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

www.sumatranforest.org

Bill Laurance asked me to reproduce his latest piece originally published at Yale University‘s Environment 360 website.

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We live in an era of unprecedented road and highway expansion — an era in which many of the world’s last tropical wildernesses, from the Amazon to Borneo to the Congo Basin, have been penetrated by roads. This surge in road building is being driven not only by national plans for infrastructure expansion, but by industrial timber, oil, gas, and mineral projects in the tropics.

Few areas are unaffected. Brazil is currently building 7,500 km of new paved highways that crisscross the Amazon basin. Three major new highways are cutting across the towering Andes mountains, providing a direct link for timber and agricultural exports from the Amazon to resource-hungry Pacific Rim nations, such as China. And in the Congo basin, a recent satellite study found a burgeoning network of more than 50,000 km of new logging roads. These are but a small sample of the vast number of new tropical roads, which inevitably open up previously intact tropical forests to a host of extractive and economic activities.

“Roads,” said the eminent ecologist Thomas Lovejoy, “are the seeds of tropical forest destruction.”

Despite their environmental costs, the economic incentives to drive roads into tropical wilderness are strong. Governments view roads as a cost-effective means to promote economic development and access natural No other region can match the tropics for the sheer scale and pace of road expansion. resources. Local communities in remote areas often demand new roads to improve access to markets and medical services. And geopolitically, new roads can be used to help secure resource-rich frontier regions. India, for instance, is currently constructing and upgrading roads to tighten its hold on Arunachal Pradesh state, over which it and China formerly fought a war.

Of course, roads are not just an environmental worry in the tropics. In forested areas of western North America, one of the best predictors of wildfire frequency is the density of roads. In Siberia, road expansion is promoting a sharp increase in logging and forest fires. And new roads in the Arctic could potentially alter epic mammal migrations.

But no other region can match the tropics for the sheer scale and pace of road expansion and the degree of environmental change roads bring. Road building has a range of direct impacts on rainforest ecology. In wet tropical environments, the cut-and-fill operations associated with road construction can impede streams, increase forest flooding, and drastically increase soil erosion. Roads also discharge chemical and nutrient pollutants into local waterways and provide avenues of invasion for many disturbance-loving exotic species.

Roads that cut through rainforests can also create barriers for sensitive wildlife, many of which are ecological specialists. Studies have shown that even narrow (30 m-wide), unpaved roads drastically reduce or halt local movements for scores of forest bird species. Many of these species prefer deep, dark forest interiors; they have large, light-sensitive eyes and avoid the vicinity of road verges, where conditions are much brighter, hotter, and drier. A variety of other tropical species — including certain insects, amphibians, reptiles, bats, and small and large mammals — have been shown to be similarly leery of roads and other clearings.

And by bringing naïve rainforest wildlife into close proximity with fast-moving vehicles, roads can also promote heavy animal mortality. For some creatures, especially those with low reproductive rates, roads could potentially become death zones that help propel the species toward local extinction.

Although the direct effects of roads are serious, they pale in comparison to the indirect impacts. In tropical frontier regions, new roads often open up a Pandora’s box of unplanned environmental maladies, including illegal land colonization, fires, hunting, gold mining, and forest clearing.

“The best thing you could do for the Amazon,” said the respected Brazilian scientist Eneas Salati, “is to bomb all the roads.”

In Brazilian Amazonia, my colleagues and I have done studies showing that around 95 % of all deforestation occurs within 50 km of highways or roads. Human-lit fires increase dramatically near Amazonian roads, even within many protected areas. In Suriname, most illegal gold mining occurs near roads, whereas in tropical Africa we have found hunting to be so intense near roads that it strongly affects the abundance and behaviour of forest elephants, buffalo, duikers, primates, and other exploited species. Roads can sharply increase trade in bushmeat and wildlife products; one study found that eight killed mammals were transported per hour along a single road in Sulawesi, Indonesia.

Paved highways are especially dangerous to forests. They provide year-round access to forest resources and reduce transportation costs, causing larger-scale impacts on forests and wildlife than do unpaved roads, which tend to become impassable in the wet season. The proposed routes of new highways often attract swarms of land speculators who rush in to buy up cheap forest land, which they then sell to the highest bidder.

