Science immortalised in cartoon

1 02 2013

Well, this is a first for me (us).

I’ve never had a paper of ours turned into a cartoon. The illustrious and brilliant ‘First Dog on the Moon‘ (a.k.a. Andrew Marlton) who is chief cartoonist for Australia’s irreverent ‘Crikey‘ online news magazine just parodied our Journal of Animal Ecology paper No need for disease: testing extinction hypotheses for the thylacine using multispecies metamodels that I wrote about a last month here on ConservationBytes.com.

Needless to say, I’m chuffed as a chuffed thing.

Enjoy!

Stripey


Comments : 5 Comments »
Tags: , , , , , , ,
Categories : Australia, conservation, decline, disease, extinction, extinction vortex, habitat loss, harvest, kangaroo, population dynamics, population viability analysis, PVA

Having more tree species makes us wealthier

28 01 2013

money treeAs more and more empirical evidence pours in from all corners of the globe, we can only draw one conclusion about the crude measure of species richness (i.e., number of species) – having more species around makes us richer.

And I’m not talking about the esoteric or ‘spiritual’ richness that the hippies dribble about around the campfire after a few dozen cones pulled off the bong (I’ll let the confused among you try to work the meaning of that one out by yourselves), I’m talking about real money (incorporated into my concept of ‘biowealth‘).

The idea that ‘more is better’ in terms of the number of species has traditionally found some (at times, conflicting) empirical support in the plant ecology literature, the latest evidence about which I wrote last year. This, the so-called ‘diversity-productivity’ relationship (DPR), demonstrates that as a forest or grass ecosystem gains more species, its average or total biomass production increases.

Read the rest of this entry »


Comments : 6 Comments »
Tags: , , , , , , , , , , , , ,
Categories : biosequestration, carbon, climate change, conservation, ecosystem function, ecosystem services, extinction, harvest, logging, modelling

Scaring our children with the future

21 01 2013

frightened childI’ve written before about how we should all be substantially more concerned about the future than what we as a society appear to be. Climate disruption is society’s enemy number one, especially considering that:

  1. all this unprecedented warming is happening on a template of highly degraded land- and seascapes. Extinction synergies (more extinctions than would otherwise be predicted by the simple sum of the different pressures) mean that climate change exacerbates the extinctions to which we are already committed;
  2. we show no sign of slowing emissions rates, partly because of the world’s ridiculous refusal to embrace the only known energy technology that can safely meet emissions-reduction requirements: nuclear power;
  3. there are 7 billion hungry, greedy humans on planet Earth, and that number is growing;
  4. scientific evidence denial, plutocracy and theocracy are all on the rise, meaning that logical, evidence-based decision making is being progressively tossed out the window.

That’s probably the most succinct way that I know of describing the mess we are in, which is why I tend to be more of a pragmatic pessimist when it comes to the future. I’ve discussed before how this outlook makes getting on with my job even more important – if I can’t reduce the rate of destruction and give my family a slightly better future in spite of this reality, at least I will damn well die trying. Read the rest of this entry »


Comments : 24 Comments »
Tags: , , , , , , ,
Categories : Australia, climate change, conservation, environmental policy, extinction, science, synergies

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 »


Comments : 4 Comments »
Tags: , , , , , , , , , , , , , , , ,
Categories : Allee effect, connectivity, conservation, disease, extinction, fish, genetic diversity, genetics, inbreeding depression, introgression, management, metapopulation, minimum viable population, threatened species

No need for disease

7 01 2013

dead or alive thylacineIt’s human nature to abhor admitting an error, and I’d wager that it’s even harder for the average person (psycho- and sociopaths perhaps excepted) to admit being a bastard responsible for the demise of someone, or something else. Examples abound. Think of much of society’s unwillingness to accept responsibility for global climate disruption (how could my trips to work and occasional holiday flight be killing people on the other side of the planet?). Or, how about fishers refusing to believe that they could be responsible for reductions in fish stocks? After all, killing fish couldn’t possibly …er, kill fish? Another one is that bastion of reverse racism maintaining that ancient or traditionally living peoples (‘noble savages’) could never have wiped out other species.

