USGS/NPS Vegetation Mapping Program Standardized National Vegetation Classification System - Final Draft
Final Draft
Standardized National Vegetation
Classification System
USGS/NPS Vegetation Mapping Program
November 1994 Prepared for:
United States Department of Interior United States Geological Survey and
National Park Service
Prepared By:
The Nature Conservancy
1815 N. Lynn Street
Arlington, Virginia 22209
Environmental Systems Research Institute
380 New York Street
Redlands, California 92373
USGS/NPS Vegetation Mapping Program Standardized National Vegetation Classification System - Final Draft
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USGS/NPS Vegetation Mapping Program Standardized National Vegetation Classification System - Final Draft
Table of Contents
- Section
- Page
Executive Summary...........................................................................................1-1 1.0 Introduction.................................................................................................1-4
1.1 Objectives of the Report ....................................................................................................1-4
1.1.1 Relationship to other reports in this series...............................................................1-5
1.2 Structure of the Report.......................................................................................................1-5 1.3 Terms of the Vegetation Mapping Project.........................................................................1-6
1.3.1 Project objectives.....................................................................................................1-6 1.3.2 Contract requirements..............................................................................................1-6
1.3.2.1 Classification Syste m.....................................................................................1-6 1.3.2.2 Map Scale ......................................................................................................1-6 1.3.2.3 Map Accurac y................................................................................................1-7 1.3.2.4 Digital Products.............................................................................................1-7
2.0 The Importance of a National Vegetation Classification Standard.......2-1
2.1 Applications of a Standard National Vegetation Classification System............................2-1
2.1.1 Facilitate regional and national resource assessments.............................................2-1 2.1.2 Advance scientific knowledge.................................................................................2-2 2.1.3 Support park planning and natural resources management .....................................2-2 2.1.4 Support ecosystem management initiatives ...................................................................2-2
2.2 Specifications/Requirement of a Candidate Standard ..............................................................2-3
3.0 Vegetation Classification: Background ........................................................ 3-1
3.1 What is Classification? ..............................................................................................................3-1
3.1.1 Community units and continua.......................................................................................3-1
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3.2 Review of Different Approaches to Classification...................................................................3-2
3.2.1 Vegetation classifications................................................................................................3-2
3.2.1.1 Physiognomic Methods.........................................................................................3-2 3.2.1.2 Floristic Methods..................................................................................................3-4
3.2.1.3 Potential versus existing vegetation.....................................................................3-5
3.2.2 Site classifications ...........................................................................................................3-6
3.2.2.1 Site classifications emphasizing vegetation.........................................................3-6 3.2.2.2 Site classifications emphasizing multiple factors ...............................................3-7
3.2.3 Land cover classifications...............................................................................................3-8 3.2.4 Combined classification approaches ..............................................................................3-8
3.2.4.1 Physiognomic-Floristic Approaches....................................................................3-9
4.0 The Nature Conservancy's Vegetation Classification System.........................4-1
4.1 Approach of the Vegetation Classifiction System....................................................................4-1
4.1.1 Background......................................................................................................................4-1 4.1.2 Guiding principles...........................................................................................................4-2
4.1.2.1 Appropriate for conservation planning and managemen t..................................4-2 4.1.2.2 Efficient use of existing information ....................................................................4-2
4.1.2.3 Flexible..................................................................................................................4-3
4.1.2.4 Emphasis on Natural and Semi-natural Vegetation............................................4-3
4.2 Development of the Nature Conservancy Classification System ............................................4-4
4.2.1 Identification of classification units................................................................................4-4 4.2.2 International Efforts ........................................................................................................4-5 4.2.3 Support from Federal and Academic Partners ...............................................................4-5
4.2.3.1 U.S. Geological Survey.........................................................................................4-6
4.2.3.2 United States Fish and Wildlife Service...............................................................4-6
4.2.3.3 United States Forest Service ................................................................................4-6 4.2.3.4 National Park Service...........................................................................................4-7 4.2.3.5 Environmental Protection Agency .......................................................................4-7 4.2.3.6 Inter-agency Groups.............................................................................................4-8 4.2.3.7 Academic Partners ...............................................................................................4-8
4.3 Tool and Methods that Support the Documentation and Development of the
Classification..............................................................................................................................4-8 4.3.1 Field sampling .................................................................................................................4-8 4.3.2 Community descriptions ...............................................................................................4-10
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4.3.2.1 Characterization variables and vegetation keys ...............................................4-10 4.3.2.2 Biological and Conservation Data System Community Records .....................4-11
4.3.3 Conservation Ranking...................................................................................................4-12
5.0 A Standard National Vegetation Classification System .............................. 5-1
5.1 Characteristics of the National Vegetation Classification System...........................................5-1
5.1.1 Based on existing vegetation ..........................................................................................5-1 5.1.2 Combined Physiognomic Floristic Classification Approach.........................................5-1 5.1.3 Role of the environment..................................................................................................5-2
5.2 Description of the Levels of the Terrestrial Vegetation ...........................................................5-3
5.2.1 System level.....................................................................................................................5-3 5.2.2 Physiognomic levels........................................................................................................5-4
5.2.2.1 Modifications to the UNESCO Hierarch y...........................................................5-5
