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Transcript of Seeing the Forest and the Trees - NatureServe the Forest and the Trees: Ecological Classification...
Ecological Classification for Conservation
Seeing the Forest and the Trees:
The classification that this publication describes was authored by:
Mark Anderson Dennis H. GrossmanPatrick Bourgeron Sally LandaalMark T. Bryer Kenneth J. MetzlerRex Crawford Karen D. PattersonLisa Engelking Milo PyneDon Faber-Langendoen Marion S. ReidMark Gallyoun Lesley SneddonKathleen L. Goodin Alan S. Weakley
and by ecologists in the network of Natural Heritage programs and Conservation Data Centers (seeback cover).
Citation: Maybury, Kathleen P., editor. 1999. Seeing the Forest and the Trees: Ecological Classification forConservation. The Nature Conservancy, Arlington, Virginia.
ISBN 0-9624590-2-X
Copyright 1999 The Nature Conservancy
Acknowledgements
Don Faber-Langendoen, Alan Weakley, Marion Reid, and Dennis Grossman, deserve special acknowledgementfor their ideas, careful review, and other contributions to this publication. Thoughtful review and commentswere also provided by Jonathan Adams, Mark Anderson, Mark Bryer, Patrick Comer, Christine A. De Joy, BethDuris, Stephanie R. Flack, Kathleen L. Goodin, Sally Landaal, Julie Lundgren, Karen D. Patterson, Milo Pyne,Carol Reschke, Lesley Sneddon, and Bruce A. Stein. Deborah A. Gries provided research assistance. JimDrake, Jonathan L. Haferman, and Stuart Sheppard assisted with maps.
Design and Production: Nicole S. Rousmaniere
Preface ............................................................................................................................. 2
Introduction ....................................................................................................................... 3
Why Communities? ............................................................................................................. 4
Why Is a Classification System Important? .............................................................................. 6
What Is the USNVC? .......................................................................................................... 7
What Is the Current Status of the USNVC? ...........................................................................10
How Is the USNVC Being Used? ........................................................................................12
Within the Conservancy .............................................................................................12
Beyond the Conservancy ............................................................................................19
Summary and Future Challenges .........................................................................................23
Appendices: The Nuts and Bolts of the USNVC System ...........................................................24
Appendix A—Key Attributes .......................................................................................24
Appendix B—Structure and Type Definition ...................................................................26
Appendix C—Partners in Development and Application ..................................................29
Cited References ..............................................................................................................36
Table ofContents
2 Seeing the Forest and the Trees: Ecological Classification for Conservation
† The Natural Heritage network is an informal designation of state and other programs that work cooperatively to collect and manageinformation on rare species and natural communities.
n the early summer of 1991, a biologist invento-
rying a pine savanna on the North Carolina
Coastal Plain came across a 3-foot-tall plant he couldn’t
identify. The puzzling plant species, a member of the sedge
family, turned out to be unknown to science—and all the
more intriguing because its nearest close relatives were
found to be boreal species that occur almost 500 miles
away. Subsequent inventories at this same small site have
documented the presence of an astounding 500 species
of vascular plants, as well as large populations of several
globally endangered plants and invertebrates.
For those dedicated to preserving the nation’s
biodiversity, remarkable discoveries like these are usually
a call to action, galvanizing efforts to forge
partnerships with members of the local
community, negotiate land deals, and ini-
tiate protection agreements. These efforts
are often imbued with a sense of urgency,
as many sites of exceptional biological value
face encroaching development or other threats. In this
case, however, no sense of crisis ever arose; nothing out
of the ordinary happened at all. At the time the scientist
discovered the anomalous sedge, large portions of the site
had been a Conservancy preserve for more than five years.
Ties to the community were already strong, and protec-
tion efforts had long been part of the day-to-day work of
the Conservancy’s North Carolina Field Office.
How did the Conservancy come to identify this
specific place as being of critical conservation concern years
before many of the important species discoveries had been
made? In large part, the answer has to do with a scientific
approach created expressly to meet conservation needs:
a classification system for ecological communities.
Classifications such as the one developed in North Caro-
lina have now been compiled, integrated, and expanded
into a system that is applicable across the nation: the U.S.
National Vegetation Classification, or USNVC. The prod-
uct of a two-decade-long collaboration between the Con-
servancy and the network of Natural Heritage programs,†
the USNVC greatly enhances our ability to recognize,
assess, and conserve natural communities everywhere we
work, in the United States and beyond. It represents the
first U.S. community classification system that is national
in scope and detailed enough in its consideration of
natural diversity to be useful in making local, site-specific
conservation decisions.
In the case of the North Carolina site, a
community classification system allowed bi-
ologists to recognize and document that at
least one plant community found there was
extremely rare on a global basis. That real-
ization was a principal factor in the decision
to make the site a Conservancy preserve long before com-
prehensive inventories of species had been conducted there.
In this report, we present several examples of how
scientists within and beyond the Conservancy are using
the USNVC to accomplish the best possible conservation.
Our hope is to make the classification, and its enormous
potential for improving conservation decisions, accessible
to a wider audience of conservation practitioners. Essen-
tially, we want this tool to be in the hands of those who
need it, wherever they need it, to carry out effective and
efficient conservation.
The ecologists of
The Nature Conservancy,
August 1998
I
Preface
3Seeing the Forest and the Trees: Ecological Classification for Conservation
hat types of natural vegetation exist across
the landscape? Which types are intrinsically
rare or have been severely degraded by human activities?
How do we identify the best remaining occurrences of natu-
ral communities across their geographic ranges? To direct
our limited conservation resources to the specific places
where they will have the greatest impact, we must have
clear answers to questions such as these—answers that
ultimately hinge on how we define and categorize the rich
ecological diversity that is one of our nation’s greatest trea-
sures. To answer these questions, The Nature Conservancy,
in partnership with the network of Natural Heritage pro-
grams, has developed a scientifically sound, consistent, and
flexible classification system that can
be applied to terrestrial ecological
communities throughout the world.
The system can be used to classify
all types of vegetated communities,
from verdant wetlands to arid deserts nearly lacking in plant
life, and from the most pristine old-growth forests to
cultivated annual crop fields. Using this system, a team of
Conservancy and Heritage ecologists has now completed a
first iteration of the natural vegetation types of the United
States. This represents the first time the country’s natural
terrestrial communities have been classified using a single
system on a scale fine enough to be useful for the conser-
vation of specific sites.
† An ecoregion is a relatively large unit of land and water delineated by the biotic and abiotic factors that regulate the structure andfunction of the communities within it. It provides a unit of geography that is more relevant than political units for organizing andprioritizing conservation planning efforts.1
This standardized approach is allowing assess-
ments of conservation status, trends, and management
practices for ecological communities across local,
regional, and national landscapes. It has enhanced the
Conservancy’s ability to identify the most important
sites for conserving our nation’s biodiversity, and it is
playing an important role in our efforts to identify a
portfolio of conservation sites representative of each
ecoregion.† Beyond the Conservancy and Heritage pro-
grams, the system’s utility has been widely appreciated:
it is now accepted as the standard for classification,
inventory, and mapping work in all U.S. federal agen-
cies, including the National Park Service, the National
Forest Service, and the Fish and
Wildlife Service. These agencies,
along with other academic and
professional conservation and
management organizations, are
increasingly becoming the Conservancy’s partners in
the ongoing development and application of the clas-
sification and its provision to a burgeoning number of
users and contributors.
This report briefly describes the classification
system and identifies major opportunities for applying
it to meet our current conservation challenges, as well as
those that lie ahead.
W
Introduction
4 Seeing the Forest and the Trees: Ecological Classification for Conservation
ttempts to conserve biological diversity can
be directed at different biological and eco-
logical levels, ranging from genes to species to commu-
nities and ecosystems. Communities can be described
as assemblages of species that co-occur in defined areas
at certain times and that have the potential to interact
with one another.2,3,4 But com-
munities are more than the
sum of their species; they also
represent the myriad biological
and environmental interactions
that are inherently a part of
each unique natural system.
Thus, by describing, tracking, and preserving commu-
nities, ecologists can protect a complex suite of organ-
isms and interactions not easily identified and protected
through other means.
In addition, a consensus has emerged within the
conservation community about the inadequacy of a
species-by-species approach to conservation. Saving
individual species once they are on the brink of extinc-
tion often demands large amounts of time, societal
concern, and money. Such an approach is clearly neces-
sary for species that are facing particular threats, and it
is also reasonable for large mammals, birds, and plants
that are of particular signifi-
cance to humans, especially
those that inspire a sense of awe
or affinity. But there are an
estimated 10 million to 100
million species on Earth, only
a fraction of which are known
to science.5 These include the little, less glamorous
species that create soils, pollinate plants, and play
numerous other ecological roles. Protecting the vast
majority of them will require a broader, natural com-
munity-based approach that conserves habitats and
species assemblages as a whole.
A
© Kate Spencer
San Gabriel Mountainslender salamander
The best approach to protecting many of our
most imperiled species, such as the elusive
and rare San Gabriel Mountain slender
salamander, is to preserve the habitats on
which they depend. Natural assemblages of
plants are widely regarded as biological
expressions of the complex factors that make
up a particular habitat—factors such as
climate, soils, natural disturbance processes,
and the structure of the plants themselves.
Thus, natural plant communities can be used
as a “coarse filter” for protecting numerous
species, even the less glamorous species whose
very existence—let alone habitat needs—we
may have yet to discover.
WhyCommunities?
5Seeing the Forest and the Trees: Ecological Classification for Conservation
• Communities have inherent value that is worth conserving. They encompass a unique set of interactions amongspecies and contribute to important ecosystem functions.
• Communities can be used as surrogates for species and for ecological processes, particularly in species-richand data-poor areas such as the tropics.
• By protecting communities, we protect many species not specifically targeted for conservation. This is especiallyimportant for poorly known groups such as fungi and invertebrates.
• Monitoring change over time is often most meaningful when done at the level of communities. Changes may bedetected in overall species abundance, including the proportion of non-native species; in structure, such as thedevelopment of old-growth characteristics; and in function, such as alterations in nutrient cycling.
