- Management increases genetic diversity of honey bees via admixture. No domestication bottleneck there!
- Enhancing innovation in livestock value chains through networks: Lessons from fodder innovation case studies in developing countries. Fodder innovators of the world, organize. If you don’t, you will lose your value chains.
- Introduction to special issue on agricultural biodiversity, ecosystems and environment linkages in Africa. Special issues? What special issue?
- The construction of an alternative quinoa economy: balancing solidarity, household needs, and profit in San Agustín, Bolivia. Despite the allure of fancy denominations of origin and the like, old-fashioned cooperatives, and the much-maligned intermediary, manage to hang on in there.
- Species–genetic diversity correlations in habitat fragmentation can be biased by small sample sizes. Can.
- The original features of rice (Oryza sativa L.) genetic diversity and the importance of within-variety diversity in the highlands of Madagascar build a strong case for in situ conservation. Actually the way I read it, the stronger case is for ex situ. But see what you think.
- Population structure of the primary gene pool of Oryza sativa in Thailand. In situ Strikes Back.
The how and why of indicators of agricultural biodiversity
Let us assume, for the sake of argument, that one crop variety does disappear every single day. The question still remains: does it matter? After all, the variety that was just lost yesterday might be very similar to one that’s still out there today. That’s part of the reason why a group of French researchers has just come up with “A new integrative indicator to assess crop genetic diversity,” which is the title of their paper in Ecological Indicators. ((Bonneuil, C., Goffaux, R., Bonnin, I., Montalent, P., Hamon, C., Balfourier, F., & Goldringer, I. (2012). A new integrative indicator to assess crop genetic diversity Ecological Indicators, 23, 280-289 DOI: 10.1016/j.ecolind.2012.04.002))
Christophe Bonneuil and his co-workers thought that, given the data, they could come up with something more powerful and more widely applicable than richness (i.e. the number of different varieties) or the standard diversity indicators (i.e. various combinations of richness and evenness). So they started with number of varieties, but then they factored in the relative extent to which each was grown in their study area, the departement of Eure-et-Loire in France (which is the evenness bit), how genetically distinct each was (which is the bit which addresses the pesky question of how different the variety that disapeared today is from all the other ones left behind), and how much genetic diversity there was inside each.
They got the data on genetic differences among varieties by comparing genebank samples of all the wheat types grown in Eure-et-Loire from 1878 and 2006 at 35 microsatellite loci, and data on acreage of each variety at different points in time from various archival sources. Internal genetic diversity was set at one of three values derived from the literature, depending on whether the variety was a landrace, an old commercial line or a modern pure line.
They put all that together into this monster indicator of allelic diversity in the landscape,
and then calculated it for different times periods, and got this:
That shows a decrease in diversity as landraces are replaced with modern varieties, but, interestingly, something of a resurgence after the mid-1960s, as more diverse germplasm is introduced into breeding programmes. The indicator has been on a downward trend just lately, as the genetic relatedness of the most frequent varieties has increased. ((A result that you might like to compare with the one we discussed not so long ago for the diversity in modern breeding programmes.)) Overall, it’s maybe a 50% drop since 1878. Not entirely dissimilar to the iconic 75% figure, and at least this wasn’t plucked out of thin air.
Interesting enough, but check out the trend in number of varieties over the same period:
Totally different. Pretty much an upward trend, albeit with some stuttering. Certainly no evidence from these data of massive erosion of diversity. Maybe the findings of Jarvis et al. (2008) that simple richness can be a useful indicator of diversity should be applied with caution if you’re not just dealing with landraces.
But how significant is it really that the value of this particular indicator of diversity, for all its fanciness, has decreased? Has anyone actually suffered as a result? I don’t know, but a second paper I came across this week suggests how one could find out. Roseline Remans and others associated with the Millennium Villages Project have a study out in PLoS ONE which adds yet another — different — nuance to diversity. ((Remans, R., Flynn, D., DeClerck, F., Diru, W., Fanzo, J., Gaynor, K., Lambrecht, I., Mudiope, J., Mutuo, P., Nkhoma, P., Siriri, D., Sullivan, C., & Palm, C. (2011). Assessing Nutritional Diversity of Cropping Systems in African Villages PLoS ONE, 6 (6) DOI: 10.1371/journal.pone.0021235)) Their index considers not just how many different crops are grown on a farm, but also how different they are in their nutritional composition. Think of it as the nutritional analogue of the inter-varietal genetic diversity term in the French indicator. The more different in nutritional composition two crops are, the more complementary they are to local diets, the more important it is that both are there, the higher the resulting “functional” diversity index. And in fact the authors did find a positive relationship between their diversity indicator and nutritional status, at least at the village level.
