My interview with Conservation Careers

10 04 2018

IMage-2

The online job-search engine and careers magazine for conservation professionals — Conservation Careers — recently published an interview with me written by Mark Thomas. Mark said that he didn’t mind if I republished the article here.

As we walk through life we sometimes don’t know where our current path will take us. Will it be meaningful, and what steps could we take? Seeking out and talking to people who have walked far ahead of us in a line of work that we are interested in could help shape the next steps we take, and help us not make the same mistakes that could have cost us precious time.

A phrase that I love is “standing on the shoulders of giants” and this conversation has really inspired me — I hope it will do for you as well.

Corey Bradshaw is the Matthew Flinders Fellow in Global Ecology at Flinders University, and author to over 260 hundred peer-reviewed articles. His research is mainly in the area of global-change ecology, and his blog ConservationBytes critiques the science of conservation and has over 11,000 followers. He has written books, and his most recent one ‘The Effective Scientist’ will be published in March (more on this later).

What got you interested in ecology and conservation?

As a child I grew up in British Columbia, Canada, my father was a fur trapper, and we hunted everything we ate (we ate a lot of black bear). My father had lots of dead things around the house and he prepared the skins for the fur market. It was a very consumptive and decidedly non-conservation upbringing.

Ironically, I learnt early in life that some of the biggest impediments to deforestation through logging was the trapping industry, because when you cut down trees nothing that is furry likes to live there. In their own consumptive ways, the hunters were vocal and acted to protect more species possibly than what some dedicated NGOs were able to.

So, at the time, I never fully appreciated it, but not having much exposure to all things urban and the great wide world, and by spending a lot of time out in the bush, I ended up appreciating the conservation of wild things even within that consumptive mind-set. Read the rest of this entry »





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.

 

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 »





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 »





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 »





Four decades of fragmentation

27 09 2017

fragmented

I’ve recently read perhaps the most comprehensive treatise of forest fragmentation research ever compiled, and I personally view this rather readable and succinct review by Bill Laurance and colleagues as something every ecology and conservation student should read.

The ‘Biological Dynamics of Forest Fragments Project‘ (BDFFP) is unquestionably one of the most important landscape-scale experiments ever conceived and implemented, now having run 38 years since its inception in 1979. Indeed, it was way ahead of its time.

Experimental studies in ecology are comparatively rare, namely because it is difficult, expensive, and challenging in the extreme to manipulate entire ecosystems to test specific hypotheses relating to the response of biodiversity to environmental change. Thus, we ecologists tend to rely more on mensurative designs that use existing variation in the landscape (or over time) to infer mechanisms of community change. Of course, such experiments have to be large to be meaningful, which is one reason why the 1000 km2 BDFFP has been so successful as the gold standard for determining the effects of forest fragmentation on biodiversity.

And successful it has been. A quick search for ‘BDFFP’ in the Web of Knowledge database identifies > 40 peer-reviewed articles and a slew of books and book chapters arising from the project, some of which are highly cited classics in conservation ecology (e.g., doi:10.1046/j.1523-1739.2002.01025.x cited > 900 times; doi:10.1073/pnas.2336195100 cited > 200 times; doi:10.1016/j.biocon.2010.09.021 cited > 400 times; and doi:10.1111/j.1461-0248.2009.01294.x cited nearly 600 times). In fact, if we are to claim any ecological ‘laws’ at all, our understanding of fragmentation on biodiversity could be labelled as one of the few, thanks principally to the BDFFP. Read the rest of this entry »





World of urban rangers

2 08 2017

Bridging the gap between an urban population and the wildlife we love.IOE_crowdfunding1_web_16-9-with-logo-C

The world continues to urbanise. According to the Population Reference Bureau, the developed nations of the world are 74% urban, and it is expected that by 2050, 70% of the entire world will be ‘urban’. Besides all the other consequences, people’s connection to nature will become more and more distant. With more people living in concrete jungles, a faster pace of life and a barrage of things competing for their attention, we cannot expect that nature, wildlife protection, ocean sustainability, et cetera will be high on the list of their priorities. Other than when the most sensational of news stories are released, how many of them will even think about wildlife, let alone take any personal steps that would make a difference to its survival?

If these are the people who define consumer behaviour and impact policy decisions, they are the ones who will also unwittingly drive the wildlife-conservation agenda. The conservation sector must therefore make a more concerted effort to connect with city dwellers and to do so, understand the motivations and desires of the greater public.

