Vegetation Monitoring
Report Section 10.10) Vegetation monitoring and control activities conducted
on and around the Hanford Site in 2005 are summarized in
the following sections. The sections include discussions on
surveys and monitoring of Hanford Site plant populations,
monitoring contaminants in perennial vegetation growing
near facilities and operations on the site, and control of
contaminated or unwanted vegetation on the site. Surveys
and monitoring of plant populations are conducted to assess
the abundance, vigor or condition, and distribution of populations
and species. These data can be integrated with contaminant
monitoring results and used to help characterize
potential risks or impact to biota. Radiological monitoring
of vegetation near onsite facilities and operations is done to
determine the effectiveness of effluent monitoring and controls
within facilities, to assess the adequacy of containment
at waste disposal sites, and to detect and monitor unusual
conditions. Site-wide and offsite vegetation samples (not
collected in 2005 but scheduled for collection in 2007)
are analyzed for information on atmospheric deposition
of contaminants in uncultivated areas offsite and around
operational areas onsite. These data provide a baseline
against which unplanned releases can be compared. Vegetation
management activities help to prevent, limit, or clean
up contaminated plants or undesirable plant species. For
further information about these monitoring and control
efforts, the programs that support them, and their purposes,
see Section 10.0 in this report or DOE/RL-91-50.
10.10.1 Plant Communitiesand Population Surveys on the Hanford Site
J. L. Downs,
K. D. Hand,
M. R. Sackschewsky,
R. E. Durham, and
R. K. Zufelt
The Hanford Site contains biologically diverse shrub-steppe
plant communities that have been protected from most
disturbances, except for fire, for more than 55 years. This
protection has allowed plant species and communities that
have been displaced by agriculture and development in other
parts of the Columbia Basin to thrive at Hanford. Surveys
and mapping efforts have documented the occurrence and
extent of rare plant populations and plant community types
on the Hanford Site (PNL-8942;
PNNL-13688;
Soll et al. 1999).
Plant populations monitored on the site include taxa
listed by Washington State as endangered, threatened, or
sensitive (Section 10.12), and those species listed as review
group 1 (i.e., taxa in need of additional field work before
status can be determined) (Washington Natural Heritage Program 1997).
Data are collected for plant populations
and plant communities on the Hanford Site to develop baseline
information and to monitor any changes resulting
from Hanford operations. The data provide information
that is used for site planning processes and land-use policy
development.
10.10.1.1 Vegetation Cover Types and Habitats
Monitoring of the plant communities and cover types on
the Hanford Site focuses on two main objectives: mapping
the distribution and extent of major plant cover types on
the uplands and riparian areas on the site, and conducting
periodic surveys to assess whether community composition
and structure are changing. Mapping the distribution and
extent of vegetation on the site provides important information
on potential and existing habitats of sensitive or rare
species as well as provides information regarding the presence
of receptor species. The spatial data for upland habitats
were updated to reflect changes in vegetation following the
24 Command Wildland Fire in 2000 (DOE/RL-2000-63).
Spatial information for the riparian vegetation cover types
was updated during 2003 and 2004 to provide a continuous
map of the Benton County shoreline of the Hanford Reach.
During 2005, further work was conducted to update the
vegetation cover type information for the 100 Areas,
200 Areas, and 300 Area to better describe the current status
of vegetation within the area boundaries. Numerous activities
associated with cleanup including excavation, remediation,
and restoration have influenced the vegetation inside
the areas and at their fenced boundaries. Revisions of the
vegetation cover type maps for these areas were accomplished
using color aerial photography and ground surveys.
Information from these surveys were also used to update
maps depicting areas with highly valued biological resources
(http://www.pnl.gov/ecomon/Veg/Veg.asp).
Periodic surveys
of the frequency, cover, and number of species found on
permanent monitoring plots provide information on trends
or changes in species diversity, presence of invasive and key
species, and the overall condition of the plant community
and available habitat (see Section 10.11.1.3).
10.10.1.2 Rare Plant Monitoring
More than 100 plant populations of 47 different taxa listed
by the Washington Natural Heritage program as endangered,
threatened, sensitive, review, or watch list are found at the
Hanford Site (http://www.pnl.gov/ecomon/Veg/Habitat.asp;
PNNL-13688).
The U.S. Fish and Wildlife Service
has designated 5 of these 47 taxa (including the two species,
Umtanum buckwheat [Eriogonum codium] and White Bluffs
bladderpod [Lesquerella tuplashensis]) as species of concern in
the Columbia River Basin ecoregion (http://www.dnr.wa.gov/nhp/refdesk/lists/plantrnk.html).
These two species
are proposed as candidates for federal listing. In addition to
the rare plant populations, several areas on the Hanford Site
are designated as special habitat types with regard to potential
occurrence of plant species of concern listed by Washington
State. These are areas that potentially support populations
of rare annual forbs that have been documented in adjacent
habitats.
In June 2004, a population of coyote tobacco, Nicotiana attenuata, was discovered in a disturbed, open sand dune adjacent to the 618-10 burial ground, approximately 3.2 kilometers (2 miles) southeast of the 400 Area. A total of approximately 30 individual plants were found at that time, and the habitat in the vicinity of the population was designated a rare plant protection area to help conserve the population while cleanup of the 618-10 burial ground proceeds. The site was inspected several times during 2005 and no living plants were found. The disappearance of coyote tobacco from this area is presumably due to below normal rainfall during the year. Between January and May 2005, there were 5.9 centimeters (2.33 inches) of precipitation compared to 11.4 centimeters (4.5 inches) between January and May 2004 (normal for that period is 5.9 centimeters [3.12 inches]).
During September 2005, monitoring transects originally established to examine the condition and status of persistent sepal yellowcress (Rorippa columbiae) were revisited along the Columbia River shoreline near the 100-F Area. No specimens were located along the original transects. However, nearly 130 individual plants, in clumps of 5 to 40 individuals, were found nearby and up the river bank from the original population. Data that describe trends in plant numbers and the timing of growth for this species are of interest because large variations in population numbers have been observed. These variations are believed to be related to river-level fluctuations that inundate habitat for this species during a large part of the growing season. Additional data were gathered in 2005 to investigate this relationship by employing a survey grade real-time global positioning system to map the location and elevation of each plant clump found along the Columbia River shoreline near the 100-F Area.