• Communities are an important tool for systematically characterizing the current pattern and condition ofecosystems and landscapes.
The ecological community concept has been recognized as an importantconservation planning tool for the following reasons:
More Than the Sumof Its Parts
Tropical forest communities
may comprise an especially
high number of species. Like
all communities, they also
comprise a complex array
of interactions among species
and between species and their
environments. Shown here:
a seasonally flooded tropical
forest, south Florida.
© J
ames
R.
Snyd
er
6 Seeing the Forest and the Trees: Ecological Classification for Conservation
he Conservancy and the Natural Heritage network
have recognized ecological communities as
important elements of conservation for many years. The
best, most viable occurrences of these communities,
along with occurrences of rare and imperiled species,
have formed the basis for protection decisions through-
out the Conservancy’s history.
In the past, despite the recognized importance of
ecological communities, no accepted framework for
national or international community classification existed.
Without a standard approach,
community protection decisions
were made only on a state-by-
state or agency-by-agency basis,
based on independently devel-
oped classifications. These clas-
sifications worked effectively for
the conservation of important
areas within states or jurisdic-
tions, but from a national and
international perspective, they risked unnecessarily redun-
dant protection of a few communities and inadequate
protection of many others. In addition, in the absence of
a common classification, the results of many inventory
and monitoring programs, such as those conducted in
national forests and parks, state forests and parks, or fish
and wildlife refuges, could not be integrated or compared.
As recently as 1995, several prominent researchers
† More detailed information about the classification system, including its development, status, and applications, can be found in the recentpublication International Classification of Ecological Communities: Terrestrial Vegetation of the United States.7 A first iteration of the list ofcommunity types can be found in the second volume of that publication.8 Both volumes are available on the World Wide Web atwww.tnc.org.
concluded that a basic question—to what extent the natu-
ral ecosystems in the United States have been reduced in
area or degraded in quality due to human activities—
could only be answered “by a relatively crude approach
because a systematic approach to understanding these
systems at a national scale was not yet available.”6 Other
basic questions, such as, What are the key environmental
factors in relationship to a particular community across
its entire range? and, What is the complete geographic
distribution of a particular community? often could not
be answered at all.
Recognizing the need for a
national and international sys-
tem for classifying terrestrial
communities to carry out its
mission effectively, the Conser-
vancy, in conjunction with the
Natural Heritage network, un-
dertook development of the U.S.
National Vegetation Classification
(USNVC) system. A team of more than 100 Conservancy
and Heritage ecologists established the standardized
classification framework and defined the first iteration
of U.S. communities within it.† In the coming years, the
USNVC will be continuously refined and developed by
the Conservancy and an expanding network of partners
who are using the system to accomplish their conserva-
tion and management goals.
T
Why Is aClassification
SystemImportant?
7Seeing the Forest and the Trees: Ecological Classification for Conservation
he USNVC system blends the features of many
existing classification systems that are most
useful for conservation. It essentially represents a
structured compilation of an enormous amount of
fine-scale state and local information on vegetation,
and an integration of this information with a modified
version of UNESCO’s worldwide framework for coarse-
scale vegetation classification.9
Terrestrial ecological communities are classified
based on vegetation as it currently exists across the land-
scape. Because of their conservation objectives, the
Conservancy and the Natural Heri-
tage network are classifying and
describing only the more natural
types of vegetation. The USNVC
framework, however, may be used
to classify all existing vegetation,
including heavily human-influ-
enced types such as those in developed areas, crop-
lands, and places severely altered by past logging or
farming. (See Appendix A for additional information
about the key attributes of the USNVC.)
In the USNVC, terrestrial vegetation is classified
within a nested, seven-level hierarchy, the finest level of
which is called the association. (See Appendix B for a com-
plete explanation of the system’s hierarchical structure.)
The confluence of three interrelated criteria—species
composition, structure, and habitat—conceptually
defines an association: it represents those plant assem-
blages that exhibit similar total species composition and
† A few associations that are restricted to specific and unusual environmental conditions are exceptions to this general rule.
T vegetation structure and that occur under similar habi-
tat conditions.
The association concept encompasses both the
dominant species (those that cover the greatest area) and
diagnostic species (those found consistently in some
vegetation types but not others) regardless of whether
they are large trees or diminutive understory plants.
This means associations can reflect a greater ecological
specificity than can a “cover type” or other type based
solely on the dominant species of the upper stratum.
Dominant cover species are often widespread, and may
occur with many different species
over large, heterogeneous land-
scapes.10,11 For example, in north-
ern Minnesota and adjacent parts of
Canada, on moist bedrock sub-
strates the “generalist” species jack
pine (Pinus banksiana) occurs with
an understory of balsam fir (Abies balsamea), whereas
on dry sandplains jack pine grows with bearberry (Arcto-
staphylos uva-ursi) under its canopy.12 These two distinct
plant assemblages, and the profoundly different environ-
mental conditions under which they occur, undoubtedly
represent differences of real ecological significance.
The differences are captured by including dominant
and diagnostic species in both the over- and understory,
as well as habitat conditions, in the association concept.
Despite their relatively high degree of ecological speci-
ficity, associations must repeat across the landscape.† Indi-
vidual occurrences of the same or different associations,
The association concept is intended to be fine enough to be useful foridentifying specific, ecologically meaningful sites for conservation, but
broad enough to be connected to landscape-scale processes and patterns.
What Is theUSNVC?
8 Seeing the Forest and the Trees: Ecological Classification for Conservation
however, may range greatly in size. For example, some west-
ern grasslands occur naturally in patches of tens of thou-
sands of acres. In contrast, southern Appalachian “beech
gaps,” characterized by stunted, gnarled beech trees,
often occur in sharply bounded mountaintop patches of
only a few acres.
Associations are grouped into the next level of the
USNVC hierarchy, the alliance, primarily on the basis of
having common dominant species in the upper stratum
of the vegetation. Alliances, in turn, are nested into
progressively coarser levels of the hierarchy, primarily
based on characteristics related to the structure (height
and spacing) and overall shape of the plants, and to
Encompassing the boreal and the tropical, alpine
summits and deserts well below sea level, the United
States is blessed with a great and beautiful variety
of natural vegetation. Conceptualizing—even in a
general way—the diversity and pattern of this vegeta-
tion across the landscape is a daunting prospect.
Doing so in a way that helps us understand relatively
small-scale but ecologically meaningful patterns is even
more of a challenge.
Hawaiian cloud forestsm
Death Valleym
Towering redwoodsm
The Evergladesm
Tallgrass prairies
characteristics of the leaves, such as seasonality, shape,
and texture. These features are referred to as physiognomic
characteristics, and they are generally much more useful
than species composition for rapidly categorizing veg-
etation over large geographic areas (or in areas where
little is known about the species composition).
At the coarsest level of the USNVC hierarchy,
the class, vegetation is divided into seven types: Forest,
Woodland, Shrubland, Dwarf-shrubland, Herbaceous,
Nonvascular, and Sparse Vegetation. A summary of the
USNVC’s seven levels is provided in the box on the
facing page.
© C
harl
ie O
tt a
nd G
unth
er M
atsc
hke
Death Valley National Monument
9Seeing the Forest and the Trees: Ecological Classification for Conservation
A Summary of the U.S. National VegetationClassification System
PRIMARY BASIS FOR CLASSIFICATION
Structure of vegetation
Leaf phenology
Leaf types, corresponding to climate
Relative human impact (natural/semi-natural, orcultural)
Additional physiognomic and environmentalfactors, including hydrology
Dominant/diagnostic species of the uppermostor dominant stratum
Additional dominant/diagnostic species fromany strata
LEVEL
Class
Subclass
Group
Subgroup
Formation
Alliance
Association
EXAMPLE (SEE PHOTO)
Woodland
Evergreen Woodland
Temperate or Subpolar Needle-LeavedEvergreen Woodland
Natural/Semi-natural
Saturated Temperate or SubpolarNeedle-Leaved Evergreen Woodland
Longleaf Pine -- (Slash Pine, Pond Pine)Saturated Woodland Alliance
Longleaf Pine / Little Gallberry /Carolina Wiregrass Woodland
The Longleaf Pine / LittleGallberry / CarolinaWiregrass Woodland. Thisassociation is found on flat,poorly drained sites on theCoastal Plain of North andSouth Carolina.
† Rules for naming alliances and associations: The names of dominant and diagnostic species are used in alliance and associationnames. Those species occurring in the same stratum are separated by a hyphen ( - ); those occurring in different strata are separatedby a slash ( / ). Species found less consistently either in all associations of an alliance, or in all occurrences of an association, areplaced in parentheses. In most cases, the word “alliance” appears in alliance names to distinguish them from associations. Examplesof alliance names: American Beech - Southern Magnolia Forest Alliance [Fagus grandifolia - Magnolia grandiflora Forest Alliance];Longleaf Pine / Oak Species Woodland Alliance [Pinus palustris / Quercus spp. Woodland Alliance]. Examples of association names:Subalpine Fir / Grouseberry Forest [Abies lasiocarpa / Vaccinium scoparium Forest]; Saltgrass - (Saltmarsh Dropseed) HerbaceousVegetation [Distichlis spicata - (Sporobolus virginicus) Herbaceous Vegetation].
© J
ulie
Moo
re,
TN
C
†
†
10 Seeing the Forest and the Trees: Ecological Classification for Conservation
What Is theCurrent
Status of theUSNVC?
he number of currently defined USNVC types at
each level of the system’s hierarchy and the per-
centage of associations in each class are presented
below. The number of types at the coarser levels of the
hierarchy will not change significantly as the classifica-
tion develops. However, changes will occur at the finest
levels as the existing alliances and associations are
refined and new types are added through additional
inventories and analyses.
Each of the currently defined
associations has a minimum set
of information associated with it,
including the association’s conser-
vation status, and a list of states and
U.S. Forest Service ecoregions 13
where it is known or thought to
occur. However, to understand
alliances and associations in depth and to recognize
them in the field, ecologists will need answers to more
detailed questions about specific types. Important
questions regarding each type include: In what types of
environments does this type occur? How much varia-
tion (in structure and in species composition) is recog-
nized within the type? How does this type differ from
similar types? and, How does this type respond to dis-
turbances, both natural and human induced?
