Cost, not biodiversity, dictates decision to conserve

26 08 2008

One for the Potential list:

originalEuroGreen_LogoI’ve just read a great new paper by Bode et al. (2008) entitled Cost-effective global conservation spending is robust to taxonomic group.

After the hugely influential biodiversity ‘hotspot concept hit the global stage, there was a series of subsequent research papers examining just how we should measure the ‘biodiversity’ component of areas needing to be conserved (and invested in). The problem was that depending on which taxa you looked at, and what measure of ‘biodiversity’ you used (e.g., species richness, endemism, latent threat, evolutionary potential, functional redundancy), the priority list of where, how much and when to invest in conservation differed quite a lot. In other words, the congruency among listed areas was rather low (summarised nicely in Thomas Brooks‘ paper in Science Global biodiversity conservation priorities and examined also by Orme et al. 2005). This causes all sorts of problems for conservation investment planners – what to invest in and where?

Bode and colleagues’ newest paper demonstrates at least for endemism, the taxon on which you base your assessment is much less important for maximising species conservation than factors such as land cost and the degree of threat (e.g., as measured by the IUCN Red List).

Of course, their findings could be considered too simplistic because they don’t (couldn’t) evaluate other potentially more important components of ‘biodiversity’ such as genetic history (evolutionary potential) or ecological functional redundancy (the idea that a species becomes more important to conserve if no other species provide the same ecosystem functions); however, I think this paper is something of a landmark in that it shows that ‘socio-economic’ uncertainty generally outweighs uncertainty due to biodiversity measures. The long and short of this is that planners should start investing if there is evidence of heightened threat and land is cheap.

A few other missing bits means that the paper is more heuristic than prescriptive (something the authors state right up front). There is no attempt to take biodiversity, threat or land cost changes arising from climate change into account (see relevant post here), so some of the priorities are questionable. Related to this is the idea of latent risk (see relevant paper by Cardillo et al. 2006) – what’s not necessarily threatened now but likely will be in the very near future. Also, only a small percentage of species are listed in the IUCN Red List (see relevant post here), so perhaps we’re missing some important trends. Finally, I had to note that almost all the priority areas outlined in the paper happened to be in the tropics, which stands to reason given the current and ongoing extinction crisis occurring in this realm. See a more detailed post on ‘tropical turmoil‘.

Despite the caveats, I think this could provide a way forward to the conservation planning stalemate.

CJA Bradshaw

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