Perhaps the most damaging aspect of paved highways is that they spawn networks of secondary roads, which spread further environmental destruction. For instance, the 2,000 km-long Belem-Brasília highway, completed in the early 1970s, has today evolved into a spider web of secondary roads and a 400 km-wide swath of forest destruction across the eastern Brazilian Amazon. As my colleagues and I showed in a 2001 study published in Science, large expanses of the Amazonian forest could be fragmented by the advance of new highways and roads in Brazil. According to our models, by the year 2020, rates of forest destruction would rise by up to 500,000 ha per year, and the area of forest that remained in large, unfragmented tracts — exceeding 100,000 km² — would decline by 36 %.

Can the environmental impacts of tropical roads be minimized? In theory, the answer is “Yes, partially.” Frequent culverts can reduce the effects on streams and hydrology. Impacts on animal movements can be reduced by keeping road clearings narrow enough so that canopy cover is maintained overhead, providing a way for arboreal species to cross. In high-priority areas, such as certain national parks, rope-bridges are being used to facilitate road crossings of monkeys and possums. For small ground-dwelling species, culverts beneath roads can allow road-crossing movements, and even large animals such as Asian elephants will use highway underpasses that are designed to be wildlife-friendly.

Measures also exist to limit the devastating indirect impacts of roads, such as illegal land colonization and forest clearing. One of the most vital steps is to establish legally parks or reserves along road routes in advance of road construction. Such reserves often substantially reduce forest incursions, though they rarely halt them entirely. Another promising idea is to promote rail roads rather than highways in tropical wilderness regions. Because railroads stop only at fixed locations, the spatial patterns of forest exploitation and movement of forest products can be more easily controlled and monitored than with roads.

In practice, however, limiting the environmental impacts of roads in developing nations is expensive and risky. Tropical nations rarely have the institutional capacity, human capital, or financial resources to adequately manage development in their remote frontier regions, frequently leading to a “resource grab” revolving around illegal trade and outright theft of natural resources, which is greatly facilitated by road expansion.

When it comes to tropical roads, I believe three conclusions are inescapable. First, highways and roads are the single biggest factor determining the pattern and pace of tropical forest destruction. New roads that slice deep into intact forest tracts are especially devastating.

Second, among the many human drivers of environmental change, road building is one of the most readily amenable to policy modification. In practical terms, it is far easier to cancel or relocate a road project than it is to, say, reduce human overpopulation or halt harmful climate change.

Finally, if we hope to maintain intact tropical forests and their vital ecosystem services and biodiversity, then we simply must get serious about tropical roads. And there is only one real solution: carefully plan and limit frontier road expansion.

How can this be achieved? First, we need to sensitize political decision-makers, economists, infrastructure planners, and the general public about If we hope to maintain intact tropical forests, then we must get serious about tropical roads. the myriad environmental costs of road expansion, especially into intact forests. The biggest road projects are often being supported by international lenders — such as the Asian, African, and Inter-American development banks — and by foreign aid doled out by China, the U.S., and the European Union. Educating such decision-makers needs to be done both generally and on a project-by-project basis.

When I was president of the Association for Tropical Biology and Conservation, one of my key goals was to use the organization’s scientific expertise and credibility to combat some of the most environmentally risky plans for frontier road expansion. We were especially active in critiquing plans to punch new roads into the cores of national parks, such as Yasuní in Ecuador, Kerinci Seblat in Indonesia, and the Serengeti in Tanzania.

Another key priority should be better frontier law enforcement and forest monitoring, given that much road building in tropical nations is illegal or unplanned. Special attention should be focused on the more-aggressive timber, oil, gas, and mineral corporations, many of which are known to engage in bribery and collusion in their efforts to gain unbridled access to forest resources.

There is also a dire need to improve environmental impact assessments (EIAs) for planned roads. In Brazil, for instance, EIAs for several major Amazonian highways focused only on a narrow strip along the road route itself, while completely ignoring the devastating indirect effects of roads. Similarly, EIAs for major development projects, such as large mines and hydroelectric dams, often ignore the impacts of road proliferation that such projects inevitably promote.

