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 »





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 »





When the cure becomes the disease

6 02 2012

I’ve always barracked for Peter Kareiva‘s views and work; I particularly enjoy his no-bullshit, take-no-prisoners approach to conservation. Sure, he’s said some fairly radical things over the years, and has pissed off more than one conservationist in the process. But I think this is a good thing.

His main point (as is mine, and that of a growing number of conservation scientists) is that we’ve already failed biodiversity, so it’s time to move into the next phase of disaster mitigation. By ‘failing’ I mean that, love it or loathe it, extinction rates are higher now than they have been for millennia, and we have very little to blame but ourselves. Apart from killing 9 out of 10 people on the planet (something no war or disease will ever be able to do), we’re stuck with the rude realism that it’s going to get a lot worse before it gets better.

This post acts mostly an introduction to Peter Kareiva & collaborators’ latest essay on the future of conservation science published in the Breakthrough Institute‘s new journal. While I cannot say I agree with all components (especially the cherry-picked resilience examples), I fundamentally support the central tenet that we have to move on with a new state of play.

In other words, humans aren’t going to go away, ‘pristine’ is as unattainable as ‘infinity’, and reserves alone just aren’t going to cut it. 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 »





Conservation is all about prioritisation

4 12 2010

Another great guest post from a previous contributor, Piero Visconti.

Biodiversity conservation is about prioritisation – making difficult choices.

With limited money and so many habitats and species in need of protection, deciding where not to expend resources is as important as deciding where to act. Saying ‘no’ will be crucial for ensuring the persistence of biodiversity and ecosystem services, simply because as individuals who value conservation, we will always be tempted to try and save everything.

In the words of Frederick the Great: “He who defends everything, defends nothing.”

As a result, much recent conservation planning research has focused on offering managers general and flexible tools for deciding which conservation features should be the highest priority. Intuitively, we should direct our resources towards areas that have high biodiversity values, and that are likely to be lost if the forces of conservation do not intervene (the most ‘vulnerable’ land parcels). This approach is known as the ‘minimize loss’ approach. Imagine we are worried about the loss of rare native vegetation in the face of ongoing urban expansion (e.g., Melbourne’s western grasslands). To minimize loss, managers would pre-emptively protect sites that are most likely to be developed. But is this decision to race the bulldozers always the best idea? How much does this choice depend on our assumptions about how land is protected, how land developers behave, and the accuracy of our future predictions? Read the rest of this entry »





Conservation Biology for All

26 12 2009

A new book that I’m proud to have had a hand in writing is just about to come out with Oxford University Press called Conservation Biology for All. Edited by the venerable Conservation Scholars, Professors Navjot Sodhi (National University of Singapore) and Paul Ehrlich (Stanford University), it’s a powerhouse of some of the world’s leaders in conservation science and application.

The book strives to “…provide cutting-edge but basic conservation science to a global readership”. In short, it’s written to bring the forefront of conservation science to the general public, with OUP promising to make it freely available online within about a year from its release in early 2010 (or so the rumour goes). The main idea here is that those in most need of such a book – the conservationists in developing nations – can access the wealth of information therein without having to sacrifice the village cow to buy it.

I won’t go into any great detail about the book’s contents (mainly because I have yet to receive my own copy and read most of the chapters!), but I have perused early versions of Kevin Gaston‘s excellent chapter on biodiversity, and Tom Brook‘s overview of conservation planning and prioritisation. Our chapter (Chapter 16 by Barry Brook and me), is an overview of statistical and modelling philosophy and application with emphasis on conservation mathematics. It’s by no means a complete treatment, but it’s something we want to develop further down the track. I do hope many people find it useful.

I’ve reproduced the chapter title line-up below, with links to each of the authors websites.

  1. Conservation Biology: Past and Present (C. Meine)
  2. Biodiversity (K. Gaston)
  3. Ecosystem Functions and Services (C. Sekercioglu)
  4. Habitat Destruction: Death of a Thousand Cuts (W. Laurance)
  5. Habitat Fragmentation and Landscape Change (A. Bennett & D. Saunders)
  6. Overharvesting (C. Peres)
  7. Invasive Species (D. Simberloff)
  8. Climate Change (T. Lovejoy)
  9. Fire and Biodiversity (D. Bowman & B. Murphy)
  10. Extinctions and the Practice of Preventing Them (S. Pimm & C. Jenkins)
  11. Conservation Planning and Priorities (T. Brooks)
  12. Endangered Species Management: The US Experience (D. Wilcove)
  13. Conservation in Human-Modified Landscapes (L.P. Koh & T. Gardner)
  14. The Roles of People in Conservation (A. Claus, K. Chan & T. Satterfield)
  15. From Conservation Theory to Practice: Crossing the Divide (M. Rao & J. Ginsberg)
  16. The Conservation Biologist’s Toolbox – Principles for the Design and Analysis of Conservation Studies (C. Bradshaw & B. Brook)

As you can see, it’s a pretty impressive collection of conservation stars and hard-hitting topics. Can’t wait to get my own copy! I will probably blog individual chapters down the track, so stay tuned.