Conservancy ecologists are providing answers to
these questions in the form of detailed descriptions of
alliances and associations. Thus far, descriptions have
been completed for about 80 per-
cent of the currently defined alli-
ances and about 40 percent of the
associations.
An example of a typical
description appears on the facing
page. It depicts the Blackjack Oak -
Eastern Red Cedar / Little Bluestem
- Orange-Grass St. John’s -Wort
Wooded Herbaceous Vegetation Association. Otherwise
known as the Shawnee Sandstone Glade, this midwestern
savanna is naturally restricted to unusually thin-soiled
places where droughty conditions prevail.
Total Number of VegetationTypes at Each Level of theUSNVC
T
Level Number of Types
Class 7Subclass 22Group 62Formation 231Alliance 1,642Association 4,515
Note: Data shown are current as of August 1998 andrepresent types in the Natural/Semi-natural Subgroup only. Percentage of Associations in Each Class
Herbaceous Vegetation27% Nonvascular Vegetation
<1%
Shrublands16%
Woodlands18%
Forests33%
Sparse Vegetation2%
Dwarf-shrublands3%
11Seeing the Forest and the Trees: Ecological Classification for Conservation
SYNONYM: Shawnee Sandstone Glade.
RANGE: This association occurs on the upper slopes and ridgetops of south-facing bluffs and escarpments in the ShawneeHills of southern Illinois, western Kentucky, and southern Indiana. The present range of this community is probably veryclose to pre-European settlement range.
VEGETATION DESCRIPTION: This community is dominated by graminoid species. Blackjack oak, post oak, and eastern redcedar are the dominant trees; they are found scattered or in patches throughout the occurrence. These trees are generally small,stunted, and limby. The overstory cover seldom exceeds 50 percent. The subcanopy is conspicuously thin or absent. Scatteredindividual and patches of shrubs occur here, with farkleberry and winged elm the most commonly encountered. Grasses such aslittle bluestem and poverty oat-grass dominate the herbaceous layer, along with a diverse mixture of forbs. The patchiness anduneven distribution of trees, shrubs, and herbaceous vegetation are a response to thin, infertile soils and droughty conditions.Lichens and mosses are common on exposed bedrock surfaces and on soils not covered with leaf litter and woody debris.
MOST ABUNDANT SPECIES: Post oak (Quercus stellata), blackjack oak (Quercus marilandica), eastern red cedar (Juniperusvirginiana), winged elm (Ulmus alata), farkleberry (Vaccinium arboreum), saw greenbrier (Smilax bona-nox), poverty oat-grass(Danthonia spicata), little bluestem (Schizachyrium scoparium), Parmelia spp., and Polytrichum spp.
DIAGNOSTIC SPECIES: Blackjack oak (Quercus marilandica), farkleberry (Vaccinium arboreum), saw greenbrier (Smilaxbona-nox), little bluestem (Schizachyrium scoparium), and orange-grass St. John’s-wort (Hypericum gentianoides).
ENVIRONMENTAL DESCRIPTION: This community occurs primarily on south- and southwest-facing slopes. This droughtyenvironment has thin, acidic soils that can erode easily. Bedrock is sandstone, which occurs on the surface as massiveoutcrops, level benches, and boulders. The slope aspect results in frequent periods of freeze and thaw and consequenterosion and mass wasting. The aspect also contributes to summer temperatures well in excess of those in the cooler andwetter north- and east-facing slopes.
SUCCESSIONAL STATUS/HISTORY: Natural disturbance includes periodic fire, wind, storm, and drought. Environmentalextremes, including rapidly drained, thin, stonysoils; summer droughts lasting three to five weeksor more; and limited water availability for mostof the growing season, favor the establishmentof this glade association. Periodic fire may helpto maintain this community, especially after dis-turbance from logging or grazing. Fire suppres-sion encourages a transition from glade to wood-land. Herds of elk, deer, and buffalo once roamedthese hills, and their grazing and browsing mayhave provided a mechanism for maintaining the“barrens” or glade character.
MANAGEMENT COMMENTS: Prescribed fire isbecoming a commonly used tool for barrens orglade restoration. Although little data are avail-able concerning presettlement fire frequency, a re-duction in this frequency has contributed to re-cent increases in woody species coverage(Robertson and Heikens 1994). Some research-ers suggest that mechanical removal of larger treesand periodic burning (every two or three years)may be necessary to maintain sparse woodlandphysiognomy.
LITERATURE CITED:Robertson, P. A., and A. L. Heikens. 1994. Firefrequency in oak-hickory forests of southern Il-linois. Castanea 59: 286-291.
Blackjack Oak - Eastern Red Cedar / Little Bluestem - Orange-Grass St. John’s-Wort WoodedHerbaceous Vegetation [Quercus marilandica - Juniperus virginiana var. virginiana / Schizachyrium scoparium- Hypericum gentianoides Wooded Herbaceous Vegetation]
Occurrence data are from the following sources: the Illinois Department ofNatural Resources, Division of Natural Heritage; the Division of NaturePreserves, Indiana Department of Natural Resources; and the KentuckyState Nature Preserves Commission.
Known Occurrences of Shawnee Sandstone Glade
12 Seeing the Forest and the Trees: Ecological Classification for Conservation
The Conservancy’s mission is “to preserve plants, animals,
and natural communities that represent the diversity of life
on Earth by protecting the land and waters they need to
survive.” Determining which community types urgently
need protection, and which occurrences represent the best
conservation opportunities for each type, provides the basis
for targeting conservation resources appropriately. The
Conservancy uses two complementary approaches to guide
these determinations:
1. The best, most viable† occurrences of all the
community types that occur in an
ecoregion, as well as occurrences
of rare species, are selected to be
included in a portfolio of sites that,
collectively, would conserve the full
suite of biodiversity within that
ecoregion. Essentially, these port-
folios serve as blueprints for con-
servation success. The USNVC is being used as a guiding
framework for these ecoregional blueprints.
Three principal entities have recently been identified
as ecological targets for conservation: USNVC associations,
ecological complexes, and ecological groups. Ecological
complexes represent associations that are tightly bound by
ecological processes and are invariably found together in
tight spatial clusters. Because of the predictable and fine-
scale occurrence patterns of the associations within them,
complexes are most efficiently inventoried, mapped, and
protected as single entities. An example is the upland/wet-
land vegetation mosaic found in coastal dune/swale com-
plexes. Ecological groups are more conceptual aggregations
† Viability is assessed through element occurrence ranking on an excellent to poor scale based on degree of altered species composi-tion and structure, condition, and inferred ecosystem processes.
Wof community types—typically 5 to 25 associations—that
occur in similar environmental settings. While the same
associations will almost always be found everywhere a par-
ticular complex occurs, similar, but not identical, associa-
tions are likely to be found in each occurrence of a group.
Examples of ecological groups include northern Rocky
Mountain alpine meadows, southwestern desert riparian
woodlands, and midwestern beech-maple forests. All
associations can be conceptually grouped in this way, and
such groups offer a simplified way of understanding and
mapping vegetation pattern over
large, diverse landscapes. Especially
in areas where there is limited
information on the precise distri-
bution of associations, ecological
groups provide a coarse-scale
assessment of community diversity
and distribution that can be used as
a basis for targeting conservation resources. Thus, while
the USNVC recognizes communities at a relatively fine
scale of resolution, it also offers the flexibility to recognize
natural ecological groupings of those communities at vari-
ous scales for practical use in conservation planning.
2. Although the Conservancy is dedicated to conserv-
ing the best occurrences of all natural vegetation types,
special attention must be focused on types that are ex-
tremely rare or imminently endangered. To identify these,
the Natural Heritage network and the Conservancy have
developed a method for evaluating each USNVC associa-
tion and assigning an appropriate conservation status
rank. Because the USNVC is a standardized classification,
ITHIN THE CONSERVANCY
How Is thethe USNVCBeing Used?
13Seeing the Forest and the Trees: Ecological Classification for Conservation
Global Rank Definitions
GX ELIMINATED throughout its range, with no restora-tion potential due to extinction of dominant or char-acteristic species.
GH PRESUMED ELIMINATED (HISTORIC) throughout itsrange, with no or virtually no likelihood that it willbe rediscovered, but with the potential for restora-tion (e.g., American Chestnut Forest).
G1 CRITICALLY IMPERILED. Generally 5 or fewer occur-rences and/or very few remaining acres or very vul-nerable to elimination throughout its range due toother factor(s).
G2 IMPERILED. Generally 6-20 occurrences and/or fewremaining acres or very vulnerable to eliminationthroughout its range due to other factor(s).
G3 VULNERABLE. Generally 21-100 occurrences. Eithervery rare and local throughout its range or foundlocally, even abundantly, within a restricted rangeor vulnerable to elimination throughout its rangedue to specific factors.
G4 APPARENTLY SECURE. Uncommon, but not rare (al-though it may be quite rare in parts of its range,especially at the periphery). Apparently not vulner-able in most of its range.
G5 SECURE. Common, widespread, and abundant(though it may be quite rare in parts of its range,especially at the periphery). Not vulnerable in mostof its range.
GU UNRANKABLE. Status cannot be determined at thistime.
G? UNRANKED. Status has not yet been assessed.
Note: “G” refers to global (rangewide) status. National (N)and subnational (S) ranks can also be assessed.
each association can be assessed and ranked based on its
relative degree of rarity and imperilment on a global, or
rangewide, basis (as well as on more local levels). See the
table and figure adjacent for the definitions of these ranks
and the percentage of associations assigned to each.
Based on this assessment, more than half of all
defined U.S. associations are of conservation concern,
with 31 percent considered critically imperiled or imper-
iled and another 26 percent considered vulnerable.