If you’re a rational person driven by evidence rather than hearsay, vested interest or faith, then the above examples probably sound ridiculous. But rest assured, millions of people adhere to these points of view because of the phenomenon mentioned in the first sentence above. With this background then, I introduce a paper that’s almost available online (i.e., we have the DOI, but the online version is yet to appear). Produced by our extremely clever post-doc, Tom Prowse, the paper is entitled: No need for disease: testing extinction hypotheses for the thylacine using multispecies metamodels, and will soon appear in Journal of Animal Ecology.

Of course, I am biased being a co-author, but I think this paper really demonstrates the amazing power of retrospective multi-species systems modelling to provide insight into phenomena that are impossible to test empirically – i.e., questions of prehistoric (and in some cases, even data-poor historic) ecological change. The megafauna die-off controversy is one we’ve covered before here on ConservationBytes.com, and this is a related issue with respect to a charismatic extinction in Australia’s recent history – the loss of the Tasmanian thylacine (‘tiger’, ‘wolf’ or whatever inappropriate eutherian epithet one unfortunately chooses to apply). Read the rest of this entry »


Comments : 8 Comments »
Tags: , , , , , , , , , , , , , ,
Categories : Australia, conservation, decline, deforestation, exploitation, extinction, function, habitat loss, harvest, livestock, mammal, modelling, population dynamics, population viability analysis, predator, PVA, synergies

The biggest go first

11 12 2012
© James Cameron

© James Cameron

The saying “it isn’t rocket science” is a common cliché in English to state, rather sarcastically, that something isn’t that difficult (with the implication that the person complaining about it, well, shouldn’t). But I really think we should change the saying to “it isn’t ecology”, for ecology is perhaps one of the most complex disciplines in science (whereas rocket science is just ‘complicated’). One of our main goals is to predict how ecosystems will respond to change, yet what we’re trying to simplify when predicting is the interactions of millions of species and individuals, all responding to each other and to their outside environment. It becomes quickly evident that we’re dealing with a system of chaos. Rocket science is following recipes in comparison.

Because of this complexity, ecology is a discipline plagued by a lack of generalities. Few, if any, ecological laws exist. However, we do have an abundance of rules of thumb that mostly apply in most systems. I’ve written about a few of them here on ConservationBytes.com, such as the effect of habitat patch size on species diversity, the importance of predators for maintaining ecosystem stability, and that low genetic diversity doesn’t exactly help your chances of persisting. Another big one is, of course, that in an era of rapid change, big things tend to (but not always – there’s that lovely complexity again) drop off the perch before smaller things do.

The prevailing wisdom is that big species have slower life history rates (reproduction, age at first breeding, growth, etc.), and so cannot replace themselves fast enough when the pace of their environment’s change is too high. Small, rapidly reproducing species, on the other hand, can compensate for higher mortality rates and hold on (better) through the disturbance. Read the rest of this entry »


Comments : 5 Comments »
Tags: , , , , ,
Categories : alien species, Australia, biodiversity, climate change, conservation, decline, deforestation, disease, ecology, ecosystem function, exploitation, extinction, fisheries, fragmentation, genetic diversity, genetics, habitat loss, harvest, logging, rain forests, synergies

Improving the Roundtable on Sustainable Palm Oil

23 11 2012

RSPO – don’t be guilty of this

Laurance & Pimm organise another excellent tropical conservation open-letter initiative. This follows our 2010 paper (Improving the performance of the Roundtable on Sustainable Oil Palm for nature conservation) in Conservation Biology.

