Executive Summary

The objective of the National Biological Survey/National Park Service
(NBS/NPS) Vegetation Mapping Program is to develop a uniform
hierarchical vegetation classification standard and methodology on a
Service-wide basis and, using that classification standard and
methodology, generate vegetation maps for most of the park units under
NPS management. This program is in response to the National Park
Service\'s Natural Resources Inventory and Monitoring Guideline (NPS-75)
issued in 1992. The vegetation data are to be automated in a
GIS-compatible format, which will provide great flexibility in map
design and production, data analysis, data management, and maintenance
activities.

The use of a standard national vegetation classification scheme and
mapping protocols will facilitate effective resource stewardship by
ensuring compatibility and widespread use of the information throughout
the NPS as well as by other federal and state agencies. These vegetation
maps and associated information will support a wide variety of resource
assessment, park management, and planning concerns. They will provide a
structure for framing and answering critical scientific questions about
vegetation types and their relationship to environmental processes
across the landscape. They will provide a consistent means for the
inventory and monitoring of plant communities and they will support
\"ecosystem management\" by providing a consistent basis for the
characterization of the biological components of different ecosystem
units.

The first step toward the implementation of the mapping program includes
the development and documentation of standards and protocols. This is
being initiated in three studies: (1) a proposed National Vegetation
Classification Standard, (2) Field Methodologies, and (3) Accuracy
Assessment Procedures. This document is the result of the second study.
The fundamental purpose of this study is to review the scientific basis
for vegetation sampling and to propose a standardized field methodology
that will serve the objectives of this project. The planning process and
field methods that will be used to sample and accurately map the
National Vegetation Classification units across all parks are described.

The National Vegetation Classification System is the result of
synthesizing a great body of earlier scientific effort as well as twenty
years of field data collection and scientific analyses by The Nature
Conservancy (TNC) and Natural Heritage Program scientists. Confidence
levels are assigned to each community type to identify the quantity and
the quality of information available. The classification is rigorously
reviewed and updated as new data become available. This work is
representative of some of the best field ecology and constitutes an
important body of vegetation descriptions and characterizations.

The starting point for this study is the classification standards and
field methods that have been developed by The Nature Conservancy and the
network of Natural Heritage Programs. Nevertheless, it is anticipated
that the methods will need to be expanded and/or modified if the study
is to meet the challenge of ecosystem management across the diversity of
National Park System environments and circumstances. This further
development of the field methods and classification system will be
accomplished with standard methods and procedures. These standards will
preserve the overall integrity of the field methods as they are further
developed, and will enable the full use of the powerful tools of a
geographic information system (GIS). The vegetation classification will
be significantly advanced during the course of this NBS/NPS mapping
program.

The field methods will begin with the evaluation of existing information
on the biology, ecology, disturbance events, and land use history of the
park. The resource management needs of the individual parks will be
assessed in relation to this program. The availability of local
expertise and collateral information will help to determine how the
sampling should be stratified, where it should be concentrated, and how
much new information will be required to meet the objectives of this
project.

Sample locations and number of sample points will be determined by the
size, accessibility, and complexity of a park. Park size will determine
the level of sampling that can be efficiently carried out. Whereas every
polygon can be visited on the small parks, pilot sites must be selected
for sampling on the large and inaccessible parks. These pilot sites are
subsections of the park that are predicted to represent the diversity of
vegetation types across the park. The selection of pilot sites will
primarily be determined from the environmental stratification of the
park and the interpretation of the photography. Environmental and
vegetational complexity will force additional field sampling to
interpret the patterns of variability.

Depending on the complexity and distribution of the environmental
gradients, there may be one or more pilot areas selected for a park. The
photography will be interpreted across the sample areas and the sampling
points will be chosen for each putative vegetation type. Areas with
unique photo signatures will need to be included as additional pilot
sites. Accessibility and sampling efficiency will be factored into the
final selection of the sample areas.

Field data will be collected to develop the classification and
characterization of the vegetation within the National Vegetation
Classification Standard, and to ensure the accurate mapping of the
vegetation types across the park. Each vegetation polygon will be
classified to the finest floristic level (community element), although
field and imagery conditions may require a coarser level of
classification for certain vegetation types. The successful
implementation of this program will require a close working relationship
between the vegetation ecologists, the photo interpreters, and the
National Park Service staff.

Based on the development of the vegetation classes and the photo
signatures, a preliminary map will be generated for the park. A map
validation exercise will proceed with a new set of stratified sampling
points. Vegetation classification will occur at these points and an
error assessment will be completed on the validity of the preliminary
map product. The methodology will be refined to address any problems
that are identified up to this point. The vegetation mapping will then
proceed across the park. New vegetation types will be documented as they
are encountered. The final stage of this program will be the generation
of the final vegetation map and the formal accuracy assessment that will
document the positional and class accuracy of this product.

Similar field methods have been previously used to produce vegetation
maps as a component of TNC conservation assessment and planning
projects. Though the general objectives have been consistent, the
applications have varied in terms of scale, resources, types of remotely
sensed data, and desired end product. Specific mapping projects at the
Gray Ranch in New Mexico and the Yampa River in Colorado are discussed
in this report.

Deliverable products from this NBS/NPS Vegetation Mapping Program will
include a digital file of vegetation maps, digital metadata files,
textual descriptions, and keys to the vegetation classes, hard-copy
maps, and map accuracy verification reports.