5.2.2.2 Physiognomic class...............................................................................................5-5 5.2.2.3 Physiognomic subclass.........................................................................................5-7 5.2.2.4 Formation group...................................................................................................5-7 5.2.2.5 Formation..............................................................................................................5-7
5.2.3 Floristic levels..................................................................................................................5-8
5.2.3.1 Alliance .................................................................................................................5-8 5.2.3.2 Community Element..............................................................................................5-8
5.2.4 Cultural Land Cover......................................................................................................5-10
5.2.4.1 Agricultural land cover ......................................................................................5-10 5.2.4.2 Urban land cover and water ..............................................................................5-10
5.3 Nomenclature Standards..........................................................................................................5-11 5.4 Development of the National Vegetation Classification System...........................................5-12
5.4.1 Development of the floristic classes (Alliances and Community Elements)..............5-12
5.4.1.1 Qualitative Assessmen t.......................................................................................5-12 5.4.1.2 Quantitative Analysis..........................................................................................5-13 5.4.1.3 Confidence Levels ..............................................................................................5-13
5.4.1.4 Example of development of the floristic classes— pine barrens.......................5-14
5.4.2 Arranging the floristic units under the physiognomic levels of the hierarchy............5-16 5.4.3 Adding new vegetation types identified during the course of the NPS/USGS mapping project ............................................................................................................................5-16
5.4.3.1 Qualitative Assessmen t.......................................................................................5-17
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5.4.3.2 Quantitative Assessment.....................................................................................5-17
5.5 Ecological Considerations and Variability .............................................................................5-17
5.5.1 Homogeneity .................................................................................................................5-18
5.5.1.1 Community complexe s........................................................................................5-18 5.5.1.2 Gradients.............................................................................................................5-18
5.5.2 Disturbance....................................................................................................................5-19 5.5.3 Succession......................................................................................................................5-19
5.6 The Relationship Between the National Vegetation Classification System and Other
Classification Systems .............................................................................................................5-20 5.6.1 An Example of Crosswalking: The relationship between the Brown, Lowe and Pase classification and the National Vegetation Classification System...............................5-20
5.7 Current Status of the National Vegetation Classification System..........................................5-23
5.7.1 State coverage................................................................................................................5-23 5.7.2 Regional coverage.........................................................................................................5-23 5.7.3 National coverage..........................................................................................................5-24 5.7.4 Gaps in the classification...............................................................................................5-25
5.7.4.1 Gaps in state-level informatio n..........................................................................5-25
5.7.4.2 Types still in need of basic work ........................................................................5-26
6.0 Vegetation Mapping ......................................................................................... 6-1
6.1 Theoretical Background.............................................................................................................6-1
6.1.1 Vegetation mapping standards........................................................................................6-1 6.1.2 Imagery analysis and vegetation mapping .....................................................................6-2
6.1.1.1 Diagnostic characteristics of the signatures .......................................................6-2 6.1.1.2 Challenges of using imagery analysis for vegetation mapping ..........................6-3
6.2 Mapping the National Vegetation Classification System.........................................................6-4
6.2.1 Decision to map the alliance vs. the community element..............................................6-4 6.2.2 Extension of the national vegetation classification system for application to vegetation maps.................................................................................................................................6-6
6.2.2.1 Mapping different expressions of the floristic units ............................................6-6 6.2.2.2 Collecting and tracking additional attribute data on a park by park basis .......6-7
6.2.3 Non-homogeneous mapping units..................................................................................6-7
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6.2.3.1 Landscapes with communities less than the minimum mapping uni t.................6-7
6.2.3.2 Community complexe s..........................................................................................6-8
6.2.3.3 Map units containing more than one community element ..................................6-8 6.2.3.4 Transition zones greater than the minimum mapping unit ................................6-8
6.3 Examples of Vegetation Mapping Projects...............................................................................6-8
6.3.1 John Crow and Blue Mountains of Jamaica...................................................................6-9 6.3.2 Altamaha River Bioreserve, Georgia..............................................................................6-9
7.0 Addressing USGS/NPS Objectives................................................................. 7-1
7.1 Management Objectives ............................................................................................................7-1 7.2 Inventory and Monitoring Objectives.......................................................................................7-1 7.3 System Wide Requirements.......................................................................................................7-1 7.4 Information Transfer and Exchange..........................................................................................7-2
8.0 Conclusions........................................................................................................ 8-1 9.0 Authors and Contributors............................................................................... 9-1 10.0 Literature Cited.............................................................................................. 10-1 11.0 Appendices...................................................................................................... 11-1
11.1 List of Documented Alliances Organized Under the Hierarchy ............................................11-1 11.2 Examples of Community Descriptions..................................................................................11-66 11.3 List of Hydrological Modifiers..............................................................................................11-90 11.4 List of Element Occurrence Record Fields with Brief Descriptions....................................11-92
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11.5 List of Community Characterization Abstract Fields with Brief Descriptions................. 11-106 11.6 The Conservation Ranking System of the Nature Conservancy....................................... 11-118