(Although 18 percent of the associations are currently
ranked G? or GU, only a relatively small percentage of
these are believed to be imperiled.) As yet, no association
is considered “extinct,” but a few are historic. Like the
American chestnut forests that once covered much of the
East, these are communities that are known to have once
been part of the national landscape, but that now occur
nowhere in the world.
The maps on the following page illustrate the per-
centage of all the currently defined associations occurring
in each state and in each U.S. Forest Service ecoregion13
that are imperiled (G1 or G2). An astounding 30 percent
Percentage of Associations atEach Conservation Status Rank
More than half of all associations are of conservation con-cern, with nearly a third considered critically imperiled orimperiled. Note: Data shown are current as of August 1998.
Critically imperiled Loulu Coastal Mesic Palm Forest, Hawaii
© Sam
uel M. G
on III, TN
C
G58%
G417%
G326%
GU/G?18%
GH<1%
G111%
G220%
14 Seeing the Forest and the Trees: Ecological Classification for Conservation
or more of the natural communities in areas such as
Hawaii, the Willamette Valley of Oregon, and vast portions
of the Midwest and Southeast are in danger of vanishing
from our national landscape.
An awareness of just how large the imperilment
problem is on a national scale is one of the most sobering,
but potentially useful, insights to emerge from the develop-
ment of a national community classification. Effective and
efficient solutions to this national problem will be grounded
in conservation planning and action on an association-
by-association, site-by-site, and ecoregion-by-ecoregion
basis. The following examples of how the Conservancy and
its partners are preserving imperiled communities, habitats,
and landscapes will illustrate some of these solutions. (For a
comprehensive overview of how the USNVC is being used
throughout the nation and beyond, see Appendix C.)
Occurrence of Imperiled Associations by State and by Ecoregion
Note: Data shown arecurrent as of August1998. Data for Alaskaare incomplete and arenot shown.
> 30%
20 – 30%
10 – 20%
< 10%
Percentage ofImperiled (G1, G2)Associations
15Seeing the Forest and the Trees: Ecological Classification for Conservation
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1
In the Great Lakes basin, scattered from northern New York across southern Ontario and northern Michigan,
there are a few places with globally rare native communities collectively known as “alvar” types. These com-
munities, composed of a mixture of prairie and boreal plant species, include woodlands, shrublands, and
grasslands that occur as a mosaic on thin soils overlying flat expanses of limestone.14 All are extremely dry in
summer, but some are very wet in spring and fall. Many are known to have locally rare species associated with
them, and certain species or subspecies of snails may be endemic to these communities. But the communities
as a whole are of fundamental significance. Each represents a unique assemblage of plants and animals and a
distinct set of species interactions and ecological processes that are inherently worth conserving. We cannot
hope to know and understand all the facets of these species, interactions, and processes, but the communities
have already provided some surprising discoveries and insights. For example, some alvar communities are
now believed to be old-growth habitats, with stunted northern white-cedar (Thuja occidentalis) trees that are
at least 500 years old and possibly much older.15
Classification of the Great Lakes alvar communities has clarified and highlighted the diversity, rarity, and
vulnerability of these systems. It has also clarified distinctions between these communities and related systems
found elsewhere in North America and Scandinavia. The ability to compare the degree of rarity of these alvar
communities relative to other types and to understand these communities across their entire geographic range
has played an important role in ensuring their protection. For example, Canadian and U.S. conservationists
recently met to review all currently known high quality sites, and to identify innovative conservation strate-
gies, including a range of pri-
vate and public initiatives, to
protect them.16 In addition,
ongoing biological and hydro-
logical monitoring studies on
several of the sites are estab-
lishing conservation and man-
agement priorities that will
protect these unique commu-
nities in perpetuity.
Preserving theRarest Communities inthe Great Lakes States
Alvar grassland transitioning to calcareous pavement barrens, Geum Prairie, ChaumontBarrens, New York
© C
arol Reschke
16 Seeing the Forest and the Trees: Ecological Classification for Conservation
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2 Preserving Habitatsand Species inNorth Carolina
Natural assemblages of plants are a biological expression of environmental conditions such as climate, soils,
hydrology, topography, and natural disturbance processes. Essentially, such assemblages are an easily observable
indicator of habitats.17 Thus, although defined on the basis of vegetation, each plant community almost certainly
represents a unique set of organisms, including vertebrates, inverte-
brates, vascular and nonvascular plants, bacteria, and fungi. For this
reason, protecting viable examples of every association is a proac-
tive way of protecting whole assemblages of species before any indi-
vidual species declines into endangerment. Although it is difficult to
precisely quantify the success or failure of this “coarse filter” approach,
some of the most easily discernible successes will occur in those
associations that are naturally rare. (Such associations are a manifes-
tation of unusual environmental conditions and are therefore likely
to support naturally rare species adapted to those conditions.)
One such success story takes place in the few places on the
Atlantic Coastal Plain where coquina limestone, a cemented mix-
ture of broken marine shells and corals, forms the bedrock. Here,
on the thin, wet, calcareous soils that form over the coquina, an
unusual woodland community occurs. Longleaf pine (Pinus palustris)
and pond pine (P. serotina) form a scattered, open canopy over a
variety of herbaceous species such as Carolina dropseed (Sporobolus
pinetorum) and toothache grass (Ctenium aromaticum). Both the com-
position and the structure of the vegetation are unusual, and the
community is known to occur only in eastern North Carolina.
In the early 1980s, the Conservancy made the Neck Savanna, a primary site for this woodland, a conserva-
tion priority. The site was chosen on the basis of the known presence of this globally rare community, as well as
several rare species. Because the site was preserved and made accessible to biologists, the ensuing 15 years have
revealed the presence of numerous additional G1�G3 species, including many invertebrates. The largest known
population of the rare Venus flytrap cutworm (Hemipachnobia subporphyria subporphyria), for example, was
found here. So was a species of sedge previously unknown to science (Carex lutea). The newly described sedge,
a tall, clump-forming plant with a long, narrow inflorescence, turned out to be a widely disjunct member of an
otherwise boreal group of plants that occur nearly 500 miles away.18 Found only in these naturally rareand
now protected“islands” of calcareous savanna, the sedge is now known from a total of nine populations in the
world. The decision to protect this site based on the presence of a rare community protected this then-
unknown species, as well as populations of other species of great biological value.
© B. A
. Sorrie
Carex lutea, a recently discovered species ofsedge, known from only nine populationsworldwide
17Seeing the Forest and the Trees: Ecological Classification for Conservation
The ability to evaluate and compare community types across broad geographic areas is one of the principal
advantages of the standardized USNVC system. The Conservancy uses this advantage in planning conserva-
tion at the ecoregional level, where types, and occurrences of types, must be compared and assessed within
and across these huge landscapes. One of the first ecoregional plans was developed for the Conservancy’s
Columbia Plateau ecoregion. Stretching across seven states, but primarily located in northern Nevada, south-
ern Idaho, and eastern Washington and Oregon, the Columbia Plateau ecoregion has been described as a
300,000-square-kilometer expanse of “sagebrush-covered volcanic plains and valleys, punctuated by isolated
mountain ranges and the dramatic river systems of the Snake, Owyhee, Boise, and Columbia.”19
In developing the ecoregion’s conservation plan, the Conservancy and its partners addressed two related
questions: Where in this vast and diverse area should we target our conservation resources? and, How can we
preserve the biological diversity that is representative of the region as a whole? One part of the answer is to
focus on preserving the best, most representative occurrences of the communities that occur in the ecoregion.
At least 449 USNVC associations have been defined within the Columbia Plateau ecoregion�a measure of
the tremendous biodiversity of the area. Of these, 105 are considered rare or imperiled (G1 or G2), including
once-extensive grassland types of the Palouse prairies that now only occur as fragmented remnants. To ensure
that these associations are not lost
entirely, the ecoregional planning
team included most of the viable
occurrences of them as priorities for
conservation site selection. Associa-
tions that are more common were
prioritized partly on the basis of how
much fidelity to the ecoregion they
exhibit. Those associations that can
be protected only within the Colum-
bia Plateau because they are endemic
or very limited to it were generally
considered to be a higher conserva-
tion priority than more widespread
types or those that primarily occur
in adjacent ecoregions and are only
peripheral in the Columbia Plateau.
The planning team chose prior-
ity occurrences of associations by
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3 Creating a Blueprint forConservation Success inthe Intermountain West
The Columbia Plateau Ecoregion
18 Seeing the Forest and the Trees: Ecological Classification for Conservation
The Columbia Plateau
© H
arold Malde
taking into account minimum size
requirements, the level to which the
occurrence had been affected by hu-
man activities, and how all the occur-
rences could best reflect the natural
distribution of the type across the
ecoregion. Where specific occurrences
of associations were unknown, cover
types were used as predictors of the
likelihood of an association occurring
in the area. However, the degree to
which the blueprint succeeds in captur-
ing all the representative biodiversity of
the ecoregion will be assessed on the
basis of how well the actual associations
were selected. Thus, the USNVC is being used as the framework for understanding the distribution of vegeta-
tion types within and among ecoregions, for determining which types are particularly imperiled,
andultimatelyfor evaluating our blueprints to ensure that they maintain all the significant aspects of the
unique biological and ecological character of the Columbia Plateau ecoregion, and of all the ecoregions in
which we work.
19Seeing the Forest and the Trees: Ecological Classification for Conservation
EYOND THE CONSERVANCYBEX
AM
PLE
1 Detecting Gaps in Protection:Superior National Forest,Minnesota
As is the case with the Conservancy’s ecoregions, a management goal for all lands owned by the U.S. Forest
Service has long been to preserve and maintain landscape-scale ecosystem and species diversity. The Forest
Service accomplishes this in part through designating research natural areas (RNAs), which, along with other
types of established natural areas, form a network of protected lands that are representative of the vegetation
and ecosystems of each national forest. The proposed targets of RNA representation include the natural com-
munities, defined by USNVC alliances, that are contained in each subsection (large areas with similar land-
forms and geologic structures).20
On one of the Forest Service’s lands, Superior National Forest, an assessment was recently completed
to determine what gaps exist in the protection of types. Occupying more than two million acres in the
Many federal agencies, including the Department of
Defense, the Environmental Protection Agency, the
National Park Service, the U.S. Fish and Wildlife
Service, and the U.S. Forest Service, have supported
the development of the USNVC as a useful tool to
help them meet their conservation and resource man-
agement goals. (See Appendix C.)
