Give way to the invader

25 01 2012

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.

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 fragmentation1-3.

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. Read the rest of this entry »





The seeds of tropical forest destruction

22 01 2012

www.sumatranforest.org

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

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.

Read the rest of this entry »





Slicing the second ‘lung of the planet’

12 12 2011

© WWF

Apologies for the slow-down in postings this past week – as many of you know, I was attending the International Congress for Conservation Biology in Auckland. I’ll blog about the conference later (and the stoush that didn’t really occur), but suffice it to say it was very much worthwhile.

This post doesn’t have a lot to do per se with the conference, but it was stimulated by a talk I attended by Conservation Scholar Stuart Pimm. Now, Stuart is known mainly as a tropical conservation biologist, but as it turns out, he also is a champion of temperate forests – he even sits on the science panel of the International Boreal Conservation Campaign.

I too have dabbled in boreal issues over my career, and most recently with a review published in Trends in Ecology and Evolution on the knife-edge plight of boreal biodiversity and carbon stores. That paper was in fact the result of a brain-storming session Navjot Sodhi and I had one day during my visit to Singapore sometime in 2007. We thought, “It doesn’t really seem that people are focussing their conservation attention on the boreal forest; how bad is it really?”.

Well, it turns out that the boreal forest is still a vast expanse and that there aren’t too many species in imminent danger of extinction; however, that’s where the good news ends. The forest itself is becoming more and more fragmented from industrial development (namely, forestry, mining, petroleum surveying and road-building) and the fire regime has changed irrevocably from a combination of climate change and intensified human presence. You can read all these salient features here.

So, back to my original thread – Stuart gave a great talk on the patterns of deforestation worldwide, with particular emphasis on how satellite imagery hides much of the fine-scale damage that we humans do to the world’s great forests. It was when he said (paraphrased) that “50,000 km2 of boreal forest is lost each year, but even that statistic hides a major checkerboard effect” that my interest was peaked. Read the rest of this entry »





Little left to lose: deforestation history of Australia

6 10 2011

© donkeycart http://ow.ly/6OSeX

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: Read the rest of this entry »





1 million hectares annually – the forest destruction of Indonesia

30 09 2011

© 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.

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. Read the rest of this entry »





How buggered are our hairy red cousins?

23 08 2011

Here’s a post from one of our lab’s post-doctoral fellows, Dr. Stephen Gregory. Stephen just got back from Borneo (jammy bastard), and will now regale you with his exploits.

© Danau Girang Field Centre

When asked to name a Bornean animal, I’ll bet the Bornean orangutan (Pongo pygmaeus) would top a public survey. This charismatic animal shares over 95 % of its genome with Homo sapiens, and so it’s little wonder that we find their infants so adorable and their popularity in the pet trade so deplorable.

Yet, I wonder how many people know that the biggest threat to our hairy red cousin is actually human eating and hygiene habits? Palm oil (oil extracted from the kernel of Elaeis spp.) is used in many foods – particularly snack foods – and hygiene products. It is our addiction to these convenient products that is destroying the orangutan’s habitat.

I’ve just returned from a trip to Sabah, the northernmost Malaysian state on Borneo, where I witnessed this distressing truth firsthand. I was meeting with the Sabah Wildlife Department, French NGO Hutan and staff at the Danau Girang Field Centre  to discuss early results from my Sabah orangutan project and seek their expert opinions. Read the rest of this entry »





Over-estimating extinction rates

19 05 2011

I meant to get this out yesterday, but was too hamstrung with other commitments. Now the media circus has beat me to the punch. Despite the lateness (in news-time) of my post, my familiarity with the analysis and the people involved gives me a unique insight, I believe.

So a couple of months ago, Fangliang He and I were talking about some new analysis he was working on where he was testing the assumption that back-casted species-area relationships (SAR) gave reasonable estimates of inferred extinction rates. Well, that paper has just been published in today’s issue of Nature  by Fangliang He and Stephen Hubbell entitled: Species–area relationships always overestimate extinction rates from habitat loss (see also the News & Views piece by Carsten Rahbek and Rob Colwell).

The paper has already stirred up something of a controversy before the ink has barely had time to dry. Predictably, noted conservation biologists like Stuart Pimm and Michael Rosenzweig have already jumped down Fangliang’s throat.

