By weird coincidence, Salvador Herrando-Pérez (student blogger extra-ordinaire – see his previous posts on evolution, pollination, bird losses, taxonomic inflation, niche conservatism, historical biogeography, ecological traps and ocean giants) has produced a post this week expanding on the problem of roads. Also weirdly coincidental is that both Salva and I are in his home country of Spain this week.

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Australia’s > 800,000-km road network would go 60 times around the equator of our planet. Confined to the boundaries of any one country, roads are a conspicuous component of the landscape, and shape the dispersion, survival and reproduction of many plants and animals in urban and remote areas.

Those who drive (or are driven by) will be familiar with the image of a crushed kangaroo on the roadside (a hedgehog in Europe), or the sticky mosaic of insects smashed against the windscreen after a high-speed run. Mortality by collision is one of the many effects that roads can have on the demography of organisms – including humans. Those effects encompass

• physical alteration of terrestrial and aquatic habitats,
• chemical pollution leakage during road construction and maintenance, and from asphalt compounds during storms,
• alteration of animal behaviour (e.g., change in home range, or in patterns of flight or vocalisation),
• access to remote areas by hunters, fishermen and gatherers in general, and
• intense habitat fragmentation^1-3.

However, some species get around those negative impacts by using the roads as pathways to new territories, thereby eluding barriers like seas, mountains, rivers, dense vegetation, or competition for vital resources with other species.

Figure 1: Road use by cane toads in the Northern Territory, Australia (2). Top panel: frequency of radio-tracked individuals recorded at different distances to the nearest dirt road (25 to 975 m in 50 m intervals). Bottom panel: frequency of toads with body axis aligned at different angles with the main axis of the Arnhem Highway (0º for toads facing the main axis of the road, to |90|º for toads facing perpendicular to the right or left of the road). Most toads were found within 25 m of dirt roads, and facing -10º to 10º to the highway axis.

Brown and colleagues⁴ illustrate the latter scenario with cane toads (formerly Bufo marinus; now Rhinella marina) in Australia. This species was introduced to Queensland in the 1930s to control (unsuccessfully) insect pests in sugar cane fields⁵. Nowadays, Aussie cane toads outnumber the human population in China, occupy a surface equivalent to 100 million soccer stadia, and only in 2009 crossed the border of Western Australia, > 2,500 km from the release point⁶ [see Rick Shine’s cane toad lab research]. For over 300 nights, Brown et al. radio-tracked 49 adult toads in farmland and eucalyptus forest in the Northern Territory. They found that these animals adjusted their movements to the local network of roads. In half of the records, toads were seen on or near dirt roads, mainly following those portions of the roads in the Northwest direction of progression of the invading front (Figure 1).

With an independent sample, they observed that the body axis of most individuals found near a highway was aligned with the principal axis of the road (Figure 1), giving evidence that the animals were moving relative to the trajectory of the highway. Undoubtedly, roads confer demographic benefits that compensate the > 200 tonnes of toads killed on the roads in (only) Queensland every year.

The invader’s backpack

Among the panoply of exotic species that are detrimental globally outside their native ranges⁷, the fungus Phytophthora lateralis is another self-explanatory example of road-loving biological invasion⁸. Rivers disperse the spores of this fungus. The spores then parasitise the roots of tree species along riverbanks and beyond (i.e., during floods), resulting in fulminating rot of the entire root system. In Oregon and California, spores have spread in most rivers in the mud stuck to vehicles and people’s shoes walking along local dirt roads. The disease was first recorded in the 1920s in Seattle in a plantation of Port Orford cedars (Chamaecyparis lawsoniana). It has since caused massive mortality of juvenile to centenary cedars in the conifer forests of Western USA, and has ruined a multi-million-dollar export of wood and ornamental trees (by means of which the fungus has already reached, at least, Asia and Europe).

Roads also contribute to the spread of insect and plant pests and human diseases^1,3. In the case of cane toads, dirt roads in the Northern Territory might be assisting in the dispersal of their toxicity (arguably the toad’s worst ecological impact⁶), present in all developmental stages (egg, tadpole, toadlet, and adult), especially for adults because toxicity increases with size. Up to 27 species of vertebrates have been reported to die from ingestion of cane toads⁵ – thus, at a population level, it is predictable that the worst ravages will occur in apex predators able to catch larger (and more toxic) toads, such as elapid snakes, varanid lizards, the freshwater crocodile (Crocodylus johnstoni) and quolls (Dasyurus spp.)⁶.

Surely we all want roads that are safe and (as much as possible) benign for biodiversity. Taylor and Goldingay² have recently reviewed the state of the art of published research into roads and wildlife worldwide, with the following highlights:

• studies on large ungulates and carnivores predominate, partly due to rocketing insurance and medical costs after collisions;
• road-crossing structures for wild animals are being widely applied, although population benefits remain poorly understood;
• behavioural avoidance with genetic and metapopulation implications occurs in some species, calling for landscape road planning;
• focused management actions are needed for globally threatened species like amphibians (surely not cane toads),
• poor experimental designs across the board.

It caught my eye that the three reviews I cite^1-3 did not encompass road impacts on subterranean ecosystems⁹ – a dark oasis of living wonders¹⁰ and reservoir of > 30 % (98 % along with glaciers) of available freshwater globally¹¹. Clearly, to those who build roads (from the politician to the engineer), environmental impact assessment should take into account their multiple ecological impacts, and not only along the route itself^2,3.

Next time you hit the road, be aware; you are never alone.

