Oooooh, Molecular Ecology Resources has a whole special issue on “Advances in the Analysis of Spatial Genetic Data.” There goes the weekend.
Nibbles: Milk-drinking, Diversity and stability, Indian sheep, Development of the African savannah, Teaching rice, Silk, Diverse diet, Huge phallic inflorescences
- Der Spiegel does its usual impressive number, this time on the Völkerwanderung. Via.
- Diversity and stability in grasslands. Yes, there’s a connection.
- Sheep breeds in India deconstructed.
- The future of the Guinea savannah. Probably not that great.
- IRRI teaches Singaporean cityslickers to grow rice.
- Silk beginning to fade where it was born.
- The diverse benefits of an agrobiodiverse diet. Should someone tell rich Indians?
- Tales of two giant inflorescences. What are the odds?
The social life of taxonomists
If you have full access to the journal Nature, you’ll be able to read Jonathan Silvertown’s correspondence about a pet project called iSpot. Silvertown says:
Through social networking, the identification process can be made more efficient while simultaneously spreading real taxonomic knowledge. The facility is available to anyone, unlike other technologies that require specialized equipment.
In its first year of operation, the website … helped 6,000 users to identify 25,000 sightings of some 2,500 species, from lichens to birds. The website works by linking experts (including amateur experts) with beginners through a sophisticated reputation system that encourages users to help and learn from each other.
This, Silvertown says, is “social networking on the Internet”. ((And yes, there is something delicious about promoting the virtues of the social networking behind a paywall.))
And it is, of a sort. Not the sort that we’ve championed here more than once, most famously in connection with some globetrotting taro. It is good that people can get good identification of things they’ve seen, and been able to photograph. My argument with iSpot is that it perpetuates the dichotomy between nature and agriculture, probably unconsciously, although very directly: “your place to share nature”.
So, while you will find crop wild relatives in there, there is no mention of the fact that that is what they are. You won’t find a single entry for Triticum. And so, while there may be lots of discussions of willow warblers vs chiffchaffs, the essential and fundamental differences between the raw materials of beer and bread go unremarked. And where would all those twitchers be without a sandwich and a pint?
Silvertown clearly knows about and cares about agriculture, and is not afraid to use agricultural examples in his teaching and popular writing. I wish he had extended that to his Citizen Science projects.
And while I’m moaning, where’s the site that will allow anyone anywhere to upload a photograph of a crop direct from a mobile phone and get it identified, preferably to variety level?
Soil biodiversity helps maintain plant genetic and species diversity
Attentive readers of this blog will recall an interesting experiment run by Richard Lankau of UC Davis and others a couple of years back which looked at how genetic diversity can help maintain species diversity in a model ecosystem. There’s now a new paper out by Dr Lankau which investigates in more detail the mechanism behind this. ((Lankau, R., Wheeler, E., Bennett, A., & Strauss, S. (2010). Plant-soil feedbacks contribute to an intransitive competitive network that promotes both genetic and species diversity Journal of Ecology DOI: 10.1111/j.1365-2745.2010.01736.x))
Let’s recap. In the earlier paper, researchers…
…grew monocultures of two genetic variants of an annual plant called black mustard [Brassica nigra], and also a mixture of three species. One of the black mustard varieties produced high levels of a compound called sinigrin, which is toxic to other plants and to beneficial soil micro-organisms, the other produced low levels. The researchers then introduced a “foreign” individual into each of these experimental communities: a low sinigrin plant into the high sinigrin monoculture and the mixture, a high sinigrin plant into the low sinigrin monoculture and the mixture, and a plant of a different species into the monocultures and the mixture. Which would survive? It turned out that the high sinigrin invader only survived in the mixture, while the low sinigrin variety only survived in the high sinigrin monoculture. No one variety was always best, which meant that each could survive somewhere. Remove any one element, whether variety or species, and the system became dominated by a single thing.
In the latest study, Lankau et al.
performed several experiments to determine whether different B. nigra genotypes and their heterospecific competitors cultivated different soil communities, and, in turn, if differences in these communities mediated some or all of the competitive interactions seen in previous field studies.
The answers were: yes, and some. Yes, indeed, the composition of the soil microbial community (bacteria, fungi, arbuscular mychorrizal fungi) was indeed quite different under the different plant communities. But this did not affect the ability of the different mustard genotypes to invade mustard monocultures, for example. In contrast, however, the fact that high sinigrin mustard genotypes competed strongly in heterospecific mixtures was probably due to changes in the soil biota.
The main conclusion of the earlier study was:
Preventing the erosion of genetic diversity within species may require maintaining a diversity of species in a community. At the same time, we may need to focus on protecting high levels of genetic diversity within species in order to maintain diverse communities of species.
We can now add that soil biodiversity can play an important role in maintaining both genetic and species diversity in plant communities by mediating competitive interactions. I’m looking forward to the next installment of this saga.
Evergreen agriculture: crops and trees
What if growing maize under trees – really under trees, under the canopy – improved yields by 280 per cent? It did in Malawi. Even if this practice doesn’t translate well to developed world agriculture, the principles of Evergreen Agriculture can.
Matt at Muddy Green takes a look at Evergreen agriculture: crops and trees, a different kind of agroforestry. I’ve always imagined that agroforestry was more about alley cropping or the like, but this idea of planting under the trees seems rather interesting and rather successful, at least in places where the trees are bare during another crop’s growing season.