Extinction rates of modern biota in the current biodiversity crisis (Ehrlich & Pringle 2008) are wildly imprecise. Indeed, it has been proposed that extinction rates exceed the deep-time average background rate by 100- to 10000-fold (Lawton & May 2008; May et al. 1995; Pimm & Raven 2000), and no rigorously quantification of these rates globally has ever been accomplished (although there are several taxon- and region-specific estimates of localised extinction rates (Brook et al. 2003; Regan et al. 2001; Hambler et al. 2011; Shaw 2005).

Much of the information used to infer past extinction rate estimates is based on  the species-area relationship (e.g., Brook et al. 2003); this method estimates extinction rates by reversing the species-area accumulation curve, extrapolating backward to smaller areas to calculate expected species loss. The concept is relatively simple, even though the underlying mathematics might not be. 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 ConservationBytes.com, 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 »





How fast are we losing species anyway?

28 03 2011

© W. Laurance

I’ve indicated over the last few weeks on Twitter that a group of us were recently awarded funding from the Australian Centre for Ecological Synthesis and Analysis – ACEAS – (much like the US version of the same thing – NCEAS) to run a series of analytical workshops to estimate, with a little more precision and less bias than has been done previously, the extinction rates of today’s biota relative to deep-time extinctions.

So what’s the issue? The Earth’s impressive diversity of life has experienced at least five mass extinction events over geological time. Species’ extinctions have kept pace with evolution, with more than 99 % of all species that have ever existed now gone (Bradshaw & Brook 2009). Despite general consensus that biodiversity has entered the sixth mass extinction event because of human-driven degradation of the planet, estimated extinction rates remain highly imprecise (from 100s to 10000s times background rates). This arises partly because the total number of species is unknown for many groups, and most extinctions go unnoticed.

So how are we going to improve on our highly imprecise estimates? One way is to look at the species-area relationship (SAR), which to estimate extinction requires one to extrapolate back to the origin in taxon- and region-specific SARs (e.g., with a time series of deforestation, one can estimate how many species would have been lost if we know how species diversity changes in relation to habitat area). Read the rest of this entry »





Wolves masquerading as sheep: the fallout

29 10 2010

 


© New Zealand Films

 

Well, we’ve managed to stimulate quite a lively conversation after dropping the Open Letter about Scientific Credibility and the Conservation of Tropical Forests regarding the questionable tactics employed by Alan Oxley and his industrial lobbyist organisations.

Mr. Oxley has responded with vitriol, hand-waving, red herrings and straw men, and failed to address even a single one of our accusations. I am particularly amused by his insinuation that we, the proven scientists, don’t know what science is – but that he does.

Below I reproduce Mr. Oxley’s reaction to our original letter, followed by our response.

I’ll let you, the reader, decide who is most reasonable.

REACTION FROM ALAN OXLEY

There is too much pseudo-scientific hype today about environmentalism and forestry and not enough fact.

I put this double-barrelled question to the Group of 12 scientists who have rather laboriously wandered over the work of World Growth: What biodiversity is expressly protected by a global cessation of conversion of forest land to other purposes and how is that biodiversity scientifically measured? And let’s have some technical response, not political blather. Read the rest of this entry »





Global erosion of ecosystem services

14 09 2010

A few months ago I was asked to give a lecture about erosion of ecosystem services to students in the University of Adelaide‘s Issues in Sustainable Environments unit. I gave that lecture last week and just uploaded a slidecast of the presentation (with audio) today.

I’ve reproduced the lecture here for your viewing pleasure. I hope you find the 45-minute presentation useful. Note that the first few minutes cover me referring to the Biodiversity film short that I posted not too long ago.

CJA Bradshaw





Global rates of forest loss – everyone’s a bastard

29 04 2010

© A. Hesse

I’ve written rather a lot about rates of forest loss around the world, including accumulated estimates of tropical forest loss and increasing fragmentation/loss in the boreal forest (see Bradshaw et al. 2009 Front Ecol Evol & Bradshaw et al. 2009 Trends Ecol Evol). For the tropics in particular, we used the index that an area of rain forest about the size of Bangladesh (> 15 million hectares) was disappearing each year, and in Russia alone, annual decline in forest area averaged 1.1 million hectares between 1988 and 1993. Mind boggling, really.

