Tahr protected, but wild carob?

WWF is announcing the establishment of a national park in the United Arab Emirates for the Arabian Tahr. Tahr are wild goats, but I think perhaps it may be pushing it to describe them as livestock wild relatives. Maybe a livestock expert will tell us.

In any case, the Arabian Tahr does share a habitat with at least one crop wild relative, Ceratonia oreothauma ssp. oreothauma. I believe that’s the only other species in the carob genus. I’ve actually collected the damn thing in Oman, and not at all easy it was too. But was an opportunity missed of making this a joint livestock-and-crop-wild-relative protected area?

How to rescue a sunflower wild relative

A paper by Jennifer R. Ellis and David E. McCauley of Vanderbilt University, just out in Biological Conservation, tries to answer a couple of quite controversial questions for conservationists: ((Ellis, J., & McCauley, D. (2009). Phenotypic differentiation in fitness related traits between populations of an extremely rare sunflower: Conservation management of isolated populations. Biological Conservation. DOI: 10.1016/j.biocon.2009.03.029)) How do you prioritize populations for conservation? And when does genetic pollution become genetic rescue? Both answers depend on something most gene-jockeys don’t do much of: growing plants and seeing how they perform.

To add piquancy, the paper deals with a crop wild relative, and a very rare one at that: Helianthus verticillatus, which is known from only four sites in the southeastern United States. The authors worked on populations from two of these, in Tennessee (fewer than 100 individuals) and Alabama (several hundred individuals). They collected seeds from sixteen of what they had previously identified as genetically distinct individuals from each population, and then made a whole bunch of crosses, both within populations and also between the two populations, for two generations. They grew the progeny of these crosses in the same environment and measured how well they did in terms of fruit viability, germination, survival and pollen quality.

So, first, to the prioritization question. Genetic markers are now routinely used to identify populations that are particularly low in diversity and thus in need of immediate in situ protection or collecting for ex situ conservation. Often, genetic diversity is positively correlated with fitness, but this is not always the case. For H. verticillatus, in fact, it was known from previous marker studies that the two populations had comparable levels of genetic diversity and only moderate genetic differentiation. However, the results of the common environment study on the offspring of the intra-population crosses showed that they different significantly in their overall “fitness,” with the Tennessee material having lower germination rates and fruit viability. In other words, molecular markers on their own would not have raised a particular concern about the long-term viability of the Tennessee population. In the words of the authors, “contrary to genetic marker information, these populations are not interchangeable with regard to quantitative fitness characters.”

Next, the genetic rescue question. The conventional wisdom of course is that conservation should strive to maintain the genetic integrity of populations. Bringing in material from elsewhere constitutes genetic pollution and is BAD. The introduction of new genetic material into relatively homogeneous populations with low fitness can of course result in heterosis and increased fitness. But it can also lead to lower fitness — inoutbreeding depression — “owing to the dilution of local adaptations or disruption of co-adapted gene combinations.” Enter the inter-population crosses. Crossing Tennessee individuals with those from Alabama resulted in offspring that were more fit, with no sign of outbreeding depression, at least for the two generations of the study. This “offers great promise” as an active conservation strategy for the Tennessee population, the authors say.

Given people’s sqeamishness about messing around with rare species, I wonder if such activism will be given a chance.

Nibbles: Sheep, Yams, Satellites, Payment for ecosystem services, Museum

Nibbes: Nettles, Rivers, Rare species, Library, Afghanistan protected area, Nordic-Baltic-Russian collaboration, Photos, Disease

Another place where the buffalo roam

The post I did yesterday about a small chunk of prairie still to be found in Calvary Cemetery, within the confines of metropolitan St Louis, ((Ah, but is it a remnant? Check out the comments on the original Economist piece.)) prompted Jeremy to tell me about his own favorite prairie remnant.

That would be the one inside the accelerator ring at Fermilab near Batavia, Illinois. Where they do indeed have a herd of bison contributing to the management of the ecosystem, as I — facetiously, I thought — suggested they should in St Louis. Too bad the beasts can’t be seen on Google Earth.

It looks like the Fermilab prairie is used as a resource by local schools, which seems like a great idea. I don’t know whether the teachers make anything in particular of the fact that at least one crop wild relative is to be found at the site. Helianthus mollis is not what I would call a star among crop wild relatives. For a start, it’s pretty difficult to cross with domesticated sunflower. And I don’t think it’s endangered or anything (or not yet). But it could be useful in illustrating to school kids an ecosystem service that is often overlooked — provision of genetic diversity for crop improvement.

Another thing it may well help illustrate is climate change. It looks like there’s really detailed data on many species, and it will be interesting to see what will happen — is already happening? — to their abundance and distribution. Maybe H. mollis will disappear from the Fermilab prairie in due course. Will it be able to go elsewhere? Or will we need to manage its relocation? To Canada…?