The good news is that despite the grander evidence against it, people do love animals. As children, we are surrounded by animals. Many of our favourite books, movies, clothes, and toys are associated with animals. Even as adults, 163 million of us have watched a video of a panda clinging to its caretaker, 100 million of us went to see Jungle Book, and 700 million more of us visited zoos last year. Marketers play into our love of animals and use the sympathetic or iconic nature of animals on a massive scale in advertising and branding.

If you threw practicality out the window, the most impactful thing you could do to convert that love of animals into a love of conservation would be to airlift those hundreds of millions of people into the Amazon, Serengeti, or Alaskan wilderness for a week. While the experience wouldn’t make all of them conservationists, it would certainly change the way they thought about the importance of nature.

Given this impossibility, the next best thing is to bring nature to them and entice them to explore more within their own means. Shows like BBC Planet Earth or Wild Kratts do a fantastic job of revealing the awesomeness of nature in a way that most everyone appreciates.

But TV shows are still a passive experience where the viewer takes in what he/she is being shown.

Our work at Internet of Elephants is to supplement this type of programming with games about wildlife that can actively be played every day. Our goal is to get people to think about wildlife for five minutes every day and convert the urban world into wildlife addicts. Read the rest of this entry »





Dangers of the global road-building tsunami

8 06 2017

New roads can be treacherous — even fatal — for wildlife, native forests, and the global environment.

If you don’t believe this, just watch this two-minute video, “Why Roads Are So Dangerous

New roads can also be surprisingly risky for human economies and societies, as shown in this brief video, “Why Roads are Like Pandora’s Box”.

Read the rest of this entry »





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 »






Not 100% renewable, but 0% carbon

5 04 2017

635906686103388841-366754148_perfection1Anyone familiar with this blog and our work on energy issues will not be surprised by my sincere support of nuclear power as the only realistic solution to climate change in the electricity (and possibly transport and industrial heat) arena. I’ve laid my cards on the table in the peer-reviewed literature (e.g., see here, here, here, here, here & here) and the standard media, and I’ve even joined the board of a new environmental NGO that supports nuclear.

And there is hope, despite the ever-increasing human population, rising consumerism, dwindling resources, and the ubiquity of ideologically driven and ethically compromised politicians. I am hopeful for several reasons, including rising safety and reliability standards of modern nuclear technology, the continued momentum of building new fission reactors in many countries, and even the beginnings of real conversations about nuclear power (or at least, the first steps toward this) in countries where nuclear energy is currently banned (e.g., Australia). I’m also heartened by the fact that nearly every conservation scientists with whom I speak is generally supportive, or at least non-resistant, to the idea of nuclear power as part of the climate change solution. An open letter by our colleagues attests to this. In fact, every day that passes brings new evidence that we cannot ignore this solution any longer.

Even despite the evidence in support of implementing a strong nuclear component into climate change-mitigation strategies, one of the most frequent arguments for not doing so is that society can achieve all of its energy needs and simultaneously combat climate change by constructing 100% renewable-energy pathways. While it is an easy mantra to repeat because it feels right intrinsically to nearly everyone with an environmental conscience, as a scientist I also had to ask if such a monumental task is even technically feasible. Read the rest of this entry »





Limited nursery replenishment in coral reefs

27 03 2017
Haemulon sciurus

blue-striped grunt (Haemulon sciurus)

Coral reef fishes are wonderfully diverse in size, form, and function, as well as their need for different habitats throughout the life cycle. Some species spend all of their life in the same kind of coral habitat, while others need different places to breed and feed.

Fishes requiring different habitats as they progress through life often have what we call ‘nurseries’ in which adults lay eggs and the subsequent juveniles remain, and these places are often dominated by mangroves or seagrasses (i.e., they are not part of the coral reef).

While we’ve known for quite some time that when these nursery habitats are not around, adjacent coral reefs have few, if any, of these nursery-dependent species. What we haven’t known until now is just how far the influence of nurseries extends along a coral reef.

In other words, if a nursery is present, just how many new recruits do different areas of a reef receive from it? Read the rest of this entry »





Not all wetlands are created equal

13 02 2017

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

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

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





The Evidence Strikes Back — What Works 2017

16 01 2017
Bat gantry on the A590, Cumbria, UK. Photo credit: Anna Berthinussen

Bat gantry on the A590, Cumbria, UK. Photo credit: Anna Berthinussen

Tired of living in a world where you’re constrained by inconvenient truths, irritating evidence and incommodious facts? 2016 must have been great for you. But in conservation, the fight against the ‘post-truth’ world is getting a little extra ammunition this year, as the Conservation Evidence project launches its updated book ‘What Works in Conservation 2017’.

