[APWG] Fw: USGS News Release: Exotic Hydrilla Benefits Chesapeake Bay?s Ecosystem
Patricia_DeAngelis at fws.gov
Patricia_DeAngelis at fws.gov
Fri May 18 13:33:01 CDT 2007
Forwarding this news release with an interesting twist on exotic aquatic
species....
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 750
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>
- - - - - - - - - - - - - - -
U.S. Department of the Interior
U.S. Geological Survey
News Release
May 18, 2007 Nancy Rybicki 703-648-5728
nrybicki at usgs.gov
Jurate Landwehr 703-648-5893 jmlandwe at usgs.gov
Exotic Hydrilla Benefits Chesapeake Bay’s Ecosystem
Editors: “Long-term changes in abundance and diversity of macrophyte and
waterfowl populations in an estuary with exotic macrophytes and improving
water quality,” is available online in the May issue of ASLO: Limnology
and Oceanography, v 52, pages 1195-1207.
An exotic species of aquatic vegetation that was deemed a severe nuisance
when it began rapidly colonizing the Potomac River, has instead benefited
the watershed’s ecosystem, according to a study by the U.S. Geological
Survey (USGS) published in the journal Limnology and Oceanography. The
robust exotic hydrilla first appeared and began to flourish in the fresh
water reaches of the tidal Potomac River just as management investments to
reduce nutrient loads from sewage treatment plants were beginning to take
effect. Submerged aquatic vegetation is an important ecosystem resource
for fish and waterfowl and it was feared that the expansion of hydrilla
would impair the reemergence of native species, but this has not proven to
be the case.
“Before and during the seventeen-year period of the study, restoration of
the Potomac has focused on reducing nitrogen loads entering the river
system and the Chesapeake Bay,” said USGS scientist Nancy Rybicki, who
with colleague Jurate Landwehr were curious how the emergence of hydrilla
would affect the benefits sought for by management investments.
Shortly after it first appeared in the Potomac in 1983, hydrilla produced
dense vegetation masses and, in some areas, impeded boat traffic and water
sports." More significantly, it was feared that hydrilla would interfere
with native vegetation, which is important for waterfowl, such as black
duck, a signature species in this area.
Using information from annual field surveys and aerial photographs,
Rybicki and Landwehr created a data base to document bed-by-bed which
species of vegetation were found in different sections of the Potomac
River system. They recorded the percentage of total coverage and biomass
each species attained annually. In comparing species coverage with water
quality composition, they discovered that, with the reduction of nitrogen
concentration in Potomac River, hydrilla coverage expanded but so did the
diversity of plant species found in the River. Hydrilla did not crowd out
native species; indeed, native species increased. In addition, hydrilla
is a good winter food source for waterfowl communities, which have
increased significantly over this period.
“This research is the only long-term, quantitative study of aquatic plant
biodiversity following the colonization of an exotic species in an estuary
where millions of dollars are spent annually to reduce nutrient input and
it demonstrates that exotics are not always harmful to an ecosystem,” said
Rybicki.
"Furthermore," Landwehr pointed out, "the methods developed for this study
are transferable to any ecological assessments that need to merge
remotely-sensed spatial coverage with field observations."
The findings support current federal and state management strategies to
improve water clarity and reduce nutrient loads to: enhance aquatic
vegetation coverage; increase waterfowl habitat; and protect biodiversity
of the existing native community.
The study was conducted as part of the USGS Chesapeake Bay studies, which
is providing integrated science to for effective conservation and
restoration of the Bay ecosystem. The USGS is a federal partner in the
Chesapeake Bay Program, the federal-state partnership to restore the Bay
ecosystem. More information can be found at http://chesapeake.usgs.gov
USGS provides science for a changing world. For more information, visit
www.usgs.gov.
Subscribe to USGS News Releases via our electronic mailing list or RSS
feed.
**** www.usgs.gov ****
Diane Noserale
Media Relations, Eastern Region
U.S. Geological Survey
150 National Center
Reston, VA 20192
phone: 703-648-4333
fax: 703-648-4588
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.plantconservation.org/pipermail/apwg_lists.plantconservation.org/attachments/20070518/b2fcee29/attachment.html>
More information about the APWG
mailing list