Wetland Classification

NREM 665 Outline

I. Why classify?

II. History & development of classification systems

III. Comparison of Cowardin, Canadian, & HGM systems

IV. Cowardin system

2 I. Why Classify?

„ Perceive order in diversity

„ Need system for grouping wetlands in an orderly, logical way

3 Used in other disciplines

„ Zoology & Botany

„ Soil Taxonomy

4 Advantages & Disadvantages

„ Helps to assess evolutionary & successional patterns

„ Aids in management

„ Systems can be biased, regionalistic, stagnant

5 II. History & Development of WtldClWetland Classifi ifitication i n th thUSe U.S.

„ 1954: USFWS conducted inventory of wetlands to assess waterfowl habitat

„ Martin et al. developed Classification of Wetlands of the United States (1953), used as a framework for inventory

„ Results of inventory published by Shaw & Fredine (1956)

„ This publication , Wetlands of the United States, became known as USFWS Circular 39

6 Circular 39

„ Emphasis: waterfowl

„ Limitations:

7 Other Classification systdldtems developed 1. Stewart & Kantrud 1971 2. Golet & Larson 1974 3. Jeglum et al. 1974 4. Odum et al . 1974 5. Zoltai et al. 1975 6. Millar 1976

Emphasis: Limitations: 8 Development of new system (Cowardi n)

„ 1974: USFWS directed Office of Biological Services to conduct new National Inventory of Wetlands

„ New classification system developed as 1st step of Inventory „ Goals of the new system were to: 1. describe homogenous ecological units 2. arrange un its in a sys tem tha t will a id in res. mgm t. 3. furnish units for inventory & mapping 4. provide uniformity in concepts & terminology

9 Improvements on Circular 39

„ Cowardin broader in scope

„ Developed by multidisciplinary team

„ Wetlands defined as possessing 1 or more of the foll ow ing 3 componen ts: a. hydrophytic vegetation bhdib. hydric so il c. wetland hydrology

10 Cowardin Summary & Commentary

„ Emphasis: on vegetation cover → interpreted from aerial photos. Ecologically-related areas of deepwater, traditionally not considered wetlands, included as deepwater habitats.

„ Limitations:

11 Development of the Canadian Classification System

„ 1976: National Wetlands Working Group (NWWG) formed as combination of gov’t, NGO, university, private groups

„ NWWG published: Atlas: Canada’s Wetlands (1986) Reports: The Canadian Wetland Classification System (1987)

„ 1997: Canadian Wetland Classification System V2

12 ‘97 version improves on ‘87

„ Goal of new version: “to establish a common language for the wetland resource, usable by all Canadians”

„ Refined terminology, dfiitidefinitions

13 Basis of Canadian System Emphasizes conditions that have effected wetland development such as:

„ wetland morphology

„ water source

„ basin depth, shape

„ plant communities

„ peat/sediment characteristics

14 3 Levels of Canadian System 1) Class

„ bog

„ fen

„ swamp

„ marsh

„ shallow water 2) Form

„ subform 3) Type 15 Classes: based on origin of wetland & nature of wetland environment

Forms: subdivisions of each class based on morphology, surface pattern, water type, soils

Types:s: subdivisions of forms & subforms based on physiognomic characteristics of vegetation communities

16 Summary & Assessment of CdiSCanadian System

„ Sy stem of ke ys w/ q uestions to help separate forms & subforms w/i a class

„ Simpler, more focused on WTLs than Cowardin

„ EhiEmphasis: dldevelopmen thdlt, hydrology, peatlan ds

„ Limitations:

17 Hydrogeomorphic (HGM) Classification System

„ Focused on evaluating functions of wetlands simply, rapidly, inexpensively.

„ Deve lope d in response to CWA Sec tion 404 regulations.

„ Permit process requires assessing effects of development on wetland functions. Available methods for assessing functions inadequate.

18 HGM emphasizes 2 abiotic controls in maintaining wetland functions

„ Hydrology controls amount, source, season of water entering wetland

„ Geomorphology controls where water comes from & whether it leaves

19 HGM int end ed t o:

1. Classify wetlands into distinct types w/ similar functions 2. For specifffic types, evaluate which functions are performed & estimate degree to which they are performed 3. Estimate amount of wetland area & corresponding functions lost w/ dvpt & provide mechanism for determining mitigation ratio

20 3 components used to classify wetlands of similar function 1. depressional 2. riverine 1) geomorphic 3. lacustrine fringe 4. tidal fringe setting {5. slope 6. mineral soil flats 7. organic soil flats

2) water source & transport

3) hydrodynamics

21 Salt marsh

Cowardin CanadianRamsar HGM

System: Class: Class: Geomorhpic Setting: Water Source: Hydrodynamics: Estuarine Marsh Coastal Tidal Fringe Surface water Bidirectional

Subsystem: Form: Type: Intertidal Tidal Marsh Intertidal Marsh

Class: Subform: Emergent Wetland Tidal Bay Marsh

Subclass: Persistent 22 Summary of Classification Systems

Circular 39 (1956) Canadian (1997) Type: Hierarchi ca l Type: Hierarchical Emphasis:waterfowl Emphasis:development Limitations: not hydrol., peatlands comprehensive Limitations: weak for swamps, shallow water Cow ardin (1979) HGM (1993) Type: Hierarchical Type: Functional Emphasis:vegetation Emphasis:abiotic controls, Limitations: too much hydrol, geomorph. deepwater not Limitations: regional enough wetland development, funding

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