Lee- No fossilized earthworms, not even in the Burgess shale? How about in rest of world? -Don
> Date: Fri, 7 Aug 2009 13:21:39 -0500 > From: [email protected] > To: [email protected] > Subject: [ENTS] Re: earthworms and invasive plants > > > Don: > > No, they don't leave any direct traces that we know of in the > sedimentary record. However, they do cause chemical and erosional > changes in the soil that might show up in the sedimentation process. If > so, no one has worked it out yet. It is also possible that some > earthworms could be preserved in sediments as macrofossils--we have tree > leaves that a several million years old, so the same could happen to > earthworms, but no one has uncovered such fossils for the glaciated > parts of North America. > > Lee > > DON BERTOLETTE wrote: > > Lee- > > Yeah, I guess it's not like earthworms leave much in the way of > > skeletal remains...is there anything in their innards that their > > remains or 'castings' might yield identifying signatures? > > -Don > > > > > Date: Fri, 7 Aug 2009 09:51:38 -0500 > > > From: [email protected] > > > To: [email protected] > > > Subject: [ENTS] Re: earthworms and invasive plants > > > > > > > > > Joe: > > > > > > Much of the earthworm literature states that earthworms were removed > > > from the northern states by glaciers and that the worms never returned, > > > and/or that North American species of earthworms can't live in > > glaciated > > > areas. > > > > > > However, there is no evidence for those statements. I have never seen > > > any proof that earthworms lived in the north prior to the last > > > glaciation, or that it takes more than 12,000 years for the earthworms > > > to move about 1200 miles from the areas where they would have lived > > > during the peak of glaciation, to places like MA, NH and MN. So, I > > think > > > that they essentially reached the limit imposed by colder climates as > > > they moved north. > > > > > > The correlations between whether an area is glaciated and native > > > earthworms are present also does not hold up very well. Southwestern > > WI, > > > for example, was not glaciated and has no native earthworm, whereas > > > Southeastern WI was glaciated and does have two species of native > > > earthworms. In addition to that, tundra and boreal forest with > > > permafrost would have extended as far south as TN and NC at the peak of > > > the last glaciation, and no North American earthworm species would find > > > those habitats suitable, so they had to move a great distance just to > > > make it back to places like MA and WI. I think earthworm ecologists are > > > not very good paleoecologists, and look at the world as static, leading > > > to their misinterpretation of glaciation versus earthworm presence. > > > > > > Lee > > > > > > J > > > > _________________________________________________________________ Get back to school stuff for them and cashback for you. http://www.bing.com/cashback?form=MSHYCB&publ=WLHMTAG&crea=TEXT_MSHYCB_BackToSchool_Cashback_BTSCashback_1x1 --~--~---------~--~----~------------~-------~--~----~ 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] -~----------~----~----~----~------~----~------~--~---