Finally, given that tropical deforestation is a massive source of greenhouse gas emissions, international carbon-trading funds should be used to better plan and mitigate road projects, to establish new protected areas in advance of road construction, and to halt the most ill-advised road projects altogether. In the end, the easiest and most cost-effective way to limit the manifold pressures from roads may be simply not to open Pandora’s box in the first place.

William F. Laurance

Before I get into specifics, I have to say that one thing we conservation biologists tend to bang on about is that MORE SPECIES = BETTER, regardless of the ecosystem in question. We tend to value species richness as the gold standard of ecosystem ‘health’ and ‘resilience’, whether or not there is strong empirical evidence in support. It’s as if the more-is-better mantra strikes an intuitive chord and must, by all that’s ecologically right in the world, be true.

Of course, measuring what is ‘better’ is a difficult task, especially when we are talking about complex ecosystems comprising thousands, if not millions, of species. Does ‘better’ refer to the most temporally stable, the most genetically diverse, the most resilient to perturbation, or the provider of the greatest number of functions and hence, ecosystem services?

It’s up to you, but all these things tend to be difficult to measure for a large number of species and over time scales of sufficient duration to measure change. So the default for plants (i.e., the structural framework of almost all ecosystems) I guess has come down to a simpler measure of success – ‘productivity’. This essentially means how much biomass is produced per unit area/volume per time step. It’s not a great metric, but it’s probably one of the more readily quantifiable indices.

Enter the so-called ‘diversity-productivity relationship’, or ‘DPR’, which predicts that higher plant species diversity should engender higher net productivity (otherwise known as the ‘net biodiversity effect’).

Nice idea, and one that is especially attractive in this day of carbon accounting (forest carbon sequestration as offsets to industrial and transport greenhouse gas production). If true, the net biodiversity effect is adequate justification for maximising species diversity in carbon plantings such that both carbon sequestration and biodiversity value are maximised – the best bang for your planting buck.

The problem is that it’s not even close to being a theory in ecology, let alone a law. In fact, the hypothesis has very mixed empirical support, and the majority of it is in manipulated and simplified grasslands, with no net effect, or even negative relationships, reported for natural forest stands. Not a good sell really if you’re trying to convince a policy maker that more species are better to maximise productivity, and hence, carbon uptake.

Enter Yu Zhang and colleagues and their recently published (online) paper: Forest productivity increases with evenness, species richness and trait variation: a global meta-analysis. Now, I’m a big fan of meta-analyses to answer big questions; there’s nothing like a lot of disparate studies collated to provide insight into broad-scale pattern (e.g., see our recent meta-analysis on the value of primary forests for tropical biodiversity published in Nature last year).

And that’s exactly what they did – Zhang and colleagues collated diversity-productivity data from 54 forest studies to determine the overall ‘average’ direction of the diversity-productivity relationship. Using boosted-regression trees (and slick way to deal with complex multi-variate data), their overall conclusion was that ‘polycultures’ (i.e., many species) were more productive than ‘monocultures’ (single-species stands). So much for the DPR debate in forest ecosystems.

More interestingly perhaps was that the biodiversity metric used dictated the strength of effect found. Even though there was a positive richness relationship (more species = higher productivity), it plateaued after a certain threshold number of species. However, when using ‘evenness’ as the measure of ‘diversity’ (i.e., a metric which includes relative abundance of each species in system), stands that were more even (i.e., not dominated by a few common species) were more productive, and this metric explained a much higher component of the variance in productivity than richness alone. This means that a simple list of species doesn’t really indicate the full potential of the stand because of things like functional redundancy. Finally, they found no evidence for a deviation of the relationship among biomes, suggesting that the effect is global and real.

Now there are a lot of fine details in the analysis that complicate matters, but I think the take-home message is clear. This is a hugely important finding and one that all conservation ecologists should be able to cite when justifying the essential role of diversity in ecosystem function.

CJA Bradshaw

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© 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

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

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

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

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

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

Back to the critique. While the title of several high-profile media outlets used the term ‘magic number‘, we never used the term or supported the idea of a ‘one-number-fits-all’ approach. MVP does, of course, vary among species, and very possibly even more among major taxonomic groups (but the data are wanting). The problem is that there are no really good ways to predict MVP from first principles (e.g., life history traits); rather, one must rely on comprehensive population viability analyses based on detailed demographic and other data that, unfortunately, simply aren’t available for most species on the planet.

