Hi, Patrick. Long time! I think we corresponded once about Poisson and NB models of fire occurrence back in 1999 or so.
Here, I am intrigued to learn that willows are insect pollinated. Putting this together with their considerable diversity (for northern species) such that reportedly almost nobody can identify them all in the field, makes me wonder if there might not be something interesting going on in the way of specialisation on pollinators, as a driver for speciation. I've always been told that interesting coevolutionary processes don't occur in the boreal, but now I wonder. Is this cwazy? As for aspens and balsam poplar, they are pretty flexible up to heights of several metres, which is probably as high as they could grow on the tundra, but I expect they are limited by some minimum size to sexual maturity. Best regards Steve Cumming Canada Research Chair in Boreal Ecosystems Modelling Sciences du bois et de la forêt Université Laval (418) 656-2131 poste 2593 -----Original Message----- From: Patrick Foley [mailto:[EMAIL PROTECTED] Sent: Sunday, August 24, 2008 12:57 PM Subject: Re: Salix success? David Inouye wrote: > What makes Salix (willows) so successful at high latitudes and high > altitudes? Unusual physiological traits? > > The genus /Salix/ has several preadaptations for life in harsh cold conditions of considerable past disturbance: 1) As a wetland plant it can handle tundra soils. 2) As a perennial it can handle short growing seasons. And for a perennial it is very flexible, hence its worldwide use for basketry. 3) It shows a lot of environmental plasticity dealing well with flooding and krumholzing. 4) It is an excellent colonizer due to wind and water dispersal (after glaciers and other flooding denudations). 5) Possibly its pollination system allows it to handle low population counts at times, or has helped to speed its diversification and adaptive evolution. The sister genus /Populus/ shows some of these traits, but is wind-pollinated, not very diverse and not very flexible. But note that aspens have an incredible geographic range. Alders Alnus are not closely related but share many of the willow traits, except animal pollination and easy wind dispersal. They make up for it with nitrogen fixation. I'm guessing that you are wondering how insect pollination evolved in /Salix/. So am I. Patrick Foley [EMAIL PROTECTED]