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1. S. C. Trombulak and C. A. Frissell, Conserv Biol 14 (1), 18 (2000) doi:10.1046/j.1523-1739.2000.99084.x
2. B. D. Taylor and R. L. Goldingay, Wildl Res 37 (4), 320 (2010) doi:10.1071/WR09171
3. W. F. Laurance, M. Goosem, and S. G. W. Laurance, Trends Ecol Evol 24 (12), 659 (2009) doi:10.1016/j.tree.2009.06.009
4. G. P. Brown, B. L. Phillips, J. K. Webb et al., Biol Conserv 133 (1), 88 (2006) doi:10.1016/j.biocon.2006.05.020
5. C. Lever, The Cane Toad. The History and Ecology of a Successful Colonist. (Westbury Academic and Scientific Publishing, Otley, UK, 2001)
6. R. Shine, Quart Rev Biol 85 (3), 253 (2010) doi:10.1086/655116
7. S. Lowe, M. Browne, and S. Boudjelas, Aliens 12, S1 (2000)
8. E. M. Hansen, Boreal Environ Res 13, 33 (2008); E. M. Hansen, D. J. Goheen, E. S. Jules et al., Plant Disease 84 (1), 4 (2000) doi:10.1094/PDIS.2000.84.1.4; E. S. Jules, M. J. Kauffman, W. D. Ritts et al., Ecology 83 (11), 3167 (2002)
9. M. Knez and T. Slabe, in Encyclopedia of Caves and Karst Science, edited by J. Gunn (Palgrave Macmillan, London, UK, 2004), pp. 419
10. J. Gibert and L. Deharveng, BioScience 52 (6), 473 (2002) doi:10.1641/0006-3568(2002)052[0473:SEATFB]2.0.CO;2; D. C. Culver and B. Sket, J Cave Karst Stud 62 (1), 11 (2000)
11. D. L. Danielopol, C. Griebler, A. Gunatilaka et al., Environmental Conservation 30 (2), 104 (2003) doi:10.1017/S0376892903000109
12. B. L. Phillips, G. P. Brown, J. K. Webb et al., Nature 439 (7078), 803 (2006) doi:10.1038/439803a
13. N. Sallam, Aust J Entomol 50 (3), 300 (2011) doi:10.1111/j.1440-6055.2010.00807.x

© 2008-2011 ~Hiuki http://fav.me/d1j3ns9

I apologise to CB readers for the unusually low frequency of posts this month. With the International Congress for Conservation Biology taking up a lot of my time earlier this month, and the standard palaver of xmas preparations (i.e., getting shit done before the end of the year), I’m afraid the blog has taken a back seat. Now officially ‘on leave’ (whatever that means for an academic), I have found a brief window during which I can put a few thoughts together.

For this post I must take you back to October 2011 when, if you were in Australia, you might have heard about the so-called ‘debacle‘ of the Macquarie Island rabbit/rate/mouse-eradication programme in which it was identified that a few thousand seabirds had become the collateral damage.

To recap, an intense poisoning programme was initiated on subantarctic Macquarie Island to eradicate these pests after years of massive environmental degradation had finally forced the government’s (of Tasmania and the Commonwealth) hand to do something. What caught my eye in all this was the sheer stupidity and politicking associated with the programme, in which hyper-conservative Eric Abetz (Liberal Senator for Tasmania) managed to turn this amazing success into a Labor-bashing political sledge-hammer.

Abetz is no stranger to anti-environmentalism and fights vehemently for Tasmania’s forest-raping industry; he considers political parties such as the Greens, environmental groups such as The Wilderness Society and pro-democracy groups such as Get Up! his mortal enemies. He’s even had a go at esteemed author Richard Flanagan for supporting the anti-deforestation movement in Tasmania!

His latest regurgitation of spectacularly uninformed and politically motivated, anti-environmental vomit couldn’t have missed the point more on the Macquarie Island feral eradication programme. Most would agree that despite our general failing of biodiversity conservation, conservation biologists have had a fair share of major wins with island pest eradications; indeed, at times it seems the only thing we can get right is killing the baddies we were originally responsible for introducing.

Now, I’m no fan of the Tasmanian legislators and government drones who for years delayed or severely under-appreciated science to inform sound environmental policy when it came to Macquarie Island (indeed, I would go so far as to say that the established environmental autocracy in the Tasmanian government is one of the principal enemies of conservation because of their entrenched anti-science stance), but for once, they finally got around to doing something good with this ~ million-dollar programme.

And I have some history there too – I was stationed on Macquarie Island over 4 years from 1999-2004 during my postdoctoral fellowship, during which time I worked on many aspects of elephant seal population and behavioural ecology (see associated publications here). In my last year there, I was shocked upon my return to the island after an 18-month stint back in mainland Australia about just how much damage the rabbits had done after the last cat had been shot a few years before. I was so moved that I wrote a popular article on the matter to bring it to the public’s attention – you can read that article (published in Australasian Science) here for more background information.

For the ultra-right wing Senator Abetz to turn this success into his own political poisoned arrow is, to be perfectly honest, an environmental crime in its own right. Using the weak argument that some protected species have suffered as a consequence is the classic tool of the so-called ‘environmentalists’ who would rather focus on a single species (or even individual) while the rest of biodiversity melts into extinction (see related post here). We just don’t have time for this nonsense, and this is why we have to consider uncomfortable choices such as triage and controversial energy-generation technology.

I’m not for a moment insinuating that Senator Abetz truly feels for the poor seabirds who had the misfortune of swallowing a bit of poisoned bait in the quest to return their island to its former pristine biodiversity greatness; rather, I think he used the weak and uninformed argument for his own political gains (a double travesty). We have to move past this double-dipped bullshit if we want to make some real gains for biodiversity in Australia.

CJA Bradshaw

The Genesis

A few years ago, a few of us (Bob Lacy, Phil Miller and JP Pollak of Vortex fame, Barry Brook, and a few others) got together in a little room at the Brookfield Zoo in the suburban sprawl of Chicago to have a crack at some new modelling approaches the Vortex crew had recently designed. The original results were pleasing, so we had a follow-up meeting last year (thanks to a few generous Zoo benefactors) and added a few post-docs and students to the mix (Damien Fordham, Clive McMahon, Tom Prowse, Mike Watts, Michelle Verant). The great population modeller Resit Akçakaya also came along to assist and talk about linkages with RAMAS.

