Ed- You have missed a primary source...many of the 'pioneering' species, as well as illegal aliens, have the advantage of long viability. Found in the seedbank, right on the site, seeds from prior disturbances may remain dormant for long enough periods of time to 'come back to life' with new disturbances. -Don
From: [email protected] To: [email protected] Subject: [ENTS] Pioneer species and Global Warming Date: Fri, 20 Mar 2009 12:34:31 -0400 ENTS, I have been thinking about various pioneer species and global warming. If you are out in the woods and find a freshly upturned root mass, and an opening, often there will be a sumac growing on it. There isn't any sumacs obviously growing anywhere in the area. The seeds for these pioneer species, like sumac and aralia spinosa, must be able to reach a long distance (or what?) in order to colonize these disturbed areas. Considering that, and the amount of man made disturbance of the soil, I am thinking that these species may be the ones that can expand their range faster in response to global warming than most other species and could migrate northward faster than most other species. Another factor is the typical lifespan of a species. The northward limit of a species can be considered the point at which the climate is too cold for the species. Many could probably live farther north than they do presently most years, except that periodically there is a real cold snap that can kill them off. So a species that lives a long time would have a greater chance of experiencing one of these killer cold snaps in its lifetime than a shorter lived species. Many of these pioneer species have a short lifespan - most seem to die out before they reach 30. So if the killer cold snap occurred every 100 years, there would be several generations of trees between cold snaps. these species could therefore migrate farther into the cold territory than longer lived species - assuming comparable amounts of northward expansion per generation. If the pioneer species expand faster per generation, they could expand their range even further. One of the concerns of the climate change is that the climate may be warming even faster than the trees can migrate northward. Perhaps this will favor the shorter lived species as the warming occurs, and perhaps it will favor the short lived, pioneer species like sumac and devils walking stick even ore than other species. This is just an idea I had on the subject. Anybody else have ideas or opinions on this subject? Ed Frank _________________________________________________________________ Internet Explorer 8 – Now Available. Faster, safer, easier. http://clk.atdmt.com/MRT/go/141323790/direct/01/ --~--~---------~--~----~------------~-------~--~----~ Eastern Native Tree Society http://www.nativetreesociety.org Send email to [email protected] Visit this group at http://groups.google.com/group/entstrees?hl=en To unsubscribe send email to [email protected] -~----------~----~----~----~------~----~------~--~---
