No substitute for primary forest

15 09 2011

© Romulo Fotos

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. Read the rest of this entry »

Tropical forests cooking their biodiversity

5 05 2011

Another ‘hot’ essay by Bill Laurance recently published online by Yale Environment 360 (a publication of the Yale University School of Forestry & Environmental Studies). Bill asked me to relay it on, so here it is in full:

Much attention has been paid to how global warming is affecting the world’s polar regions and glaciers. But a leading authority on tropical forests [that would be Bill] warns that rising temperatures could have an equally profound impact on rainforests and are already taking a toll on some tropical species.

On Jan. 12, 2002, in the Australian state of New South Wales, biologist Justin Welbergen was observing a colony of flying foxes for his Ph.D. research. The temperatures that day on Australia’s subtropical, eastern coast reached record highs, soaring to 42.9 ° C (109 ° F) at the weather station closest to Welbergen’s study site — nearly 8 ° C higher than the average summer maximum temperature.

The flying foxes, or giant fruit bats, normally just doze in the treetops through the day, but on this afternoon they were fanning themselves, panting frantically, jostling for shady spots, and licking their wrists in a desperate effort to cool down. Suddenly, when the thermometer hit 42 ° C, the bats began falling from the trees. Most quickly died. Welbergen and his colleagues counted 1,453 flying foxes that died from the heat in one colony alone. The scorching heat that day killed at least 2,200 additional flying foxes in eight other colonies along a 250-kilometre stretch of coastline. All the deaths occurred in colonies where temperatures soared above 41.7 ° C. Read the rest of this entry »

Tropical forests worth more standing

4 06 2009
© R. Butler

© R. Butler

Keeping with the oil palm theme…

A paper just published online in Conservation Letters by Venter and colleagues entitled Carbon payments as a safeguard for threatened tropical mammals gets my vote for the Potential list.

We’ve been saying it again and again and again… tropical forests, the biodiversity they harbour and the ecosystem services they provide are worth more to humanity than the potential timber they represent. Now we find they’re even worth more than cash crops (e.g., oil palm) planned to replace them.

A few years ago some very clever economists and environmental policy makers came up with the concept of ‘REDD’ (reducing carbon emissions from deforestation and forest degradation), which is basically as system “… to provide financial incentives for developing countries that voluntarily reduce national deforestation rates and associated carbon emissions below a reference level”. Compensation can occur either via grant funding or through a carbon-trading scheme in international markets.

Now, many cash-greedy corporations argue that REDD could in no way compete with the classic rip-it-down-and-plant-the-shit-out-of-it-with-a-cash-crop approach, but Venter and colleagues now show this argument to be a bit of a furphy.

The authors asses the financial feasibility of REDD in all planned oil palm plantations in Kalimantan – Indonesia’s part of the island of Borneo in South East Asia. Borneo is also the heart of the environmental devastation typical of the tropics. They conclude that REDD is in fact a rather financially competitive scheme if we can manage to obtain carbon prices of around US$10-33/tonne. In fact, even when carbon prices are as low as US$2/tonne (as they are roughly now on the voluntary market), REDD is still competitive for areas of high forest carbon content and lower agricultural potential.

But the main advantage isn’t just the positive cash argument – many endangered mammals (and there are 46 of them in Kalimantan) such as the South East Asian equivalent of the panda (the orang-utan – ‘equivalent’ in the media-hype and political sensitivity sense, not taxonomic, of course) and the Bornean elephant (yes, they have them) are currently found in areas planned for plantation. So saving the forest obviously saves these and countless other taxa that only exist on this highly endemic island. Finally, Venter and colleagues found that where emission reductions were cheapest, these are also areas with higher-than-average densities of endangered mammals, suggesting that REDD is a fantastic option to keep developing countries in the black without compromising their extensive species richness and endemism.

Brilliant. Now if we can just get the economists and pollies to agree on a REDD model that actually works.

CJA Bradshaw

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One more (excellent) reason to conserve tropical forests

26 02 2009

© K. Sloan Brown

© K. Sloan Brown

Another nail in the deforesters’ justification coffin – tropical forests are worth more intact than cut down. This one from and one for the Potential section:

Undisturbed tropical forests are absorbing nearly a fifth of carbon dioxide released annually by the burning of fossil fuels, according to an analysis of 40 years of data from rainforests in the Central African country of Gabon.

Writing in the journal Nature, Simon Lewis and colleagues report that natural forests are an immense carbon sink, helping slow the rise in atmospheric CO2 levels.

“We are receiving a free subsidy from nature,” said Simon Lewis, a Royal Society research fellow at the University of Leeds. “Tropical forest trees are absorbing about 18% of the CO2 added to the atmosphere each year from burning fossil fuels, substantially buffering the rate of climate change.”

But the good news may not last for long. Other research suggests that as tropical forests fall to loggers, dry out due to rising temperatures, and burn, their capacity to absorb carbon is reduced.

The research, which combined the new data from African rainforests with previously published data from the Americas and Asia, lends support to the idea that old-growth forests are critical to addressing climate change. Recent climate negotiations have included debates on compensating tropical countries for reducing emissions from deforestation and forest degradation (“REDD” or “avoided deforestation”).

“To get an idea of the value of the sink, the removal of nearly 5 billion tonnes of carbon dioxide from the atmosphere by intact tropical forests, based on realistic prices for a tonne of carbon, should be valued at around £13 billion per year,” said study co-author Lee White, Gabon’s Chief Climate Change Scientist. “This is a compelling argument for conserving tropical forests.”

“Predominantly rich polluting countries should be transferring substantial resources to countries with tropical forests to reduce deforestation rates and promote alternative development pathways,” added Lewis.

The new findings show that tropical forests account for roughly half of the 8.5 billion tons of carbon that is sequestered in terrestrial sources each year, the balance is absorbed by soils and other types of vegetation. Another 8.5 billion tons dissolved in oceans, leaving 15 billion of the 32 billion tons emitted by humans each year in the atmosphere. Deforestation accounts for roughly 6 billion tons of greenhouse gas emissions – greater than the emissions from all the world’s planes, ships, trucks, and cars.

Note – the contention by Muller-Landau that the Lewis and colleagues’ findings are not realistic due to ‘regeneration’ demonstrates her ignorance of recent work demonstrating the sequestration aspect of mature forests. But more importantly, this cherry-picked gripe, even if it were plausible, is almost of no consequence. With much of the world’s tropical forests already badly degraded or destroyed, there will inevitably be large areas of regenerating forests for centuries to come (i.e., time periods relevant to climate change projections). We haven’t even managed to reduce the RATE of tropical deforestation, so the opportunities for regeneration will persist, making the Lewis result all the more important. Muller-Landau is known for her unrealistic and anti-conservationist views, so her comments are hardly surprising. My advice – take her opinions with a very large shaker of salt (or better yet, ignore entirely).

CJA Bradshaw


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