Out of that particular meeting a series of projects was spawned, and one of those has now been published online: Novel coupling of individual-based epidemiological and demographic models predicts realistic dynamics of tuberculosis in alien buffalo.

The Coupling

So what’s so novel about modelling disease in buffalo, and why would one care? Well, here’s the interesting part. The buffalo-tuberculosis example was a great way to examine just how well a new suite of models – and their command-centre module – predicted disease dynamics in a wild population. The individual-based population modelling software Vortex has been around for some time, and is now particularly powerful for predicting the extinction risk of small populations; the newest addition to the Vortex family, called Outbreak, is also an individual-based epidemiological model that allows a population of individuals exposed to a pathogen to progress over time (e.g., from susceptible, exposed, infectious, recovered/dead).

The problem was that Vortex and Outbreak generally operated at different time scales, such that you really couldn’t model disease dynamics well within the Vortex population framework, nor could you incorporate the complexities of population dynamics very well in Outbreak. That clever Lacy-Miller-Pollak trio figured out a way of coupling the two via something they called MetaModel Manager (MMM – about which I blogged last year) which could allow the daily step of Outbreak to run effectively within the annual step of Vortex (other breeding cycles are possible within Vortex, of course).

Buffalo-Tuberculosis

Now for the example in question, we wanted to see if we could effectively model the dynamics of tuberculosis in feral swamp buffalo (Bubalus bubalis) in northern Australia. A little background is required here.

Buffalo were introduced to northern Australia in 1826, 1827 and 1843 from Timor-Leste, and subsequently spread rapidly throughout the Northern Territory, growing to ~ 350,000 by the 1970s. Unfortunately, buffalo harboured bovine tuberculosis, which also crossed over readily to commercial cattle livestock. So the government at the time initiated a broad-scale culling programme called the ‘Brucellosis-Tuberculosis Eradication Campaign’ (BTEC) in the 1980s and 1990s. The cull successfully reduced or eradicated buffalo from major pastoral lands in the Northern Territory (taking tuberculosis with it), but since then, no follow-up culling has occurred and the population is re-invading the formerly culled areas. Although Australia now trades its livestock under the ‘TB-free’ banner, the disease is prevalent throughout Africa, southern Europe, the Middle East and parts of Asia, so in many ways, it’s only a matter of time before it rears its ugly head again here. And if it does, it could cost our cattle industry over $10 billion to fix.

The bottom line is that we need tools like Vortex-MMM-Outbreak to plan the optimal culling regimes should TB (or other, nastier diseases like foot-and-mouth) (re-)enter Australia.

The Implications

I won’t go into too many of the finer details of the paper here, although we did find that the population dynamics (especially age at first breeding) most dictated the prevalence of TB in the population – not the characteristics of the disease itself (e.g., transmission probability, incubation time, contact rate, etc.). This has HUGE implications for wildlife disease modelling in general; if one fails to incorporate the dynamics of the population in gory detail, chances are the predictions relating to the disease itself will be erroneous.

Second, we found that the probability of detecting a disease as well-known as TB was vanishingly small, such that current monitoring programmes in northern Australia done by the Northern Australia Quarantine Strategy (NAQS), a division of the Australian Quarantine and Inspection Service (AQIS), are woefully inadequate for monitoring wildlife disease in our vast northern regions.

Third, we found that if the goal was to reduce prevalence to near-zero, somewhere between 30 and 50 % of the population would have to be culled each year for about 15 years. That’s a lot of buffalo.

Now, those are really the ‘meat’ results of the paper, but I do want to re-iterate that it’s the software coupling itself that’s the most novel. In fact, part of the review process required us to model our system using ‘analogous’ software for comparison. The problem is, there just simply isn’t any customisable software out there that can do what Vortex-MMM-Outbreak can. And the best part is, it’s all free.

Yes, you can download all the software here:

1. Vortex
2. Outbreak
3. MetaModel Manager (64-bit here)

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The reasons for the decline of Australia’s unique biodiversity are many, and most are well known. Clearing of vegetation for urban and agricultural land uses, introduced species and changed fire patterns are regularly cited in State of the Environment reports, recovery plans and published studies as major threats to biodiversity. But, while these threats are widely acknowledged, little has been done to quantify them in terms of the proportion of species affected, or their spatial extent at a national, state or local scale. To understand why such information on threats may be useful, consider for instance how resources are allocated in public health care¹.

Threat knowledge

Conditions such as cancer, heart disease and mental health are regarded as National Health Priority Areas in Australia, and have been given special attention when prioritising funds since the late 1980s. The burden of disease in these priority areas are quantified according to the incidence or prevalence of disease or condition, and its social and economic costs. Estimates of burden of disease and their geographic distribution (often according to local government areas) can assist in communicating broad trends in disease burden, but also in prioritising efforts to achieve the best outcomes for public health. An approach similar to that used in healthcare could help to identify priorities for biodiversity conservation – using information on the species which are impacted by key threats, the spatial distributions of species and threats, and the costs of implementing specific management actions to address these threats.

In a study recently published in BioScience¹, we examined in detail the threats reported for threatened species listed under the Environmental Protection and Biodiversity Conservation Act 1999 (EPBC Act). We first calculated the percentage of threatened species affected by eight key threats:

• habitat loss
• introduced species
• inappropriate fire regimes
• disease
• pollution
• overexploitation
• native species interactions, and
• natural causes.

Figure 1. Relative impacts of major threatening processes expressed as the % of extant species threatened, the % of mapped species threatened (subset of extant threatened species for which spatial data were available), and the % of continental area of Australia across which the threat occurs within sub-catchments.

