Four decades of fragmentation

27 09 2017

fragmented

I’ve recently read perhaps the most comprehensive treatise of forest fragmentation research ever compiled, and I personally view this rather readable and succinct review by Bill Laurance and colleagues as something every ecology and conservation student should read.

The ‘Biological Dynamics of Forest Fragments Project‘ (BDFFP) is unquestionably one of the most important landscape-scale experiments ever conceived and implemented, now having run 38 years since its inception in 1979. Indeed, it was way ahead of its time.

Experimental studies in ecology are comparatively rare, namely because it is difficult, expensive, and challenging in the extreme to manipulate entire ecosystems to test specific hypotheses relating to the response of biodiversity to environmental change. Thus, we ecologists tend to rely more on mensurative designs that use existing variation in the landscape (or over time) to infer mechanisms of community change. Of course, such experiments have to be large to be meaningful, which is one reason why the 1000 km2 BDFFP has been so successful as the gold standard for determining the effects of forest fragmentation on biodiversity.

And successful it has been. A quick search for ‘BDFFP’ in the Web of Knowledge database identifies > 40 peer-reviewed articles and a slew of books and book chapters arising from the project, some of which are highly cited classics in conservation ecology (e.g., doi:10.1046/j.1523-1739.2002.01025.x cited > 900 times; doi:10.1073/pnas.2336195100 cited > 200 times; doi:10.1016/j.biocon.2010.09.021 cited > 400 times; and doi:10.1111/j.1461-0248.2009.01294.x cited nearly 600 times). In fact, if we are to claim any ecological ‘laws’ at all, our understanding of fragmentation on biodiversity could be labelled as one of the few, thanks principally to the BDFFP. Read the rest of this entry »





Not all wetlands are created equal

13 02 2017

little-guyLast year I wrote what has become a highly viewed post here at ConservationBytes.com about the plight of the world’s freshwater biodiversity. In a word, it’s ‘buggered’.

But there are steps we can take to avoid losing even more of that precious freshwater biodiversity. The first, of course, is to stop sucking all the water out of our streams and wetlands. With a global population of 7.5 billion people and climbing, the competition for freshwater will usually mean that non-human life forms lose that race. However, the more people (and those making the decisions, in particular) realise that intact wetlands do us more good as wetlands rather than carparks, housing developments, or farmland (via freshwater filtering, species protection, carbon storage, etc.), the more we have a chance to save them.

My former MSc student, the very clever David Deane1, has been working tirelessly to examine different scenarios of wetland plant biodiversity change in South Australia, and is now the proud lead author of a corker of a new paper in Biological Conservation. Having already published one paper about how wetland plant biodiversity patterns are driven by rare terrestrial plants, his latest is a very important contribution about how to manage our precious wetlands. Read the rest of this entry »





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 »





Too small to avoid catastrophic biodiversity meltdown

27 09 2013
Chiew Larn

Chiew Larn Reservoir is surrounded by Khlong Saeng Wildlife Sanctuary and Khao Sok National Park, which together make up part of the largest block of rainforest habitat in southern Thailand (> 3500 km2). Photo: Antony Lynam

One of the perennial and probably most controversial topics in conservation ecology is when is something “too small’. By ‘something’ I mean many things, including population abundance and patch size. We’ve certainly written about the former on many occasions (see here, here, here and here for our work on minimum viable population size), with the associated controversy it elicited.

Now I (sadly) report on the tragedy of the second issue – when is a habitat fragment too small to be of much good to biodiversity?

Published today in the journal Science, Luke Gibson (of No substitute for primary forest fame) and a group of us report disturbing results about the ecological meltdown that has occurred on islands created when the Chiew Larn Reservoir of southern Thailand was flooded nearly 30 years ago by a hydroelectric dam.

As is the case in many parts of the world (e.g., Three Gorges Dam, China), hydroelectric dams can cause major ecological problems merely by flooding vast areas. In the case of Charn Liew, co-author Tony Lynam of Wildlife Conservation Society passed along to me a bit of poignant and emotive history about the local struggle to prevent the disaster.

“As the waters behind the dam were rising in 1987, Seub Nakasathien, the Superintendent of the Khlong Saeng Wildlife Sanctuary, his staff and conservationist friends, mounted an operation to capture and release animals that were caught in the flood waters.

It turned out to be distressing experience for all involved as you can see from the clips here, with the rescuers having only nets and longtail boats, and many animals dying. Ultimately most of the larger mammals disappeared quickly from the islands, leaving just the smaller fauna.