Yes, we did find some remarkable consistency among species for the magnitude of MVP size, and some taxonomic differences (remember, we controlled for mass differences by standardising MVP sizes to 40 generations), but the fact remains there is always unexplained variation. However, throwing the MVP baby out with the conservation bathwater is just plain silly. You will NEVER get adequate data to develop PVAs for all species of conservation of concern, which means generalisations, or rules of thumb, are a conservation necessity.

And this is the slightly amusing part – the Flather critique essentially agrees with us; they state:

“We also suspect. . .that multiple populations totalling thousands (not hundreds) of individuals will be needed to ensure long-term persistence”

This is pretty much what we’ve been emphasising all along. You need thousands (and ~ 5000 [note the ~] is around the median mark), not hundreds, to reduce the probability of stochastic extinctions to acceptably low values. But where Flather and colleagues fall down is that they provide no viable alternative to our suggested approach.

The critique also completely glosses over the effects of genetic erosion – when few individuals are left in a population, inbreeding suppresses vital rates and reduces the population’s potential for recovery following disturbance. And yes, there’s plenty of evidence for this. It’s also interesting that genetic data suggest too that thousands, not hundreds, should be the target range to avoid inbreeding depression – an entirely independent line of evidence that supports the demographic analyses.

So I don’t really get what their critique is all about, apart from some elaborate and long-winded way of saying ‘things vary’. Yes, yes they do. But that shouldn’t stop us from developing generalisations. Now, just in case you’ve heard through the grapevine that our follow-up piece on the Species Ability to Forestall Extinction (SAFE) index has triggered the hounds to bay for blood, stay tuned shortly for our response to a series of related critiques in Frontiers in Ecology and the Environment.

CJA Bradshaw

References

• BROOK, BW, LW TRAILL, CJA BRADSHAW. 2006. Minimum viable population size and global extinction risk are unrelated. Ecology Letters 9: 375-382. doi:10.1111/j.1461-0248.2006.00883.x
• BROOK, BW, CJA BRADSHAW, LW TRAILL, R FRANKHAM. 2011. Minimum viable population size: not magic, but necessary. Trends in Ecology and Evolution doi:10.1016/j.tree.2011.09.006
• CLEMENTS, GR, CJA BRADSHAW, BW BROOK, WF LAURANCE. 2011. The SAFE index: using a threshold population target to measure relative species threat. Frontiers in Ecology and the Environment doi:10.1890/100177
• FLATHER CH, HAYWARD GD, BEISSINGER SR, STEPHENS PA. 2011. Minimum viable populations: is there a “magic number” for conservation practitioners?6. Trends in Ecology and Evolution 26: 307-316
• HALLIDAY, T. 1978. Vanishing Birds: Their Natural History and Conservation. 1st edn. Holt, Rinehart and Winston, New York
• TRAILL, LW, CJA BRADSHAW, BW BROOK. 2007. Minimum viable population size: a meta-analysis of 30 years of published estimates. Biological Conservation 139: 159-166. doi:10.1016/j.biocon.2007.06.011
• TRAILL, LW, BW BROOK, R FRANKHAM, CJA BRADSHAW. 2010. Pragmatic population viability targets in a rapidly changing world. Biological Conservation 143: 28-34. doi:10.1016/j.biocon.2009.09.001

Filed under: Allee effect, biodiversity, conservation, conservation biology, demography, ecological triage, environmental policy, extinction debt, extinction vortex, inbreeding depression, minimum viable population, mvp, population viability analysis, PVA ]]> http://conservationbytes.com/2011/10/18/not-magic-but-necessary/feed/ 3 -34.917731 138.603034 -34.917731 138.603034 CJAB triage http://conservationbytes.com/2011/10/06/little-left-to-lose/ http://conservationbytes.com/2011/10/06/little-left-to-lose/#comments Thu, 06 Oct 2011 02:08:45 +0000 CJAB http://conservationbytes.com/?p=6274 ]]>

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I don’t usually do this, but I’m going to blog about a paper I’ve just had accepted in the Journal of Plant Ecology that isn’t yet out online. The reason for the early post is that the paper itself won’t appear until 2012 in a special issue of the journal, and I think the information needs to get out there.