From this we were able to confirm that habitat loss is the most important threat to Australian biodiversity, affecting 81% of threatened species (Figure 1). However, we also found that changes to the natural fire patterns and introduced species threaten proportionally more species in Australia than in other countries including the United States of America, Canada and China.

Reporting on statistics such as these can be useful for making broad comparisons in the relative importance of threats, or to communicate better the dire situation facing Australia’s biodiversity – but the value of such analyses in informing practical efforts to conserve threatened species can be limited. One important reason for this is that the distribution of threats and species vary across the landscape. To become useful in conservation planning, we need to quantify threats spatially.

Which species, where?

To do this, we used species distribution models from the Species of National Environmental Significance database, and matched the listed threats for each species to their corresponding spatial models. From this we determined which of the 62,629 sub-catchments across the Australian continent contained species affected by each threat.

Figure 2. Distribution of the predominant threats to biodiversity across Australia. The ‘predominant threat’ is the threat affecting the greatest number of species in each sub-catchment. Where 2 or more threats affect an equivalent number of species, we assume no predominant threat occurring in these sub-catchments (shades of grey). Darker colours indicate a larger overall number of threats occurring in the sub-catchment. White indicates areas where no threatened species occur.

Our first effort revealed important connections between the distributions of species and threats. For instance, changed fire patterns are a threat to species across almost 90 % of the Australian landscape, but affect less than half of the threatened species. We then calculated the proportion of species affected by each threat contained within each sub-catchment, and subsequently determined the predominant threat in each sub-catchment. From this it became clear that multiple stressors are impacting native biodiversity over much of the continent (Figure 2) – even in regions sparsely populated by humans such as northern Australia.

This means that effective conservation management is critical even in areas considered to be wilderness. Our study has shown that the majority of Australia’s threatened species are affected by multiple pressures (over 75% of species), and these threats are distributed across most of the continent – many of which cannot be eased through the protection of habitat alone⁴. This is an important result – as it means that getting the best outcomes for biodiversity requires a broad understanding of factors to decide best direct conservation efforts: what threats exist, what are the potential benefits of conservation management, what are the most suitable management actions and how much will they cost?

What’s the priority?

The next step in this research is to understand how we can effectively prioritise resources to maximise conservation outcomes where a range of threats to biodiversity exist. We pursued this by developing a multiple-action, return-on-investment framework³. Similar approaches have been used to determine what conservation management actions to do, where and when – but so far, a lack of information on the threats to species and their spatial distributions means that the additional complexity of how to address the impacts of multiple threats on species has not yet been considered.

There are two possible consequences of ignoring the issue of multiple threats: first, the benefits of abating a single threat may be overestimated because species might be threatened by multiple processes; second, the cost of abating two threats in one place might be cheaper than the sum of the costs of abating each threat alone.

We tested our approach by considering two key threats to Australian biodiversity: the red fox and the European rabbit. Some species are threatened only by foxes, some only by rabbits, but some are affected by both – and so require management actions directed at both threats in order to persist. Using spatial data on the distributions of threatened species, and of the two introduced species, we calculated the area within each of Australia’s bioregions requiring management for foxes rabbits, or both. We then tested four return-on-investment frameworks (Figure 3).

Figure 3. Investment into conservation actions at a continental scale for all 72 bioregions, according to our 4 return-on-investment (ROI) frameworks: (a) Two-action-independent ROI, (b) three-action-independent ROI, (c) action-dependent ROI and (d) action-dependent ROI with spatial targeting. Map shows the priority bioregions for investment as indicated by the total percentage of funding for a bioregion summed over all actions, which is shown as low (up to 1%), medium (up to 2%) or high (up to 6%).

The first ignored the presence of more than one threat on threatened species. In this case, it was best to spend the majority of funds over all bioregions (68 %) on rabbit control – as many more species are threatened by rabbits than foxes. Our second method considered species impacted simultaneously by both foxes and rabbits, but ignored the benefits of integrated fox and rabbit control to species affected by only one of the threats. In this case, rabbit control was still the best option (receiving 62 % funds overall).

But when we fully considered the management requirements of species affected by multiple threats, as well as the benefits of integrated management for species only affected by one threat, we found that 96 % of the total funds were allocated to integrated management of foxes and rabbits. In short, fully accounting for the potential to implement integrated management actions that address more than one threat to biodiversity resulted in improved cost efficiencies and better conservation outcomes.

Our final analysis investigated whether detailed information on the spatial overlap of species’ distributions within each bioregion influenced the timing or amount of investment directed to management. For example, a bioregion where species are more densely concentrated than others might provide a greater return with targeted investment in conservation. However, we found that accounting for spatial overlap in the distributions of threatened species did not alter the prioritisation of funds to alternative management actions or locations (Figure 3d).

This suggests that refined data on distributions of threatened species might not improve our ability to determine where and when funding should be directed to conservation actions to mitigate specific threats to biodiversity. Our research suggests that efforts to prioritise conservation investments would be improved by gaining better information on the specific threats impacting on species, the distribution of these threats and the costs of management actions.

In a time when getting conservation outcomes through wise investments is crucial, we should also focus on gaining a greater understanding of the efficiencies gained through integrated management, and the institutional structures that facilitate this.