Easy to imagine (though perhaps less easy to actually implement) a further refinement of Bonneuil et al.’s indicator which additionally integrates nutritional data, to yield an indicator of crop genetic and functional diversity. And, of course, once you have such a super-indicator, it might actually be possible to reward people on the basis of their success in maintaining it at high levels. Which, as it happens, is the subject of yet another paper I happened across last week. ((Hasund, K. (2013). Indicator-based agri-environmental payments: A payment-by-result model for public goods with a Swedish application Land Use Policy, 30 (1), 223-233 DOI: 10.1016/j.landusepol.2012.03.011)) But maybe that’s a paper too far for now. ((And yes, you do remember these papers from Brainfood. It’s just that it sometimes takes a day or two for us to tease out the connections.))
One silly thing is said about agricultural biodiversity every single day
You know, I think communicating about agrobiodiversity is really important. That’s why I contribute to this blog. Among various other things. But when I see the collective communication efforts of the agricultural biodiversity community culminate in the statement, made apparently in all seriousness, that “One crop seed becomes extinct every single day,” I do wonder whether the game is worth the candle. ((Admittedly, the rest of the article is not as bad as the title.))
LATER: Ok, maybe I was too sweeping in my vilification. Let me clarify. I don’t mind an editor crafting an attention-grabbing title for an article aimed at a popular audience. I can perhaps even live with a broad, “not even wrong” generalization about genetic erosion in such a title, if explained further in the text. No, what I really object to is the misuse of the word “seed” for “variety” in this particular context. Because it is unforgivably confusing, and simply not necessary. A seed, as the word is commonly understood, is just not something that goes extinct.
Brainfood: Dietary diversity, Diversity and diseases, Soil IK, Insect symbionts, Rhizobia, Wild lettuce, Tree genetic erosion, Pre-domestication barley, Strampelli
- Relating dietary diversity and food variety scores to vegetable production and socio-economic status of women in rural Tanzania. Dietary diversity was all too often alarmingly low, and when it was it was associated with seasonal fluctuations in the production and collecting of vegetables. But a more varied diet need not necessarily be healthier, so more procedural sophistication will be necessary in follow-up studies.
- A risk-minimizing argument for traditional crop varietal diversity use to reduce pest and disease damage in agricultural ecosystems of Uganda. For Musa and beans, more varietal diversity meant less damage and less variation in damage.
- Exploring farmers’ local knowledge and perceptions of soil fertility and management in the Ashanti Region of Ghana. Soils which farmers described as being more fertile were, ahem, more fertile.
- Population genetics of beneficial heritable symbionts. Of insects, that is. Important because they can confer protection from natural enemies, among other things. They behave a bit, but not entirely, like beneficial nuclear mutations.
- Widespread fitness alignment in the legume–rhizobium symbiosis. There are no cheaters.
- Genetic polymorphism in Lactuca aculeata populations and occurrence of natural putative hybrids between L. aculeata and L. serriola. Not much diversity in Israel, surprisingly. But isozymes?
- Meta-Analysis of Susceptibility of Woody Plants to Loss of Genetic Diversity through Habitat Fragmentation. The standard story — that trees suffer less genetic erosion because they are long-lived — is apparently wrong, even for wind pollinated trees.
- Large-scale cereal processing before domestication during the tenth millennium cal BC in northern Syria. “This was a community dedicated to the systematic production of food from wild cereals.”
- Nazareno Strampelli, the ‘Prophet’ of the green revolution. Before Norman, there was Nazareno.
- The memory remains: application of historical DNA for scaling biodiversity loss. Historical collections of salmon scales reveal many connections between modern evolutionary significant units (ESUs) in the Columbia River and old ones; but also, intriguingly, some differences.
Nibbles: Small farmers, Wild bananas, Titan arum, Fish for diversity, Tenure, Treaty, Australian genebank, Mexican genebank, Mexican drought, Potato record, Khat and fodder in Ethiopia
- On my signal, unleash the potential of small farmers and food producers worldwide. Has a return ring to it.
- More than anyone could reasonably want to know about wild banana relatives in Thailand.
- Big stinky flower with its own webcam. Must be a wild relative of something.
- Better in many ways to catch a diversity of fish species than to focus on one.
- Could probably do with some guidelines for access to fisheries, though, right?
- International Seed Treaty secretariat knocks ‘em dead down under. “THREE-quarters of the world’s crop biodiversity has been irrevocably lost since 1900.”
- Of course it has. Did Dr Bhatti visit this place during his tour of Oz, I wonder? If not, maybe he’ll visit Mexico next and see this place. And speaking of Mexico…
- Mexico sneezes, US grain exports catch a cold?
- World record potato harvest in Bihar; there’s a lot that’s fishy about this story.
- “Khat cultivation in Ethiopia fuels economy, reduces deforestation.” And makes people sick, but who’s counting.
- Ah but here’s a possible alternative. Now, if only CIFOR and ILRI would talk together about this.