—

Scientists Statement on the Roundtable on Sustainable Palm Oil’s Draft Revised Principles and Criteria for Public Consultation – November 2012

As leading scientists with prominent academic and research institutions around the world, we write to encourage the Roundtable on Sustainable Palm Oil (RSPO) to use this review of the RSPO Principles and Criteria as an opportunity to ensure that RSPO-certified sustainable palm oil is grown in a manner that protects tropical forests and the health of our planet. We applaud the RSPO for having strong social and environmental standards, but palm oil cannot be considered sustainable without also having greenhouse gas standards. Nor can it be considered sustainable if it drives species to extinction.

Tropical forests are critical ecosystems that must be conserved. They are home to millions of plant and animal species, are essential for local water-cycling, and store vast amounts of carbon. When they are cleared, biodiversity is lost and the carbon is released into the atmosphere as carbon dioxide, a greenhouse gas that drives climate change.

Moreover, tropical areas with peat soils store even larger amounts of carbon and when water is drained and the soils exposed, carbon is released into the atmosphere for several decades, driving climate changei. In addition, peat exposed to water in drainage canals may decay anaerobically, producing methane – a greenhouse more potent than carbon dioxide.

Palm oil production continues to increase in the tropics, and in some cases that production is directly driving tropical deforestation and the destruction of peatlandsii. Given the large carbon footprint and irreparable biodiversity loss such palm oil production cannot be considered sustainable. Read the rest of this entry »


Comments : 4 Comments »
Tags: , , , , , ,
Categories : agriculture, biodiversity, cartoon, climate change, conservation, conservation scholars, deforestation, extinction, food, fragmentation, habitat loss, oil palm, palm oil, rain forests, tropical

Protected areas work, but only when you put in the effort

15 11 2012

Apologies for the delay in getting this latest post out. If you read my last one, you’ll know that I’ve been in the United Kingdom for the last week. I’m writing this entry in the train down from York to Heathrow, from which I’ll shortly begin the gruelling 30-hour trip home to Adelaide.

Eight days on the other side of the planet is a bit of a cyclonic trip, but I can honestly say that it was entirely worth it. My first port of call was London where I attended the Zoological Society of London’s Protected Areas Symposium, which is the main topic on which I’ll elaborate shortly.

But I also visited my friend and colleague, Dr. Kate Parr at the University of Liverpool, where I also had the pleasure of talking with Rob Marrs and Mike Begon. Liverpool was also where I first observed the habits of a peculiar, yet extremely common species – the greater flabby, orange-skinned, mini-skirted, black-eyed scouser. Fascinating.

I then had the privilege and serendipitous indulgence of visiting the beautiful and quaint city of York where I gave another talk to the Environment Department at the University of York. My host, Dr. Kate Arnold was simply lovely, and I got to speak with a host of other very clever people including Callum Roberts, Phil Platts, Andy Marshall and Murray Rudd. Between the chats and real ales, mushy peas, pork pies and visits to the Minster, I was in north English heaven.

Enough of the cultural compliments – the title of this post was the take-home message of the ZSL symposium. There I gave a 25-minute talk summarising our recent paper on the performance of tropical protected areas around the globe, and added a few extra analyses in the process. One interesting result that was missing from the original paper was the country-level characteristics that explain variation in protected area ‘health’ (as we defined it in the Nature paper). After looking at a number of potential drives, including per-capita wealth, governance quality, environmental performance, human population density and the proportion of high conservation-value protected areas (IUCN Ia, Ib, II and IV categories), it came out that at least at that coarse country scale that only the proportion of high conservation-value protected areas explained any additional variation in health. In other words, the more category Ia, Ib, II and IV protected areas a country has (relative to the total), the better their protected areas do on average (and remember, we’re talking largely about developing and tropical nations here). Read the rest of this entry »


Comments : 7 Comments »
Tags: , , , , , , , , ,
Categories : biodiversity, conference, conservation, decline, deforestation, environmental policy, extinction, governance, habitat loss, harvest, logging, management, planning, protected area, tropical

The Biodiversity Club

11 10 2012

The International Union for Conservation of Nature (IUCN) Red List of Threatened Species uses 5 quantitative criteria to allocate species to 9 categories of extinction risk. The criteria are based on ecological theory (1, 2), and are therefore subject to modification and critique. With pros and cons (3-6), and intrigues (7, 8), the list has established itself as an important tool for assessing the state of biodiversity globally and, more recently, regionally.

