Tropical forest resilience depends on past disturbance frequency

16 07 2014

I’ve recently come across an interesting study that perfectly marries palaeo-ecological data with modern conservation philosophy. It’s not often that such a prehistorical perspective dating at least to the Last Glacial Maximum has been used so effectively to inform future conservation outlooks. I’m particularly interested in this sort of approach considering my own palaeo dabblings of late.

Published in Nature Communications this May, Lydia Cole and colleagues’ paper Recovery and resilience of tropical forests after disturbance is a meta-analysis of 71 studies covering nearly 300 disturbance events in tropical forests over the last 20,000 years or so. Using fossil pollen records as an index of vegetation change, they demonstrated the (somewhat intuitive) main result that the time to recovery following a disturbance generally decreases as the past disturbance frequency increased.

This appears to be a vindication of the idea that a system’s adaptive strategies evolve as a product of the local disturbance regime. More importantly, they found that recovery was faster following ‘large infrequent events’, which are natural perturbations such as cyclones and major fires. While most past disturbances were caused by humans clearing forest, the fact that tropical forest systems were most resilient to ‘natural’ events means that if we can’t stop human disturbances, at least we can attempt to emulate natural processes to maximise the rebound potential. Much like many modern forestry operations try to emulate natural disturbances to limit their damage, we should at least manage our impacts by understanding so-called ‘natural’ regimes as much as possible. Read the rest of this entry »

Influential conservation papers of 2013

31 12 2013

big-splash1This is a little bit of a bandwagon – the ‘retrospective’ post at the end of the year – but this one is not merely a rehash I’ve stuff I’ve already covered.

I decided that it would be worthwhile to cover some of the ‘big’ conservation papers of 2013 as ranked by F1000 Prime. For copyright reasons, I can’t divulge the entire synopsis of each paper, but I can give you a brief run-down of the papers that caught the eye of fellow F1000 faculty members and me. If you don’t subscribe to F1000, then you’ll have to settle with my briefest of abstracts.

In no particular order then, here are some of the conservation papers that made a splash (positively, negatively or controversially) in 2013:

Read the rest of this entry »

Quantity, but not quality – slow recovery of disturbed tropical forests

8 11 2013

tropical regrowthIt is a sobering statistic that most of the world’s tropical forests are not ‘primary’ – that is, those that have not suffered some alteration or disturbance from humans (previously logged, cleared for agriculture, burned, etc.).

Today I highlight a really cool paper that confirms this, plus adds some juicy (and disturbing – pun intended – detail). The paper by Phil Martin and colleagues just published in Proceedings of the Royal Society B came to my attention through various channels – not least of which was their citation of one of our previous papers ;-), as well as a blog post by Phil himself. I was so impressed with it that I made my first Faculty of 1000 Prime recommendation1 of the paper (which should appear shortly).

As we did in 2011 (to which Phil refers as our “soon-to-be-classic work” – thanks!), Martin and colleagues amassed a stunning number of papers investigating the species composition of disturbed and primary forests from around the tropics. Using meta-analysis, they matched disturbed and undisturbed sites, recording the following statistics: Read the rest of this entry »

Conservation: So easy a child could do it

13 09 2013

child's playI don’t like to talk about my family online. Call me paranoid, but there are a lot of crazy people out there who don’t like what scientists like me are saying (bugger the evidence). Yes, like many climate scientists, I’ve also been threatened. That’s why my personal life remains anonymous except for a select group of people.

But I’ve mentioned my daughter before on this blog, and despite a few people insinuating that I am a bad parent because of what I said, I am happy that I made the point that climate change is a scary concept of which our children must at least be cognisant.

My daughter’s story today is a little less confronting, but equally enlightening. It’s also a little embarrassing as a scientist who has dedicated my entire research career to the discipline of conservation biology.

As a normal six year-old without the ability to refrain from talking – even for a moment – I hear a lot of stories. Many of them are of course fantastical and ridiculous, but those are just part of a healthy, imaginative childhood (I am proud to say though that she is quite clear about the non-existence of fictitious entities like faeries, easter bunnies and gods).

Every once in a while, however, there are snippets of wisdom that ooze out from the cracks in the dross. In the last few months, my daughter has independently and with no prompting from me come up with two pillars of conservation science: (i) protected areas and (ii) biodiversity corridors. Read the rest of this entry »

Having more tree species makes us wealthier

28 01 2013

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

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

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

Read the rest of this entry »

Damned by nature; damned by man

26 10 2012

I am a forest officer from India. I want to narrate a story. No, my story is not about elephants or tigers or snakes. Those stories about India are commonplace. I wish to narrate a simple story about people, the least-known part of the marathon Indian fable.

