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USGS-NPS Vegetation Mapping Program 1
Thomas Owens 2
Abstract-The USGS Center for Biological Informatics is cooperatingwith the National Park Service to classify and map vegetation
communities on 235 Park units. The USGS-NPS Vegetation Mapping Program's approach is to develop scientifically valid basic
vegetation classification and spatial vegetation which can be used
as building blocks for management planning, inventory, monitoring
and research by local, regional, and national managers and scientists. The Program is noteworthy for its approach to vegetation
mapping which includes developing: 1) a national vegetation classification system, 2) standardized inventory and mapping protocols,
3) accuracy assessment, and 4) scientific peer review. The Program
uses extensive field work and aerial photography to perform classification and mapping work. Products include digital databases,
comprised of classifications and descriptions of vegetation communities, spatial vegetation data, and metadata, which are important for detailed Park management as well as regional and
national assessments of biodiversity. The Program has attracted
the interest of other federal and state agencies, including the Fish
and Wildlife Service, the Bureau of Reclamation, the Forest Service,
and the EPA. These agencies are interested in incorporating the
Program's protocols and standards into their own vegetation inventory and monitoring projects. For more information visit the website
at http://www.biology.usgs.gov/npsveg.
Basic data are fundamental to the management ofnatural resources. Natural resource inventories allow managers
and scientists to account for resources under their management and study, including the presence, class, distribution,
and normal variation of plants and animals, and such
important abiotic components as water, soils, landforms,
and climate. It is necessary to compile the basic building
blocks of information on these resources in order for the
information to be combined in different ways to answer
different questions. The USGS-NPS (U.S. Geological Survey, N ational Park Service) Vegetation Mapping Program is
a vegetation inventory program that provides basic vegetation community information to National Park managers
and scientists. The USGS Biological Resources Division's
Center for Biological Informatics administers the Program
and provides scientific and technical oversight for the National Park Service.
Program Goals
The Program's goals are to create highly accurate, detailed vegetation spatial databases in an efficient manner
lpaper presented at the North American Science Symposium: Toward a
Unified Framework for Inventorying and Monitoring Forest Ecosystem
Resources, Guadalajara, Mexico, November 1-6,1998.
Ztrhomas Owens is Coordinator, USGS-NPS Vegetation Mapping Program,
at the USGS Center for Biological Informatics, Building 810, Denver Federal
Center MS 302, P.O. Box 25406, Denver, CO 80225-0046 U.S.A Phone: (303)
202-4259; Fax: (303) 202-4219; e-mail: tom_owenS@Usgs.gov
USDA Forest Service Proceedings RMRS-P-12. 1999
for the park units and vicinities, and expand the National
Vegetation Classification Standard (NVCS) to include all
detailed classes at these units. The data must be spatial1.1
and thematically accurate, meet the professional standards
of the scientific community and applicable standards of
the Federal Geographic Data Committee FGDC), have a
nationally consistent, hierarchical, useful, classification
scheme, have a level of detail (spatial resolution and classification level) useful to park management. The Program
serves local management needs of each park while providing
comprehensive vegetation information at national and regionallevels. The Program is founded on good science, which
means all data are based on stati3tically sound field work
and proven, up-to-date technology is used.
Program Standards and
Protocols
The maj or standards for the Program are 1) the vegeta tion
standard, 2) the accuracy standard, 3) the metadata standard, and 4) the spatial data transfer standard.
The classification system must be based on sound science,
be repeatable across the landscape, be based on standard
field and data analysis methods, be broadly accepted, be
ecologically meaningful and classify existing biological associations, and be mappable from imagery. In addition, it must
be hierarchically organized, appropriately scaled, flexible
and open ended, well documented, and can be cross-walked
with vther frequently used systems. The system that meets
all these requirements is the NVCS. It is organized in the
following manner:
classificat~on
Physiognomy
Division/Order-dominant life form (example: Tree
Dominant)
Class-spacing & height of dominant form (example:
Woodland)
Subclass-morphological & phenological similarity (example: Evergreen Woodland)
Group-climate, latitude, growth form, leafform (example:
Temperate Evergreen Needle-leaved)
Formation-mappable units (example: Evergreen Needleleaved Woodland with Rounded Crowns)
Floristics
Alliance (Cover Type)-dominant species (example:
Douglas-fir Woodland)
Community (Association)-subdominant or associated
species (example: Douglas-fir / Snowberry Woodland)
Uniformity in classification methodology over the entire
park system is critical to achieve the overall inventory and
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monitoring goals of this initiative. All parks must be
mapped at the same level of classification detail (i.e. plant
association/cover type) and must be able to be re-aggregated
to the FGDC vegetation classification scheme.