Conservation Evidence, as many readers of this blog will know, is the brainchild of conservation heavyweight Professor Bill Sutherland, based at Cambridge University in the UK. Like all the best ideas, the Conservation Evidence project is at once staggeringly simple and breathtakingly ambitious — to list every conservation intervention ever cooked up around the world, and see how well, in the cold light of evidence, they actually worked. The project is ongoing, with new chapters of evidence added every year grouped by taxa, habitat or topic — all available for free on www.conservationevidence.com.

What Works in Conservation’ is a book that summarises the key findings from the Conservation Evidence website, and presents them in a simple, clear format, with links to where more information can be found on each topic. Experts (some of us still listen to them, Michael) review the evidence and score every intervention for its effectiveness, the certainty of the evidence and any harmful side effects, placing each intervention into a colour coded category from ‘beneficial’ to ‘likely to be ineffective or harmful.’ The last ‘What Works’ book included chapters on birds, bats, amphibians, soil fertility, natural pest control, some aspects of freshwater invasives and farmland conservation in Europe; new for 2017 is a chapter on forests and more species added to freshwater invasives. Read the rest of this entry »





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 »





Potential conservation nightmare unfolding in South Africa

31 10 2016

fees-must-fallLike most local tragedies, it seems to take some time before the news really grabs the overseas audience by the proverbial goolies. That said, I’m gobsmacked that the education tragedy unfolding in South Africa since late 2015 is only now starting to be appreciated by the rest of the academic world.

You might have seen the recent Nature post on the issue, and I do invite you to read that if all this comes as news to you. I suppose I had the ‘advantage’ of getting to know a little bit more about what is happening after talking to many South African academics in the Kruger in September. In a word, the situation is dire.

We’re probably witnessing a second Zimbabwe in action, with the near-complete meltdown of science capacity in South Africa as a now very real possibility. Whatever your take on the causes, justification, politics, racism, or other motivation underlying it all, the world’s conservation biologists should be very, very worried indeed.

Read the rest of this entry »





Inexorable rise of human population pressures in Africa

31 08 2016
© Nick Brandt

© Nick Brandt

I’ve been a bit mad preparing for an upcoming conference, so I haven’t had a lot of time lately to blog about interesting developments in the conservation world. However, it struck me today that my preparations provide ideal material for a post about the future of Africa’s biodiversity.

I’ve been lucky enough to be invited to the University of Pretoria Mammal Research Unit‘s 50th Anniversary Celebration conference to be held from 12-16 September this year in Kruger National Park. Not only will this be my first time to Africa (I know — it has taken me far too long), the conference will itself be in one of the world’s best-known protected areas.

While decidedly fortunate to be invited, I am a bit intimidated by the line-up of big brains that will be attending, and of the fact that I know next to bugger all about African mammals (in a conservation science sense, of course). Still, apparently my insight as an outsider and ‘global’ thinker might be useful, so I’ve been hard at it the last few weeks planning my talk and doing some rather interesting analyses. I want to share some of these with you now beforehand, although I won’t likely give away the big prize until after I return to Australia.

I’ve been asked to talk about human population pressures on (southern) African mammal species, which might seem simple enough until you start to delve into the complexities of just how human populations affect wildlife. It’s simply from the perspective that human changes to the environment (e.g., deforestation, agricultural expansion, hunting, climate change, etc.) do cause species to dwindle and become extinct faster than they otherwise would (hence the entire field of conservation science). However, it’s another thing entirely to attempt to predict what might happen decades or centuries down the track. Read the rest of this entry »





Seeing the wood for the trees

11 07 2016
The Forest Synopsis: Photo of the Anamalai Tiger Reserve, India, by Claire Wordley

The Forest Synopsis: Photo of the Anamalai Tiger Reserve, India, by Claire Wordley

From the towering kapoks of South America to the sprawling banyans of South Asia, from misty cloud forests to ice-covered pines, forests are some of the most diverse and important ecosystems on Earth. However, as conservationists and foresters try to manage, conserve and restore forests across the world, they often rely on scanty and scattered information to inform their decisions, or indeed, no information at all. This could all change.

This week sees the launch of the Forest Synopsis from Conservation Evidence, a free resource collating global scientific evidence on a wide range of conservation-related actions. These aim to include all interventions that conservationists and foresters are likely to use, such as changing fire regimes, legally protecting forests or encouraging seed-dispersing birds into degraded forests.