CJA Bradshaw

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A magic conservation number

15 12 2009

Although I’ve already blogged about our recent paper in Biological Conservation on minimum viable population sizes, American Scientist just did a great little article on the paper and concept that I’ll share with you here:

Imagine how useful it would be if someone calculated the minimum population needed to preserve each threatened organism on Earth, especially in this age of accelerated extinctions.

A group of Australian researchers say they have nailed the best figure achievable with the available data: 5,000 adults. That’s right, that many, for mammals, amphibians, insects, plants and the rest.

Their goal wasn’t a target for temporary survival. Instead they set the bar much higher, aiming for a census that would allow a species to pursue a standard evolutionary lifespan, which can vary from one to 10 million years.

That sort of longevity requires abundance sufficient for a species to thrive despite significant obstacles, including random variation in sex ratios or birth and death rates, natural catastrophes and habitat decline. It also requires enough genetic variation to allow adequate amounts of beneficial mutations to emerge and spread within a populace.

“We have suggested that a major rethink is required on how we assign relative risk to a species,” says conservation biologist Lochran Traill of the University of Adelaide, lead author of a Biological Conservation paper describing the projection.

Conservation biologists already have plenty on their minds these days. Many have concluded that if current rates of species loss continue worldwide, Earth will face a mass extinction comparable to the five big extinction events documented in the past. This one would differ, however, because it would be driven by the destructive growth of one species: us.

More than 17,000 of the 47,677 species assessed for vulnerability of extinction are threatened, according to the latest Red List of Threatened Species prepared by the International Union for Conservation of Nature. That includes 21 percent of known mammals, 30 percent of known amphibians, 12 percent of known birds and 70 percent of known plants. The populations of some critically endangered species number in the hundreds, not thousands.

In an effort to help guide rescue efforts, Traill and colleagues, who include conservation biologists and a geneticist, have been exploring minimum viable population size over the past few years. Previously they completed a meta-analysis of hundreds of studies considering such estimates and concluded that a minimum head count of more than a few thousand individuals would be needed to achieve a viable population.

“We don’t have the time and resources to attend to finding thresholds for all threatened species, thus the need for a generalization that can be implemented across taxa to prevent extinction,” Traill says.

In their most recent research they used computer models to simulate what population numbers would be required to achieve long-term persistence for 1,198 different species. A minimum population of 500 could guard against inbreeding, they conclude. But for a shot at truly long-term, evolutionary success, 5,000 is the most parsimonious number, with some species likely to hit the sweet spot with slightly less or slightly more.

“The practical implications are simply that we’re not doing enough, and that many existing targets will not suffice,” Traill says, noting that many conservation programs may inadvertently be managing protected populations for extinction by settling for lower population goals.

The prospect that one number, give or take a few, would equal the minimum viable population across taxa doesn’t seem likely to Steven Beissinger, a conservation biologist at the University of California at Berkeley.

“I can’t imagine 5,000 being a meaningful number for both Alabama beach mice and the California condors. They are such different organisms,” Beissinger says.

Many variables must be considered when assessing the population needs of a given threatened species, he says. “This issue really has to do with threats more than stochastic demography. Take the same rates of reproduction and survival and put them in a healthy environment and your minimum population would be different than in an environment of excess predation, loss of habitat or effects from invasive species.”

But, Beissinger says, Traill’s group is correct for thinking that conservation biologists don’t always have enough empirically based standards to guide conservation efforts or to obtain support for those efforts from policy makers.

“One of the positive things here is that we do need some clear standards. It might not be establishing a required number of individuals. But it could be clearer policy guidelines for acceptable risks and for how many years into the future can we accept a level of risk,” Beissinger says. “Policy people do want that kind of guidance.”

Traill sees policy implications in his group’s conclusions. Having a numerical threshold could add more precision to specific conservation efforts, he says, including stabs at reversing the habitat decline or human harvesting that threaten a given species.

“We need to restore once-abundant populations to the minimum threshold,” Traill says. “In many cases it will make more economic and conservation sense to abandon hopeless-case species in favor of greater returns elsewhere.





