Biodiversity important? The simple case of bees

30 12 2009

If you can’t convince people that biodiversity is important, then you have to use the lowest common denominator. Even a 3-year old understands the importance of bees for pollination (see previous post on loss of pollination services). Another entertaining TED talk to drive the point home as my last post for 2009 – hidden message: don’t put all your (biodiversity) eggs in one basket. I’ll let you figure that out for yourself. Warning – a little Ameri-centric, but gets the point across.

Catch you in 2010.

CJA Bradshaw





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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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.

CJAB

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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





A magic conservation number

15 12 2009

Although I’ve already blogged about our recent paper in Biological Conservation on minimum viable population sizes, American Scientist just did a great little article on the paper and concept that I’ll share with you here:

Imagine how useful it would be if someone calculated the minimum population needed to preserve each threatened organism on Earth, especially in this age of accelerated extinctions.

A group of Australian researchers say they have nailed the best figure achievable with the available data: 5,000 adults. That’s right, that many, for mammals, amphibians, insects, plants and the rest.

Their goal wasn’t a target for temporary survival. Instead they set the bar much higher, aiming for a census that would allow a species to pursue a standard evolutionary lifespan, which can vary from one to 10 million years.

That sort of longevity requires abundance sufficient for a species to thrive despite significant obstacles, including random variation in sex ratios or birth and death rates, natural catastrophes and habitat decline. It also requires enough genetic variation to allow adequate amounts of beneficial mutations to emerge and spread within a populace.

“We have suggested that a major rethink is required on how we assign relative risk to a species,” says conservation biologist Lochran Traill of the University of Adelaide, lead author of a Biological Conservation paper describing the projection.

Conservation biologists already have plenty on their minds these days. Many have concluded that if current rates of species loss continue worldwide, Earth will face a mass extinction comparable to the five big extinction events documented in the past. This one would differ, however, because it would be driven by the destructive growth of one species: us.

More than 17,000 of the 47,677 species assessed for vulnerability of extinction are threatened, according to the latest Red List of Threatened Species prepared by the International Union for Conservation of Nature. That includes 21 percent of known mammals, 30 percent of known amphibians, 12 percent of known birds and 70 percent of known plants. The populations of some critically endangered species number in the hundreds, not thousands.

In an effort to help guide rescue efforts, Traill and colleagues, who include conservation biologists and a geneticist, have been exploring minimum viable population size over the past few years. Previously they completed a meta-analysis of hundreds of studies considering such estimates and concluded that a minimum head count of more than a few thousand individuals would be needed to achieve a viable population.

“We don’t have the time and resources to attend to finding thresholds for all threatened species, thus the need for a generalization that can be implemented across taxa to prevent extinction,” Traill says.

In their most recent research they used computer models to simulate what population numbers would be required to achieve long-term persistence for 1,198 different species. A minimum population of 500 could guard against inbreeding, they conclude. But for a shot at truly long-term, evolutionary success, 5,000 is the most parsimonious number, with some species likely to hit the sweet spot with slightly less or slightly more.

“The practical implications are simply that we’re not doing enough, and that many existing targets will not suffice,” Traill says, noting that many conservation programs may inadvertently be managing protected populations for extinction by settling for lower population goals.

The prospect that one number, give or take a few, would equal the minimum viable population across taxa doesn’t seem likely to Steven Beissinger, a conservation biologist at the University of California at Berkeley.

“I can’t imagine 5,000 being a meaningful number for both Alabama beach mice and the California condors. They are such different organisms,” Beissinger says.

Many variables must be considered when assessing the population needs of a given threatened species, he says. “This issue really has to do with threats more than stochastic demography. Take the same rates of reproduction and survival and put them in a healthy environment and your minimum population would be different than in an environment of excess predation, loss of habitat or effects from invasive species.”

But, Beissinger says, Traill’s group is correct for thinking that conservation biologists don’t always have enough empirically based standards to guide conservation efforts or to obtain support for those efforts from policy makers.

“One of the positive things here is that we do need some clear standards. It might not be establishing a required number of individuals. But it could be clearer policy guidelines for acceptable risks and for how many years into the future can we accept a level of risk,” Beissinger says. “Policy people do want that kind of guidance.”

Traill sees policy implications in his group’s conclusions. Having a numerical threshold could add more precision to specific conservation efforts, he says, including stabs at reversing the habitat decline or human harvesting that threaten a given species.

“We need to restore once-abundant populations to the minimum threshold,” Traill says. “In many cases it will make more economic and conservation sense to abandon hopeless-case species in favor of greater returns elsewhere.





December Issue of Conservation Letters

11 12 2009

Gemsbok (Oryx gazella) in Namibia

Another great line-up in Conservation Letters‘ last issue for 2009. For full access, click here.





Breaking the waves – conservation conundrum of bioshields

9 12 2009

Today’s post covers a neat little review just published online in Conservation Letters by Feagin and colleagues entitled Shelter from the storm? Use and misuse of coastal vegetation bioshields for managing natural disasters. I’m covering this for three reasons: (1) it’s a great summary and wake-up call for those contemplating changing coastal ecosystems in the name of disaster management, (2) I have a professional interest in the ecosystem integrity-disaster interface and (3) I had the pleasure of editing this article.

I’ve blogged about quite a few papers on ecosystem services (including some of my own) because I think making the link between ecosystem integrity and human health, wealth and well-being are some of the best ways to convince Joe Bloggs that saving species he’ll never probably see are in his and his family’s best (and selfish) interests. Convincing the poverty-stricken, the greedy and the downright stupid of biodiversity’s inherent value will never, ever work (at least, it hasn’t worked yet).

Today’s feature paper discusses an increasingly relevant policy conundrum in conservation – altering coastal ecosystems such that planted/restored/conserved vegetation minimises the negative impacts of extreme weather events (e.g., tsunamis, cyclones, typhoons and hurricanes): the so-called ‘bioshield’ effect. The idea is attractive – coastal vegetation acts to buffer human development and other land features from intense wave action, so maintain/restore it at all costs.

The problem is, as Feagin and colleagues point out in their poignant review, ‘bioshields’ don’t really seem to have much effect in attenuating the big waves resulting from the extreme events, the very reason they were planted in the first place. Don’t misunderstand them – keeping ecosystems like mangroves and other coastal communities intact has enormous benefits in terms of biodiversity conservation, minimised coastal erosion and human livelihoods. However, with massive coastal development in many parts of the world, the knee-jerk reaction has been to plant up coasts with any sort of tree/shrub going without heeding these species’ real effects. Indeed, many countries have active policies now to plant invasive species along coastal margins, which not only displace native species, they can displace humans and likely play little part in any wave attenuation.

This sleeping giant of a conservation issue needs some serious re-thinking, argue the authors, especially in light of predicted increases in extreme storm events resulting from climate change. I hope policy makers listen to that plea. I highly recommend the read.

CJA Bradshaw

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ResearchBlogging.orgFeagin, R., Mukherjee, N., Shanker, K., Baird, A., Cinner, J., Kerr, A., Koedam, N., Sridhar, A., Arthur, R., Jayatissa, L., Lo Seen, D., Menon, M., Rodriguez, S., Shamsuddoha, M., & Dahdouh-Guebas, F. (2009). Shelter from the storm? Use and misuse of coastal vegetation bioshields for managing natural disasters Conservation Letters DOI: 10.1111/j.1755-263X.2009.00087.x





Nothing’s changed – scientific peer review

7 12 2009

Couldn’t resist posting this – a gem for anyone who has ever had their paper go through the peer-review crunch.