It’s not always best to be the big fish

3 02 2016

obrien_fish_2Loosely following the theme of last week’s post, it’s now fairly well established that humans tend to pick on the big species first.

From fewer big trees, declines of big carnivores, elephant & rhino poaching, to fishing down the web, big species tend to cop it hardest when it comes to human-caused ecological disturbance.

While there are a lot of different combinations of traits that make some species more vulnerable to extinction than others (see examples for legumes, amphibians, sharks & teleosts, and mammals), one of the main ones is species size.

Generally speaking, larger species tend to produce fewer offspring and breed later in life than smaller species. This means that despite larger species tending to live longer than their smaller counterparts, their ‘slow’ reproductive output means that they are generally more susceptible to rapid environmental change (mainly via human intervention). In other words, their capacity for self-replacement is often too low to counteract the offtake from direct exploitation or habitat loss.

Despite a reasonable scientific understanding of this extinction-risk principle, the degree to which human disturbance affects species’ distributions is much less well quantified, and this is especially true for marine species.

I’m proud to announce another fascinating paper led by my postdoc, Camille Mellin, that has just come out online in Nature CommunicationsHumans and seasonal climate variability threaten large-bodied coral reef fish with small ranges.

With the world’s largest combined dataset of coral reef fish surveys for the entire Indo-Pacific (including the coral reef fish biodiversity hotspot — the Coral Triangle), we examined which conditions best described the distribution of fishes over a range of body sizes. Read the rest of this entry »

Rise of the phycologists

22 09 2011

Dead man's fingers (Codium fragile) - © CJA Bradshaw

I’ve had an interesting week. First, it’s been about 6 years since I was last in Japan, and I love coming here; the food is exquisite, the people are fantastic (polite, happy, accommodating), everything works (trains, buses, etc.) and most importantly, it has an almost incredible proportion of its native forests intact.

But it wasn’t for forests that I travelled to Japan (nor the sumo currently showing on the guest-room telly where I’m staying – love the sumo): I was here for a calcareous macroalgae workshop.


First, what are ‘macroalgae’, and why are some ‘calcareous’? And why should anyone in their right mind care?

Good questions. Answers: 1. Seaweeds; 2. Many incorporate calcium carbonate into their structures as added structural support; 3. Read on.

Now, I’m no phycologist (seaweed scientist), but I’m fascinated by this particular taxon. I’ve written a few posts about their vital ecological roles (see here and here), but let me regale you with some other important facts about these amazing species.

Some Japanese macroalgae - © CJA Bradshaw

There are about 12,000 known species of macroalgae described by phycologists, but as I’ve learnt this week, this is obviously a vast underestimate. For most taxa that people are investigating now using molecular techniques, the genetic diversity is so high and so geographically structured that there are obviously a huge number of ‘cryptic’ species within our current taxonomic divisions. This could mean that we’re out by up to a factor of 2 in the number of species in the world.

Another amazing fact – about 50 % of all known seaweed species are found in just two countries – Japan and Australia (hence the workshop between Japanese and Australian phycologists). Southern Australia in particular is an endemism hotspot.

Ok. Cool. So far so good. But so what? Read the rest of this entry »

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

Add to FacebookAdd to NewsvineAdd to DiggAdd to Del.icio.usAdd to StumbleuponAdd to RedditAdd to BlinklistAdd to Ma.gnoliaAdd to TechnoratiAdd to Furl

Carbon = biodiversity

21 12 2009

I’ve decided to blog this a little earlier than I would usually simply because the COP15 is still fresh in everyone’s minds and the paper is now online as an ‘Accepted Article’, so it is fully citable.

The paper published in Conservation Letters by Strassburg and colleagues is entitled Global congruence of carbon storage and biodiversity in terrestrial ecosystems is noteworthy because it provides a very useful answer to a very basic question. If one were to protect natural habitats based on their carbon storage potential, would one also be protecting the most biodiversity (and of course, vice versa)?

Turns out, one would.

Using a global dataset of ~ 20,000 species of mammal, bird and amphibian, they compared three indices of biodiversity distribution (species richness, species threat & range-size rarity) to a new global above- and below-ground carbon biomass dataset. It turns out that at least for species richness, the correlations were fairly strong (0.8-ish, with some due to spatial autocorrelation); for threat and rarity indices, the correlations were rather weaker (~0.3-ish).

So what does this all mean for policy? Biodiversity hotspots – those areas around the globe with the highest biodiversity and greatest threats – have some of the greatest potential to store carbon as well as guard against massive extinctions if we prioritise them for conservation. Places such as the Amazon, Borneo Sumatra and New Guinea definitely fall within this category.

However, not all biodiversity hotspots are created equal; areas such as Brazil’s Cerrado or the savannas of the Rift Valley in East Africa have relatively lower carbon storage, and so carbon-trading schemes wouldn’t necessarily do much for biodiversity in these areas.

The overall upshot is that we should continue to pursue carbon-trading schemes such as REDD (Reduced Emissions from Deforestation and forest Degradation) because they will benefit biodiversity (contrary to what certain ‘green’ organisations say about it), but we can’t sit back and hope that REDD will solve all of biodiversity’s problems world wide.