—

We all carry codes of some sort; that is, unique alphanumeric labels identifying our membership in a collectivity. Some of those codes (e.g., a videoclub customer number) make sense only locally, some do internationally (e.g., passport number). Species are also members of the club of biodiversity and, by virtue of our modern concern for their conservation, the status of many taxa has been allocated to alphanumeric categories under different rationales such as extinction risk or trading schemes (5, 9-13). Contradiction emerges when taxa might be threatened locally but not internationally, or vice versa.

In the journal Biological Conservation, a recent paper (14) has echoed the problem for the seagrass Zostera muelleri. This marine phanerogam occurs in Australia, New Zealand and Papua New Guinea, and is listed as “Least Concern” (LC) with “Stable” population trend by the IUCN. Matheson et al. (14) stated that such status neglects the “substantial loss” of seagrass habitats in New Zealand, and that the attribution of “prolific seed production” to the species reflects the IUCN assessment bias towards Australian populations. The IUCN Seagrass Red List Authority, Fred Short, responded (15) that IUCN species ratings indicate global status (i.e., not representative for individual countries) and that, based on available quantitative data and expert opinion, the declines of Z. muelleri are localised and offset by stable or expanding populations throughout its range. Read the rest of this entry »


Comments : 1 Comment »
Tags: , ,
Categories : algae, biodiversity, conservation, environmental policy, extinction, habitat loss, IUCN, Red List, threatened species

Tropical protected areas still in trouble

8 10 2012

© P. Harris

There’s nothing like a bit of good, intelligent and respectful debate in science.

After the publication in Nature of our paper on tropical protected areas (Averting biodiversity collapse in tropical forest protected areas), some interesting discussion has ensued regarding some of our assumptions and validations.

As is their wont, Nature declined to publish these comments (and our responses) in the journal itself, but the new commenting feature at Nature.com allowed the exchange to be published online with the paper. Cognisant that probably few people will read this exchange, Bill Laurance and I decided to reproduce them here in full for your intellectual pleasure. Any further comments? We’d be keen to hear them.

—

COMMENT #1 (by Hari Sridhar of the Centre for Ecological Sciences at the Indian Institute of Science in Bangalore)

In this paper, Laurance and co-authors have tapped the expert opinions of ‘veteran field biologists and environmental scientists’ to understand the health of protected areas in the tropics worldwide. This is a novel and interesting approach and the dataset they have gathered is very impressive. Given that expert opinion can be subject to all kinds of biases and errors, it is crucial to demonstrate that expert opinion matches empirical reality. While the authors have tried to do this by comparing their results with empirical time-series datasets, I argue that their comparison does not serve the purpose of an independent validation.

Using 59 available time-series datasets from 37 sources (journal papers, books, reports etc.), the authors find a fairly good match between expert opinion and empirical data (in 51/59 cases, expert opinion matched empirically-derived trend). For this comparison to serve as an independent validation, it is crucial that the experts were unaware of the empirical trends at the time of the interviews. However, this is unlikely to be true because, in most cases, the experts themselves were involved in the collection of the time-series datasets (at least 43/59 to my knowledge, from a scan of references in Supplementary Table 1). In other words, the same experts whose opinions were being validated were involved in collection of the data used for validation.