First, a little history – In May this year I blogged about a workshop that I attended at Sun Yat-Sen University in Guangzhou, China at the behest of Fangliang He. The workshop (International Symposium for Biodiversity and Theoretical Ecology) was attended by big-wig overseas ecologists and local talent, and was not only informative, but a lot of fun (apart from the slight headache on the way home from a little too much báijiǔ the night before). More importantly, we  lǎo wài (老外) were paired with various students to assist with publications in progress, and I’m happy to say that for me, two of those have already produced fruit (one paper in review, another about to be submitted).

But the real reason for this post was the special issue of papers written by the invitees – I haven’t published in the journal before, and understand that it is a Chinese journal that has gone mainstream internationally now. I’m only happy to contribute to lifting its profile.

Given that I’m not a plant ecologist per se (although I’ve dabbled), I decided to write a review-like paper that I’ve been meaning to put together for some time now examining the state of Australia’s forests and the history of her deforestation and forest degradation. The reason I thought this was needed is that there is no single peer-reviewed resource one can turn to for a concise synopsis of the history of our country’s forest destruction. The stats are out there, but they’re buried in books, government reports and local-scale scientific papers. My hope is that my paper will be used as a general reference point for people wishing to get up to speed with Australia’s deforestation history.

The paper is entitled Little left to lose: deforestation and forest degradation in Australia since European colonisation, and it describes the general trends in forest loss and degradation Australia-wide, followed by state- and territory-level assessments. I’ve also included sections on plantations, biodiversity loss from deforestation and fragmentation, the feedback loop between climate change and deforestation, the history of forest protection legislation, and finally, a discussion of the necessary general policy directions needed for the country’s forests.

I’ve given a few titbits of the stats in a previous post, but let me just summarise some of the salient features here:

• Australian forests were by no means ‘pristine’ when Europeans arrived a little over 200 years ago – Aboriginal fire-stick farming had already changed the landscape substantially
• We’ve lost about 40 % of our total forest cover over the last 200 years
• Australia has only about 4 % of the world’s forests on about 5 % of the world’s total land area
• Remaining forests are highly fragmented, with some forest ecosystems now almost completely destroyed
• ~ 50 % of Australia’s forest have now been completely cleared or severely modified, with > 80 % of eucalypt forests in particular having been altered
• Most deforestation occurred originally in the most fertile coastal areas of NSW, VIC and SA. Later, government policies urged landholders to destroy vast swathes of forest land in WA, and most recently, in QLD
• QLD has the greatest area of native forest, but has had some of the highest deforestation rates in the world in the last 30 years
• TAS has the highest proportion of its land area covered in native forest (ACT has nearly the same)
• There have been hundreds of localised extinctions arising from deforestation and fragmentation around Australia
• There are around 2,000,000 ha of plantations (most exotic species) in Australia today
• Deforestation has increased droughts and temperatures, especially in WA
• The proportion of forests in Australia now falling within nature  conservation reserves has increased from 11 to 16 % from 1998-2008, but much of this area has been previously cleared or severely modified

My main take-home policy recommendations are that existing tracts of native forest MUST be conserved first (given the irreplaceableness of primary forests), followed by a concerted effort to regenerate areas between existing native fragments to maximise the size of the latter.

If you’d like a pre-print copy, just let me know by sending a message through the ConservationBytes.com feedback/comment form. I’ll probably have to check with Fangliang if he’s happy for this, but I reckon it shouldn’t be a problem.

CJA Bradshaw

© A. Kenyon http://goo.gl/UpG3m

Bill Laurance wrote a compelling and very dour piece in The Conversation this week. He asked for some ‘link love’, so I decided to reproduce the article here for ConservationBytes.com readers. Full credit to Bill and The Conversation, of course.

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What comes to mind when you think of Indonesia?

For biologists like myself, Australia’s northern neighbour provokes visions of ancient rainforests being razed by slash-and-burn farmers, and endangered tigers and orangutans fleeing from growling bulldozers.

This reality is true, but there is also hope on the horizon.

Indonesia is a vast, sprawling nation, spanning some 17,000 islands. Among these are Java, Sumatra, half of New Guinea and much of Borneo.