Add to FacebookAdd to NewsvineAdd to DiggAdd to Del.icio.usAdd to StumbleuponAdd to RedditAdd to BlinklistAdd to Ma.gnoliaAdd to TechnoratiAdd to Furl

ResearchBlogging.orgStrassburg, B., Kelly, A., Balmford, A., Davies, R., Gibbs, H., Lovett, A., Miles, L., Orme, C., Price, J., Turner, R., & Rodrigues, A. (2009). Global congruence of carbon storage and biodiversity in terrestrial ecosystems Conservation Letters DOI: 10.1111/j.1755-263X.2009.00092.x

Few people, many threats – Australia’s biodiversity shame

31 07 2009

bridled_nailtail_400I bang on a bit about human over-population and how it drives biodiversity extinctions. Yet, it isn’t always hordes of hungry humans descending on the hapless species of this planet  – Australia is a big place, but has few people (just over 20 million), yet it has one of the higher extinction rates in the world. Yes, most of the country is covered in some fairly hard-core desert and most people live in or near the areas containing the most species, but we have an appalling extinction record all the same.

A paper that came out recently in Conservation Biology and was covered a little in the media last week gives some telling figures for the Oceania region, and more importantly, explains that we have more than enough information now to implement sound, evidence-based policy to right the wrongs of the past and the present. Using IUCN Red List data, Michael Kingsford and colleagues (paper entitled Major conservation policy issues for biodiversity in Oceania), showed that of the 370 assessed species in Australia, 80 % of the threatened ones are listed because of habitat loss, 40 % from invasive species and 30 % from pollution. As we know well, it’s mainly habitat loss we have to control if we want to change things around for the better (see previous relevant posts here, here & here).

Kingsford and colleagues proceed to give a good set of policy recommendations for each of the drivers identified:

Habitat loss and degradation

  • Implement legislation, education, and community outreach to stop or reduce land clearing, mining, and unsustainable logging through education, incentives, and compensation for landowners that will encourage private conservation
  • Establish new protected areas for habitats that are absent or poorly represented
  • In threatened ecosystems (e.g., wetlands), establish large-scale restoration projects with local communities that incorporate conservation and connectivity
  • Establish transparent and evidence-based state of environment reporting on biodiversity and manage threats within and outside protected areas.
  • Protect free-flowing river systems (largely unregulated by dams, levees, and diversions) within the framework of the entire river basin and increase environmental flows on regulated rivers

Invasive species

  • Avoid deliberate introduction of exotic species, unless suitable analyses of benefits outweigh risk-weighted costs
  • Implement control of invasive species by assessing effectiveness of control programs and determining invasion potential
  • Establish regulations and enforcement for exchange or treatment of ocean ballast and regularly implement antifouling procedures

Climate change

  • Reduce global greenhouse gas emissions
  • Identify, assess, and protect important climate refugia
  • Ameliorate the impacts of climate change through strategic management of other threatening processes
  • Develop strategic plans for priority translocations and implement when needed


  • Implement restrictions on harvest of overexploited species to maintain sustainability
  • Implement an ecosystem-based approach for fisheries, based on scientific data, that includes zoning the ocean; banning destructive fishing; adopting precautionary fishing principles that include size limits, quotas, and regulation with sufficient resources based on scientific assessments of stocks and; reducing bycatch through regulation and education
  • Implement international mechanisms to increase sustainability of fisheries by supporting international treaties for fisheries protection in the high seas; avoiding perverse subsidies and improve labelling of sustainable fisheries; and licensing exports of aquarium fish
  • Control unsustainable illegal logging and wildlife harvesting through local incentives and cessation of international trade


  • Decrease pollution through incentives and education; reduce and improve treatment of domestic, industrial, and agriculture waste; and rehabilitate polluted areas
  • Strengthen government regulations to stop generation of toxic material from mining efforts that affects freshwater and marine environments
  • Establish legislation and regulations and financial bonds (international) to reinforce polluter-pays principles
  • Establish regulations, education programs, clean ups, labelling, and use of biodegradable packaging to reduce discarded fishing gear and plastics


  • Establish early-detection programs for pathological diseases and biosecurity controls to reduce translocation
  • Identify causes, risk-assessment methods, and preventative methods for diseases
  • Establish remote communities of organisms (captive) not exposed to disease in severe outbreaks


  • Establish regional population policies based on ecologically sustainable human population levels and consumption
  • Ensure that all developments affecting the environment are adequately analysed for impacts over the long term
  • Promote economic and societal benefits from conservation through education
  • Determine biodiversity status and trends with indicators that diagnose and manage declines
  • Invest in taxonomic understanding and provision of resources (scientific and conservation) to increase capacity for conservation
  • Increase the capacity of government conservation agencies
  • Focus efforts of nongovernmental organisations on small island states on building indigenous capacity for conservation
  • Base conservation on risk assessment and decision support
  • Establish the effectiveness of conservation instruments (national and international) and their implementation

A very good set of recommendations that I hope we can continue to develop within our governments.

CJA Bradshaw

Add to FacebookAdd to NewsvineAdd to DiggAdd to Del.icio.usAdd to StumbleuponAdd to RedditAdd to BlinklistAdd to Ma.gnoliaAdd to TechnoratiAdd to Furl

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

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 »