Given the magnitude of the challenge before us—
preserving the plants, animals, and natural communi-
ties that represent the diversity of life on Earth—
organizations like the Conservancy are becoming
increasingly aware of the importance of working with
partners and leveraging our effectiveness by sharing
the best conservation tools and practices. The follow-
ing examples illustrate how the USNVC is helping
effect conservation “beyond the Conservancy.”
Silhouettes of pine, birch, spruce,fir, and cedar—examples of treesthat can be found in SuperiorNational Forest, Minnesota.Provided by staff of NorthwestScience and Technology, OntarioMinistry of Natural Resources.
20 Seeing the Forest and the Trees: Ecological Classification for Conservation
† At least 1 example of nearly all of the 37 alliances is protected within one area of the national forest, the Boundary WatersCanoe Area Wilderness, but natural areas in other parts of the forest do not protect a representative mix of natural foresttypes.
In part because of restricted public access to many of its lands, the U.S. Department of Defense has become an
important steward of many sites of significant biological value. The U.S. Naval Station at Guantanamo Bay,
Cuba, is no exception. Like many islands, Cuba has a high biological value because of the many species and
communities that have evolved there and occur nowhere else. Within Cuba, the U.S. Naval Station is of
especially high value. It encompasses a wide variety of coastal and dry tropical habitats and harbors several
species of animals that appear to be abundant and thriving within the station’s confines, even as their popula-
tions elsewhere are in decline.21
To meet its obligations regarding management of natural resources, the Department of Defense recently
funded a rapid ecological assessment (REA) of the station to take a quick, scientific “snapshot” of its biodiversity
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2 Meeting Our Global StewardshipResponsibilities: GuantanamoBay Naval Station, Cuba
Given the magnitude of the challenge it faces, the Conservancy
is becoming increasingly aware of the importance of working with
partners and leveraging its effectiveness by sharing the best
conservation tools and practices.
Arrowhead region of northeastern Minnesota, Superior National Forest is a lake-studded, hilly expanse char-
acterized by a diverse mix of jack, red, and white pine; balsam fir; white and black spruce; white cedar; birch;
and aspen. Thirty-seven USNVC alliances have been found there. High-quality examples of every alliance
occurring in each of the forest’s six subsections are the proposed targets for an RNA network representative of
the vegetation throughout Superior National Forest. Ecologists identified 117 of these alliance-by-subsection
targets, only 32 of which (27 percent) were currently protected in natural areas.† Perhaps surprisingly, par-
ticular gaps were noted in some of the most widespread, predominant alliances, which were not represented
at all in RNAs or other natural areas within most of the subsections. Detecting these fundamental gaps in
protection is the first step toward ensuring that our national forest lands remain truly representative of our
nation’s forests.
21Seeing the Forest and the Trees: Ecological Classification for Conservation
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3 Understanding Our NationalPark Lands: Scotts Bluff NationalMonument, Nebraska
What types of communities and species may already be protected on public, Conservancy, or other lands? Are
we achieving our management goals in these places? How can the wealth of natural diversity on these lands be
portrayed to their ownersU.S. taxpayers, Conservancy members, and others? Standardized inventory and
monitoring programs are the keys to answering these questions.
As the foundation of its inventorying and monitoring program, the National Park Service is using the
USNVC system to map the vegetation across all of its lands. An example can be seen in the detail of the map of
Scotts Bluff National Monument shown on the following page. Scotts Bluff is a prominent natural landmark
in western Nebraska that was used by emigrants on the Oregon Trail. In 1919 it was set aside with adjacent
lands in a 3,000-acre national monument within the National Park Service system. Recent surveys have found
that the monument contains 20 USNVC associations
For each of Scotts Bluff’s 20 associations, a description has been written characterizing the type on a range
wide basis, as well as its local expression at the monument. Monument staff will use the map and associated
descriptions in several ways: to direct searches for state-listed rare plant species suspected to occur within the
and inform a plan for
managing its resources.
USNVC alliances and
associations were used to
help create this snapshot.
Aerial photographs and
satellite imagery were
used to target and supple-
ment more time- and
labor-intensive field sur-
veys, and 25 associations
were delineated at the station. Ecologists targeted 11 of these for conservation action, including several unique
palm scrub, cactus scrub, and tropical arid forest types that are known to provide critical habitat for birds of
conservation concern. Many of the targeted types are restricted in the total geographic area in which they occur
and are degraded nearly everywhere they occur except within the confines of the naval station. The Navy now
has a documented, compelling reason to seize this exceptional opportunity to protect these globally endangered
ecological communities and their component species.
Guantanamo Bay Naval Station
CU
BA
22 Seeing the Forest and the Trees: Ecological Classification for Conservation
monument; to locate long-term monitoring plots in major prairie types of concern; to monitor the results of
restoration efforts; and to track long-term changes in vegetation at the monument. Staff members also intend to
use the vegetation descriptions as a means of assessing potential fuel loads and fire behavior when they plan
prescribed burns. In addition to these applications, the map and descriptions will form the basis of interpretive
displays used to provide visitors with a better understanding of the natural diversity present at the monument.
Published courtesy of the USGS-NPS Vegetation Mapping Program
Community Map of Scotts Bluff National Monument - Detail
Siltstone - Clay Butte SparseVegetation
Inland Siltstone Bluff - Cliff SparseVegetation
Ponderosa Pine / Rocky MountainJuniper Woodland
Sand Bluestem - Prairie SandreedHerbaceous Vegetation
Needle-and-Thread Grass - BlueGrama - Threadleaf SedgeHerbaceous Vegetation
Nebraska
500 feet
Approximate Scale
23Seeing the Forest and the Trees: Ecological Classification for Conservation
ver the past decade, the Conservancy and the
Natural Heritage programs have developed
a national classification system for vegetation, and many
types within this system have been defined and charac-
terized. This classification, the USNVC, has been invalu-
able in supporting conservation planning, site identifi-
cation, and biodiversity monitoring and management.
Use of the system has now expanded to a broader part-
nership that includes conservationists, vegetation scien-
tists, and resource managers across academic institutions,
federal and state agencies, private
organizations, and other nonprofit
organizations. The following chal-
lenges remain for the Conservancy
and its partners in their ongoing
efforts to develop, maintain, docu-
ment, and support the USNVC:
m Continue to develop and refineUSNVC types and type descriptions
The Nature Conservancy and the network of Heritage
programs are continuously collecting and analyzing
new data, with a particular focus on communities of
conservation concern, areas in which classifications are
lacking, and areas in which classification confidence is
low. Groups of experts will continue to be brought to-
gether on a project-by-project and geographic basis to
refine the classification system and the descriptions of
the vegetation types so that users will have the infor-
mation they need to use the system to its fullest.
O m Maintain and expandpartnerships
Existing partnerships between the Conservancy, Heritage
programs, and federal and state agencies have been very
successful in developing the USNVC. In addition, the Eco-
logical Society of America has established a panel for veg-
etation classification that has brought together many
ecologists from academia to refine standards and provide
review. Future development and implementation of the
USNVC increasingly depends on a
strong, shared vision of a national
classification system and a heightened
spirit of cooperation among all part-
ners. In addition, new partnerships
will need to be forged to address the
needs of an increasingly broad net-
work of contributors and users.
m Maintain momentum
For the Conservancy and its partners, the ongoing devel-
opment of the USNVC is immensely rewarding. The
undertaking has gained momentum as the importance of
a national classification system to address conservation,
stewardship, and research needs has become increasingly
obvious. Strong commitments to the USNVC’s develop-
ment are critical to its continued use in effectively and
efficiently conserving and managing our nation’s extraor-
dinary biodiversity.
Summaryand FutureChallenges
24 Seeing the Forest and the Trees: Ecological Classification for Conservation
APPENDICES: The Nuts and Bolts of the USNVC System
1. It is based on vegetation.
Classifications of ecological systems can be based on a
variety of factors, such as vegetation, soils, and landforms,
that can be used either singly or in combination. Conser-
vancy ecologists, however, made a pivotal decision to
develop a terrestrial classification system that is based
primarily on vegetation. Several factors led to that deci-
sion. First, because the Conservancy’s mission is to pro-
tect biodiversity, a classification that emphasizes the
biotic component of ecological systems was seen as being
the most relevant. Second, vegetation is an easily measured
component of an ecological system. Indeed, it is often cho-
sen as the most useful single factor for classifying terres-
trial ecological systems because it integrates more measur-
ably than any other factor or set of factors the environ-
mental conditions, ecological processes, and biogeographi-
cal dynamics that operate on a site or landscape.10,11 Third,
vegetation can describe many facets of biological and eco-
logical patterns across the landscape. Plants provide the
habitat and structure for many other organisms in an eco-
logical community, and vegetation is often used to infer
soil and climate patterns. Fourth, building a single-factor
system was simply more practical than building a more
complex, multifactor system.
2. It has been applied to natural vegetation.
The USNVC framework may be used to classify all
vegetation, from the extremes of natural (types that
appear to be unmodified by human activities) to cul-
tural (planted and maintained types, such as annual
croplands, tree plantations, orchards, and vineyards).
However, because the Conservancy’s focus is on the pro-
tection of natural vegetation, only the more natural types
are being classified and described by the Conservancy
and the Natural Heritage network. These include types
that occur spontaneously without regular management,
maintenance, or planting, and that generally have a
strong component of native species.