The accuracy standard requires that the minimum mapping unit is 0.5 hectares, that locational accuracy meets the
National Map Accuracy Standards at 1:12,000 (a welldefined object is located within 10 meters of its actual
location on the ground), and classification accuracy will
greater than 80% for each vegetation class. To ensure that
the classification accuracy requirement is met an accuracy
assessment is performed at all park projects. Stratified
random sampling with replacement is used for.the accuracy
assessment. Ground visits are used to independently verify
the mapping classes; the field crews have no knowledge of
the mapped classes to ensure no bias exists in the accuracy
assessment.
The metadata standard requires that all datasets are
documented with metadata meeting the FGDC metadata
standard. The meta data compilation tool MetaMaker is
used to achieve this standard.
All spatial data produced must be in the Spatial Data
Transfer Standard (SDTS) format.
Basic protocols were generated early on the program.
There are four documents which outline the protocols: 1) Developingand documenting a National Vegetation Classification Standard, 2) Establishing standards for field methods
and mapping procedures, 3) Producing rigorous and consistent accuracy assessment procedures, and 4) Establishing
standards for using existing vegetation data.
The protocols provide general guidance to each park
project. The protocols are being tested in prototype studies,
protocols will vary based on a matrix of variables related to
size of area to be mapped (park & environs), existing data
and knowledge, complexity of vegetation and access/logistics. All field samples, accuracy assessment samples and
potential mapping approaches (i.e. softcopy) will be GPSbased. The GPS based approach is important because all
field data becomes spatial data. and relatable to other layers
in a spatial analysis. The development of protocols is near its
final stage, although there will always be new challenges
and issues as the program maps new units in different parts
of the country.
Specifically, the protocols for classification field methods include data and information discovery meetings at the
start of each project and the "gradsect" (short for gradient
tran~ approach. The gradsect approach stratifies the
park into bio-physical units using geological, soils, topographic, wetland, disturbance and other data to find ''hot
spots" of environmental diversity where sampling will be
the most efficient. This enables sampling the greatest
amount of vegetational diversity within the smallest area.
It is an efficient way to gather data for testing classification,
describing classes and developing photointerpretation
signatures/keys.
The specific protocols for mapping are that
photointerpretation will be used. New aerial photography of
the appropriate type(s), scale(s), and season(s) will be acquired for all areas (if useful, recent aerial photography does
not exist). Small parks will be mapped at scales larger than
1:24,000. Softcopy approaches to mapping will be used, if
technically feasible and cost effective.
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Program Methods
The major steps that are taken to complete each park
are 1) data review, 2) data acquisition, 3) gradsect, 4) initial
field reconnaissance, 5) field sampling, 6) classification
characterization, 7) photointerpretation, mapping and
automation, 8) accuracy assessment, and 9) final product
review. There are many other intermediate steps required,
and these steps are often iterative, but this is the basic
process flow for each park project. The Program contracts
with experts in vegetation mapping and vegetation ecology
around the country to provide the best expertise for each
project. The Nature Conservancy is a major national partner, and the individual state Natural Heritage Program
ecologists are heavily involved in specific park projects.
National Parks tend to be centers of scientific research
and monitoring and have long histories of data collection.
Data review and analysis can be a major task because of
the wealth of available data and information. It is important
to carefully analyze existing datasets because they may
provide efficiencies in the project. Datasets that usually
exist and may be useful are aerial photography, field plots,
historical vegetation maps and spatial data, reports and
monographs.
The next step is to acquire baseline data. This includes
taking aerial photography, acquiring ortho images (usually
USGS digital ortho quarter quads), acquiring other spatial
datasets such as elevation, soils, geology, and disturbance
history to be used in the gradsect. The gradsect is run
(perhaps several times with different combinations ofvariabIes) to model the major environment drivers in a park.
The resulting spatial database is used to help allocate
sample points for field sampling, and to inform the
photointerpretation process.
The mappers and ecologists who perform the classification participate in the initial field reconnaissance. The
purpose of this trip is to familiarize the mappers with the
photo signatures of the major vegetation classes, provide
more information to the ecologists on the local environment,
and to allow a discussion between the mappers and ecologists on how the park will be classified and mapped. Once the
initial reconnaissance is complete, the mappers will initiate
photointerpretation and provide this information to the
ecologists to help them plan their field sampling strategy.
The field sampling may take one or more field seasons,
depending on the size of the park. Three to five plots are
taken in each vegetation association to measure the variability for each class. If the association is well defined in an
area, only one plot may be taken. However, it is more
common to develop many new associations for an area based
on the work in a park. The field sampling strategy will evolve
as plots are taken and photointerpretation proceeds, beca use new associations may be discovered.
