Nature Blog Network

Friday, May 16, 2008

Vertebrates as "Good Indicators of Overall Biodiversity Trends"???????

WTF!!11! OMG11!!!eleven!! WTF!!!!111!!!!11! I DON'T THINK SO!?!?!?!!!??!one!!!!!!111!1!!!

Well, I don't have any offhand evidence for it, but I seriously doubt it. Especially in the ocean where vertebrates IMHO probably aren't the majority in ... oh I don't know... diversitybiomassabundanceandeverythingelse. CNN reports this quote paraphrasing the World Wildlife Fund (WWF) in an article today titled "Humans Blamed for Sharp Drop in Wildlife" (duh!).

The Living Planet Index measured 4,000 populations of 1,477 vertebrate species, which the WWF says is a good indicator of overall biodiversity trends.
OK, I understand its hard to get cuddly dollars from donors out of a jelly like you can a polar bear, but I really doubt vert "biodiversity trends", whatever that means, are indicative of the Living Planet. I don't have the time or patience to delve into the literature for this, so lets use a bit of the ole common sense.

Those containing backbones account for roughly 5% of animal diversity (by generous estimates), while those without said characteristic are embodied in THE OTHER 95% (ahem, *clears throat*). Of course the purpose of an indicator taxon in ecology is to be able to characterize and extrapolate the dynamics of a given genus or family to the whole community level. For instance, in agricultural landscapes one might use use carabid beetles to extrapolate to the rest of the insect community. This might be founded on an earlier study saying that carabid beetles made of 87% of the insect community. Therefore one may suppose that it is easier and cheaper to use beetles in the family Carabidae as an indicator for the community. Then you can perform experiments using this taxon to test ecological hypotheses and implement a monitoring program using carabids to make sure a protected parcel of land is be preserved, etc. etc. The key point is that for an indicator taxon to be useful it must be shown it represents the community or excompasses its diversity well enough.

Admittedly, I haven't read all of the WWF report 2010 and Beyond: Rising to the Biodiversity Challenge. But because of their select sampling, all they can say is that vertebrates (or 5% of animal diversity) is severely affected by "human demands on the biosphere". With their study design, you cannot extrapolate to all wildlife, unless by wildlife they mean cuddly little furballs and other relatives of our spined pets.

I do not disagree that human activities are responsible for accelerated biodiversity loss. It is a real phenomena as it has been directly observed and reported in many studies. But that is not what this study addresses and I remain unconvinced that marine vertebrates can indicate for deep sea sediment communities, cold-water corals, rocky intertidal, mudflat or any other ecosystem dominated by invertebrates.


  1. i feel your pain, brother...

    the vertebrate-centric focus in conservation is daunting... do you know how easy my job could be if coral polyps had a face?

  2. You can even take it a step further. Even in some invertebrate-dominated systems such as tropical coral reefs, the choices of groups to use to monitor condition (scleractinian corals, molluscs, reef fishes[uh oh, another vertebrate]) can often lead a bias for larger species that may not be the best indicators or measures of system biodiversity. Once again, the problem is that it is harder to "sell" an approach that uses, for example, reef amphipods (not exactly charismatic to many non-invert geeks) rather than corals or reef fishes even though they may be more effective and sensitive indicators of change.

  3. Rick, this goes beyond vertocentrism into misleading extrapolation.

    Tony, I wonder if it may be a correlation between easier to photograph organisms and public 'awe'. Larger vertebrates and even inverts (i.e. giant squid, coral reefs, giant isopod, etc.) draw people in while amphipods, worms and rotifers tune people out. Sea stars, shrimp, crabs and snails seem to be borderline, perhaps because they seen and readily identified as such on shores.

    Do we need a TO95 uncharismatic invert photo contest?

  4. I'm down for that!

    Right now one of the labs here is doing an impact study for some cross sound power cable deployments. One part of it involves examining benthic invert communities. Most of which are tiny worms and amphipods... all day, day after day in front of a dissecting scope counting tiny inverts....


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