Category: Threats

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Pollinator diversity, pollination services and landscape change

That’s the title (or part of it) of a guest editorial ((Ingolf Steffan-Dewenter, Catrin Westphal (2008) The interplay of pollinator diversity, pollination services and landscape change. Journal of Applied Ecology 45(3), 737–741 doi:10.1111/j.1365-2664.2008.01483.x)) in the latest issue of the Journal of Applied Ecology which introduces a Special Profile entitled “Pollination and Pollinators” (mainly bees, actually).

The papers in this Special Profile cover several of these topics: two papers address the impact of habitat fragmentation and semi-natural landscape elements for population densities, species richness and community composition of bees (Brosi et al. 2008; Osborne et al. 2008). The next three papers focus on the combined effects of local and landscape-scale land use intensity and semi-natural or natural landscape elements on pollinators (Kohler et al. 2008; Rundlöf, Bengtsson & Smith 2008; Winfree et al. 2008). The last two papers focus on pollination functions and consider cross-pollination rates in a major crop (Devaux et al. 2008) and plant–pollinator networks in heathlands (Forup et al. 2008).

The papers are behind paywalls, but the abstracts are still quite useful.

I guess the overall message is that “land use intensification and habitat fragmentation do not only affect pollinator diversity and abundance, but also pollination services” because “pollination success of insect-pollinated plant species is usually not dependent on single, highly specialized pollinator species, but rather on a diverse community of pollinators.” In some places, of course, bees have lots more to contend with.

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Nibbles: Tea, Commodity dependence, Wild pigs, Organic ag, Fungus

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Reindeer domestication

From our occasional contributor Michael Kubisch.

Reindeer have been domesticated by denizens of the Northern hemisphere for some time – but exactly for how long and  whether domestication occurred at different sites or only once has been the matter of some debate. Estimates of how long ago domestication might have happened have ranged from as long as 20,000 years ago to as little as 3000. Part of the problems stems from the lack of archaeological records that could pinpoint  a more exact time frame. The evidence for the shorter period relies mostly on ethnographic observation, such as the development of certain implements (for example saddles) that early reindeer herders developed apparently after contact with other people of the central Asian steppes.

But did domestication  happen more than once? A recent paper by a group of researchers from Oslo sheds some light on this question.  After analysis of a number of DNA markers they conclude that the Sami people of Northern Scandinavia domesticated reindeer independently from indigenous people in what is now Russia.  Moreover the evidence points to the existence of three distinct gene pools suggesting that domestication even within Russia may have occurred more than once.

And there  is another interesting observation: comparisons with gene markers from wild reindeer suggests that introgression of “wild” genes into domestic reindeer appears to have happened quite frequently through the ages,  but that only some of the  wild populations have made genetic contributions suggesting perhaps different propensities for domestication among animals of various wild herds.

Unfortunately there is increasing concern about the future of reindeer agriculture. The Sami herders, who live in Scandinavia, Finland and parts of Russia, are beginning to feel the effects of global climate changes. The rapid warming trend that seems to occur in the Northern hemisphere interferes not only with foraging but also with the ability to move animals across what used to be solid ice. And many Sami now fear not only the loss of their livelihood, but also the disappearance of a substantial part of the culture, which has always been intricately linked to reindeer. Â