Some of the planet’s most biologically rich and most endangered real estate is found on this archipelago.

Today, Indonesia is losing around 1.1 million hectares of forest annually. That’s an area a third the size of Belgium, bigger than Australia’s Wet Tropics World Heritage Area.

With forest loss now slowing in Brazil, Indonesia has the dubious distinction of being the world’s deforestation “leader”. No nation is destroying its forests faster.

In Sumatra, where I visited recently, the world’s biggest paper-pulp corporations are chopping down hundreds of thousands of hectares of native rainforest to make paper and cardboard.

Some of these corporations also fund aggressive lobbyists, such as World Growth in Washington DC [CJA Bradshaw's note: see our piece on one particular patron of WG - Alan Oxley], to combat their critics and dissuade major retail chains from dropping their products.

In addition to rapid deforestation, large expanses of Indonesia’s forests are being selectively logged, with bulldozers used to extract the biggest trees from the forest. Much of this is illegal — the timber is effectively stolen and there are no environmental controls over the cutting operations.

Aside from having serious environmental impacts, illegal logging is losing the Indonesian government up to $4 billion in timber royalties every year.

This all sounds pretty bad — but there are glimmers of light behind the storm-clouds.

The best news is that in 2010, Indonesia and Norway hammered out a billion-dollar deal to help save Indonesia’s forests and reduce atmospheric carbon emissions.

This is important because the destruction of tropical forests globally spews almost 5 billion metric tonnes of CO₂ into the atmosphere every year. That’s more than every car, truck, train, boat and airplane on earth combined.

Indonesia is the world’s third-largest producer of greenhouse gases (behind China and the US), with 85% of its emissions coming from forest destruction and degradation.

The funds from Norway are being used to enact a two-year moratorium on granting new licenses for clearing or logging of native forests and carbon-rich peatlands.

Some of these funds are also being used to establish a taskforce to zone and monitor Indonesia’s forests, and to introduce desperately needed bureaucratic reforms. These are necessary so the Norway funds can be distributed equitably to different levels of the Indonesian government and people.

Doing all of this is a tall order, and there are still many hurdles in the way.

For starters, a vast expanse of selectively logged forest in Indonesia — around 35 million hectares; an area the size of Germany — is being left out of the Norway deal. Even though these forests retain much of their biodiversity and carbon storage, Indonesia says they aren’t “natural”, and hence are being excluded. These forests might be cleared or re-logged at any time.

In addition, in the days just before the Norway deal was to be implemented, there was a landslide of new clearing and logging licenses granted. These totalled around 3 million hectares.

That means there is plenty of forest that can be exploited in the next two years, at which point the moratorium will have ended.

It also appears that many forests protected under the Norway deal are in steep or remote areas that are relatively safe from loggers, farmers and forest-pulpers. The most endangered forests — those remaining in the flatter lowlands, outside of national parks — are mostly excluded from protection.

To some people, this sounds a lot like business as usual in Indonesia. But it’s too soon to give up on the Norway deal.

If nothing else, the Norway deal has helped encourage Indonesian President Susilo Bambang Yudhoyono to take a more pro-forest perspective.

Although under enormous pressure from industrial timber, oil palm and pulpwood interests in Indonesia, the president is urging reform at many levels.

He is pushing hard to fight the scourge of illegal logging, and is sticking by a commitment to slash the country’s greenhouse gas emissions.

In his remaining three years in office, President Yudhoyono has committed to seeing the Norway deal succeed while also pressing ahead with rapid economic development — a vital priority in a populous and growing country where standards of living are often perilously low.

It is a difficult balancing act, and one that might yet fail.

One should bear in mind, however, that there might be a lot more carbon funds available in the coming years. Australia has already contributed over $200 million to help slow Indonesian deforestation and, with the Gillard government’s new carbon tax about to be enacted, there might even be more Aussie funding to come.

Add to this the potential for billions of dollars in additional carbon funding from Europe, the US and other countries, and suddenly the prospects for forest conservation in Indonesia don’t look quite so bleak.

If Indonesia can establish itself as a reliable partner and forest protector, it stands to reap some real economic benefits.

And it’d be brilliant to see Indonesia getting paid for conserving its forests, rather than just for cutting them down.