There are at least two versions of the classification system. A preliminary version is developed early in the project
by analysis of regional TNC databases and advice from local
experts. This preliminary version is used to start the
photointerpretation process, and is modified during the
course of the project. The field data are automated into a
database and analyzed quantitatively using computer
programs or qualitatively using methods described in the
NVCS document to develop the final classification. The
USDA Forest Service Proceedings RMRS-P-12. 1999
photointerpretation and classification process are heavily
interdependent and new information gleaned from one process may modify the other process.
Once a preliminary classification system is in place
photointerpretation may begin. It is done under a stereoscope to allow topographic information to assist the process
of identifying vegetation associations. The photointerpreters may take several field trips to the park for ground
truth data which mayor may not coincide with the field
work for the classification. When the photointerpretation is
completed, the data are rectified and automated. This may
be a heads-up digitizing process using the ortho image as a
background, or it may be a manual transfer to a hard copy
ortho image with subsequent scan digitizing. Whichever
process used, the products must meet the Program accuracy
requirements for classification and location accuracy.
When the spatial database of the vegetation communities
is complete a stratified random sample strategy for accuracy
assessment is designed. Each vegetation association, that is
extensively represented in the park, has at least 30 plots
located in it. Fewer plots may be taken if the association is
rare. The plots are navigated to with the aid of GPS receivers. The field crews may take a plot of the orthoimage with
polygons delineated on them for locational purposes, but do
not know how the polygons are classified. The field crews
take extensive information in each sample polygon. The
point data from the accuracy assessment are then compared
to the mapped data to ensure that the spatial data meets
the classification accuracy requirement of 80%.
The final data products, including the spatial data, the
classification data, the accuracy assessment data, and the
reports and metadata are reviewed by Program and park
staffto ensure that all standards are met. Then the data are
delivered to the park and placed on the website.
Peer Review -----------------------------------------------------------Peer review is an import.ant component of the program.
Reviews by independent scientists and managers ensure
that the program is effective at meeting the users' needs,
while maintaining strong standards. A review of the program occurred in September 1996 by USGS and Park Service scientists and managers. A second review has been
recently completed by the National Park Service and another review ofthe program is currently being conducted the
USGS. The reviews findings and recommendations have
placed on the Program's website at http://biology.usgs.gov/
npsveg. Recommendations made by the 1996 review have
been implemented. Recommendations by the Park Service
review and the USGS will be implemented as appropriate.
Program Status _ _ _ _ _ _ __
The Program has developed and published protocol documents that establish the basic methods (discussed above).
The Program has initiated mapping and classification
projects in twenty parks and has completed five of these
USDA Forest Service Proceedings RMRS-P-12. 1999
(Tuzigoot National Monument, Devils Tower National Monument, Mount Rushmore National Monument, Jewel Cave
National Monument, and Scotts Bluff National Monument).
The program plans to initiate projects in five new parks
this fiscal year.
Applications _ _ _ _ _ _ _ __
The Program's data and information can be applied in
numerous ways. Some examples include 1) invasive exotics
inventory, such as leafy spurge at Theodore Roosevelt National Park, by combining the spatial data with the classification descriptions, 2) Threatened and Endangered plant
species inventory by applying the spatial data with the
community description data to model the possible distribution of these species, 3) Using the vegetation associations'
distribution, along with the structure information the Program collects, and topographic data to model fire behavior,
4) Scotts Bluff National Monument used the species listings
in the community description data to develop seed mixes to
restore natural prairies in disturbed areas, 5) use the spatial
and description data to model wildlife habitat, for example
grizzly bears in Glacier National Park, and 6) Use the
vegetation classification data and descriptions for regional,
national, and global assessments of endangered vegetation
communities.
Conclusions --------------------------------------------------------The program has been in existence since 1994. The lessons
learned from the experiences to date are: 1) providing all
products is critical-not just mapping products. The classification data and information at as important as the mapping products to resource managers and scientists. The
results from the Park Service review indicate that parks
where work has been completed are using all the data for
resource and management applications. The parks do not
wan t a cut-back in the products produced for each park or the
resolution of the products, because they feel that each
product is valuable, the resolution is adequate for sitespecific management purposes, and the process is costeffective, 2) these products are the basic building blocks of
vegetation information, which is in turn a basic building
block for a management and information support database,
along with other information building blocks as topography, soils, wildlife habitat, transportation, and humans
factors. Once these data have been developed, it is relatively
simple to combine these data with other datasets and
expert systems to answer management and scientific questions. It is not easy to dis aggregate information into its basic
building blocks, and 3) providing sound, scientific, well
documented baseline information is critical to developing a
monitoring program. The experience has been that there
are many interesting historical datasets that have been
developed for national parks, but if good meta data are not
available that document the data development process, the
data are worthless.
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