3. It is based on existing vegetation.
Vegetation classifications are based on either existing
or potential natural vegetation (PNV). PNV types repre-
sent the projected mature or stable end points of veg-
etation development over time (late seral types). These
are vegetation types projected to occur and persist on a
site in the absence of disturbance, whether human-
caused or natural. PNV classifications offer insight
into vegetation-site relationships and can be helpful in
FAppendix A—
Key Attributes
our key attributes characterize the USNVC system:
25Seeing the Forest and the Trees: Ecological Classification for Conservation
projecting the type of vegetation expected under a cer-
tain set of ecological factors. However, disturbances have
a profound influence on the structure and composition
of vegetation, and each major successional stage follow-
ing a natural disturbance (or a human-caused distur-
bance that closely mimics a natural one) is biologically
and ecologically distinct and of inherent worth. Indeed,
important habitat is provided by many communities
that are not at mature or stable end points of vegetation
development. For this reason, the Conservancy believes
the conservation of all existing natural community types
will ensure the survival of the greatest possible number
of species, both plant and animal.
In addition to its usefulness for conservation
purposes, a classification of existing, rather than
potential, vegetation makes fewer assumptions about
natural processes and vegetation dynamics and allows
the classification to be grounded in what is directly
observable and measurable. Finally, the focus on exis-
ting vegetation can support a wide number of uses,
including inventorying and monitoring the current sta-
tus of vegetation. Thus, while the USNVC framework
is comprehensive with regard to existing vegetation—
encompassing the spectrum from natural to culti-
vated—the Conservancy’s efforts have focused on the
best existing occurrences of natural types, both natu-
rally disturbed (early and mid-seral) and naturally
undisturbed (late seral).
4. It is a hierarchical system, defined byphysiognomy and floristics.
The USNVC has a hierarchical taxonomic structure with
physiognomic criteria used at the coarsest levels of the
hierarchy and floristic criteria used at the finest. Physiog-
nomy refers to the structure (height and spacing) and over-
all shape of plants, and to leaf characteristics, such as sea-
sonality, shape, duration, size, and texture. These features
provide a fast, efficient way to categorize vegetation on
broad geographic scales. Physiognomic features can
often be linked to remote sensing signatures, are easily
recognized in the field, and can be applied even in places
where very little information about the flora exists.
Floristics refers to species composition. Using species com-
position or species groups to characterize vegetation
reveals finer-scale local and regional patterns than are
likely to be perceived using physiognomic characters.
A combined physiognomic-floristic system allows
for most of the advantages of both approaches and pro-
vides a unifying framework within which to relate typi-
cally coarse-scale physiognomic systems to more local and
regional floristic systems. Additionally, structuring the
USNVC in a hierarchical fashion allows it to be used at
different taxonomic scales, depending on the amount of
information available and the resolution needed.
26 Seeing the Forest and the Trees: Ecological Classification for Conservation
he USNVC terrestrial† classification system
consists of a seven-level hierarchy. Five levels
(class, subclass, group, subgroup, and formation) are
based on physiognomic characteristics, and two
levels (alliance and association) are based on species
composition.
Physiognomic Levels
The physiognomic levels of the USNVC are a modifica-
tion of the UNESCO world physiognomic classification
of vegetation.9
CLASS
The formation class (or “class”) is based on the structure
of the vegetation: classes are determined by the type,
height, and relative percentage of cover of the dominant,
uppermost life-forms. There are seven classes:
Forest: Trees with their crowns overlapping (generally
forming 60 percent to 100 percent cover).
Woodland: Open stands of trees with crowns not usu-
ally touching (generally forming 25 percent to 60 percent
cover).
STRUCTURE
Shrubland: Shrubs generally greater than 0.5 meter tall
with individuals or clumps overlapping to not touching
(generally forming greater than 25 percent cover, with
trees generally forming less than 25 percent cover). Veg-
etation dominated by woody vines is generally treated in
this class.
Dwarf-shrubland: Low-growing shrubs, usually less
than 0.5 meter tall, with individuals or clumps overlap-
ping to not touching (generally forming greater than 25
percent cover; with trees and tall shrubs generally form-
ing less than 25 percent cover).
Herbaceous: Herbaceous plants dominant (generally
forming at least 25 percent cover, with trees, shrubs, and
dwarf-shrubs generally forming less than 25 percent cover).
Nonvascular: Nonvascular cover (bryophytes, non-
crustose lichens, and algae) dominant (generally forming
at least 25 percent cover).
Sparse Vegetation: Abiotic substrate features dominant.
Vegetation is scattered to nearly absent and generally re-
stricted to areas of concentrated resources (total vegeta-
tion typically forming less than 25 percent cover).
† The terrestrial system is defined to include all wetland and shallow-water vegetation with rooted vascular plants.
APPENDICES: The Nuts and Bolts of the USNVC System
Appendix B—
Structure &Type Definition
T
27Seeing the Forest and the Trees: Ecological Classification for Conservation
SUBCLASS
The Forest, Woodland, Shrubland, and Dwarf-shrubland
Classes each include three formation subclasses (or “sub-
classes”) based on leaf character: evergreen, deciduous, or
mixed evergreen-deciduous. The Herbaceous Class com-
prises four subclasses based on a combination of persis-
tence and growth-form characteristics: perennial grasslands,
perennial forb vegetation, annual grasslands or forb veg-
etation, and hydromorphic vegetation. The relative domi-
nance of either lichens, mosses, or algae divides the
Nonvascular Class into three subclasses. Lastly, the three
subclasses of the Sparse Vegetation Class are defined pri-
marily by the particle sizes of the substrate features: con-
solidated rock; boulder, gravel, cobble, or talus; and un-
consolidated material (soil, sand, or ash).
GROUP
The subclasses of the Forest, Woodland, Shrubland,
and Dwarf-shrubland Classes are further divided into
formation groups (or “groups”) based on leaf charac-
teristics, such as broad-leaved or needle-leaved. These
units are defined and named in conjunction with broad
climatic types. For example, the Evergreen Woodland
Subclass includes the Tropical or Subtropical Broad-
Leaved Evergreen Woodland Group, the Tropical or
Subtropical Needle-Leaved Evergreen Woodland
Group, the Temperate Broad-Leaved Evergreen Wood-
land Group, and the Temperate or Subpolar Needle-
Leaved Evergreen Woodland Group.
Both climate and the presence and character of
woody strata are used to separate subclasses into groups
in the Herbaceous and Nonvascular Classes. For example,
in the Perennial Graminoid (grassland) Subclass, the
Tropical or Subtropical Grassland Group is separated from
Temperate or Subpolar Grasslands, as well as from Tropi-
cal or Subtropical Grasslands with a Sparse Tree Layer.
Sparse Vegetation subclasses are separated into
groups based on major topographic position types or
landforms (for example, cliffs versus flat to gently slop-
ing bedrock).
SUBGROUP
Each group is divided into either a Natural/Semi-natural
Formation Subgroup or a Cultural Formation Subgroup,
providing a consistent dichotomy between vegetation
actively planted or maintained by humans and all other
types of vegetation. This distinction is useful for mapping
vegetation types across the natural and cultural landscape.
Its placement at the subgroup level allows for the develop-
ment of culturally distinct formations (for example,
orchards and annual croplands) within the overall USNVC
hierarchy.
Hierarchical Vegetation Classification Systemfor the Terrestrial Ecological Communities
SYSTEM: TERRESTRIAL
FORMATION CLASSFORMATION SUBCLASS
FORMATION GROUPFORMATION SUBGROUP
FORMATION
ALLIANCEASSOCIATION
physiognomic levels
floristic levels
28 Seeing the Forest and the Trees: Ecological Classification for Conservation
FORMATION
The formation level represents vegetation types that share
a definite physiognomy within broadly defined environ-
mental factors, landscape position, or hydrologic regime.
Structural factors such as crown shape and lifeform of the
dominant stratum are used in addition to the physiogno-
mic characters already specified at the higher levels.
Hydrologic modifiers, adapted from Cowardin and
others22, are used for wetlands. Examples include the
Rounded-Crowned Temperate or Subpolar Needle-Leaved
Evergreen Forest Formation, the Semipermanently
Flooded Tropical or Subtropical Broad-Leaved Evergreen
Shrubland Formation, and the Short Alpine or Subalpine
Sod Grassland Formation.
Floristic Levels
The lower two levels of the hierarchy—the alliance and
the association—are based on species composition. Both
are primarily defined by their dominant species (those
that are most abundant or prevalent). Diagnostic
species (those found consistently in some vegetation
types but not in others) are considered as well.
ALLIANCE
Within a formation, the alliance is a group of plant
associations (see “Association” below) sharing one or
more dominant or diagnostic species, usually found in
the uppermost or dominant stratum of the vegetation.
ASSOCIATION
An association is defined as a plant community with a
definite floristic composition, uniform habitat condi-
tions, and uniform physiognomy. With the exception
of a few associations that are restricted to specific and
unusual environmental conditions, associations repeat
across the landscape. They occur at variable spatial scales
depending on the steepness of environmental gradients
and the patterns of disturbances. The association is the
lowest level of the USNVC hierarchy, as well as the basic
unit for vegetation classification in the USNVC in North
America.
HOW TYPES ARE DEFINED
Many methods are used to define USNVC alliances and
associations. They range from directly adopting types
from compatible state or local classification systems,
especially Heritage program classifications, to conduct-
ing field studies in which new vegetation information is
collected and analyzed. The great majority of existing
associations has been defined with a mixture of quanti-
tative analysis of available vegetation data and a review
of more qualitative, descriptive types of information
about vegetation patterns. About 80 percent of the
associations have been defined with the benefit of quan-
titative analyses of plot data, analyses either published
in the scientific literature or, less commonly, conducted
by Conservancy or Heritage ecologists expressly to
define USNVC types. Regardless of the specific approach
used, the cornerstone of type definition is structured peer
review by experienced local, state Heritage program, and
regional ecologists.
29Seeing the Forest and the Trees: Ecological Classification for Conservation
APPENDICES: The Nuts and Bolts of the USNVC System
artnerships with federal agencies have been instru-
mental throughout the development of the USNVC.