—

OUR RESPONSE (William F. Laurance, Corey J. A. Bradshaw, Susan G. Laurance)

Sridhar raises a relevant point but one that, on careful examination, does not weaken our validation analysis. Read the rest of this entry »


Comments : 2 Comments »
Tags: , , , , , , ,
Categories : biodiversity, bushmeat, conservation, decline, deforestation, environmental policy, exploitation, extinction, fragmentation, governance, habitat loss, harvest, invasive species, logging, management, protected area, rain forests, science, South America, South East Asia, threatened species

No-extinction targets are destined to fail

21 09 2012

I’ve been meaning to write about this for a while, and now finally I have been given the opportunity to put my ideas ‘down on paper’ (seems like a bit of an old-fashioned expression these days). Now this post might strike some as overly parochial because it concerns the state in which I live, but the concept applies to every jurisdiction that passes laws designed to protect biodiversity. So please look beyond my navel and place the example within your own specific context.

As CB readers will appreciate, I am firmly in support of the application of conservation triage – that is, the intelligent, objective and realistic way of attributing finite resources to minimise extinctions for the greatest number of (‘important’) species. Note that deciding which species are ‘important’ is the only fly in the unguent here, with ‘importance’ being defined inter alia as having a large range (to encompass many other species simultaneously), having an important ecological function or ecosystem service, representing rare genotypes, or being iconic (such that people become interested in investing to offset extinction.

But without getting into the specifics of triage per se, a related issue is how we set environmental policy targets. While it’s a lovely, utopian pipe dream that somehow our consumptive 7-billion-and-growing human population will somehow retract its massive ecological footprint and be able to save all species from extinction, we all know that this is irrevocably  fantastical.

So when legislation is passed that is clearly unattainable, why do we accept it as realistic? My case in point is South Australia’s ‘No Species Loss Strategy‘ (you can download the entire 7.3 Mb document here) that aims to

“…lose no more species in South Australia, whether they be on land, in rivers, creeks, lakes and estuaries or in the sea.”

When I first learned of the Strategy, I instantly thought to myself that while the aims are laudable, and many of the actions proposed are good ones, the entire policy is rendered toothless by the small issue of being impossible. Read the rest of this entry »


Comments : 11 Comments »
Tags: , , , , , , ,
Categories : Australia, biodiversity, conservation, conservation biology, deforestation, ecosystem function, ecosystem services, environmental policy, extinction, extinction debt, function, genetic diversity, habitat loss, human overpopulation, management, monitoring, planning, prioritisation, reforestation, South Australia

You’re not even remotely concerned enough

31 08 2012

I’ve just returned from a 6-week trip to the United States and I am now dealing with the intensity of things left undone for so long [sigh]. But that trip was interesting for many reasons. First, and as I’ve already posted, I finished a book with Paul Ehrlich that will be out sometime early in 2013 (but I won’t deal with that here). I also attended an interesting, if slightly confusing, conference on ecosystem services. And finally, I had the pleasure of meeting Tony Barnosky in person, and we decided that we should definitely collaborate on a few things.

Another thing that struck me – and this happens no matter how often I visit the U.S., is just how completely insane that country’s politics are. The extremist, libertarian, plutotheocratic bullshit spewed by the far right to the detriment of the very people who support them is enough to make you vomit. And this startling and thoroughly backward world-view is now starting to penetrate more and more into Australian society and politics. From an environmental perspective, it’s a continuation of a downhill slide that started with Reagan’s destruction of environmentalism in the U.S., and Joh Bjelke-Petersen‘s war on the environment in Australia, and will only continue to get worse.

Of course, the main victim of reason in all these polemic politics is that we are doing next to nothing to mitigate horrendous climate disruption. Only yesterday, George Monbiot was lamenting (nay, pleading) that our governments are doing practically nil to avoid what can only be described as the greatest threat to our way of life since the World War II – in fact, the War and its associated holocaust is small bikkies compared to what awaits us.

And this is the most stressing part – even people who choose to use their brains and accept that we have an immense, global problem on our hands generally are not even remotely concerned enough. Read the rest of this entry »


Comments : 15 Comments »
Tags: , , , , , ,
Categories : anthropocene, Australia, climate change, climate shift, conservation, environmental policy, extinction, extremism, poverty, USA

Empty seas coming to a shore near you

12 07 2012

Last week I had the pleasure of entertaining some old friends and colleagues for a writing workshop in Adelaide (don’t worry – they all came from southern Australia locations, so no massive carbon footprints for overseas travel). I’m happy to report it was a productive (and epicurean) week, but that’s not really the point of today’s post.