But some of these estimates were a bit old, relied on some imprecise satellite data, and didn’t differentiate forest types well. In addition, many have questioned whether the rates are continuing and which countries are being naughty or nice with respect to forest conservation.

It was great therefore when I came across a new paper in PNAS by Hansen & colleagues entitled Quantification of global gross forest cover loss because it answered many of the latter questions.

Part of the problem in assessing worldwide forest cover loss in the past was the expense of satellite imagery, access problems, data storage and processing issues. Happily, new satellite streams and easing of access has rectified many of these limitations. Hansen & colleagues took advantage of data from the MODIS sensor to create a stratification for forest cover loss. They then used the Landsat ETM+ sensor as the primary data for quantifying gross forest cover loss for the entire planet from 2000 to 2005. They defined ‘forest cover’ as “… 25% or greater canopy closure at the Landsat pixel scale (30-m × 30-m spatial resolution) for trees > 5 m in height”.

For your reading pleasure (and conservation horror), the salient features were: Read the rest of this entry »





New April Issue of Conservation Letters out now

22 04 2010

Low intensity fire in a longleaf pine-wiregrass system

Another great line up of papers has just come out in the April Issue of Conservation Letters:

CJA Bradshaw

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China’s insatiable lust for tropical timber

4 04 2010

If you’ve been following ConservationBytes.com for the past few weeks, you’ll know that William Laurance was in town and gave a fantastic set of talks (download podcasts here). As a parting gift, he put together a brief post on one huge aspect of the tropical deforestation crisis we know face. Thanks, Bill.

© AAAS

I greatly enjoyed my recent visit to the University of Adelaide, and especially want to thank my host, Corey Bradshaw, for showing me a wonderful time there.

Corey asked me to contribute a brief blog for ConservationBytes.com and so I thought I’d highlight a paper in Science last week by my old friend Jianguo “Jack” Liu at Michigan State University. In his paper China’s road to sustainability, Jack describes the battle to improve environmental sustainability in China–a battle that is not progressing very well, all factors considered.

China’s explosive economic growth and environmental deterioration is also affecting other countries, especially those with timber, minerals or other resources that China wants. Today, more than half of the timber shipped anywhere in the world is destined for China–some 45 million m3 per year, an incredible total. Read the rest of this entry »





Don’t miss Bill

25 03 2010

Yes, yes, I know I’ve posted only a little under two weeks ago that the venerable William (Bill) Laurance is coming to Adelaide, and anyone even remotely interested in biodiversity conservation would be a fool to miss his talks, and ra, ra, ra…

Well, you would be.

However, I don’t want anyone to miss this opportunity simply because of non-recognition. So I thought it prudent to remind people just how special this visit is, and what a researcher extraordinaire Bill really is. For those not necessarily following the trends in tropical conservation biology (probably not many in Adelaide, at least), you might not necessarily recognise his name.

So, I thought I’d give a little broadsheet of his achievements, Read the rest of this entry »





Bill Laurance coming to Adelaide

13 03 2010

We’ve got a real treat for biodiversity buffs scheduled for the end of March. Eminent (Distinguished, Famous, Respected… the list goes on) Professor William (Bill) Laurance is briefly leaving his tropical world and coming south to the temperate climes of Adelaide to regale us with his fascinating biodiversity research career.

Bill is a leading conservation biologist who has worked internationally on many high-profile threats to tropical forests—in the Amazon, Central America, Africa, and Australasia. A highly prolific scientist, to date he has published five books and over 300 scientific articles. Bill has recently commenced a position as Distinguished Research Professor at James Cook University and is involved with the Smithsonian Tropical Research Institute in Panama. He also happens to be the bloke that blew the lid open on the devastating effects of tropical fragmentation in the Amazon with some of the best long-term experiments ever done in conservation biology.