© Romulo Fotos http://goo.gl/CrAsE

A little over five years ago, a controversial and spectacularly erroneous paper appeared in the tropical ecology journal Biotropica, the flagship journal of the Association for Tropical Biology and Conservation. Now, I’m normally a fan of Biotropica (I have both published there several times and acted as a Subject Editor for several years), but we couldn’t let that paper’s conclusions go unchallenged.

That paper was ‘The future of tropical forest species‘ by Joseph Wright and Helene Muller-Landau, which essentially concluded that the severe deforestation and degradation of tropical forests was not as big a deal as nearly all the rest of the conservation biology community had concluded (remind you of climate change at all?), and that regenerating, degraded and secondary forests would suffice to preserve the enormity and majority of dependent tropical biodiversity.

What rubbish.

Our response, and those of many others (including from Toby Gardner and colleagues and William Laurance), were fast and furious, essentially destroying the argument so utterly that I think most people merely moved on. We know for a fact that tropical biodiversity is waning rapidly, and in many parts of the world, it is absolutely [insert expletive here]. However, the argument has reared its ugly head again and again over the intervening years, so it’s high time we bury this particular nonsense once and for all.

In fact, a few anecdotes are worthy of mention here. Navjot once told me one story about the time when both he and Wright were invited to the same symposium around the time of the initial dust-up in Biotropica. Being Navjot, he tore off strips from Wright in public for his outrageous and unsubstantiated claims – something to which Wright didn’t take too kindly.  On the way home, the two shared the same flight, and apparently Wright refused to acknowledge Navjot’s existence and only glared looks that could kill (hang on – maybe that had something to do with Navjot’s recent and untimely death? Who knows?). Similar public stoushes have been chronicled between Wright and Bill Laurance.

Back to the story. I recall a particular coffee discussion at the National University of Singapore between Navjot Sodhi (may his legacy endure), Barry Brook and me some time later where we planned the idea of a large meta-analysis to compare degraded and ‘primary’ (not overly disturbed) forests. The ideas were fairly fuzzy back then, but Navjot didn’t drop the ball for a moment. He immediately went out and got Tien Ming Lee and his new PhD student, Luke Gibson, to start compiling the necessary studies. It was a thankless job that took several years.

However, the fruits of that labour have now just been published in Nature: ‘Primary forests are irreplaceable for sustaining tropical biodiversity‘, led by Luke and Tien Ming, along with Lian Pin Koh, Barry Brook, Toby Gardner, Jos Barlow, Carlos Peres, me, Bill Laurance, Tom Lovejoy and of course, Navjot Sodhi [side note: Navjot died during the review and didn't survive to hear the good news that the paper was finally accepted].

Using data from 138 studies from Asia, South America and Africa comprising 2220 pair-wise comparisons of biodiversity ‘values’ between forests that had undergone some sort of disturbance (everything from selective logging through to regenerating pasture) and adjacent primary forests, we can now hammer the final nails into the coffin containing the putrid remains of Wright and Muller-Landau’s assertion – there is no substitute for primary forest.

Our metrics were fairly straight forward – after standardising effect sizes (i.e., the difference between measured variables) for species richness, species abundance, community structure, forest structure and demographics, degraded forests had without fail lower biodiversity values (perhaps with the exception of demographics which are extremely difficult to measure precisely and accurately for sufficient samples).

Another interesting finding was that birds were by far the most sensitive taxon – once you start to degrade tropical forests, birds start to drop off the perch almost immediately (and yes, we did test for lag effects, before you ask). Arthropods and plants were the next-most sensitive, followed by mammals (there seemed to be in some cases and actual ‘positive’ response by mammals, driven largely by higher abundance of certain species [e.g., rats] in disturbed forests).

Another not-so-surprising finding was that Asia had the worst outcomes – biodiversity is failing faster there than anywhere else in the tropics. We also found, again rather unsurprisingly, that there was a gradient of responses, with the worst effects felt in abandon agricultural plots, and the least in selectively logged forests (although all forms of disturbance constituted some biodiversity loss).

Of course, it must be said that we live in a less-than-perfect world (really?), so even though this evidence is incontrovertible, it doesn’t mean that suddenly everyone will preserve all remaining primary tropical forest on the planet (wouldn’t that be lovely). So we need to consider the secondary and degraded forests in our conservation planning too – even bad forest is better than no forest at all.