One of those participants was long-time colleague, Dr. Rik Buckworth. Rik and I first met in Darwin back in the early 2000s when he was lead fisheries scientist for Northern Territory Fisheries; this collaboration and friendship blossomed into an ARC Linkage Project (with Dr. Mark Meekan of AIMS) on shark fisheries (see some of the scientific outputs from that here, here, here and here). Rik has since moved to CSIRO in Brisbane, but keeps a hand in NT fisheries’ affairs. Incidentally, Rik trained under one of the most well-known fisheries modellers in the world – Carl Walters – when he did his PhD at the University of British Columbia back in the early 1990s.

During our workshop, Rik pointed out a paper he had co-authored back in 2009 in Reviews in Fish Biology and Fisheries that had completely escaped my attention – it’s a frightening and apocalyptic view of the Australasian marine tropics that seems to confirm our predictions about northern Australia’s marine future. Just take a look at the following two figures from their paper (Elasmobranchs in southern Indonesian fisheries: the fisheries, the status of the stocks and management options): Read the rest of this entry »


Comments : Leave a Comment »
Tags: , , , , , , , , , , , , ,
Categories : Australia, biodiversity, China, conservation, decline, exploitation, extinction, fish, fisheries, food, harvest, illegal fishing, Indonesia, IUU fishing, predator, shark, tropical

Ghost extinctions

5 07 2012

The Philippine bare-backed fruit bat (Dobsonia chapmani; body size = < 220 mm, < 150 g; IUCN status: ‘Critically Endangered A2cd’) is endemic to lowland rain forests [top habitat image] from Negros and Cebu islands. This species of flying fox had been missing from the 1970s and was declared extinct in 2002 (34). In May 2003, five specimens [one shown in the picture above] were trapped in night nets in the Calatong forest (Negros Island), a ~ 1,000-ha fragment of secondary rain forest and agricultural lands [bottom habitat image] (35). The species is reliant on fruit-bearing vegetation and caves for feeding and roosting, respectively. As with many other Philippine bats, it suffers from habitat degradation and hunting. The family Pteropodidae comprises > 150 species. Despite their Draculian look, they all feed on fruits and nectar, and act as important plant pollinators (36), as well as disease vectors such as Ebola virus (37). Flying foxes are distributed in the tropics and subtropics from the Eastern Mediterranean, through the Arabian Peninsula, Asia, Australia, and many islands of the Indian Ocean. Photos courtesy of Ely L. Alcala.

Jared Diamond (1) coined the expression ‘evil quartet’ for the four main human causes of species extinctions: habitat loss/fragmentation, overkill, introduced species and extinction chains [with climate change and extinction synergies (2), the updated expression would be ‘evil sextet”]. However, one third of ‘extinct’ mammal species has been ‘found’ again. Recent studies reveal that the probability of rediscovery depends on the cause of extinction.

Arriving in a city to search for an old friend, I would first look in the suburb where he lived, the pub where we enjoyed a drink and some music, or the park where we used to play football. But if my friend was an outlaw, or had recently gone through a traumatic experience, my chances of finding him at his favourite spots would shrink.

If, instead of a friend, we are searching for the last survivors of an extinct-declared species, surveys also tend to take place in the habitat in which the species was previously found. Such a strategy rests on the classical hypothesis that, given the spatial distribution of a species, its gradual decline must occur from the periphery to the core of its distribution (‘range collapse’) where, in theory, the habitat should be of better quality and the number of individuals higher (3). In contrast, recent work supports that the trajectory of demise of threatened vertebrates progresses from the core to the periphery (‘range eclipse’) (4), because many perturbations make their way as a progressive wave, e.g, fire, logging or urbanisation.

