Category: Threats

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Reindeer, caribou, genetics and global warming

Reindeer (Rangifer tarandus tarandus) were domesticated probably around 20,000 years ago in northern Europe and Asia. They are still kept by many herders in the Eurasian Arctic, who derive their livelihood from their animals. Reindeer from Siberia were imported into Alaska in the late 19th century in an attempt to provide income for indigenous people. In the 1930s an estimated 600,000 reindeer existed in Alaska, but that number is now down to about 20,000. It seems that most people didn’t quite see the point of managing reindeer when all they had to do was go out and hunt its wild cousin, the caribou (Rangifer tarandus granti). One of the unforeseen consequences of this endeavor has been the migration of reindeer into caribou herds and until recently it was unknown to what extent this influx has had an impact on the genetic diversity of caribou. A recent analysis of microsatellite DNA in caribou and reindeer in Alaska, however, shows that very little genetic introgression seems to have taken place into either species and the authors think the reason could be that hybrid offspring may have a lower chance of survival. It is interesting to note that their study also indicates that the Alaskan/Russian reindeer and the Alaskan and Canadian caribou are much more closely related to each other than either is to the Scandinavian reindeer.

Caribou, which can be found throughout Alaska and the Canadian territories, migrate often in large herds between their summer and winter pastures. The porcupine herd, for example, numbers in excess of 100,000 animals and covers a distance of over 2000 km on its yearly route from the Yukon to the calving grounds on the Alaskan Arctic coast (the very same area the US government is trying to open up for oil exploration).  Many native people in Canada and Alaska still depend on these animals for their survival and they are becoming concerned that increasing human development and global warming may either affect the size of caribou herds or change their migration patterns.

From Michael Kubisch

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Buzz on GM crops and bees

We’ve written a bit here about pollinator problems. The looming shortage of bees in the US, and in Spain. We pointed to a piece that said maybe the problems in the US weren’t any worse than they had been, just better reported. Maybe the problem is monoculture? Throughout the recent buzz of hive-related news, though, we’ve ignored a few items that laid the blame on GMO crops. Why? Because they seemed a bit shrill, maybe even a tad one-sided. But a long and apparently comprehensive piece in the German news magazine Der Spiegel is neither shrill nor one-sided. And it seems to adduce good evidence that bees who are suffering a parasite infestation are abnormally susceptible to pollen from maize engineered to express the Bt bacterial toxin from Bacillus thuringiensis.

The work Der Spiegel reports is a long way from conclusive. But it does give pause for thought, and it is causing huge excitement among opponents of GM in all its forms. At the very least, it deserves a closer look. But wouldn’t it be weird if it proved true? And how would industrial agriculture respond?

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Good ethnobotanists have healthier children

A study of the Tsimane, an indigenous group of foragers and farmers inhabiting a remote area of the Amazon lowlands of Bolivia, has determined that mothers who are more knowledgeable about plants and their uses tend to have healthier children. According to this summary of the results, Dr Victoria Reyes-García, one of the co-authors of the study, pointed out that “globalization threatens this knowledge to the extent that formal schooling and jobs in emerging markets devalue folk knowledge and provide access to products not made from local resources, but without providing adequate medical treatment substitutes.” I’ll have to find the original paper, because what the summary doesn’t say, and which it would be great to know, is whether better ethnobotanical knowledge translated into more diverse family gardens and more diverse diets.

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Climate change and extinction

Predicting the effects of climate change on biodiversity is very much a growth industry, and understandably so. I’ve contributed to it myself (together with lots of friends), as I immodestly noted here in a previous posting. Many studies have predicted drastic increases in rates of extinctions, but then, why have so few species gone extinct during the past 2.5 millions years of recurring ice ages? This “Quaternary conundrum” is addressed in a new paper announced, and available for downloading, here. The conclusion of the 19 co-authors is that current approaches do not adequately take into account the factors which allow species to persist when conditions change for the worse. They make eight recommendations for improving predictions, ranging from better models to better validation of model results. Well worth reading.

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Trees in Kenya

There were two interesting articles about trees in Kenya in the Money section of this morning’s Daily Nation. Not online, though, so I’ll have to summarize. One piece describes how farmers in Nyeri are adopting a number of short-statured mango varieties from South Africa and Israel, apparently including things called Apple, Kent, Vydke and Tommy. This is not a mango-growing region, but these particular varieties have been found to be a good fit on the small farms of the area, to yield heavily and early, and to be good for juice. So now there’s no need to truck mangoes in from the coast. Good for Nyeri farmers, perhaps not so good for coast farmers? This may not be a zero-sum game: I don’t know enough about the supply of, and demand for, mango in Kenya to predict what will happen, but I would try to conserve those coastal varieties ex situ somewhere just to be on the safe side.

Then there was also a piece on how the Tree Biotechnology Project has been successful in cloning a number of indigenous trees (including for example Prunus africana, whose bark feeds a large international market for a prostate cancer drug) and providing planting materials to farmers. It seems previously the project’s focus has been on eucalypts. This is expected to take pressure off wild populations and contribute to reforestation, but there was nothing in the Daily Nation article about the downside of planting large areas of genetically identical clones. However, this is clearly a problem the project recognizes, as you can see for example by reading on page 28 of this brief on some of its activities:

Planting large areas of single clones will have the effect of decreasing rather than increasing biodiversity, and the risk of narrowing the genetic base needs to be managed to avoid growing pest and disease problems. Mondi has a policy to restrict planting of a single clone to no more than 5% of any planting area, and the project is adhering to this policy. In order to maintain biodiversity, the project team will select a wide range of local tree species of economic value and will feed these into the clonal production system through adaptive tissue culture research. Once the capacity to adapt the techniques of micro-propagation to different species is fully in place, there will be great potential for the project to multiply and disseminate a wide range of improved germplasm of different tree species, including those that are under threat of over-exploitation and extinction, such as ebony.