Making conservation work

“We hear a lot about how important it is to do evidence-based conservation”, says Professor Bill Sutherland at the University of Cambridge, UK, “but in reality getting a handle on what works is not easy. That’s why we set up Conservation Evidence, to break down the barriers between conservationists and the scientific evidence that they need to do their jobs.” Read the rest of this entry »





Sensitive numbers

22 03 2016
toondoo.com

A sensitive parameter

You couldn’t really do ecology if you didn’t know how to construct even the most basic mathematical model — even a simple regression is a model (the non-random relationship of some variable to another). The good thing about even these simple models is that it is fairly straightforward to interpret the ‘strength’ of the relationship, in other words, how much variation in one thing can be explained by variation in another. Provided the relationship is real (not random), and provided there is at least some indirect causation implied (i.e., it is not just a spurious coincidence), then there are many simple statistics that quantify this strength — in the case of our simple regression, the coefficient of determination (R2) statistic is a usually a good approximation of this.

In the case of more complex multivariate correlation models, then sometimes the coefficient of determination is insufficient, in which case you might need to rely on statistics such as the proportion of deviance explained, or the marginal and/or conditional variance explained.

When you go beyond this correlative model approach and start constructing more mechanistic models that emulate ecological phenomena from the bottom-up, things get a little more complicated when it comes to quantifying the strength of relationships. Perhaps the most well-known category of such mechanistic models is the humble population viability analysis, abbreviated to PVA§.

Let’s take the simple case of a four-parameter population model we could use to project population size over the next 10 years for an endangered species that we’re introducing to a new habitat. We’ll assume that we have the following information: the size of the founding (introduced) population (n), the juvenile survival rate (Sj, proportion juveniles surviving from birth to the first year), the adult survival rate (Sa, the annual rate of surviving adults to year 1 to maximum longevity), and the fertility rate of mature females (m, number of offspring born per female per reproductive cycle). Each one of these parameters has an associated uncertainty (ε) that combines both measurement error and environmental variation.

If we just took the mean value of each of these three demographic rates (survivals and fertility) and project a founding population of = 10 individuals for 1o years into the future, we would have a single, deterministic estimate of the average outcome of introducing 10 individuals. As we already know, however, the variability, or stochasticity, is more important than the average outcome, because uncertainty in the parameter values (ε) will mean that a non-negligible number of model iterations will result in the extinction of the introduced population. This is something that most conservationists will obviously want to minimise.

So each time we run an iteration of the model, and generally for each breeding interval (most often 1 year at a time), we choose (based on some random-sampling regime) a different value for each parameter. This will give us a distribution of outcomes after the 10-year projection. Let’s say we did 1000 iterations like this; taking the number of times that the population went extinct over these iterations would provide us with an estimate of the population’s extinction probability over that interval. Of course, we would probably also vary the size of the founding population (say, between 10 and 100), to see at what point the extinction probability became acceptably low for managers (i.e., as close to zero as possible), but not unacceptably high that it would be too laborious or expensive to introduce that many individuals. Read the rest of this entry »





Disadvantages of marine protected areas

29 02 2016

 

 

 

Stop wasting time

Stop wasting time





Biowealth

24 02 2016

frogWhile I’ve blogged about this before in general terms (here and here), I thought it wise to reproduce the (open-access) chapter of the same name published in late 2013 in the unfortunately rather obscure book The Curious Country produced by the Office of the Chief Scientist of Australia. I think it deserves a little more limelight.

As I stepped off the helicopter’s pontoon and into the swamp’s chest-deep, tepid and opaque water, I experienced for the first time what it must feel like to be some other life form’s dinner. As the helicopter flittered away, the last vestiges of that protective blanket of human technological innovation flew away with it.

Two other similarly susceptible, hairless, clawless and fangless Homo sapiens and I were now in the middle of one of the Northern Territory’s largest swamps at the height of the crocodile-nesting season. We were there to collect crocodile eggs for a local crocodile farm that, ironically, has assisted the amazing recovery of the species since its near-extinction in the 1960s. Removing the commercial incentive to hunt wild crocodiles by flooding the international market with scar-free, farmed skins gave the dwindling population a chance to recover.

redwoodConservation scientists like me rejoice at these rare recoveries, while many of our fellow humans ponder why we want to encourage the proliferation of animals that can easily kill and eat us. The problem is, once people put a value on a species, it is usually consigned to one of two states. It either flourishes as do domestic crops, dogs, cats and livestock, or dwindles towards or to extinction. Consider bison, passenger pigeons, crocodiles and caviar sturgeon.

As a conservation scientist, it’s my job not only to document these declines, but to find ways to prevent them. Through careful measurement and experiments, we provide evidence to support smart policy decisions on land and in the sea. We advise on the best way to protect species in reserves, inform hunters and fishers on how to avoid over-harvesting, and demonstrate the ways in which humans benefit from maintaining healthy ecosystems. Read the rest of this entry »