Tropical Turmoil II

8 03 2009

In August last year I covered a paper my colleagues (Navjot Sodhi and Barry Brook) and I had in press in Frontiers in Ecology and the Environment entitled Tropical turmoil – a biodiversity tragedy in progress. The paper is now available in the March 2009 issue of the journal (click here to access). We were also fortunate enough to grab the front cover (shown here) and have a dedicated podcast that you can listen to by clicking here about the paper and its findings. I encourage readers to have a listen if they’re interested in learning more about the woeful state of tropical biotas worldwide, and maybe some ways to rectify the problems. The intro to the podcast can be viewed by clicking here.

CJA Bradshaw

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

Tropical Conservation Biology

8 09 2008

An obvious personal plug – but I’m allowed to do that on my own blog ;-)

1405150734I’d like to introduce a (relatively) new textbook that my colleagues, Navjot Sodhi and Barry Brook, and I wrote and published last year with Blackwell (now Wiley-Blackwell) Scientific Publishing – Tropical Conservation Biology.

We’re rather proud of this book because it was a timely summary and assessment of the scientific evidence for the degree of devastation facing tropical biodiversity today and in the future. I’ve summarised some of the main issues in a previous post covering a paper we have ‘in press’ that was born of the text book, but obviously the book is a far more detailed account of the problems facing the tropics.

This introductory textbook examines diminishing terrestrial and aquatic habitats in the tropics, covering a broad range of topics including the fate of the coral reefs; the impact of agriculture, urbanisation, and logging on habitat depletion; and the effects of fire on plants and animal survival.

One of the highlights of the book is that each chapter (see below) Includes case studies and interviews with prominent conservation scientists to help situate key concepts in a real world context: Norman Myers (Chapter 1), Gretchen Daily (Chapter 2), William Laurance (Chapter 3), Mark Cochrane (Chapter 4), Daniel Simberloff (Chapter 5), Bruce Campbell (Chapter 6), Daniel Pauly (Chapter 7), Stephen Schneider (Chapter 8), Stuart Pimm (Chapter 9) and Peter Raven (Chapter 10). These biographies are followed by a brief set of questions and answers that focus on some of the most pertinent and pressing issues in tropical conservation biology today. It is our intention that readers of Tropical Conservation Biology will benefit from the knowledge and be inspired by the passion of these renowned conservation experts.


  1. Chapter 1: Diminishing habitats in regions of high biodiversity. We report on the loss of tropical habitats across the tropics (e.g., deforestation rates). We also highlight the drivers of habitat loss such as human population expansion. Finally, we identify the areas in immediate need of conservation action by elucidating the concept of biodiversity hotspots. Read the rest of this entry »

Native forests reduce the risk of catastrophic floods

20 08 2008

A-Pakistan-Army-helicopte-004Each year extreme floods kill or displace hundreds of thousands of people and cause billions of dollars in damage to property. The consequences of floods are particularly catastrophic in developing countries generally lacking the infrastructure to deal adequately with above-average water levels.

For centuries it has been believed that native forest cover reduced the risk and severity of catastrophic flooding, but there has been strong scientific debate over the role of forests in flood mitigation.

Forest loss is currently estimated at 13 million hectares each year, with 6 million hectares of that being primary forest previously untouched by human activities. These primary forests are considered the most biologically diverse ecosystems on the planet, but this realisation has not halted their immense rate of loss.

Last year my colleagues and I published a paper entitled Global evidence that deforestation amplifies flood risk and severity in the developing world in Global Change Biology (highlighted in Nature and Faculty of 1000) that has finally provided tangible evidence that there is a strong link between deforestation and flood risk. Read the rest of this entry »

Tropical turmoil – a biodiversity tragedy in progress

18 08 2008

fragmentationWe recently published (online) a major review showing that the world is losing the battle over tropical habitat loss with potentially disastrous implications for biodiversity and human well-being.

Published online in the Ecological Society of America’s journal Frontiers in Ecology and the Environment, our review Tropical turmoil – a biodiversity crisis in progress concludes that we are “on a trajectory towards disaster” and calls for an immediate global, multi-pronged conservation approach to avert the worst outcomes.

Tropical forests support more than 60 % of all known species, but represent only about 7 % of the Earth’s land surface. But up to 15 million hectares of tropical rainforest are being lost every year and species are being lost at a rate of up to 10000 times higher than would happen randomly without humans present.

This is not just a tragedy for tropical biodiversity, this is a crisis that will directly affect human livelihoods. This is not just about losing tiny species found in the canopies of big rain forest trees few people will ever see, this is about a complete change in ecosystem services that directly benefit human life. Read the rest of this entry »