The first national list of rare and threatened ecological
communities was compiled with the support of the
U.S. Fish and Wildlife Service.23 The development of the
national list of vegetation alliances and their descriptions
is being strongly supported by the Gap Analysis
Program, a multi-agency program that employs alliances
as the standard for state vegetation cover maps used in
evaluating the conservation status of target species. A
biodiversity assessment across 13 Great Plains states,
funded by the U.S. Environmental Protection Agency,
helped to standardize the associations between the
Conservancy’s Midwest, Southeast, and West Regions.24
The U.S. Forest Service is providing ongoing support to
Conservancy ecologists to revise all levels of the classifi-
cation hierarchy and to document the vegetation on
national forests in the Southeast. The Forest Service
is also supporting classification efforts in other regions.
On a national scale, it supports the development and
documentation of conservation status ranks for rare
associations.
These agencies and others have also provided fund-
ing at local, or project-specific, scales. This support has
been important in the development and application of
the USNVC in many portions of the country. In addi-
tion, the Federal Geographic Data Committee facilitated
a multi-agency review of the physiognomic levels of the
classification hierarchy as part of a process that led to
the endorsement of the USNVC system as the federal
standard for vegetation classification and information.25
Finally, the Ecological Society of America has established
a panel of experts to refine the processes for defining
and reviewing floristic types..
Strong partnerships such as these have evolved over
the course of the USNVC’s development as agencies and
organizations have become increasingly aware of the need
for a standardized national classification to accomplish
their conservation and resource management goals more
efficiently and effectively. At the same time, within the
Conservancy and in other conservation organizations, the
importance of working with partners has become increas-
ingly obvious as we strive to dramatically expand our
impact in an era of pressing conservation needs.
An overview of how and where the USNVC has
been used and, where possible, some measure of its
impact are presented here in the hope that the range
and scope represented will inspire even greater use of
the classification as a tool to accomplish the important
work ahead.
P
Appendix C —
Partners inDevelopment &
Application
30 Seeing the Forest and the Trees: Ecological Classification for Conservation
SITE-BASED APPLICATIONS
NATIONAL PARK SERVICE
U.S. FOREST SERVICE
Site, State Projected or Actual Use Approximate Acres Affected
Angelina National Forest, Texas Community classification, keys, ecological classification 153,179
Apalachicola National Forest, Florida Community classification, keys, ecological classification 565,543
Bienville National Forest, Mississippi Community classification, keys, ecological classification 178,400
Black Hills National Forest, South Dakota and Wyoming Community classification, keys, ecological classification, comprehensive inventory of all natural communities
1,531,735
Cherokee National Forest, Tennessee and North CarolinaCommunity classification, keys, ecological classification 634,075
Conecuh National Forest, Alabama Community classification, keys, ecological classification 83,859
Daniel Boone National Forest, Kentucky Community classification, keys, ecological classification 547,285
Acadia National Park, Maine Inventory and mapping, monitoring, management 70,000
Agate Fossil Beds National Monument, Nebraska Inventory and mapping, monitoring, management 3,300
Assateague Island National Seashore, Maryland Inventory and mapping, monitoring, management, acquisition
15,977
Badlands National Park, South Dakota Inventory and mapping, monitoring, management 1,314,447
Chickamauga and Chattanooga National Military Park, Georgia and Tennessee
Pilot community mapping and classification 8,119
Congaree Swamp National Monument, South Carolina Inventory and mapping, monitoring, management 24,400
Devils Tower National Monument, Wyoming Inventory and mapping, monitoring, management 5,920
Fort Laramie National Historic Site, Wyoming Inventory and mapping, monitoring, management 1,200
Gates of the Arctic, Alaska Inventory, classification, and mapping 8,202,517
Glacier National Park, Montana Inventory and mapping, monitoring, management, rare species habitat modeling
1,250,000
Golden Gate National Recreation Area, California Inventory and mapping, monitoring, management 80,000
Great Smoky Mountains National Park, North Carolina and Tennessee
Inventory and mapping, monitoring, management 120,000
Isle Royale National Park, Michigan Inventory and mapping, monitoring, management 133,781
Jewel Cave National Monument, South Dakota Inventory and mapping, monitoring, management 9,658
Joshua Tree National Monument, California Inventory and mapping, monitoring, management 792,749
Kennesaw Mountain National Military Park, Georgia Pilot community mapping and classification 2,884
Mount Rushmore National Memorial, South Dakota Inventory and mapping, monitoring, management 5,946
Point Reyes National Seashore, California Inventory and mapping, monitoring, management 78,000
Rock Creek National Park, Washington, D.C. Inventory and mapping, monitoring, management 1,800
Russell Cave National Military Park, Alabama Pilot community mapping and classification 310
Scotts Bluff National Monument, Nebraska Inventory and mapping, monitoring, management (including planning prescribed burning), planning restoration activity, rare species habitat modeling
3,200
Shiloh National Military Park, Tennessee Pilot community mapping and classification 3,972
Theodore Roosevelt National Park, North Dakota Inventory and mapping, monitoring, management, exotic
species habitat modelling, animal habitat modeling
384,041
Tuzigoot National Monument, Arizona Inventory and mapping, monitoring, management 800
Voyageurs National Park, Minnesota Inventory and mapping, monitoring, management 300,000
Wind Cave National Park, South Dakota Inventory and mapping, monitoring, management 84,201
Yosemite National Park, California Inventory and mapping, monitoring, management, fire modeling
1,000,000
31Seeing the Forest and the Trees: Ecological Classification for Conservation
U.S. FOREST SERVICE (CONTINUED)
U.S. DEPARTMENT OF DEFENSE
U.S. FISH AND WILDLIFE SERVICE
Site, State Projected or Actual Use Approximate Acres Affected
Chincoteague National Wildlife Refuge, Virginia Inventory and mapping, monitoring, management, land
acquisition, breeding bird monitoring and management
14,014
Grays Lake National Wildlife Refuge, Idaho Vegetation mapping and classification and application to
resource management
16,739
Red Rock Lakes National Wildlife Refuge, Montana Vegetation mapping and classification and application to
resource management
45,597
De Soto National Forest, Mississippi Community classification, keys, ecological classification 506,026
George Washington National Forest, Virginia and West Virginia
Community classification, keys, ecological classification 1,064,562
Homochitto National Forest, Mississippi Community classification, keys, ecological classification 191,572
Jefferson National Forest, Virginia and Kentucky Community classification, keys, ecological classification 716,073
Kisatchie National Forest, Louisiana Community classification, keys, ecological classification 603,158
Monongahela National Forest, West Virginia Community classification, keys, ecological classification 909,136
Nantahala National Forest, North Carolina Community classification, keys, ecological classification 527,486
Ouachita National Forest, Arkansas and Oklahoma Community classification, keys, ecological classification 1,762,567
Ozark National Forest, Arkansas Community classification, keys, ecological classification 1,133,567
Pisgah National Forest, North Carolina Community classification, keys, ecological classification 504,787
Sabine National Forest, Texas Community classification, keys, ecological classification 160,656
Shawnee National Forest, Illinois Community classification, keys and descriptions, ecological classification
277,506
Sumter National Forest, South Carolina Community classification, keys, ecological classification 360,753
Talladega National Forest, Alabama Community classification, keys, ecological classification 389,189
Uwharrie National Forest, North Carolina Community classification, keys, ecological classification 50,189
Caribbean National Forest (El Yunque), Puerto Rico Alliance-level community classification 27,831
Arnold Air Force Base, Tennessee Vegetation mapping and classification, and application to resource management
40,118
Camp Shelby, Mississippi Consultation on community classification and conservation
significance
134,000
Eglin Air Force Base, Florida Tier mapping, community classification, and inventory 463,452
Fort Benning, Georgia and Alabama Vegetation mapping and classification, and application to resource management
182,000
Fort Bliss, New Mexico Inventory and characterization of natural resources on part
of the Fort
* acres affected not
available
Fort Gordon, Georgia Vegetation mapping and classification, and application to resource management
56,000
Fort Stewart, Georgia Longleaf pine restoration and community monitoring 279,270
Guantanamo Bay Naval Station, Cuba Rapid Ecological Assessment, community classification,
mapping, inventory, and management recommendations
20,000
Moody Air Force Base, Georgia Inventory and characterization of natural resources 6,050
Naval Station Ingleside, Texas Inventory and characterization of natural resources 483
Nellis Air Force Bombing and Gunnery Range, Nevada Inventory and characterization of natural resources 3,500,000
Panama Department of Defense lands Rapid ecological assessment, inventory, classification at the sub-formation level, mapping, and conservation
recommendations
75,000
Shepherd Air Force Base, Texas Inventory and characterization of natural resources 5,480
White Sands Missle Range, New Mexico Inventory and characterization of natural resources 2,000,000
32 Seeing the Forest and the Trees: Ecological Classification for Conservation
THE NATURE CONSERVANCY(Bioreserves and Other Multi-jurisdictional Areas of Interest)
Site, State Projected or Actual Use Approximate Acres Affected
United States
ACE (Ashepoo - Combahee - Edisto) Basin, South Carolina Community classification, inventory, mapping, and
management recommendations
350,000
Altamaha River Bioreserve, Georgia Community classification, mapping, and management
planning
1,200,000
Block Island, Massachusetts Inventory and mapping; maps used for understanding
large landscapes
6,400
Gauley River, West Virginia Inventory and mapping; maps used for understanding
large landscapes
acres affected not
available
Gray Ranch, New Mexico Protection of representative vegetation with compatible use 32,700
Lahontan Valley Wetlands, Nevada Classification, mapping, and management planning 200,000
Meadow River, West Virginia Inventory and mapping; maps used for understanding
large landscapes
Schenob Brook, Massachusettes Inventory and mapping 15
Shawangunks, New York Inventory and mapping; maps used for understanding
large landscapes (Mapped to a state Heritage classification; data
gathered and analyzed during the project were used to further development
of the state classification and the USNVC.)
90,000
Waterboro Barrens, Maine Inventory and mapping; maps used for understanding
large landscapes (Mapped to a state Heritage classification; data
gathered and analyzed during the project were used to further development
of the state classification and the USNVC.)