Raise targets to prevent extinction

12 11 2009

I know I’ve blogged recently about this, but The Adelaidean did a nice little article that I thought I’d reproduce here. The source can be found here.

Adelaidean story Nov 2009





Managing for extinction

9 10 2009

ladderAh, it doesn’t go away, does it? Or at least, we won’t let it.

That concept of ‘how many is enough?’ in conservation biology, the so-called ‘minimum viable population size‘, is enough to drive some conservation practitioners batty.

How many times have we heard the (para-) phrase: “It’s simply impractical to bring populations of critically endangered species up into the thousands”?

Well, my friends, if you’re not talking thousands, you’re wasting everyone’s time and money. You are essentially managing for extinction.

Our new paper out online in Biological Conservation entitled Pragmatic population viability targets in a rapidly changing world (Traill et al.) shows that populations of endangered species are unlikely to persist in the face of global climate change and habitat loss unless they number around 5000 mature individuals or more.

After several meta-analytic, time series-based and genetic estimates of the magic minimum number all agreeing, we can be fairly certain now that if a population is much less than several thousands (median = 5000), its likelihood of persisting in the long run in the face of normal random variation is pretty small.

We conclude essentially that many conservation biologists routinely underestimate or ignore the number of animals or plants required to prevent extinction. In fact, aims to maintain tens or hundreds of individuals, when thousands are actually needed, are simply wasting precious and finite conservation resources. Thus, if it is deemed unrealistic to attain such numbers, we essentially advise that in most cases conservation triage should be invoked and the species in question be abandoned for better prospects

A long-standing idea in species restoration programs is the so-called ‘50/500’ rule; this states that at least 50 adults are required to avoid the damaging effects of inbreeding, and 500 to avoid extinctions due to the inability to evolve to cope with environmental change. Our research suggests that the 50/500 rule is at least an order of magnitude too small to stave off extinction.

This does not necessarily imply that populations smaller than 5000 are doomed. But it does highlight the challenge that small populations face in adapting to a rapidly changing world.

We are battling to prevent a mass extinction event in the face of a growing human population and its associated impact on the planet, but the bar needs to be a lot higher. However, we shouldn’t necessarily give up on critically endangered species numbering a few hundred of individuals in the wild. Acceptance that more needs to be done if we are to stop ‘managing for extinction’ should force decision makers to be more explicit about what they are aiming for, and what they are willing to trade off, when allocating conservation funds.

CJA Bradshaw

(with thanks to Lochran Traill, Barry Brook and Dick Frankham)

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This post was chosen as an Editor's Selection for ResearchBlogging.orgResearchBlogging.org

Traill, L.W., Brook, B.W., Frankham, R.R., & Bradshaw, C.J.A. (2009). Pragmatic population viability targets in a rapidly changing world Biological Conservation DOI: 10.1016/j.biocon.2009.09.001





Classics: Ecological Triage

27 03 2009

It is a truism that when times are tough, only the strongest pull through. This isn’t a happy concept, but in our age of burgeoning biodiversity loss (and economic belt-tightening), we have to make some difficult decisions.In this regard, I suggest Brian Walker’s1992 paper Biodiveristy and ecological redundancy makes the Classics list.

Ecological triage is, of course, taken from the medical term triage used in emergency or wartime situations. Ecological triage refers to the the conservation prioritisation of species that provide unique or necessary functions to ecosystems, and the abandonment of those that do not have unique ecosystem roles or that face almost certain extinction given they fall well below their minimum viable population size (Walker 1992). Financial resources such as investment in recovery programmes, purchase of remaining habitats for preservation, habitat restoration, etc. are allocated accordingly; the species that contribute the most to ecosystem function and have the highest probability of persisting are earmarked for conservation and others are left to their own devices (Hobbs & Kristjanson 2003).

This emotionally empty and accounting-type conservation can be controversial because public favourites like pandas, kakapo and some dolphin species just don’t make the list in many circumstances. As I’ve stated before, it makes no long-term conservation or economic sense to waste money on the doomed and ecologically redundant. Many in the conservation business apply ecological triage without being fully aware of it. Finite pools of money (generally the paltry left-overs from some green-guilty corporation or under-funded government initiative) for conservation mean that we have to set priorities – this is an entire discipline in its own right in conservation biology. Reserve design is just one example of this sacrifice-the-doomed-for-the good-of-the-ecosystem approach.