Megan Evans

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References

¹Mitchell, R. J., R. J. McClure, J. Olivier, and W. L. Watson. 2009. Rational allocation of Australia’s research dollars: does the distribution of NHMRC funding by National Health Priority Area reflect actual disease burden? The Medical Journal of Australia 191:648-652

²Evans, M. C., J. E. M. Watson, R. A. Fuller, O. Venter, S. C. Bennett, P. R. Marsack, and H. P. Possingham. 2011a. The spatial distribution of threats to species in Australia. BioScience 61:281-289. doi:10.1525/bio.2011.61.4.8

³Evans, M. C., H. P. Possingham, and K. A. Wilson. 2011b. What to do in the face of multiple threats? Incorporating dependencies within a return on investment framework for conservation. Diversity and Distributions 17: 437-450. doi:10.1111/j.1472-4642.2011.00747.x

⁴Watson J.E.M., Evans M.C., Carwardine J, Fuller R.A., Joseph L.N., Segan D.B., Taylor M.F.J., Fensham R.J., Possingham H.P. 2011. The capacity of Australia’s protected-area system to represent threatened species. Conservation Biology 25: 324-332. doi:10.1111/j.1523-1739.2010.01587.x

Megan C. Evans, James E. M. Watson, Richard A. Fuller, Oscar Venter, Simon C. Bennett, Peter R. Marsack, & Hugh P. Possingham (2011). The spatial distribution of threats to species in Australia BioScience, 61 (4), 281-289 : 10.1525/bio.2011.61.4.8

This post doubles as a Conservation Classic and a new take on an old concept. It’s new in the sense that it updates what we believe is an advance on a major milestone in conservation biology, even though some of the add-on concepts themselves have been around for a while.

First, the classic.

The ‘evil quartet’, or ‘four horsemen of the ecological apocalypse’, was probably the first treatment of extinction dynamics as a biological discipline in its own right. Jarod Diamond (1984) took a sweeping historical and contemporary view of extinction, then simplified the problem to four principal mechanisms:

1. overhunting (or overexploitation),
2. introduced species,
3. habitat destruction and
4. chains of linked extinctions (trophic cascades, or co-extinctions).

Far from a mere review or list of unrelated mechanisms, Diamond’s evil quartet crystallized conservation biologists’ thinking about key mechanisms and, more importantly, directed attention towards those factors likely to drive extinctions in the future. The unique combination of prehistorical through to modern examples gave conservation biologists a holistic view of extinction dynamics and helped spawn many of the papers described hereafter.It would now appear prudent to add a fifth ghoul to the team - severe anthropogenic interference with the global climate system. The response of biodiversity to past global climate change characteristically unfolded over thousands to millions of years, whereas anthropogenic global warming is now occurring at a greatly accelerated rate. If carbon emissions are not reduced rapidly, the Intergovernmental Panel on Climate Change’s Fourth Assessment Report 2007 projects a rate and magnitude of 21^st Century planetary heating that is 5–9 times greater than that of the past century. This is comparable to the difference between now and the height of the last glacial maximum.

A clear lesson from the past is that the faster and more severe the rate of global change, the more devastating the biological consequences, and as I’ve covered before here on ConservationBytes.com in a separate Conservation Classic, this has seriously negative implications for biodiversity.

Now it’s time though to add a sixth rider – extinction synergies (Brook et al. 2008). For example, exacerbating the problems associated with recent climate change is that species trying to shift distribution must now contend with massively modified landscapes. Even in cases where global warming might allow species to expand their range, these benefits can be outweighed by other threats such as habitat change. The new conditions and altered communities might also allow more invasions by alien species that outcompete native species or act as predators to reduce their populations further. Harvest, habitat modification and changed fire regimes will also interact with and probably enhance the direct impacts of climate change.

In summary, we now appreciate that most extinctions involve a synergy of these factors (Brook et al. 2008), with individual causes being difficult or impossible to isolate. These synergies thus represent a situation where the combined effects are substantially more problematic for biodiversity than the mere sum of their individual effects.

To extend the apocalypse analogy further, it’s as though the horsemen’s orgy of species destruction has finally produced a bastard son far more evil then his vile parents.

We should no longer talk of the ‘evil quartet’ – it is now (at least) the ‘evil sextet’.

CJA Bradshaw (& Navjot Sodhi, William Laurance & Barry Brook)

–

References

• Brook, B.W.; Sodhi, N.S. & Bradshaw, C.J.A. (2008). Synergies among extinction drivers under global change. Trends in Ecology and Evolution 25: 453-460
• Diamond, J.M. (1984). ‘Normal’ extinction of isolated populations In: Extinctions, M.H. Nitecki (Ed.), 191-246, Chicago University Press, Chicago, USA

Before I proceed to regale you with the salient details of the ‘International Symposium for Biodiversity and Theoretical Ecology‘, I am compelled to state publicly that I offer my sincerest condolences to Fangliang and his family; unfortunately Fangliang’s brother passed away while we were at the workshop and so Fangliang wasn’t able to spend much time reaping the fruits of his organisational labour. If you know Fangliang, please send him a supporting email.

That sad note aside, I am delighted to say that the workshop was compelling, challenging and also rather fortuitous. I was one of many overseas invitees, and I must say that I was at times overwhelmed by the size of the brains they managed to pack into the auditorium. Many colleagues I didn’t know attended, and I hope that many will become collaborators. The international invitees were:

• Rob Colwell
• Sean Connolly
• Rampal Etienne
• Alan Hastings
• Subhash Lele
• Brian McGill
• Annette Ostling
• John Spence
• Doug Wu
• Weini Huang

But it wasn’t just a show of us lǎo wài (老外) – there was an abundance of excellent talks by many fine Chinese ecologists (professors, post-docs and students). I am constantly amazed how the Chinese just give it a go in English even though it is an incredible challenge to present good science in a foreign tongue.

