All In my view, the term "invasive" really refers to life history characteristics (dispersal, reproduction, growth characteristics) whereas "native" refers to where a species was...basically... prior to the "Columbian Exchange." I think your argument highlights the importance of recognizing that there are "non-native invasive species" and also non-native species that have "naturalized." The naturalized species are innocuous members of an ecological community, the invasive species have significant impacts on biodiversity and ecosystem function (think of the forest floor under Lonicera).
I imagine that if you focus on life history traits, some native species are "invasive," but, most deciduous forest shrub-layer species don't fall into that category in my view- Smilax, Viburnum, Lindera, etc., just dont have the same impact on biodiversity and ecosystem function as invasives such as Lonicera or Ligustrum. What about Rhododendron, though? I think it is an interesting case...and maybe Kalmia in some settings, I am sure there are others I am not thinking of. The other really important thing to keep in mind is that native weeds should not be considered "invasive" if they are part of an ephemeral community. Think of poke (Phytolacca)...it has all the features of an "invasive" species, but it does NOT form a persistent community...it is ephemeral, holding the niche for a brief time. Ultimately, I think native weeds might be the key for management of invasives...you need something aggressive to hold those disturbed areas until you can get the forest floor in place and some shade from the canopy. Native "weeds" like Phytolacca, Rubus, Eupatorium rugosum, maybe even Acer negundo, and others, might be very helpful in that context. ryan On Wed, Dec 10, 2008 at 11:18 PM, Steve Galehouse <[EMAIL PROTECTED]>wrote: > Russ, ENTS- > > Not to be a heretic, but I think we have to realize we humans are as much > agents of dispersal of plant species as are birds, squirrels, wind patterns, > etc. Were it not native in my area, I think any of the Smilax species would > be considered invasive, as well as Viburnum acerifolium and Vaccinium > stamineum. The "alien" barberries, buckthorns, burning bushes and the rest > that have become naturalized are now effectively native species--just > because we can document how they came here from distant origins, doesn't > mean they don't belong here in the grand scheme. We don't know how "native" > species expanded their ranges, but I'm sure many did so with the help of > human influence(agriculture). I also think that observing and recording the > shrub layer of the forest, without taking in to account the herbaceaous > layer, is limiting the mix of the forest community. > > Steve > > > On Wed, Dec 10, 2008 at 1:48 PM, <[EMAIL PROTECTED]> wrote: > >> ENTS: >> >> There is no doubt that the spread of certain invasive species is >> accelerated by white tail deer. In the Appalachians Microstegium vimineum, >> Japanese stiltgrass is changing the condition of the "natural" hardwood >> forest faster than researchers can keep up with the evolving idea of what a >> "natural" forest or "natural" regeneration is likely to be defined as in the >> future. >> >> Invasive plants are showing up in tracts of woodland where nothing more >> than a stream passing through the property is a part of the disturbance >> regime. >> >> In so many forested situations I have encountered, the invasive species >> are not filling in a vacant niche...they are replacing a dynamic and diverse >> forest understory comprised of hundreds of native plant species per acre >> with a green desert that consists of a dozen or less of the most persistent >> native plants fighting for space against the overwhelming assault of non >> resident alien invaders that are capable of altering their adopted >> environment to suit their needs while producing prodigious amounts of seed >> that enjoy extremely high germination rates in the absence of fertility >> depleting microorganisms that keep resident plan populations in balance. >> >> Again, the changes being wrought on our forests by climate change and >> nonnative plants, insects and diseases is validating the ENTS historical >> mission of documenting what a "natural" forest is by today's definition. >> >> >> Russ >> >> >> >> ------------------------------ >> One site keeps you connected to all your email: AOL Mail, Gmail, and Yahoo >> Mail. The NEW >> AOL.com<http://www.aol.com/?optin=new-dp&icid=aolcom40vanity&ncid=emlcntaolcom00000019> >> . >> >> >> > > > > -- Ryan McEwan The University of Dayton http://academic.udayton.edu/RyanMcEwan --~--~---------~--~----~------------~-------~--~----~ Eastern Native Tree Society http://www.nativetreesociety.org You are subscribed to the Google Groups "ENTSTrees" group. To post to this group, send email to [email protected] To unsubscribe send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/entstrees?hl=en -~----------~----~----~----~------~----~------~--~---