I’m personally very pleased for several reasons: (1) Although I have never met Bill in person yet, I’ve recently co-authored two papers with him (Wash and spin cycle threats to tropical biodiversity and Improving the performance of the Roundtable on Sustainable Palm Oil for nature conservation) and I’m keen to meet the man behind the pen; (2) we have had many email discussions (some of them rather heated!), so I’m keen to flesh some of these out over a nice glass of South Australian Shiraz; (3) he’s been a keen supporter of my work for years, and has given me many opportunities to get my research noticed; and (4) it’s high time to met one of ConservationBytes.com Conservation Scholars.

Bill has recently shifted shop from Panama (Smithsonian Tropical Research Institute) to Australia’s own James Cook University, and so we at the Environment Institute thought we should take advantage of his geographical disorientation and bring him down south for a while. But he’s going to have to sing for his supper, so he’s kindly agreed to give three talks in 3 days from 29-31 March 2010.

His first talk (on Monday 29 March) will be an in-house Environment Institute seminar, but the second two will be public events that I urge anyone remotely interested in biodiversity conservation research to attend. In fact, his Tuesday 30 March presentation (18.00-20.00 Napier G03, University of Adelaide) is even more generic than that, and word on the street is it is highly entertaining and extremely well attended wherever Bill’s is gracious enough to give it:

Amplify Your Voice: Keys to Having a Prolific Scientific Career (and Bill would know).

This will include (1) How to be more prolific: strategies for writing and publishing scientific papers and (2) Further ways to maximise your scientific impact – interacting with the popular media and how to promote yourself. Each topic will run for 50 minutes and will include 10 minutes for audience questions. A tea and coffee break will be held between sessions. Book here.

His second public talk on Wednesday 31 March (18.00-19.30 Napier 102, University of Adelaide) will be:

Diagnosis Critical | The lungs of our Planet

Here he will be discussing how the forests of our world are in crisis. Our drive for continued economic growth has had devastating consequences for the world’s ecosystems that provide critical human services. Our forests are a haven for countless plant and animal species that form the basis of ecological services, these services are the biological mechanisms that make the world our home. Book here.

So, if you have a couple of free nights at the end of the month and are in Adelaide, I strongly recommend you come out and see Bill do his thing.

CJA Bradshaw

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Covet thy neighbour’s paddock

2 03 2010

Apologies to Matt Lucas

An interesting, frightening and and at the same time, potentially hopeful, paper has just appeared in the latest issue of Proceedings of the Royal Society B.

Co-authored by a previously highlighted Conservation Scholar Georgina Mace, the paper by Boakes and colleagues entitled Extreme contagion in global habitat clearance is probably one of the strongest bits of evidence to save intact habitat complexes.

Yes, yes – save things so you don’t destroy biodiversity. What’s new about that? Well, Boakes and colleagues’ paper shows at a global scale that over the last 300+ years, the chance of a patch of forest or grassland being converted to agriculture depends strongly on whether its neighbouring patch has already been cleared. In other words, once you start to hack away at natural habitats, people have a tendency to assume that it’s perfectly acceptable to do the same on their own patch.

The authors reprojected the History Database of the Global Environment to ~ a 50 x 50 grid and examined habitat conversion from 1700 to the present (in 50-year increments). Using some rather simple contagion statistics, they came up with the startling result that conversion probability is strongly dependent on whether an adjacent cell has already been converted.

What I found particularly frightening was the result that:

“A quarter of the world’s forest and half its grassland has been converted to agriculture since 1700.”

and from a personal perspective, the highest grassland conversion rates have happened in Australasia (the highest forest conversion rates have been in the Indo-Malay and Nearctic realms).

What are the implications for conservation? In my opinion, this relatively simple analysis and result confirms even more strongly that saving intact, large tracts of forest and grassland is essential for long-term biodiversity conservation. Cutting up the forest into smaller bits not only compromises biodiversity via fragmentation, it ends up speeding the entire process of full-scale ecosystem degradation.

‘Get ‘em protected while they’re still unaffected’.

CJA Bradshaw

ResearchBlogging.orgBoakes, E., Mace, G., McGowan, P., & Fuller, R. (2009). Extreme contagion in global habitat clearance Proceedings of the Royal Society B: Biological Sciences, 277 (1684), 1081-1085 DOI: 10.1098/rspb.2009.1771

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Conservation Biology for All

26 12 2009

A new book that I’m proud to have had a hand in writing is just about to come out with Oxford University Press called Conservation Biology for All. Edited by the venerable Conservation Scholars, Professors Navjot Sodhi (National University of Singapore) and Paul Ehrlich (Stanford University), it’s a powerhouse of some of the world’s leaders in conservation science and application.