Humans are said to have arrived in India very early in world civilisation. Some were raised here from the seed of their ancestors; others migrated here from all over the world. Over the centuries these people occupied every inch of soil that could support life. The population of India today is 1.2 billion. Each year, India’s population increases by a number nearly equal to the complete population of Australia. Such a prolific growth of numbers is easy to explain; the fertile soil, ample water and tropical warmth of India support the growth of all life forms.

Not all numbers are great, however, and big numbers sometimes exact the price from the wrong persons.

This is my story.

I went to work in the state of Meghalaya in north-eastern India. Pestilence, floods and dense vegetation have made north-eastern India a most inhospitable place. Population is scanty by Indian standards. Life does not extend much beyond the basic chores of finding food and hearth. In the hills, far away from the bustle of modern civilisation, primitive tribal families practice agriculture in its most basic form. Fertilisers are unknown to them, so they cultivate a parcel of land until it loses its fertility, ultimately abandoning it to find other arable land. When the original parcel has finally recovered its fertility after a few years, they move back. It is a ceaseless cycle of migrating back and forth – the so-called practice known as ‘shifting cultivation’.  Ginger, peas, pumpkin, brinjal and sweet potato can be seen growing on numerous slopes in the Garo Hills of Meghalaya beside the huts of the farmers built on stilts, with chickens roosting below.

When I reached Meghalaya and looked about at the kind of world I had never seen before, I admit that I found the tribal folk a little strange. They lived in a way that would have appeared bizarre to a modern community. The people did not seem to know how many centuries had passed them by. For me as a forest officer, what looked worst was that that these people appeared to have no comprehension of the value of forests for the planet. They built their huts with wood. They cooked on firewood. Most of their implements were made of wood. A whole tree would be cut and thrown across the banks to make a bridge over a stream. Above all, their crazy practice of shifting cultivation would ultimately remove all the remaining forest.

I decided my main job in this place was to save the forest from its own people, and we enforced Indian laws to preserve the forests.

On one occasion my staff saw a young local man running with an illegally obtained log of wood and started to chase him, waving their guns in the air to scare him. He ran barefoot amid dense bushes a long distance before we managed to apprehend him. I had bruises on my arms and a leech hanging from my armpit drinking my blood by the time the race was over. I admit that in my anger at the time, I wanted to impale the man to the earth at the spot where he had cut down the tree. It was not the leeches and the bruises that angered me. The tree he was carrying was (until quite recently) in perfect condition.

But Meghalaya isn’t populated solely by subsistence-farming villagers – there are also a few successful traders originally from big cities who have settled in this economically depressed region. They dress smartly and speak impeccable English. At the time, I remembered wondering how these more sophisticated types could be maintaining their relatively lavish lifestyles among the poor villagers who walked barefoot in the dense forests. On a couple of occasions I dropped in at the home of a prominent trader.  He hosted me graciously in his beautiful home. I admit that I enjoyed these visits because they were my only link to the civilisation I had become used to prior to moving to Meghalaya. But I never visited the home of any tribal villager, for what could I talk to them about anyway?

Read the rest of this entry »

If a tree falls… preventing deforestation with insurance

3 05 2012

As CB readers will know, I’ve reported a few times on our iREDD idea, and it got a little pick-up overseas. Here’s a great article by Rachel Nuwer covering the concept, published in

Almost everything we own – our houses and cars and our very health – is insured. It works on a simple principal: the higher the risk, the higher the premium. It’s an age-old concept that ecological modelers have decided to apply to a new area: forest preservation.

A new proposal, published in the journal Conservation Letters, would create forest insurance to make the U.N. forest preservation program Reduced Emissions from Deforestation and forest Degradation, or REDD, more effective. REDD is generally supposed to function by paying developing countries to protect their forests in exchange for carbon pollution credits. Currently the program has 42 partner countries across the globe. The program is crucial to the fight against climate change since deforestation and forest degradation accounts for about 20 percent of global greenhouse gas emissions and threatens biodiversity.

“REDD is a fantastic idea,” said Corey Bradshaw, director of ecological modeling at the University of Adelaide and co-author of the study. “You get a carbon advantage and biodiversity doesn’t get wiped out at the same time, it seems perfect.”

But it has a few major flaws that the insurance scheme, called iREDD, seeks to remedy.

REDD only works if the parties are honest and stick to the agreement. Bradshaw doesn’t have much faith that will happen. “If there’s a way to cheat, people will cheat. That’s the nature of all life, not just humans, but we excel at it,” he said. If, for example, a country is paid to conserve one forest but moves its deforestation efforts to an adjacent forest in order to get both money and timber, in terms of carbon offsets, that transaction was a failure. This phenomenon is called “leakage.”

Carbon-capture also only works if it’s maintained indefinitely. If a country accepts money for ten years and then cuts its forest the day after the agreement expires, then all of that conservation was for naught. This issue is called “permanence,” usually translated into an arbitrarily defined period of time set by countries in terms of decades or centuries. Read the rest of this entry »


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