So, on to the content. I won’t cover everything, but here are some highlights:

• Alan Hastings, whose work I’ve highlighted before here on ConservationBytes.com, presented some of his work on how regime shifts can arise from apparently simple, relative ‘stable’ dynamics
• Rampal Etienne presented his work on speciation-extinction models from which phylogenies can be simulated. He talked a lot about ‘diversity dependence’, which is something I’d like to model within the Cronus framework
• Sean Connolly talked about lognormal patterns approximate coral and coral fish distributions
• Rob Colwell showed how tropical species wax and wane in response to deep-time climate changes, and the processes underlying the patterns
• Brian McGill presented a new way to model species distributions, something he calls the Gause Liebig biogeographic law
• John Spence talked about the biggest forestry experiment in history – EMEND. Amazing stuff.
• Doug Wu gave a two-part talk in two languages (Mandarin & English) on the theory of symbiosis (he claims most interactions are mutualistic, not competitive) and on the revolution in molecular markers for biodiversity assessment
• Annette Ostling gave a great talk on demographic complexity and neutral theory
• Subhash Lele contests that with some independent information on species detection covariates, multiple surveys are not needed to estimate measurement error in biodiversity surveys

–

© 中國蜂

Over the last few weeks there has been much media attention given to the Asian honeybee (Apis cerana) incursion in far north Queensland. The Asian honeybee was first detected near Cairns in May 2007. Since then an effort to eradicate the bee has been made. This peaked during 2010, when over 40 bee eradication personnel were employed to hunt and destroy in areas around Cairns, the Atherton Tablelands, and other nearby locations.

In late January this year, the committee established to manage the eradication program (governments and industry), decided to pull the plug on eradication efforts (on money to pay for efforts that is). They decided it was no longer possible to achieve eradication (a majority decision, not a unanimous decision). The position to stop resources for eradication is not supported by industry, or ecological commentators. Arguments have been made that this is the only window of opportunity for eradication (for ever!), and that more resources need to be put towards it now, while there is still a chance of success.

A few points to be made about the Asian honeybee in Australia:

• Over 340 colonies have been found since the original incursion in 2007 (mostly after 2009).
• Based on the Asian honeybee’s native range, it has the potential to survive in most parts of Australia.
• Being a cavity nester, the Asian honeybee will compete for nesting sites with native stingless bees, birds, and mammals (much as the Western honeybee (Apis mellifera) does already).
• The bee is a little bit smaller, and behaves in a slightly different manner than the Western honeybee, so might compete with native fauna differently at floral resources.
• Asian bees are believed to be less efficient as crop pollinators than Western honeybees, and are also known to rob Western honeybee hives of honey.
• Industry is worried about the Asian honeybee competing with managed Western honeybee colonies.

There is also much concern about Asian honeybees being the natural carrier of the Varroa mite (which it is). However, some interesting points to be made on this are:

In early 2010 I was informed that all colonies that had been destroyed were genetic descendants from the first 2007 colony. Thus, this has all resulted from a single incursion. None of the nests found yet have been positive for Varroa, which is unsurprising because the original colony was not a carrier. I think the real Varroa worry comes if this Asian honeybee incursion does establish in Australia, as it will then be harder to detect subsequent incursions, which may carry Varroa. As I have stated on ConservationBytes.com previously, Varroa only affects Apis cerana and Apis mellifera. It is potentially fatal only to Apis mellifera.

There have been comments made about this being the next cane toad or rabbit for Australia. Who knows, but it will certainly have a major impact. It will certainly be very bad for biodiversity, and it will probably be bad for agriculture. ONLY $3 million has been spent on the Asian honeybee eradication program so far.

Listen to Tim Low talk about the politics surrounding the Asian bee eradication program being stopped, on ABC Radio National Breakfast here.

Those to make demands to about putting resources towards further eradication efforts are: Federal Agriculture Minister Joe Ludwig, as well as any local members, and State and Territory politicians, in all States and Territories.

Tobias Smith

I finally got around to uploading it on Youtube. I hope I haven’t contravened some copyright law, but I figure after such a lag, no one will care. I await the imminent contradiction from the ABC’s lawyers…

I hope you enjoy.

For the scientific papers arising from the work, see:

• Bowman, DMJS, BP Murphy, CR McMahon. 2010. Using carbon isotope analysis of the diet of two introduced Australian megaherbivores to understand Pleistocene megafaunal extinctions. Journal of Biogeography 37: 499-505
• Bradshaw, CJA, Y Isagi, S Kaneko, BW Brook, DMJS Bowman, R Frankham. 2007. Low genetic diversity in the bottlenecked population of endangered non-native banteng in northern Australia. Molecular Ecology 16: 2998-3008
• Bradshaw, CJA, BW Brook. 2007. Ecological-economic models of sustainable harvest for an endangered but exotic megaherbivore in northern Australia. Natural Resource Modeling 20: 129-156
• Bradshaw, CJA, Y Isagi, S Kaneko, DMJS Bowman, BW Brook. 2006. Conservation value of non-native banteng in northern Australia. Conservation Biology 20: 1306-1311
• Brook, BW, DMJS Bowman, CJA Bradshaw, BM Campbell, PJ Whitehead. 2006. Managing an endangered Asian bovid in an Australian national park: the role and limitations of ecological-economic models in decision-making. Environmental Management 38: 463-469
• Bradshaw, CJA, WH White. 2006. Rapid development of cleaning behaviour by Torresian crows Corvus orru on non-native banteng Bos javanicus in northern Australia. Journal of Avian Biology 37: 409-411
• Bradshaw, CJA, LW Traill, KL Wertz, WH White, IM Gurry. 2005. Chemical immobilisation of wild banteng (Bos javanicus) in northern Australia using detomidine, tiletamine and zolazepam. Australian Veterinary Journal 83: 616-617

CJA Bradshaw

P.S. Thanks to host Paul Willis (@Fossilcrox) for putting together such a great little exposé of our research.

Phill is a distinguished Australian Research Council Future Fellow. He conducts research on the subject of human contributions to changes in biodiversity through the dual processes of species extinction and introduction. Phill’s research encompasses a broad range of analytical and applied skills and has led to significant advances in the discipline of global change biology.

