric to mourn someone who you do not really know personally – but that’s just my opinion), but I did think at the time that the conservation community had lost another clever progenitor of good conservation science. As many CB readers already know, we lost a great conservation thinker and doer last year, Professor Navjot Sodhi (and that, I did take personally). Coincidentally, both Navjot and David died at about the same age (49 and 48, respectively). I hope that the being in one’s late 40s isn’t particularly presaged for people in my line of business!

My friend, colleague and lab co-director, Professor Barry Brook, did, however, work a little with David, and together they published some pretty cool stuff (see References below). David was particularly good at looking for cross-taxa generalities in conservation phenomena, such as minimum viable population sizes, effects of inbreeding depression, applications of population viability analysis and extinction risk. But more on some of that below. Read the rest of this entry »





Better SAFE than sorry

30 11 2011

Last day of November already – I am now convinced that my suspicions are correct: time is not constant and in fact accelerates as you age (in mathematical terms, a unit of time becomes a progressively smaller proportion of the time elapsed since your birth, so this makes sense). But, I digress…

This short post will act mostly as a spruik for my upcoming talk at the International Congress for Conservation Biology next week in Auckland (10.30 in New Zealand Room 2 on Friday, 9 December) entitled: Species Ability to Forestall Extinction (SAFE) index for IUCN Red Listed species. The post also sets a bit of the backdrop to this paper and why I think people might be interested in attending.

As regular readers of CB will know, we published a paper this year in Frontiers in Ecology and the Environment describing a relatively simple metric we called SAFE (Species Ability to Forestall Extinction) that could enhance the information provided by the IUCN Red List of Threatened Species for assessing relative extinction threat. I won’t go into all the detail here (you can read more about it in this previous post), but I do want to point out that it ended up being rather controversial.

The journal ended up delaying final publication because there were 3 groups who opposed the metric rather vehemently, including people who are very much in the conservation decision-making space and/or involved directly with the IUCN Red List. The journal ended up publishing our original paper, the 3 critiques, and our collective response in the same issue (you can read these here if you’re subscribed, or email me for a PDF reprint). Again, I won’t go into an detail here because our arguments are clearly outlined in the response.

What I do want to highlight is that even beyond the normal in-print tête-à-tête the original paper elicited, we were emailed by several people behind the critiques who were apparently unsatisfied with our response. We found this slightly odd, because many of the objections just kept getting re-raised. Of particular note were the accusations that: Read the rest of this entry »





Not magic, but necessary

18 10 2011

In April this year, some American colleagues of ours wrote a rather detailed, 10-page article in Trends in Ecology and Evolution that attacked our concept of generalizing minimum viable population (MVP) size estimates among species. Steve Beissinger of the University of California at Berkeley, one of the paper’s co-authors, has been a particularly vocal adversary of some of the applications of population viability analysis and its child, MVP size, for many years. While there was some interesting points raised in their review, their arguments largely lacked any real punch, and they essentially ended up agreeing with us.

Let me explain. Today, our response to that critique was published online in the same journal: Minimum viable population size: not magic, but necessary. I want to take some time here to summarise the main points of contention and our rebuttal.

But first, let’s recap what we have been arguing all along in several papers over the last few years (i.e., Brook et al. 2006; Traill et al. 2007, 2010; Clements et al. 2011) – a minimum viable population size is the point at which a declining population becomes a small population (sensu Caughley 1994). In other words, it’s the point at which a population becomes susceptible to random (stochastic) events that wouldn’t otherwise matter for a small population.

Consider the great auk (Pinguinus impennis), a formerly widespread and abundant North Atlantic species that was reduced by intensive hunting throughout its range. How did it eventually go extinct? The last remaining population blew up in a volcanic explosion off the coast of Iceland (Halliday 1978). Had the population been large, the small dent in the population due to the loss of those individuals would have been irrelevant.

But what is ‘large’? The empirical evidence, as we’ve pointed out time and time again, is that large = thousands, not hundreds, of individuals.

So this is why we advocate that conservation targets should aim to keep at or recover to the thousands mark. Less than that, and you’re playing Russian roulette with a species’ existence. Read the rest of this entry »





Life, death and Linneaus

9 07 2011

Barry Brook (left) and Lian Pin Koh (right) attacking Fangliang He (centre). © CJA Bradshaw

I’m sitting in the Brisbane airport contemplating how best to describe the last week. If you’ve been following my tweets, you’ll know that I’ve been sequestered in a room with 8 other academics trying to figure out the best ways to estimate the severity of the Anthropocene extinction crisis. Seems like a pretty straight forward task. We know biodiversity in general isn’t doing so well thanks to the 7 billion Homo sapiens on the planet (hence, the Anthropo prefix) – the question though is: how bad?

I blogged back in March that a group of us were awarded a fully funded series of workshops to address that question by the Australian Centre for Ecological Synthesis and Analysis (a Terrestrial Ecosystem Research Network facility based at the University of Queensland), and so I am essentially updating you on the progress of the first workshop.

Before I summarise our achievements (and achieve, we did), I just want to describe the venue. Instead of our standard, boring, windowless room in some non-descript building on campus, ACEAS Director, Associate Professor Alison Specht, had the brilliant idea of putting us out away from it all on a beautiful nature-conservation estate on the north coast of New South Wales.

What a beautiful place – Linneaus Estate is a 111-ha property just a few kilometres north of Lennox Head (about 30 minutes by car south of Byron Bay) whose mission is to provide a sustainable living area (for a very lucky few) while protecting and restoring some pretty amazing coastal habitat along an otherwise well-developed bit of Australian coastline. And yes, it’s named after Carl Linnaeus. Read the rest of this entry »





Classics: Effective population size ratio

27 04 2011

Here’s another concise Conservation Classic highlighted in our upcoming book chapter (see previous entries on this book). Today’s entry comes from a colleague of mine, Dick Frankham, who has literally written the book on conservation genetics. I’ve published with Dick a few times – absolutely lovely chap who really knows his field more than almost any other. It is a great pleasure to include one of his seminal works as a Conservation Classic.

