The services of agricultural biodiversity

The latest (number 18) Biodiversity and Society Bulletin of the Poverty and Conservation Learning Group discusses a new UNEP-WCMC publication ((Ash, N. and Jenkins, M. (2007). Biodiversity and Poverty Reduction: The Importance of Ecosystem Services. United Nations Environment Programme-World Conservation Monitoring Centre, Cambridge.)) entitled “Biodiversity and Poverty Reduction: The Importance of Ecosystem Services.”

It’s a very good assessment of the services provided by biodiversity, in particular to the poor. These services include:

  1. fresh water quality
  2. protection from natural hazards
  3. regulation of infectious diseases
  4. regulation of climate and air quality
  5. waste processing and detoxification
  6. nutrient cycling
  7. medicines
  8. timber, fibres and fuel
  9. cultural services

But food provision and food security are right up front, and that discussion doesn’t just deal with species diversity in farming systems (although this is somewhat underplayed, I think), landraces (though not, unfortunately, wild crop relatives, to any great extent) and wild foods. It also ranges over the wider agricultural biodiversity which supports food production. That means soil micro-organisms, pollinators and the natural enemies of pests:

Although some or all these functions can in theory be replaced by artificial, technologically-derived substitutes, these are often expensive and increase the dependency of poor people on industries and producers beyond their control.

The document ends with some implications for policy. I guess this is the bottom line:

The medium and long-term interests of the poor are likely to be best served by the maintenance of a diverse resource base at the landscape (i.e. accessible) scale, at the very least as a vital risk mitigation measure. This does not, of course, mean that all forms of intensification and adoption of new technologies should be avoided – far from it. Judicious application of new technologies and techniques, use of improved varieties (not necessarily excluding those developed with gene transfer technologies) in agriculture, and appropriate levels of inputs such as nitrogen and phosphate-based fertiliser, can increase productivity and help towards eliminating poverty. Increasing the efficiency of use of existing agricultural lands can actually reduce environmental degradation by reducing the incentive to convert marginal lands. The key is that such development should not be at the expense of the existing natural resource base and should be planned to ensure delivery of medium and long-term benefits, rather than maximising short-term gains.

Pity that the International Treaty on Plant Genetic Resources for Food and Agriculture is not mentioned in the section on international obligations, though.

Backyard domestication

There’s a “dump heap” hypothesis of agricultural origins which suggests that people first got interested in actively managing and manipulating plants for food or other products when they saw them sprouting out of piles of garbage in and about settlements. There they could observe them daily and experiment with them. A slight variation on this theme — involving corrals in pastoralist campsites rather than garbage dumps — has been proposed for the domestication of quinoa.

One of the things that might have happened in these fertile micro-environments in close proximity to human habitations is that different related species might have been brought accidentally together, leading to hybridization and the development of interesting new — polyploid — types. But there really hasn’t been much empirical evidence for this.

No more. A new paper ((Colin E. Hughes, Rajanikanth Govindarajulu, Ashley Robertson, Denis L. Filer, Stephen A. Harris, and C. Donovan Bailey. Serendipitous backyard hybridization and the origin of crops. PNAS published August 17, 2007, 10.1073/pnas.0702193104.)) looks at the domestication of the legume tree Leucaena in Mexico, where it is grown for food (it is also used as a fodder in some parts of the world). A variety of evidence is discussed which suggests that there has indeed been much hybridization among up to 13 different wild species of Leucaena in Mexican backyards. This has proved “a potent trigger for domestication.” The authors think a similar thing also happened in Mexico with two other perennial crops, Agave and Opuntia.

Solanaceous information

There’s a global online monograph of the genus Solanum called Solanaceae Source. Each species treatment includes illustrations, a clickable list of specimens, links to molecular data and a dot distribution map (which mashes herbarium specimen locality data with Google Maps), among other things. The National Science Foundation (NSF) funds the project as part of the Planetary Biodiversity Inventories mission. Collaborators are eligible for small awards in support of their contributions to the completion of the worldwide Solanum monograph.