[APWG] NEWS: Invasive Species Widespread, but Not More Than at Home

[Marc Imlay]

It would be interesting to know if the only 2.5 sites per species in home
ranges were natural sites or unnatural disturbed sites without competition
from native species. Native Switch Grass has been found invasive in America
in unnatural habitats but not in natural habitats and is a new invasive in
Europe. 

  

Marc Imlay, PhD,

Conservation biologist, Park Ranger Office

(301) 442-5657 cell

 <blocked::mailto:Marc.Imlay at pgparks.com> Marc.Imlay at pgparks.com
<blocked::mailto:ialm at erols.com>  <mailto:ialm at erols.com> ialm at erols.com

Natural and Historical Resources Division

The Maryland-National Capital Park and Planning Commission

 <blocked::http://www.pgparks.com/>  <http://www.pgparks.com/>
www.pgparks.com <http://www.pgparks.com/> 

 



-----Original Message-----
From: apwg-bounces at lists.plantconservation.org [
<mailto:apwg-bounces at lists.plantconservation.org>
mailto:apwg-bounces at lists.plantconservation.org] On Behalf Of Reinhart, Kurt
Sent: Thursday, March 10, 2011 11:59 AM
To: apwg at lists.plantconservation.org
Subject: Re: [APWG] NEWS: Invasive Species Widespread,but Not More Than at
Home

Okay, I'll bite & also do some shameless self promotion.

A contrary view to Firn et al. is provided using a single species (a
prominent invasive tree species) that was carried out across 40 total
populations with slightly more than half in its native range and nearly half
in its non-native range in Reinhart et al. (2010, New Phytologist
<http://onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.2009.03159.x/abst>
http://onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.2009.03159.x/abst
ract).  This study concluded that measures of local relative abundance were
considerably greater in the non-native than native ranges.  This study may
not seem like a direct comparison because the main topic relates to Enemy
release but comparable data are in the supplement (which apparently hasn't
been read by many).  Others have made similar observations though often
without quantitative evidence for species like spotted knapweed, garlic
mustard, etc.

Firn et al's ELE study's main advantage over Reinhart et al.'s is their use
of considerably more species (26 species, 12 grass and 14 forb
species) at 39 sites.  They concluded species have similar levels of
abundance in native vs. non-native ranges.  A conclusion from their paper is
that many of the grasses were common at home and away while many of the
forbs were rare at home and away.  However based on information in their
supplement, I calculated that on average they have measurements for only 2.5
sites per species in home ranges and 7.6 sites per species in exotic ranges.
Sampling more species per region is valued because many species have
incredibly large distributions and local abundances are variable throughout.
Sampling broadly is necessary to avoid forms of regional sampling bias
though researchers have to balance logistics (also see Adams et al. 2009 as
an example of an extensive sampling network
( <http://www.plantecology.org/Full%20text%20papers%20and%20abstracts/2009>
http://www.plantecology.org/Full%20text%20papers%20and%20abstracts/2009
%20papers/Adams%20Bioinvasions%202009.pdf).  Firn et al. help avoid this
limitation by looking at numerous species though more than half represent
relatively minor invasions.

I think what we would mostly like to know is what
traits/processes/interactions can we attribute to the success of the most
invasive species and whether their abundances, effects of enemies, etc.
differ at biogeographical scales.  Following the rule of 10s, these species
represent the most improbable invasion scenarios.  So we shouldn't be too
surprised if such rare events can never be predicted without the benefit of
hindsight.  However, I wouldn't be surprised if further studies, focusing on
highly invasive species which are the exceptions, reveal that most/many are
cases where the species attain greater levels of local abundance/dominance
in their non-native than native ranges.  My 2 cents.  You decide.

Kurt Reinhart

  31. NEWS: Invasive Species Widespread,        but Not More Than at
Home
      Range (Olivia Kwong)
Message: 31
Date: Thu, 3 Mar 2011 08:27:30 -0600 (CST)
From: Olivia Kwong <plant at plantconservation.org>
To: apwg at lists.plantconservation.org
Subject: [APWG] NEWS: Invasive Species Widespread,      but Not More
Than
        at Home Range
Message-ID:
        <Pine.LNX.4.64.1103030826390.1121 at cpanel1-bb.epconline.net>
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed

 <http://www.sciencedaily.com/releases/2011/03/110301111459.htm>
http://www.sciencedaily.com/releases/2011/03/110301111459.htm

Invasive Species Widespread, but Not More Than at Home Range

ScienceDaily (Mar. 1, 2011) -- Invasive plant species have long had a
reputation as being bad for a new ecosystem when they are introduced.

Stan Harpole, assistant professor of ecology, evolution and organismal
biology at Iowa State University, is founding organizer of a team of more
than 70 researchers working at 65 sites worldwide that tested that
assumption.

See the link above for the full article text.




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