[MPWG] Insect in hemlock forests causes loss of canopy, gain of invasive plants

[Patricia_DeAngelis at fws.gov]

Thanks to MPWG listmember, Russ Richardson, for forwarding this link! 

I'm sure it's readily apparent why I've posted this to the Alien Plant 
listserve (APWG) - but I'm also posting it to the Medicinal Plant 
listserve (MPWG) because many of our medicinal plants live in the 
understory.

 
Insect in hemlock forests causes loss of canopy, gain of invasive plants 
By Sarah Yang, Media Relations | 26 May 2009
BERKELEY ? Deep in the hemlock forests of the Eastern United States, a 
tiny, aphid-like insect may be playing a giant role in transforming an 
ecosystem, according to new research by ecologists at the University of 
California, Berkeley.

The understory environment of hemlock forests, characterized by uniformly 
low light levels and little plant cover, has been significantly altered by 
the decline of the hemlock canopy caused by an exotic pest, the hemlock 
woolly adelgid. (Anne Eschtruth photo)

It's been well-documented that the spread of the hemlock woolly adelgid, 
an exotic pest native to Asia and introduced to the Eastern United States 
in the 1950s, has led to a decline of the shade-providing canopy in 
forests of eastern hemlock trees. The insect (Adelges tsugae) sucks fluid 
from the base of hemlock needles, causing the needles to drop and the 
branches to die.


Full story at: 
http://www.berkeley.edu/news/media/releases/2009/05/26_exoticpests.shtml


Patricia S. De Angelis, Ph.D.
Botanist - Division of Scientific Authority
Chair - Plant Conservation Alliance - Medicinal Plant Working Group
US Fish & Wildlife Service
4401 N. Fairfax Dr., Suite 110
Arlington, VA  22203
703-358-1708 x1753
FAX: 703-358-2276
Working for the conservation and sustainable use of our green natural 
resources.
<www.nps.gov/plants/medicinal
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