Phill has also hit the ground running here in Adelaide, and now offers two PhD projects for people interested to work at the forefront of invasive species research in Australia. Students will be members of the School for Earth and Environmental Sciences, which includes world-class researchers in the disciplines of Ecology and Evolutionary Biology and Global Ecology as well as ongoing research links with the South Australian Museum, Adelaide Zoo, and State Herbarium of South Australia. Successful candidates will be part of a strong research group with a highly successful and innovative culture of scientific communication and study.

The first project is on the comparative biogeography of exotic vertebrate species in Australia. Exotic species pose a dire threat to Australia’s biodiversity and natural resources due to the speed at which they spread and the ecological and environmental damage they are capable of causing. In this project, the student will compile ecological, life-history, and range data on the overlapping distributions of exotic species in Australia. In collaboration with the Institute of Zoology, London the student will analyse how these distributions will be modified under different predicted models of environmental change.

The second project will examine the evolution of species traits during invasion colonisation. This project will test how dispersal capabilities vary among different populations of an expanding exotic species. In collaboration with the South Australian Museum, the student will collect data to directly parameterize, and test, different models of spread in a high-profile exotic species. This project will provide further empirical research to identify the behavioural and morphological traits affecting the distribution (and frequency) of dispersal events in exotic species, and to investigate the selective pressures upon them.

Interested applicants should first email Phill with an expression of interest and request an application form. Applicants must be Australian (or New Zealand) Citizens or permanent residents of Australia who are acceptable as candidates for a PhD degree at the University of Adelaide. Candidates should be highly motivated and must hold, or shortly expect to hold, a 1^st-class Honours degree. Please include a current CV which should contain relevant information on your ranking within your year group, previous research experience, and a statement providing evidence of your interest in the subjects of invasion biogeography and global change biology.

Successful applicants will receive a PhD stipend of AUD$22,500 tax free per year, plus access to computing support, a well-resourced research project, and the possibility to attend an international conference during their candidature. As part of their professional development, the students will be provided with the opportunity to develop long-standing research skills in experimental design, data analysis, fieldwork and behavioural observation, distribution range mapping, and climate modelling scenarios.

The AWC is a non-government, non-profit organisation dedicated to the conservation of Australia’s wildlife and their habitats. AWC’s south-east region has a team of 7 ecologists who work closely with the land managers to carry out AWC’s Conservation and Science Program. The Science Program includes strategic research designed to help us manage threatened species more effectively. Several of these research projects are suitable for Honours, Masters or PhD projects.

This prospectus provides an outline of the student projects that are currently on offer in the south-east region. The majority of the projects are based on one sanctuary, although some aspects of the research may be done on other AWC sanctuaries and/or government conservation areas.

AWC will partially support these projects with equipment, staff time and expertise, and accommodation. In some cases, AWC may also provide some vehicle use and office facilities onsite at The Scotia Field Research Centre. We anticipate these projects will be collaborative efforts with input from students, academics and AWC staff, with appropriate acknowledgement for all involved. These projects are offered on a first in, first approved basis and have been offered to multiple universities.

More details on the sanctuaries and AWC are available here. If you are keen do one of these projects, please contact Matt Hayward and we will then formulate a research proposal and research agreement. Eight project descriptions follow.

Project 1: Conservation ecology of numbats at Scotia and Yookamurra Sanctuaries

The key question AWC needs to solve is how many numbats our sanctuaries are supporting. Distance sampling has been trialled with limited success due to the low detectability and resultant low precision of the estimates. Estimates derived from non-overlapping female home ranges may be an alternative way of deriving a population estimate. Consequently, estimates of home range size of adult females at Scotia (in particular) are needed. Forty collars are available for use on numbats in Stage I; these will operate for 3 months on 10 individuals for one year. An additional 17 collars will be fitted to numbats in Stage II to monitor their survival during the initial stages of a translocation. Numerous additional components to this project are available including:

• Home range and activity patterns of adult female numbats. Studies on numbat home range size have been conducted in Western Australia’s Dryandra Forest by Tony Friend and his team from DEC WA. These Western Australian estimates may differ from those of Scotia’s numbats given the impact that climate-driven resource availability is likely to have on home range use.
• Resource availability, habitat use and preferences of radio-collared female numbats at Scotia. Resource availability is likely to differ between habitats at Scotia. Habitat/resource use will be determined via telemetry, and resource availability will be measured using standard termite density estimates and quadrants to measure the abundance of refuge sites (hollow logs/burrows). Compare hollow log density at Scotia with other sites and with other Mallee areas to show the decline in coarse woody debris and ground based hollows. Using techniques created for estimating hollow density in forest trees, determine the density of hollow logs.
• Population density estimation using transects and distance sampling techniques 1 at Scotia and Yookamurra, for comparison to estimates generated from the radio-tracking studies.
• Estimating carrying capacity of numbats. The population density of numbats is likely to be tied to food (termite) availability. Relating food availability to numbat population density may be a way of estimating the carrying capacity of sites.
• Survival of reintroduced and founder populations of numbats.

Project 2: Spatial interactions between cats and foxes at Scotia Sanctuary

The removal of foxes in Western Australian forests may have led to mesopredator release of cats, and thus an increase in predation pressure on a suite of native fauna. This process may explain the current decline of the woylie. This and other research suggests that large carnivores might be useful in reducing the impact of smaller predators. A critical element of this is that intraguild predation by the dominant predator limits the population density of the smaller or whether the smaller mesopredator simply alters its spatial behaviour to avoid the apex predator.