However, we cannot dismiss the notion that there is no replacement for primary forests, that we should definitely not being staying stupid shit like ‘oil palm plantations hold just the same amount of biodiversity as primary forests’ [see previous post regarding that shining display of ignorance]. We need to conserve as much remaining primary forest as we can, while striving to regenerate those areas that have already come under the fire of development.

If you’d like a reprint, just email me here (or any other co-author, for that matter) and I’ll send you one.

CJA Bradshaw

© Taren McCallan-Moore

Last week, The Conversation published a particularly wonderful example of uninformed drivel that requires a little bit of a reality injection.

Like our good friend, the Destroyer of Forests (a.k.a. Alan Oxley), a new pro-deforestation, pro-development cheerleader on the scene, a certain Phillip Lawrence apparently undertaking a PhD entitled ‘Ecological Modernization of the Indonesian Economy: A Political, Cultural and Historical Economic Study‘ at Macquarie University in Sydney (The Conversation mistakenly attributes him to the University of Sydney, unless of course, he’s moved recently), has royally stuck his foot in it with respect to the dangers of oil palm in South-East Asia.

Mr. Lawrence runs an interestingly titled blog ‘Eco Logical Strategies‘, especially considering there is nothing whatsoever regarding ‘ecology’ on the site, and this ignorance comes forth in a wonderful array of verbal spew in his latest Conversation piece. He’s also a consultant for one of the most destructive forces in Indonesia – Asia Pulp and Paper – a company with a more depressive environmental track record than the likes of Monsanto, General Electric and BP combined. That preface of conflict of interest now explained, I will now expose Mr. Lawrence for the wolf in sheep’s clothing he really is.

Banging the development and anti-poverty drum like Oxley, albeit with much less panache and linguistic flourish, Mr. Lawrence boldly claims, without a shred of evidence, that “There is ample peer-reviewed research that is supportive of the palm oil industry in Indonesia.”

Excuse me? Supportive of just what component of the palm oil industry, Mr. Lawrence? Would that be that it makes a shit-load of cash for a preciously small component of Indonesian (and foreign) society? Let’s just look at the peer-reviewed literature, shall we?

Oil palm is the single-most destructive practice in the South-East Asian environment, an area with the world’s which can boast some of the greatest endemic biodiversity. With classic greenwashes, the industry claims (but has been refuted time and time again) that:

• palm oil plantations are safe for tropical biodiversity – They are most definitely not (see Fitzherbert et al. 2008, Koh & Wilcove 2008, Brüle & Eltz 2009, Danielson et al. 2009, Venter et al. 2009). In two days’ time too, a paper of ours will be coming out in Nature showing how primary forest cannot be replaced by any other type of forest, and oil palm is one of the worst [I will post something here on that early Thursday morning]
• oil palm is planted forest – It is not, either in terms of the amount of carbon it sequesters (see also here) or the biodiversity it supports (see above and Edwards et al. 2010).
• native forest conversion no longer occurs – An outright lie (Chazdon 2008, Butler 2008)

As we discussed in our open letter last year, we expose the fallacy of such an unsubstantiated assumption:

“… frequently invoke “poverty alleviation” as a key justification for their advocacy of oil palm expansion and forest exploitation in developing nations, and it is true that these sectors do offer significant local employment. Yet forest loss and degradation also have important societal costs. There are many examples in which local or indigenous communities in the tropics have suffered from large-scale forest loss and disruption, have had their traditional land rights compromised, or have gained minimal economic benefits from the exploitation of their land and timber resources (Laurance et al. 2010; Colchester 2010). Such costs are frequently ignored in the arguments…”

Like the fallacy of the environmental Kuznets’ curve which attempts to justify wealth accumulation as a means to bring down environmental damage (we demonstrated last year that the idea is nothing but an economist’s pipe-dream), there is no demonstration whatsoever that oil palm is ultimately ‘good’ for countries like Indonesia.

It destroys forests, destroys livelihoods, destroys biodiversity and lines the pockets of the fat cats as they laugh their way to the bank.

How much does Asian Pulp and Paper pay you, Mr. Lawrence?

CJA Bradshaw