Diana Fisher (5) supports the ‘range eclipse’ hypothesis for ‘extinct’ mammals which have been rediscovered. She quantifies that 60% of the new records are made from peripheral habitats, mainly when the principal cause of extirpation is habitat loss. Not only that, on average species are rediscovered at altitudes 35 % higher than historical records, and only in 5 % of the cases at the locality where it had been last seen.

Read the rest of this entry »


Comments : 1 Comment »
Tags: , , , , , , , ,
Categories : Australia, biodiversity, climate change, conservation, decline, extinction, habitat loss, species-area curve

It couldn’t have been us!

29 05 2012

A few months ago I asked Chris Johnson of the University of Tasmania to put together a post on his recent Science paper regarding Australian megafaunal extinctions. It seems that it stirred, yet again, some controversy among those who refuse to accept (mainly archaeologists) that humans could have had anything to do with pre-European extinctions. Indeed, how could humans possibly have anything to do with extinctions?!

—

Like Corey, I am mainly interested in current environmental problems. But now and then I wade into the debate over the extinction of Australia’s Pleistocene megafauna [editor’s note: Chris literally wrote the book on Australian mammal extinctions over the last 50,000 years], those huge animals that wandered over the Australian landscape until about 40,000 years ago.

This is an endlessly fascinating topic. The creatures were wonderful and bizarre – it’s great fun doing work that lets you think about marsupial lions, giant kangaroos, geese bigger than emus, echidnas the size of wombats, and the rest. The cause of their extinction is perhaps the biggest mystery, and the most vexed controversy, in the environmental history of Australia. And for reasons that I will explain in a minute, solving this mystery is profoundly important for our understanding of contemporary Australian ecology.

The latest bit of work on this is a paper that a group of us (including Corey’s close colleague, Barry Brook) published in Science. You can see it here (if you don’t have access to Science, email me for a copy). So far, research on this problem has concentrated on dating fossils to find out when megafauna species went extinct. Several recent studies have found evidence for extinction between 40,000 and 50,000 years ago, which is about when people first came to Australia. But the conclusion that people caused a mass extinction of megafauna has been strenuously criticised, because so far it is based on only a few species with good collections of dates. The critics argue that other species disappeared before humans arrived, maybe in an extended series of extinctions caused by something else, like a deteriorating climate.

This argument over fossils will be with us for a long time. Because finding and dating fossils is such hard, slow work, the fossil record will inevitably give a seriously incomplete picture of what happened. One way around this problem would be to analyse the fossil record using mathematical approaches that take into account the problem of incomplete sampling. Corey is lead author of a recent paper that introduced a great new set of tools for this, and we are part of a group that is currently assembling a complete database of all recent dates on Australian fossils so that we can analyse them using these tools. Stay tuned for the result. Read the rest of this entry »


Comments : 5 Comments »
Tags: , , , , , ,
Categories : Australia, bushmeat, climate change, conservation, decline, ecosystem function, exploitation, extinction, fire, harvest, invasive species, mammal

Can Australia afford the dingo fence?

18 05 2012

I wrote this last night with Euan Ritchie of Deakin University in response to some pretty shoddy journalism that misrepresented my comments (and Euan’s work). Our article appeared first in The Conversation this morning (see original article).

—

We feel we have to set the record straight after some of our (Bradshaw’s) comments were taken grossly out of context, or not considered at all (Ritchie’s). A bubbling kerfuffle in the media over the last week compels us to establish some facts about dingoes in Australia, and more importantly, about how we as a nation choose to manage them.

A small article in the News Ltd. Adelaide Advertiser appeared on 11 May in which one of us (Bradshaw) was quoted as advocating the removal of the dingo fence because it was not “cost effective” (sic). Despite nearly 20 minutes on the telephone explaining to the paper the complexities of feral animal management, the role of dingoes in suppressing feral predators, and the “costs” associated with biodiversity enhancement and feral control, there wasn’t a single mention of any of this background or justification.