Later Seub moved to Huai Kha Khaeng Wildlife Sanctuary and fought an unsuccessful battle with poachers and loggers, which ended in him taking his own life in despair in 1990. A sad story, and his friend, a famous folk singer called Aed Carabao, wrote a song about Seub, the music of which plays in the video. Read the rest of this entry »





The invisible hand of ecosystem services

4 08 2012

I’ve just spent nearly an entire week trying to get my head around ecosystem services (ES).

You’d think that would have been a given based on my experience, my research, my writings and the fact that I’ve just spent the last week with 400 ES specialists from around the world at the 5th international Ecosystem Services Partnership (ESP) Conference in Portland, Oregon, USA.

Well, prior to this week I thought I knew what ES were, but now I think I’m just a little more confused.

Of course, I’m not talking about the concept of ES or what they are (hell, I’ve written enough about them on this blog and in my papers); my problem is understanding how we as society end up valuing them in a practical, sensible and feasible way.

So I’m going to describe the ESP Conference as I saw it, and not necessarily in chronological order.

First up is the term ‘ecosystem services’ itself – horrible name, and something rammed home again after attending the conference. Most people on the planet that are not scientists (that would be nearly everyone) just might have the most tenuous and ethereal of grasps of ‘ecosystem’ in the first place, and I’d bet that 99 % of most undergraduate students couldn’t provide a comprehensive description. This is because ecosystems are mind-bogglingly, chaotically and awesomely complex. Just ask any ecosystem ecologist.

The second part of the term – services – is particularly offensive in its presumption and arrogance. It’s not like you ring up an ecosystem and get it to clean your carpets, or fill your water tank or gas cylinder. No, the natural world did not evolve to pamper humanity; we are merely part of it (and bloody efficient at modifying it, I might add).

So try to sell this ‘incredibly complex thingy’ that is ‘there to do some (intangible) shit for us’ to the public, policy makers and politicians, and you mostly get a dog’s regurgitated breakfast and some blank, slack-jawed stares. Read the rest of this entry »





Deforestation partly to blame for Queensland floods

17 01 2011

© recoverling

Last week I sent a fairly random Tweet about deforestation in south-eastern Queensland being partially responsible for the record floods there. It went more or less unnoticed, but I thought the comment deserved a proper explanation.

As many of you might know, my colleagues and I wrote an article a few years ago about the global-scale evidence for deforestation leading to a higher incidence and severity of floods in the developing world. This was fairly controversial, but it was nonetheless the first broad-scale evidence for the fabled deforestation-flood link yet published (in my not-so-humble opinion). Subsequent comment reiterated the point with new data.

Now, I will begin by saying I have no data yet to back up my Queensland-specific hypothesis, but I am contemplating a time-series paper on floods in Australia, especially after the events of the last month. This post is therefore merely a reasoned hypothesis.

The hypothesis itself is rather simple. Testing is not. I submit that the recent flooding in Australia has been exacerbated (not caused) by the rapid loss of forest cover over the last 40 years. We know that this is a particularly intense La Niña in Australia and our unusually high rainfall arises from this meteorological phenomenon, but I hypothesise that it wouldn’t have been as bad if this part of Australia hadn’t been so careless with its forest cover since the 1970s. Read the rest of this entry »





Yangtze River, colossal dams and famous scientists

23 10 2010

 


© CJA Bradshaw

 

Apologies for the silence over the last week – I’ve been a little preoccupied with some business in China. I’ll devote an entire post to my recent trip there (actually, I’m still there – Beijing to be precise), but I thought I’d just explain my absence and provide a little post to sate you until next week.

It’s worth mentioning that I had the enlightening experience of travelling down the Yangtze River between Chongqing and Sandouping last week – this is the area that was flooded by the world’s largest hydro-electric project, the Three Gorges Dam. This is my fourth trip to China and I’ve usually come away with the adjective ‘big’ describing pretty much everything I see here (big agriculture, big population, big pollution, big hotels, big cities…); however, in this case, ‘big’ doesn’t even come close. It’s bloody massive, and the ecological devastation (not to mention the 1.3 million people it displaced) is hard to describe in words. Sure, there are beautiful bits left (see the accompanying photo), but most of the damage is under water and along the banks of the mighty (and now, a lot mightier) Yangtze River. Read the rest of this entry »