Walker (1992) advocated that we should endeavour to maintain ecosystem function first, and recommended that we abandon programmes to restore functionally ‘redundant’ species (i.e., some species are more ecologically important than others, e.g., pollinators, prey). But how do you make the choice? The wrong selection might mean an extinction cascade (Noss 1990; Walker 1992) whereby tightly linked species (e.g., parasites-hosts, pollinators-plants, predators-prey) will necessarily go extinct if one partner in the mutualism disappears (see Koh et al. 2004 on co-extinctions). Ecological redundancy is a terribly difficult thing to determine, especially given that we still understand relatively little about how complex ecological systems really work (Marris 2007).

The more common (and easier, if not theoretically weaker) approach is to prioritise areas and not species (e.g., biodiversity hotspots), but even the criteria used for area prioritisation can be somewhat arbitrary and may not necessarily guarantee the most important functional groups are maintained (Orme et al. 2005; Brooks et al. 2006). There are many different ways of establishing ‘priority’, and it depends partially on your predilections.

More recent mathematical approaches such as cost-benefit analyses (Possingham et al. 2002; Murdoch et al. 2007) advocate conservation like a CEO would run a profitable business. In this case the ‘currency’ is biodiversity, and so a fixed financial investment must maximise long-term biodiversity gains (Possingham et al. 2002). This essentially estimates the potential biodiversity saved per dollar invested, and allocates funds accordingly (Wilson et al. 2007). Where the costs outweigh the benefits, conservationists move on to more beneficial goals. Perhaps the biggest drawback with this approach is that it’s particularly data-hungry. When ecosystems are poorly measured, then the investment curve is unlikely to be very realistic.

CJA Bradshaw

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(Many thanks to Lochran Traill and Barry Brook for co-developing these ideas with me)





Cost, not biodiversity, dictates decision to conserve

26 08 2008

One for the Potential list:

originalEuroGreen_LogoI’ve just read a great new paper by Bode et al. (2008) entitled Cost-effective global conservation spending is robust to taxonomic group.

After the hugely influential biodiversity ‘hotspot concept hit the global stage, there was a series of subsequent research papers examining just how we should measure the ‘biodiversity’ component of areas needing to be conserved (and invested in). The problem was that depending on which taxa you looked at, and what measure of ‘biodiversity’ you used (e.g., species richness, endemism, latent threat, evolutionary potential, functional redundancy), the priority list of where, how much and when to invest in conservation differed quite a lot. In other words, the congruency among listed areas was rather low (summarised nicely in Thomas Brooks‘ paper in Science Global biodiversity conservation priorities and examined also by Orme et al. 2005). This causes all sorts of problems for conservation investment planners – what to invest in and where?

Bode and colleagues’ newest paper demonstrates at least for endemism, the taxon on which you base your assessment is much less important for maximising species conservation than factors such as land cost and the degree of threat (e.g., as measured by the IUCN Red List).

Of course, their findings could be considered too simplistic because they don’t (couldn’t) evaluate other potentially more important components of ‘biodiversity’ such as genetic history (evolutionary potential) or ecological functional redundancy (the idea that a species becomes more important to conserve if no other species provide the same ecosystem functions); however, I think this paper is something of a landmark in that it shows that ‘socio-economic’ uncertainty generally outweighs uncertainty due to biodiversity measures. The long and short of this is that planners should start investing if there is evidence of heightened threat and land is cheap.

A few other missing bits means that the paper is more heuristic than prescriptive (something the authors state right up front). There is no attempt to take biodiversity, threat or land cost changes arising from climate change into account (see relevant post here), so some of the priorities are questionable. Related to this is the idea of latent risk (see relevant paper by Cardillo et al. 2006) – what’s not necessarily threatened now but likely will be in the very near future. Also, only a small percentage of species are listed in the IUCN Red List (see relevant post here), so perhaps we’re missing some important trends. Finally, I had to note that almost all the priority areas outlined in the paper happened to be in the tropics, which stands to reason given the current and ongoing extinction crisis occurring in this realm. See a more detailed post on ‘tropical turmoil‘.

Despite the caveats, I think this could provide a way forward to the conservation planning stalemate.

CJA Bradshaw

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Classics: Biodiversity Hotspots

25 08 2008

‘Classics’ is a category of posts highlighting research that has made a real difference to biodiversity conservation. All posts in this category will be permanently displayed on the Classics page of ConservationBytes.com

info-chap7-slide-pic03Myers, N., Mittermeier, R.A., Mittermeier, C.G., da Fonseca, G.A.B. & Kent, J. (2000). Biodiversity hotspots for conservation priorities. Nature, 403, 853-858

According to Google Scholar, this paper has over 2500 citations. Even though it was published less than a decade ago, already Myers and colleagues’ ‘hotspots’ concept has become the classic lexicon for, as they defined it, areas with high species endemism and degradation by humans. In other words, these are places on the planet (originally only terrestrial, but the concept has been extended to the marine realm) where at the current rates of habitat loss, exploitation, etc., we stand to lose far more irreplaceable species. The concept has been criticised for various incapacities to account for all types of threats – indeed, many other prioritisation criteria have been proposed (assessed nicely by Brooks et al. 2006 and Orme et al. 2005), but it’s the general idea proposed by Myers and colleagues that has set the conservation policy stage for most countries. One little gripe here – although the concept ostensibly means areas of high endemic species richness AND associated threat, people often take the term ‘hotspot’ to mean just a place with lots of species. Not so. Ah, the intangible concept of biodiversity!