This entry is highly related to our work on minimum viable population size, and the controversial SAFE index (more on that later).

Although it had long been recognized that inbreeding and loss of genetic diversity were accentuated in small, isolated populations (Charlesworth & Charlesworth, 1987), genetic hazards were generally considered to be of less consequence to extinction risk than demographic and environmental stochasticity. Frankham (1995) helped overturn this viewpoint, using a meta-analysis to draw together comprehensive evidence on the ratio of genetically effective to actual population size (Ne:N). Read the rest of this entry »





Species’ Ability to Forestall Extinction – AudioBoo

8 04 2011

Here’s a little interview I just did on the SAFE index with ABC AM:

Not a bad job, really.

And here’s another one from Radio New Zealand:

CJA Bradshaw





Classics: demography versus genetics

16 03 2011

Here’s another short, but sweet Conservation Classic highlighted in our upcoming book chapter (see previous entries on this book). Today’s entry comes from long-time quantitative ecology guru, Russ Lande, who is now based at the Silwood Park Campus (Imperial College London).

© IBL

In an influential review, Lande (1988) argued that

“…demography may usually be of more immediate importance than population genetics in determining the minimum viable size of wild populations”.

It was a well-reasoned case, and was widely interpreted to mean that demographic and ecological threats would provide the ‘killer blow’ to threatened species before genetic factors such as inbreeding and fitness effects of loss of genetic diversity had time to exert a major influence on small population dynamics.

Read the rest of this entry »





S.A.F.E. = Species Ability to Forestall Extinction

8 01 2011

Note: I’ve just rehashed this post (30/03/2011) because the paper is now available online (see comment stream). Stay tuned for the media release next week. – CJAB

I’ve been more or less underground for the last 3 weeks. It has been a wonderful break (mostly) from the normally hectic pace of academic life. Thanks for all those who remain despite the recent silence.

© Ezprezzo.com

But I’m back now with a post about a paper we’ve just had accepted in Frontiers in Ecology and Environment. In my opinion it’s a leap forward in how we measure relative threat risk among species, despite some criticism.

I’ve written in past posts about the ‘magic’ minimum number of individuals that should be in a population to reduce the chance of extinction from random events. The so-called ‘minimum viable population (MVP) size’ is basically the abundance of a (connected) population below which random events take over from factors causing sustained declines (Caughley’s distinction between the ‘declining’ and ‘small’ population paradigms).

Up until the last few years, the MVP size was considered to be a population- or species-specific value, and it required very detailed demographic, genetic and biogeographical data to estimate – not something that biologists tend to have at their fingertips for most high-risk species. However, several papers published by our group (Minimum viable population size and global extinction risk are unrelated, Minimum viable population size: a meta-analysis of 30 years of published estimates and Pragmatic population viability targets in a rapidly changing world) have shown that there is in fact little variation in this number among the best-studied species; both demographic and genetic data support a number of around 5000 to avoid crossing the deadly threshold.

Now the fourth paper in this series has just been accepted (sorry, no link yet, but I’ll let you all know as soon as it is available), and it was organised and led by Reuben Clements, and co-written by me, Barry Brook and Bill Laurance.

The idea is fairly simple and it somewhat amazes me that it hasn’t been implemented before. The SAFE (Species Ability to Forestall Extinction) index is simply the distance a population is (in terms of abundance) from its MVP. In the absence of a species-specific value, we used the 5000-individual threshold. Thus, Read the rest of this entry »





Biodiversity: from conservation science to action

11 09 2010

© tidechaser.blogspot.com

About 3 weeks ago I blogged about Guillaume Chapron‘s vision to notch up conservation implementation around the globe. After that little piece Guillaume invited me and a few others (including one of Australia’s own conservation gurus, Hugh Possingham) to co-author a piece on the new Nature Network‘s ‘Soapbox Science‘ blog. The Soapbox Science blog is:

“… a new group blog, covering the whole of science. Over the coming months, we’ll be inviting researchers from all over the world to write one-off posts. The subjects may be controversial, opinionated, speculative, or just plain interesting, and may be written by any scientist with something to say.”

We managed to grab the first post in this endeavour, so I reproduce it here for ConservationBytes.com readers. Enjoy!

Ecosystem degradation and species extinction rates are steadily accelerating, mainly as a result of unbounded human population growth, extravagant consumption patterns and associated land and sea degradation. Researchers are pushing science forward in an attempt to reverse the biodiversity ‘crisis’. In their papers they systematically stress how their results can serve to enhance conservation management or implement new corrective actions to reduce biodiversity loss. Still, they are becoming increasingly frustrated that their published research is having little, if any impact in halting the ongoing sixth mass extinction. Everything remains purely theoretical and is not leading to direct action. Read the rest of this entry »





Webinar: Modelling water and life

27 08 2010

Another quick one today just to show the webinar of my recent 10-minute ‘Four in 40′ talk sponsored by The Environment Institute and the Department for Water. This seminar series was entitled ‘Modelling as a Tool for Decision Support’ held at the Auditorium, Royal Institution Australia (RiAus).

“Four in 40″ is a collaboration between The University of Adelaide and the Department for Water, where 4 speakers each speak for 10 minutes on their research and its implications for policy. The purpose is to build understanding of how best to work with each other, build new business for both organisations and raise awareness of activity being undertaken in water/natural resource management policy and research.

CJA Bradshaw








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