100% sure that 75% is incorrect

A familiar number was much bandied about during the otherwise wonderful celebration that has been the just-ended Settimana della Biodiversitá here in Rome. We have lost 75% of the diversity of crops during the past century, we were repeatedly told. So I will take this opportunity to repeat from my part that while for all I know this number may indeed be accurate, we have no evidence to that effect. Nobody has counted up all the tomato heirlooms lost in Italy, all the bean landraces lost in Mexico, all the mango varieties lost in India, all the taro clones lost in Papua New Guinea, divided by the number of those things that there used to be, repeated the feat for all other countries in which these crops are grown, ((Taking care to account for synonyms etc.)) done the whole thing again for all other crops, taken an overall average and come out with 75%. In fact, as we have said here before, that 75% number is probably an extrapolation from one, probably hardly representative, data point. We should recognize this fact, admit that we don’t know how much crop diversity has been lost overall, quote what numbers there are for genetic erosion with circumspection, and go out and get better numbers.

Crop genebanks in the Global Biodiversity Outlook

Seed banks play an important role in conserving the diversity of plant species and crop varieties for future generations. Among the most ambitious programmes for ex situ conservation are the Millennium Seed Bank Partnership, initiated by the Royal Botanic Gardens Kew and its partners worldwide, which now includes nearly 2 billion seeds from 30,000 wild plant species, mainly from drylands; and the complementary Svalbard Global Seed Vault, which has been constructed in Norway, close to the Arctic Circle, to provide the ultimate safety net against accidental loss of agricultural diversity in traditional gene banks. The vault has capacity to conserve 4.5 million crop seed samples.

That’s from the section on genetic diversity from the CBD/UNEP Global Biodiversity Outlook 3, just out (pp 51-53 of a large pdf). And very welcome it is too.

Some of it is not particularly well done, but one is surprised to see it done at all. It would have been nice to have had more examples of genetic erosion than this estimate for rice in China, for example:

…the number of local rice varieties being cultivated has declined from 46,000 in the 1950s to slightly more than 1,000 in 2006.

And what does this mean exactly? Who cultivates wild relatives of rice?

In some 60 to 70 per cent of the areas where wild relatives of rice used to grow, it is either no longer found or the area devoted to its cultivation has been greatly reduced.

Probably something has been lost in translation. On the positive side of the conservation ledger, there is the assertion that:

For some 200 to 300 crops, it is estimated that over 70% of genetic diversity is already conserved in gene banks, meeting the target set under the Global Strategy for Plant Conservation.

This figure is much quoted, but I’ve never fully understood how it was arrived at.

Anyway, as I say, at least crop diversity and its ex situ conservation is in there. And the International Treaty on Plant Genetic Resources for Food and Agriculture gets a mention. We should be grateful for that.

Gulf oil spill not much of a threat to one crop wild relative

The Gulf oil spill is threatening some Globally Important Bird Areas, according to the LA Times:

And other protected areas too. Unfortunately, we don’t have a similar map for crop wild relatives, at least not just yet, at least not so easily available. So it’s hard to estimate the overall threat posed by the oil spill on these genetic resources — which are arguably of greater importance than most birds, but there you go. What we can do — just about — is look at the distribution of individual species. And that is what our friend Julian at CIAT has done for a wild bean, Phaseolus polystachyus.

Not in any particular danger, though one or two coastal populations may be affected, I suppose. But I just wonder if one day the LA Times will publish a map showing the Globally Important Crop Wild Relative Areas threatened by some calamity or other.