Another News Ltd. article denouncing Ritchie’s work on the role of predators in Australian ecosystems appeared in The Weekly Times the day before, to which Ritchie responded in full.

So it’s damage control, and mainly because we want to state categorically that our opinion is ours alone, and not that of our respective universities, schools, institutes or even Biosecurity SA (which some have claimed or insinuated, falsely, that we represent). Biosecurity SA is responsible for, inter alia, the dingo fence in South Australia. Although our opinions differ on its role, we are deeply impressed, grateful and supportive of their work in defending us from biological problems. Read the rest of this entry »


Comments : 15 Comments »
Tags: , , , , , , , ,
Categories : Australia, biodiversity, cat, conservation, dingo, ecosystem function, ecosystem services, environmental policy, extinction, fox, function, harvest, invasive species, livestock, mammal, management, predator, southern Australia, threatened species, trophic cascades

We only have decades…

26 04 2012

… not centuries.

Here’s a little video production The Environment Institute put together that explains some of our lab‘s work and future directions.

—

—

CJA Bradshaw


Comments : 2 Comments »
Tags: , , , , , , , , ,
Categories : anthropocene, Australia, biodiversity, climate change, conservation, ecosystem, ecosystem services, environmental science, extinction, modelling

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 »


Comments : 9 Comments »
Tags: , , , ,
Categories : Australia, biodiversity, connectivity, conservation, deforestation, environmental policy, extinction, fragmentation, habitat loss, island biogeography, metapopulation, minimum viable population, protected area, reforestation, reserve, restoration

Take a leaf from insurance industry’s book

18 04 2012

Just a quick one rehashing today’s media release on the iREDD paper I blogged about a while back. The full, online version is available upon request. Stay tuned for media coverage.

—

A group of environmental scientists say a problem-ridden economic model designed to slow deforestation can be improved by applying key concepts from the insurance industry.

REDD (Reduced Emissions from Deforestation and forest Degradation) is a UN-promoted scheme that allows countries to trade in carbon credits to keep forests intact. It is mainly targeted at developing nations where deforestation and exploitation are a major threat.

In a paper published online in the journal Conservation Letters, ecology researchers from Australia and South Africa argue that REDD projects can suffer from three major problems. They have proposed strengthening the scheme by using insurance policies and premiums, creating a new scheme known as iREDD.

“The idea of paying a nation to protect its forests in exchange for carbon pollution offsets can potentially reduce overall emissions by keeping the trees alive, and ensure a lot of associated biodiversity gets caught up in the conservation process,” says Professor Corey Bradshaw,, Director of Ecological Modelling at the University of Adelaide’s Environment Institute and a senior author of the paper.

“However, there are three main problems with REDD: these are known as leakage, permanence and additionality.” Read the rest of this entry »


Comments : 3 Comments »
Tags: , , ,
Categories : biocarbon, biodiversity, biosequestration, carbon, carbon trading, climate change, deforestation, ecosystem services, environmental policy, extinction, governance, investment, protected area

Tentacles of destruction

5 04 2012

This last post before Easter is something I’ve thought more and more about over the last few years. I wouldn’t have given it much time in the past, but I’m now convinced roads are one of the humanity’s most destructive devices. Let me explain.

Before I had a good grasp of extinction dynamics, I wouldn’t have attributed much import to the role of roads in conservation. I mean, really, a little road here and there (ok, even a major motorway) couldn’t possibly be a problem? It’s mostly habitat destruction itself, right?

Not exactly. With our work on extinction synergies, I eventually came to realise that roads are some of the first portals to the devastation to come. Read the rest of this entry »


Comments : 3 Comments »
Tags: , , , , , ,
Categories : Allee effect, Amazon, connectivity, conservation, deforestation, environmental policy, extinction, fragmentation, habitat loss, logging

« Previous Entries Next Entries »