The book strives to “…provide cutting-edge but basic conservation science to a global readership”. In short, it’s written to bring the forefront of conservation science to the general public, with OUP promising to make it freely available online within about a year from its release in early 2010 (or so the rumour goes). The main idea here is that those in most need of such a book – the conservationists in developing nations – can access the wealth of information therein without having to sacrifice the village cow to buy it.

I won’t go into any great detail about the book’s contents (mainly because I have yet to receive my own copy and read most of the chapters!), but I have perused early versions of Kevin Gaston‘s excellent chapter on biodiversity, and Tom Brook‘s overview of conservation planning and prioritisation. Our chapter (Chapter 16 by Barry Brook and me), is an overview of statistical and modelling philosophy and application with emphasis on conservation mathematics. It’s by no means a complete treatment, but it’s something we want to develop further down the track. I do hope many people find it useful.

I’ve reproduced the chapter title line-up below, with links to each of the authors websites.

  1. Conservation Biology: Past and Present (C. Meine)
  2. Biodiversity (K. Gaston)
  3. Ecosystem Functions and Services (C. Sekercioglu)
  4. Habitat Destruction: Death of a Thousand Cuts (W. Laurance)
  5. Habitat Fragmentation and Landscape Change (A. Bennett & D. Saunders)
  6. Overharvesting (C. Peres)
  7. Invasive Species (D. Simberloff)
  8. Climate Change (T. Lovejoy)
  9. Fire and Biodiversity (D. Bowman & B. Murphy)
  10. Extinctions and the Practice of Preventing Them (S. Pimm & C. Jenkins)
  11. Conservation Planning and Priorities (T. Brooks)
  12. Endangered Species Management: The US Experience (D. Wilcove)
  13. Conservation in Human-Modified Landscapes (L.P. Koh & T. Gardner)
  14. The Roles of People in Conservation (A. Claus, K. Chan & T. Satterfield)
  15. From Conservation Theory to Practice: Crossing the Divide (M. Rao & J. Ginsberg)
  16. The Conservation Biologist’s Toolbox – Principles for the Design and Analysis of Conservation Studies (C. Bradshaw & B. Brook)

As you can see, it’s a pretty impressive collection of conservation stars and hard-hitting topics. Can’t wait to get my own copy! I will probably blog individual chapters down the track, so stay tuned.

CJA Bradshaw

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Connectivity paradigm in extinction biology

6 10 2009

networkI’m going to do a double review here of two papers currently online in Proceedings of the Royal Society B: Biological Sciences. I’m lumping them together because they both more or less challenge the pervasive conservation/restoration paradigm that connectivity is the key to reducing extinction risk. It’s just interesting (and slightly amusing) that the two were published in the same journal and at about the same time, but by two different groups.

From our own work looking at the correlates of extinction risk (measured mainly by proxy as threat risk), the range of a population (i.e., the amount of area and number of habitats it covers) is the principal determinant of risk – the smaller your range, the greater your chance of shuffling off this mortal coil (see also here). This is, of course, because a large range usually means that you have some phenotypic plasticity in your habitat requirements, you can probably disperse well, and your not going to succumb to localised ‘catastrophes’ as often. It also probably means (but not always) that your population size increases as your range size increases; as we all know, populations must be beyond their minimum viable population size to have a good chance of persisting random demographic and environmental vagaries.

Well, the two papers in question, ‘Both population size and patch quality affect local extinctions and colonizations‘ by Franzén & Nilssen and ‘Environment, but not migration rate, influences extinction risk in experimental metapopulations‘ by Griffen & Drake, show that connectivity (i.e., the probability that populations are connected via migration) are probably the least important components in the extinction-persistence game.

Using a solitary bee (Andrena hattorfiana) metapopulation in Sweden, Franzén & Nilssen show that population size and food patch quality (measured by number of pollen-producing plants) were directly (but independently) correlated with extinction risk. Bigger populations in stable, high-quality patches persisted more readily. However, connectivity between patches was uncorrelated with risk.

