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


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?


• 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


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?


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?


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


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

†

†


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%


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


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?


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%


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


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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


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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


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


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.


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.


† 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.


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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


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


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


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:


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.


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.


Appendix B—

Structure &Type Definition

T


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


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.



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


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


U.S. FOREST SERVICE (CONTINUED)

U.S. DEPARTMENT OF DEFENSE

U.S. FISH AND WILDLIFE SERVICE


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


THE NATURE CONSERVANCY(Bioreserves and Other Multi-jurisdictional Areas of Interest)


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


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


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


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


THE NATURE CONSERVANCY (CONTINUED)


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


1. The Nature Conservancy. 1996. Conservation by de-

sign: A framework for mission success. The Nature Con-

servancy, Arlington, Virginia.

2. Whittaker, R. H. 1962. Classification of natural com-

munities. Botanical Review 28:1–239.

3. Reschke, C. 1990. Ecological communities of New

York State. New York Natural Heritage Program. New

York State Department of Environmental Conservation,

Latham, New York.

4. McPeek, M. A., and T. E. Miller. 1996. Evolutionary

biology and community ecology. Ecology 77:1319-1320.

5. Wilson, E. O. 1992. The diversity of life. W. W. Norton

& Company, New York.

6. Noss, R. F., E. T. La Roe III, and J. M. Scott. 1995.

Endangered ecosystems of the United States: A prelimi-

nary assessment of loss and degradation. Biological Re-

port 28. U.S. Department of Interior, National Biological

Service, Washington, D.C.

7. Grossman, D. H., D. Faber-Langendoen, A. S. Weakley,

M. Anderson, P. Bourgeron, R. Crawford, K. Goodin, S.

Landaal, K. Metzler, K. D. Patterson, M. Pyne, M. Reid,

and L. Sneddon. 1998. International classification of eco-

logical communities: Terrestrial vegetation of the United

States. Volume I. The National Vegetation Classification

System: Development, status, and applications. The Na-

ture Conservancy, Arlington, Virginia.

8. Anderson, M., P. Bourgeron, M. T. Bryer, R. Crawford,

L. Engelking, D. Faber-Langendoen, M. Gallyoun, K.

Goodin, D. H. Grossman, S. Landaal, K. Metzler, K. D.

Patterson, M. Pyne, M. Reid, L. Sneddon, and A. S.

Weakley. 1998. International classification of ecological

communities: Terrestrial vegetation of the United States.

CitedReferences

Volume II. The National Vegetation Classification System:

List of types. The Nature Conservancy, Arlington, Virginia.

9. UNESCO [United Nations Educational, Scientific and

Cultural Organization]. 1973. International classification

and mapping of vegetation. Series 6. Ecology and conser-

vation. United Nations Educational, Scientific and Cul-

tural Organization, Paris.

10. Mueller-Dombois, D., and H. Ellenberg. 1974. Aims

and methods of vegetation ecology. John Wiley and Sons,

New York.

11. Kimmins, J. P. 1997. Forest ecology: A foundation

for sustainable management. Second edition. Prentice Hall,

Upper Saddle River, New Jersey.

12. Sims, R. A., W. D. Towill, K. A. Baldwin, and G. M.

Wickware. 1989. Field guide to the forest ecosystem clas-

sification for northwestern Ontario. Forestry Canada,

Ontario Ministry of Natural Resources, Thunder Bay,

Ontario.

13. Bailey, R. G. 1995. Description of the ecoregions of

the United States. U.S. Forest Service Miscellaneous Pub-

lication 1391 (revised), with separate map at a scale of

1:7,500,000. U.S. Forest Service, Washington, D.C.

14. Reschke, C. 1995. Biological and hydrological moni-

toring at the Chaumont Barrens Preserve. The Nature

Conservancy, Latham, New York.

15. Schaefer, C. A., and D. W. Larson. 1997. Vegetation

and maintenance of alvars of the Bruce Peninsula, Canada.

Journal of Vegetation Science 8:797-810.

16. Reid, R., C. Reschke, H. Potter, and The Nature

Conservancy’s Great Lakes Program. Final technical re-

port. In preparation. The Nature Conservancy, Chicago.


17. Alpert, J., and P. Kagan. 1998. The utility of plant

community types: A practical review of riparian vegeta-

tion classification in the Intermountain United States.

Natural Areas Journal 18:124-137.

18. LeBlond, R. J., A. S. Weakley, A. A. Reznicek, and W.

J. Crins. 1994. Carex lutea (Cyperaceae), a rare new

Coastal Plain endemic from North Carolina. Sida 16:153-

161.

19. Columbia Plateau Ecoregional Planning Team. Co-

lumbia Plateau: A pilot effort in ecoregional conservation.

Unpublished draft, March 13, 1998. The Nature Conser-

vancy, Arlington, Virginia.

20. McNab, W. H., and P. E. Avers, editors. 1994. Eco-

logical subregions of the United States: Section descrip-

tions. U.S. Forest Service Administrative Publication WO-

WSA-5. U.S. Forest Service, Washington, D.C.

21. Asociación Nacional Pro Medio Ambiente y Recursos

Naturales (PROAMBIENTE), and The Nature Conser-

vancy. 1998. U.S. Naval Station Guantanamo Bay, Cuba:

Rapid ecological assessment. The Nature Conservancy,

Arlington, Virginia.

22. Cowardin, L. M., V. Carter, F. C. Golet, and E. T. La

Roe. 1979. Classification of the wetlands and deepwater

habitats of the United States. U.S. Fish and Wildlife Ser-

vice, Washington, D.C.

23. Grossman, D. H., K. L. Goodin, and C. L. Reuss,

editors. 1994. Rare plant communities of the contermi-

nous United States: An initial survey. The Nature Conser-

vancy, Arlington, Virginia.

24. Schneider, R. E., D. Faber-Langendoen, R. C.

Crawford, and A. S. Weakley. 1997. Great Plains vegeta-

tion classification. Supplement document 1 in Ostlie, W.

R., R. E. Schneider, J. M. Aldrich, T. M. Faust, R. L. B.

McKim, and S. J. Chaplin. The status of biodiversity in

the Great Plains. The Nature Conservancy, Arlington,

Virginia.

25. Federal Geographic Data Committee. 1997. Vegeta-

tion classification standard, FGDC-STD-005. Web

address: http://www.fgdc.gov/Standards/Documents/

Standards/Vegetation.

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

Seeing the Forest and the Trees - NatureServe the Forest and the Trees: Ecological Classification...

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