CJA Bradshaw

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Captive breeding for conservation

7 08 2008

My first attempt at this potentially rather controversial section of ConservationBytes.com. Inspired by my latest post (30/07/2008), I must comment on what I believe is one of the biggest wasters of finite conservation (financial) resources – captive breeding for population recovery. The first laureate of the Toothless category goes to 7 authors (Snyder et al.) who I believe deserve at least a round of beers for their bold paper published way back in 1996 in Conservation BiologyLimitations of captive breeding in endangered species recovery.

The paper describes basically that in most situations, captive breeding for population recovery is ill-conceived, badly planned, overly expensive and done without any notion of the particular species’ minimum viable population size (the population size required to provide a high probability of persistence over a long period). Examples of ridiculous cloning experiments done in the name of ‘conservation’ (one example with which I am familiar is the case of the SE Asian banteng cloning experiment – these conservation-challenged scientists actually claimed “We hope that the birth of these animals will open the way for a new strategy to help maintain valuable biodiversity and to respond to the challenge of large-scale extinctions ahead.” after spending amounts that would make Bill Gates blush). Come on! Minimum viable population sizes number in the thousands to tens of thousands (e.g., Brook et al. 2006; Traill et al. 2007), not to mention the genetic diversity necessary for persistence captive populations generally lack (see Frankham et al. 2004).

In the spirit of ecological triage, we must focus on conservation efforts that have a high probability of changing the extinction risk of species. Wasting millions of dollars to save a handful of inbred individuals (insert your favourite example here) WILL NOT, in most cases, make any difference to population viability (with only a few exceptions). Good on Snyder et al. (1996) for their analysis and conclusions, but zoos, laboratories and other captive-rearing organisations around the world continue to throw away millions using the ‘conservation’ rationale to justify their actions. Rubbish. I’m afraid there is little evidence that the Snyder et al. paper changed anything. (post original published in Toothless 31/07/2008).

CJA Bradshaw

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Wasting precious money on the conservation-irrelevant

30 07 2008
© Michael H.

© Michael H.

I’ve just attended the Joint Meeting of Ichthyologists and Herpetologists held in Montréal, Canada (by the way, if you are ever thinking of staying at Le Centre Sheraton in Montréal, my advice is to make a wide berth – one of the least-satisfying, over-priced, deliberately scrooging hotels I have ever had the displeasure of occupying).

The conference itself was interesting, if not somewhat tangential to most of the major conservation issues facing fish, amphibians and reptiles in the modern context (it is only fair though to state that it wasn’t a ‘conservation’ conference per se). One thing that did astound me though was an open-microphone presentation by someone from the Oceanário de Lisboa in Portugal who described the €100000 operation to release a very large (> 3.5 m wingspan) manta ray (Manta birostris) from its restrictive enclosure. Yes, you read correctly – €100000 to save one individual manta ray. Not even a threatened species (currently classified as ‘Near Threatened’ on the IUCN Red List), these good people at what I am sure is an excellent aquarium spent more money on one animal than most projects spend on the conservation of entire species.

Have these people not heard of ecological (or ‘conservation’) triage? Similar to medical triage in emergency or wartime situations, ecological triage directs finite resources to those species that require the most attention and have the highest chance of long-term persistence. I’m not sure who coined the term (perhaps Holt & Viney 2001), but the concept has been developed by a number of excellent conservation planning researchers over the last few years to become the cornerstone of modern conservation investment strategies (see Possingham et al. 2002; Hobbs & Kristjanson 2003; Wilson et al. 2007). Ecological triage essentially means that immediate conservation action and resources are directed toward populations that are highly threatened but where the probability of persistence is high. The flip side is that we shouldn’t waste our precious resources either on irrelevant and useless actions like the one described above.

Saving one manta ray would not change the species’ long-term persistence probability – full stop. In an age where conservation action and research are suffering from human apathy and stupidity, surely we can spend our money more wisely. For example, that €100000 could have purchased some primary rain forest somewhere and saved literally thousands of species from extinction. What a waste.

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