2,140
Virginia Coast Reserve, Virginia Community classification 444,551
Winyah Bay Focus Area / Sandy Island, South Carolina Community classification, mapping, and management
planning
525,000
International
Amapa, Brazil (Champion Paper Company lands) Rapid ecological assessment, inventory, and mapping 700,000
Blue and John Crow Mountains National Park, JamaicaRapid ecological assessment, inventory, mapping, park
planning
194,000
Chaco, Paraguay Rapid ecological assessment, inventory, and mapping 2,000,000
TOTAL ACRES AFFECTED 39,359,365
33Seeing the Forest and the Trees: Ecological Classification for Conservation
OTHER APPLICATIONS
U.S. FOREST SERVICE
U.S. DEPARTMENT OF DEFENSE
U.S. DEPARTMENT OF ENERGY
TENNESSEE VALLEY AUTHORITY
ENVIRONMENTAL PROTECTION AGENCY
Location Projected or Actual Use
Research Natural Area (RNA) Projects
All U.S. Forest Service Region 1, Region 2, Region 4, and Region 8 Forests Identifying gaps in protection by assessing alliance coverage in designated RNAs
All U.S. Forest Service Region 9 Forests Identifying gaps in protection by assessing alliance distribution and
protection status in RNAs or RNA-equivalents for all subsections that include U.S. Forest Service land
Other projects
All national forests in the northern Great Plains: Montana, northern
Nebraska, North Dakota, South Dakota, Wyoming
Descriptions of all G1 and G2 associations
Southern Appalachian Assessment for Pisgah, Nantahala, Cherokee, George Washington, Jefferson, Talladega, Chattahoochee, and Sumter National
Forests (Alabama, North Carolina, South Carolina, Tennessee, Virginia, West Virginia)
Rare community classification and matrix with rare species occurrences
Alabama, Arkansas, Connecticut, Delaware, Florida, Georgia, Kentucky,
Louisiana, Maine, Maryland, Massachusetts, Mississippi, New Hampshire, New Jersey, New York, North Carolina, Oklahoma, Pennsylvania, Puerto
Rico, Rhode Island, South Carolina, Tennessee
Attribution of all alliances to all U.S. Forest Service subsections to
characterize subsection vegetation
Region 4 Forests: Payette, Boise, and Sawtooth National Forests, Southwest Idaho Ecogroup Forest Plan Amendment
Attribution of all alliances to all U.S. Forest Service subsections to characterize vegetation
Region 8 Forests Comprehensive classification for all units for ecosystem
management, forest planning, timber typing, and biodiversity conservation
U.S. Forest Service ranking project Development of conservation status ranks, descriptions, and
supporting information for imperiled community types
Arnold Air Force Base: Tennessee, Kentucky, Alabama Barrens Assessment; management planning and context for barrens ecosystems
Oak Ridge Reservation, Tennessee Inventory, management, natural area planning
Savannah River Site, South Carolina Historic vegetation mapping and modeling
Hanford Nuclear Reserve, Washington Inventory, management, natural area planning
TVA: Alabama, Georgia, Kentucky, Mississippi, North Carolina, Tennessee, Virginia
Pilot community mapping
Multistate Surveys
Calcareous fens: Maine, New Hampshire, Vermont, Massachusetts, New
York, Pennsylvania, Connecticut, Rhode Island
Inventory and prioritization for conservation action
Atlantic white cedar swamps: Massachusetts and New Hampshire Inventory and prioritization for conservation action
Northern white cedar swamps: Vermont and New Hampshire Inventory and prioritization for conservation action
Floodplain forests: Maine, New Hampshire, Massachusetts, Maryland, West
Virginia
Inventory and prioritization for conservation action
Seeps and seepage forests: Pennsylvania, Maryland, New Hampshire Inventory and prioritization for conservation action
34 Seeing the Forest and the Trees: Ecological Classification for Conservation
ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
U.S. GEOLOGICAL SURVEY GAP ANALYSIS PROGRAM
U.S. FISH AND WILDLIFE SERVICE
STATE HERITAGE PROGRAMS AND CANADIAN CDCs*
THE NATURE CONSERVANCY
Location Projected or Actual Use
East Gulf Coastal Plain savannas and flatwoods: Alabama, Florida, Mississippi
Inventory for high-quality communities for conservation planning
Conterminous United States Development of a list of rare imperiled types for protection
prioritization
*Heritage Programs and CDCs are using the USNVC to various degrees. Many are using it in conjunction with state and other classifications.
State Natural Heritage programs: Alabama, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana,
Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts,
Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina,
North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South
Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming
CDCs: Alberta, British Columbia, Ontario, Saskatchewan
Various inventory and conservation planning work
United States multistate surveys
Coastal Plain ponds: Maine, Massachusetts, Connecticut, New Jersey, Maryland, Delaware
Inventory, data collection and prioritization for conservation action
Pine barrens: Maine, Massachusetts, Connecticut, New Jersey, Maryland,
Delaware
Inventory, data collection and prioritization for conservation action
Shale barrens: Pennsylvania, Maryland, Virginia, West Virginia Inventory, data collection and prioritization for conservation action
Arizona, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Michigan, Minnesota, Nebraska, North Carolina, South Carolina, South Dakota, Tennessee, Wisconsin
Consultation relative to alliance classification and GAP mapping
Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, Virginia,
West Virginia
Regional classifications used by all states; ongoing GAP work incorporating national classification in some states
Nationwide Development of alliance descriptions for use by state GAP programs
Other Projects
Colorado riparian vegetation Standardized descriptions of all riparian types for EPA use produced by the Conservancy and the Colorado Natural Heritage Program
(USGS-BRD develped a CD-ROM for delivery of these data to partners in an easy-to-use medium)
Connecticut River Watershed: Vermont, New Hampshire, Massachusetts,
Connecticut
Conservation of neotropical migrant birds, predictive community
modeling, biophysical/vegetation assessment of watershed
Midwest Oak Ecosystem Recovery Plan Classification of oak savanna and woodland types in the Midwest
prairie-forest border region
South Platte Watershed: Nebraska, Colorado, Wyoming Inventory of natural resources, management planning
Southern Idaho wetlands Identification, classification, inventory, and prioritization of wetlands
Upper Arkansas Watershed, Colorado Inventory and prioritization for conservation action
Upper Yellowstone Watershed: Montana, Wyoming Inventory and prioritization for conservation action
35Seeing the Forest and the Trees: Ecological Classification for Conservation
THE NATURE CONSERVANCY (CONTINUED)
Location Projected or Actual Use
United States active Conservancy ecoregional plans
Central Appalachians, Central Shortgrass Prairie, Central Tallgrass Prairie, Columbia Plateau, East Gulf Coastal Plain, Great Lakes, Interior Low
Plateau, Lower New England, Mid-Atlantic Coastal Plain, Mississippi River Alluvial Plain, Mojave Desert, North Atlantic Coast, Northern Appalachians,
Northern Great Plains Steppe, Northern Tallgrass Prairie, Osage Plains/Flint Hills, Puget Trough/Willamette Valley, Sonoran Desert, South Atlantic
Coastal Plain, Southern Blue Ridge, West Gulf Coastal Plain (Pineywoods), Western Allegheny Plateau
Assessment of viable communities, conservation portfolio design, conservation prioritization, GAP analysis of inventory needs
International
International Alvar Initiative: Michigan, New York, Ohio, Ontario, Wisconsin.
Inventory, classification, ecological research, conservation planning and stewardship
West Indies/Caribbean Islands Various: rapid ecological assessment, development of classification, conservation prioritization, inventory, mapping, park planning
36 Seeing the Forest and the Trees: Ecological Classification for Conservation
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Natural Heritage Programs and Conservation Data Centersin North America north of Mexico
Alabama Natural Heritage ProgramAlaska Natural Heritage ProgramAlberta Natural Heritage Information CentreArizona Heritage Data Management SystemArkansas Natural Heritage ProgramAtlantic Canada Conservation CentreBritish Columbia Conservation Data Centre
California Natural Heritage DivisionColorado Natural Heritage ProgramConnecticut Natural Diversity DatabaseDelaware Natural Heritage ProgramDistrict of Columbia Natural Heritage
ProgramFlorida Natural Areas InventoryGeorgia Natural Heritage ProgramHawaii Natural Heritage ProgramIdaho Conservation Data CenterIllinois Natural Heritage DivisionIndiana Natural Heritage Data CenterIowa Natural Areas InventoryKansas Natural Heritage InventoryKentucky Natural Heritage ProgramLouisiana Natural Heritage ProgramMaine Natural Areas Program and Maine
Department of Inland Fisheries andWildlife
Manitoba Conservation Data CentreMaryland Heritage and Biodiversity
Conservation ProgramsMassachusetts Natural Heritage and
Endangered Species ProgramMichigan Natural Features InventoryMinnesota Natural Heritage and Nongame
Research and Minnesota CountyBiological Survey
Mississippi Natural Heritage ProgramMissouri Natural Heritage DatabaseMontana Natural Heritage Program
Navajo Natural Heritage ProgramNebraska Natural Heritage ProgramNevada Natural Heritage ProgramNew Hampshire Natural Heritage InventoryNew Jersey Natural Heritage ProgramNew Mexico Natural Heritage ProgramNew York Natural Heritage ProgramNorth Carolina Natural Heritage ProgramOhio Natural Heritage Data BaseOklahoma Natural Heritage InventoryOntario Natural Heritage Information
CentreOregon Natural Heritage ProgramPennsylvania Natural Diversity Inventory-
CentralPennsylvania Natural Diversity Inventory-
EastPennsylvania Natural Diversity Inventory-
WestLe Centre de Données sur le Patrimoine
Naturel du QuébecRhode Island Natural Heritage ProgramSaskatchewan Conservation Data CentreSouth Carolina Heritage TrustSouth Dakota Natural Heritage Data BaseTennessee Division of Natural HeritageTennessee Valley Authority Regional Natural
HeritageTexas Conservation Data CenterUtah Natural Heritage ProgramVermont Nongame and Natural Heritage
ProgramVirginia Division of Natural HeritageWashington Natural Heritage ProgramWest Virginia Natural Heritage ProgramWisconsin Natural Heritage ProgramWyoming Natural Diversity Database