Wednesday, 9 April 2008

Indicator species

I noticed that there is a workshop at the next BirdLife Conference on birds as indicator species for biodiversity. This is a concept that I find rather annoying -- birders love to suggest that their favourite organism is somehow a more important type of animal than others. There is an implication that the areas that are important for bird biodiversity are likely to be equally important for other forms of biodiversity. To start with, I really don't like using the term biodiversity, because you never really know what is meant. The majority of times it is being used as a synonym for species diversity, which is not really the same. It's a dangerous route -- rather like the hotspot concept. And like the latter does as much harm as good. Hotspots tend to be equated with species richness, but as any naturalist knows, deserts tend not to have as great a species richness as tropical rainforests. The only problem is that if you want to conserve desert species, conserving hotspots in the rainforest wont help a lot. And the same is true for bird biodiversity. The Galapagos islands are important for bird species diverssity, but to all intents and purposes irrelevant for terrestrial mammalian diversity -- just like New Zealand, with only two native mammals, both bats.

Trying to sell birds as biodiversity indicators is, to me, missing the point. Birds, and all wildlife deserve to be saved for a varity of very good reasons, but trying to kid someone that some taxa are more equal than others, smaks a little of two legs good, four legs bad.

I have nothing against materialist arguments for wildlife conservation, but I think if science is going to be used, we should be very careful that th arguments really stand up -- and when it comes to biodiversity, hotspots, species diversity, biomass etc etc., there is often not nearly enough known to justify some of the claims being made. All to often the species diversity has direct correlations with observer activity. It is very well known, that rare species of orchid, for example are likely to be discovered close to other rare species of orchids -- this is because botanists are more likely to go to those localaities. Just as bird reserves often have far longer bird lists than very similar habitat a half mile away, simply because that's where the birders go.

1 comment:

  1. ...and just as my earthworm-specialist lecturer at uni discovered a new species of earthworm in his garden... (Not much chance of your average gardener giving each worm a close inspection when working the flower beds!)