In this study, we aim to determine spatial behaviour and mortality rates of radio collared cats when freed from persecution by dominant mesopredators – the red fox. We aim to monitor both species for 2-3 months and then eradicate foxes and monitor the response of collared individuals of both species (obviously, the expectation is that foxes will have a rapid turnover). Key components of this research will be:

• Activity patterns of cats for 3 months before and after 3 months fox control is initiated.
• Movement patterns of cats for 3 months before and after 3 months fox control is initiated.
• Macro- and microhabitat preferences of cats before and after fox control.
• Diet of cats before and after fox control.
• Home range of foxes during fox control compared to an unbaited site in Danggali Conservation Park, South Australia.
• Habitat use and preferences of foxes in semi-arid Australia.
• Activity patterns of foxes.
• Diet and prey preferences of foxes in an area of fox control and a control site (Danggali).

Project 3: Deriving population density estimates for foxes

Accurate, robust, repeatable and reliable population estimates are fundamental to effective wildlife management. It is impossible to monitor management activities if your monitoring methods are no good. The existing method of monitoring foxes involves deriving an index based on footprints in sand or along tracks; however, this is more an index of activity rather than abundance. Work in Western Australia suggests that the actual density of foxes is largely unrelated to such indices. More robust techniques are desperately required.

Lions and hyenas are censused in Africa using call playback. Foxes do respond to auditory attractants and so similar methods might be feasible for them. Consequently, we would like to use similar techniques to see if a population density estimate can be derived for foxes at Scotia.

The key components of this research will be to monitor the response of radio-collared foxes of both sexes to auditory stimuli (rabbit squeals, vixen breeding call, etc) to derive a detection function to use to estimate population density.

This project could be expanded to include a genetic mark-recapture study using faeces and/or photo captures.

Project 4: Carcass breakdown with and without introduced predators

The extinction of the larger marsupial carnivores and the persecution of dingoes has likely altered the rate of carcass decomposition in Australia and the way carcasses breakdown. Nuria Selva’s work in Europe suggests there is a succession of scavengers that utilise carcasses. This succession must be different at sites where introduced predators have been eradicated and where native species have been reintroduced.

We plan to place harvested goat carcasses in the field to monitor their decomposition at sites with and without introduced predators and native fauna. The carcasses will be weighed a frequent intervals to determine the rate of carcass breakdown. Camera traps will be used to monitor the larger scavengers, while targeted sampling of invertebrates will monitor their succession as the carcass is broken down. Numerous additional components to this project are available including:

• Describe the breakdown of carcasses at Scotia: (a) What species initiate entry into the carcass and how does that affect breakdown; (b) What parts of the carcass are first to be eaten.
• Describe the scavenging community of mammals, birds, reptiles and invertebrates at sites with and without introduced predators.
• What factors affect carcass utilisation at Scotia.

Project 5: Reintroduction ecology of bush stone-curlew

The bush stone-curlew is a ground-dwelling bird that has declined throughout much of southern Australia. Twenty captive-bred bush stone-curlews will be reintroduced to Scotia in two groups – the first in Stage 2 (4000 ha feral-free) and the second in Stage 4 (an unbounded area where pest animal control is occurring). The animals will be held in soft release pens for three months on site, before being released. Thereafter, they will be monitored by radio transmitters for a year to determine their survival and site fidelity. Consequently, key aspects of this project could involve:

• Ecological niche modelling (Maxent) of the original distribution of bush stone-curlew.
• A review of bush stone-curlew reintroductions – there have been several bush stone-curlew reintroductions throughout NSW and northern Victoria (Albury-Wodonga and Moulamein). Cath Price may be worth involving to assist in this review and as a co-supervisor of this project.
• Captive behaviour of bush stone-curlews.
• Home range establishment and movements of bush stone-curlews at sites with and without introduced predators.
• Habitat use of bush stone-curlews at sites with and without introduced predators.
• Diet of bush stone-curlews at sites with and without introduced predators.
• Survival of bush stone-curlews at sites with and without introduced predators.
• Breeding success of bush stone-curlews at sites with and without introduced predators – this could incorporate the use of camera traps at nest sites to monitor fledging and the presence of potential nest predators. This could also incorporate an experimental aspect of monitoring the detectability of curlew nests by potential predators using clay eggs.

Project 6: Diet of barn owls at Dakalanta Sanctuary

AWC’s ecology team collected approximately 300 barn owl pellets from their most recent field trip to Dakalanta. We will also collect all pellets deposited at the roost between July 2010 and March 2011 for analysis of modern diet. Pellet contents will be identified based on hair, bone and exoskeleton within them leading to an interpretation of historic and recent diet of barn owls at Dakalanta.

Project 7: Predatory behavioural ecology of dingoes, red foxes and feral cats at Kalamurina Sanctuary

Dingoes, red foxes and feral cats are sympatric at Kalamurina. This study aims to investigate the interactions between the placental predators on Kalamurina. Specifically, it aims to measure dietary overlap and prey preferences to ascertain whether they are competing for the same prey resources or whether they have partitioned the prey according to morphological characteristics that drive the evolution of preferential predation.

This study will use scat analysis to determine the diet of Kalamurina’s larger predators. Scat analysis is a common way of determining the diet of predators by identifying the hairs of prey species within the scat. Scats for all three predators have been collected at Kalamurina since 2009. The results of these analyses will be combined with relative prey availability data derived from annual pitfall trapping at Kalamurina to derive prey preferences using Jacobs’ index as has occurred with large predators elsewhere. Combining this lab work with a detailed literature review along the lines of that conducted for African lions, might provide comparison of red fox and cat prey preferences where they are native and where they are exotic. Ultimately, this kind of information can be used to predict carrying capacity and diet of dingoes, cats and foxes.

Project 8: Crest-tailed mulgara diet at Kalamurina Sanctuary

Mulgaras are widely distributed throughout Kalamurina. AWC currently uses their characteristic scats at the entrances to their burrows to monitor mulgara presence and distribution. By June 2009, we had collected 79 mulgara scats and this is continuing. We also record the number of invertebrates (to Order), reptiles and small mammals captured in pitfall traps, so prey preferences will be derived using the same methods as described for the placental predators at Kalamurina.