Griffen & Drake took quite a different approach and stacked experimental aquaria full of daphnia (Daphnia magna) on top of one another to influence the amount of light (and hence, amount of food from algal growth) to which the populations had access (it’s interesting to note here that this was unplanned in the experiment – the different algal growth rates related to the changing exposure to light was a serendipitous discovery that allowed them to test the ‘food’ hypothesis!). They also controlled the migration rate between populations by varying the size of holes connecting the aquaria. In short, they found that environmentally influenced (i.e., food-influenced) variation was far more important at dictating population size and fluctuation than migration, showing again that conditions promoting large population size and reducing temporal variability are essential for reducing extinction risk.

So what’s the upshot for conservation? Well, many depressed populations are thought to be recoverable by making existing and fragmented habitat patches more connected via ‘corridors’ of suitable habitat. The research highlighted here suggests that more emphasis should be placed instead on building up existing population sizes and ensuring food availability is relatively constant instead of worrying about how many trickling migrants might be moving back and forth. This essentially means that a few skinny corridors connecting population fragments will probably be insufficient to save our imperilled species.

CJA Bradshaw

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ResearchBlogging.org

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Franzen, M., & Nilsson, S. (2009). Both population size and patch quality affect local extinctions and colonizations Proceedings of the Royal Society B: Biological Sciences DOI: 10.1098/rspb.2009.1584

Griffen, B., & Drake, J. (2009). Environment, but not migration rate, influences extinction risk in experimental metapopulations Proceedings of the Royal Society B: Biological Sciences DOI: 10.1098/rspb.2009.1153





How to make an effective marine protected area

22 09 2009

Here’s a nice little review from the increasingly impressive Frontiers in Ecology and the Environment which seems to be showcasing a lot of good conservation research lately.

© USGS

© USGS

As we know, the world’s oceans are under huge threat, with predictions of 70 % loss of coral reefs by 2050, decline in kelp forests, loss of seagrasses, over-fishing, pollution and a rapidly warming and acidifying physical environment. Given all these stressors, it is absolutely imperative we spend a good deal of time thinking about the right way to impose restrictions on damage to marine areas – the simplest way to do this is via marine protected areas (MPA).

The science of MPA network design has matured over the last 10-20 years such that there is a decent body of literature now on what we need to do (now the policy makers just have to listen – some  progress there too, but see also here). McLeod and colleagues in the latest issue of Frontiers in Ecology and the Environment have published a review outlining the best, at least for coral reefs, set of recommendations for MPA network design given available information (paper title: Designing marine protected area networks to address the impacts of climate change). Definitely one for the Potential list.

Here’s what they recommend:

Size

  • bigger is always better
  • minimum diameter of an MPA should be 10-20 km to ensure exchange of propagules among protected benthic populations

Shape

  • simple shapes best (squares, rectangles)
  • avoid convoluted shapes to minimise edge effects

Representation

  • protect at least 20-30 % of each habitat

Replication

  • protect at least 3 examples of each marine habitat

Spread

  • select MPA in a variety of temperature regimes to avoid risk of all protected reefs succumbing to future climate changes

Critical Areas

  • protect nursery areas, spawning aggregations, and areas of high species diversity
  • protect areas demonstrating natural resilience or rapid recovery from previous disturbances

Connectivity

  • measure connectivity between MPA to ensure replenishment
  • space maximum distance of 15-20 km apart
  • include whole ecological units
  • buffer core areas
  • protect adjacent areas such as outlying reefs, seagrass beds, mangroves

Ecosystem Function

  • maintain key functional groups of species (e.g., herbivorous fishes)

Ecosystem Management

  • embed MPA in broader management frameworks addressing other threats
  • address and rectify sources of pollution
  • monitor changes

Of course, this is just a quick-and-dirty list as presented here – I highly recommend reading the review for specifics.

CJA Bradshaw

ResearchBlogging.orgMcLeod, E., Salm, R., Green, A., & Almany, J. (2009). Designing marine protected area networks to address the impacts of climate change Frontiers in Ecology and the Environment, 7 (7), 362-370 DOI: 10.1890/070211








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