Working to understand and conserve genetic diversity

Just catching up on a couple of useful resources.

The Genetics Composition working group [of the Group on Earth Observations’s Biodiversity Observation Network] aims to develop, test and improve approaches for assessing and interpreting genetic diversity.

You can join it here. And thus contribute to the Genetic diversity targets and indicators proposed for the CBD post-2020 Global Biodiversity Framework. About which you can read more on the work blog, as it happens. The working group seems to have some overlap with the Conservation Genetic Coalition, which came out with its formal “Statement on genetic diversity in CBD” just before Christmas.

Meanwhile, over at USDA, there are posters on crop diversity and genebanks in multiple languages.

Gotta wonder whether any of this will reach the policy-makers, but one can hope, can’t one?

One Reply to “Working to understand and conserve genetic diversity”

  1. The “work blog” refers to the multi-authored Science paper which claims:

    • “…multiple goals are required because of nature’s complexity…”
    • The CBD process has already set such clear vision: “living in harmony with nature.”

    There is a fatal misunderstanding of how diversity is package in nature, dependent, to a large extent, on environmental selection pressure. In 1977 Grime published a key paper on “three primary strategies in plants” (American Naturalist 111, 1169-94). These were plant responses (1) to competition, (2) to unproductive conditions of stress, and (3) to disturbance. In the triangle of these forces the points of the triangle were the positions of greatest selection pressure – and, therefore, of vegetation with the fewest species. At strong selection pressure only one species – the monodominant – can survive. [Of course, at greater selection pressure no plant species whatever can survive and we have bare ground.]

    The CBD process ignores the value of monodominant species and insists that nature is always complex. It isn’t. And it is the simpler bits that are the more important. Grimes type (2) is vastly important for ecosystem services in unproductive conditions. Specialised plant families have adapted to marginal conditions and form monodominant vegetation. For example, sea grasses dominate the more exposed intertidal mud flats and bind silt (Families Posidoniaceae, Zosteraceae, Hydrocharitaceae and Cymodoceaceae). Mangroves dominate sheltered mud flats and are key to protect coastlines (Families Avicenniaceae, Combretaceae, Arecaceae, Rhizophoraceae and Lythraceae – with multiple genera). There are hundreds of other examples of extreme plant adaptation leading to monodominance.

    For agriculture, Grimes type (3) is also of extreme importance: environmental disturbance has underpinned the evolution of monodominant cereal wild relatives and directly lead to crop domestication and the cultivation of crop monocultures. The first three cereals evolved from their wild relatives in (roughly) the Fertile Crescent. The level of disturbance is profound. There are three or more Continental Plates colliding, there is a big Rift Valley, there are multiple Phytogeographic Zones in close proximity, there are two climate zones (Mediterranean and Monsoon), there is vulcanism and (we think) a natural fire regime that favours annual large-seeded species that have adaptive mechanisms to bury large seed. The take home message is that cereal agriculture originated from monodominant species and not from “nature’s complexity” (at least, not from species complexity). The irony is that this specific eco-evolutionary heritage of seed burial mandates all that ploughing and tilling in agriculture to mimic the former natural disturbance, not least preventing competition from perennial species. This “copy-cat” human management post-domestication is as close as you can get to living in harmony with nature, far better than vague talk of agroecology.

    The main need is not the broad-brush conservation of genetic diversity but to focus on the conservation of the highly selected monodominant species that provide ecosystem services and lots of our food. The CBD has no clue on this. Unfortunately, neither has the ITPGRFA, which talks of: “maximizing intra- and inter-specific variation for the benefit of farmers.”

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