Federal Register / Vol. 56, No. 157 / Wednesday, August 14, 1991 / Proposed Rules 



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indicators of wetland hydrology in this 

 manual (see hydrology criterion), since 

 they are a response to inundation and/ 

 or soil saturation. Probably all plants 

 growing in wetlands possess 

 physiological mechanisms to cope with 

 periodic anaerobic soil conditions or life 

 in water. Because they are not 

 observable in the field, physiological 

 and reproductive adaptations are not 

 included in this manual. 



Persons making wetland 

 determinations should be able to 

 identify at least the dominant wetland 

 plants in each stratiun (layer of 

 vegetation) of a plant community. Plant 

 identification requires the use of field 

 guides or more technical taxonomic 

 manuals. When necessary, seek help in 

 identifying difficult species. Once a 

 plant is identified to genus and species, 

 consult the appropriate Federal list of 

 plants that occur in wetlands to 

 determine the "wetland indicator 

 status" of the plant (see explanation 

 below). This information will be used to 

 help determine whether the hydrophytic 

 vegetation criterion is met. 



One should also become familiar with 

 the technical literature on wetlands, 

 especially for one's geographic region. 

 Sources of available literature include: 

 taxonomic plant manuals and field 

 guides; scientific journals dealing with 

 botany, ecology, and wetlands in 

 particular technical government reports 

 on wetlands; proceedings of wetland 

 workshops, conferences, and symposia; 

 and the FWS's national wetland plant 

 database, which contains habitat 

 information on about 7,000 plant species. 

 In addition, the FWS's National 

 Wetlands Inventory (NWI) maps 

 provide information on locations of 

 hydrophytic plant communities that can 

 be studied in the field to improve one's 

 knowledge of such communities in 

 particular regions. 



If all wetland plant species grew only 

 in wetlands, plants alone could be used 

 to identify and delineate wetlands. 

 However, of the nearly 7,000 vascular 

 plant species which have been found 

 growing in U.S. wetlands (Reed 1988), 

 only about 27 percent are "obligate 

 wetland" species that nearly always 

 ocou" in wetlands under natural 

 conditions. This means that the majority 

 of plant species growing in wetlands 

 also grow in nonwetlands to varying 

 degrees. These plants may or may not 

 be hydrophytes depending on where 

 they are growing. This variability in 

 habitat occurrence causes certain 

 difficulties in identifying wetlands from 

 a purely botanical standpoint in many 

 cases. This is a major reason for 



evaluating soils and hydrology when 

 identifying wetlands. 



National List of Wetland Plant Species 



The FWS in cooperation with CE, 

 EPA. and SCS has published the 

 "National List of Plant Species That 

 Occur in Wetlands" from a review of the 

 scientific literature and review by 

 selected wetland experts and botanists 

 (Reed 1988). The list separates vascular 

 plants into four basic groups, commonly 

 called "wetland indicator status," based 

 on a plant species' frequency of 

 occurrence in wetlands: (1) Obligate 

 wetland plants (OBL) that occur almost 

 always (estimated probability >99%) in 

 nonwetlands under natural conditions; 



(2) facultative wetland plants (FACW) 

 that usually occur in wetlands 

 (estimated probability 67-99%), but 

 occasionally are foimd in nonwetlands; 



(3) facultative plants (FAC) that are 

 nearly equally likely to occur in 

 wetlands or nonwetlands (estimated 

 probability 34-66%); and (4) facultative 

 upland plants (FACU) that usually occur 

 in nonwetlands (estimated probability 

 67-99%), but occasionally are found in 

 wetlands (estimated probability 1-33%). 

 If a species occurs almost always 

 (estimated probability >99%) in 

 nonwetlands under natural conditions, it 

 is considered an obligate upland plant 

 (UPL). These latter plants do not usually 

 appear on the wetland plant list; they 

 are listed only in some regions of the 

 coimtry. If a species is not on the list, it 

 is presumed to be an obligate upland 

 plant, yet be advised that the list 

 intentionally does not include 

 nonvascular plant species (e.g., algae 

 and mosses) or epiphytic plants. 'These 

 omitted plants should not be considered 

 in determining whether the hydrophytic 

 vegetation criterion is met, unless one 

 has particular knowledge of their 

 frequency of occurrence in wetlands. 

 Also be sure to check for synonyms in 

 plant scientific names, since the 

 nomenclature used in the list varies for 

 some species from that used in regional 

 taxonomic manuals or commonly used 

 plemt identification field guides. 



The "National List of Plant Species 

 That Occur in Wetlands" has been 

 subdivided into regional and state lists. 

 There is a formal procedure to petition 

 the interagency plant review committee 

 for making additions, deletions, and 

 changes in indicator status. Since the 

 lists are periodically updated, the U.S. 

 Fish and Wildlife Service should be 

 consulted to be sure that the most 

 current version is being used for 

 wetiand determinations. The 

 appropriate plant list for a specific 

 geographic region should be used when 

 making a wetland determination and 



evaluating whether the hydrophytic 

 vegetation criterion is satisfied. (Note: 

 The "National List of Plant Species That 

 Occur in WeUands" uses a plus (+) sign 

 or a minus ( — ) sign to signify a higher or 

 lower portion of a particular weUand 

 indicator frequency for the three 

 facultative-type indicators; for purposes 

 of identifying hydrophytic vegetation 

 according to this manual, however, 

 FACW+, FACW-. FAC + , and FAC- 

 are included as FACW and FAC, 

 respectively, in the hydrophytic 

 vegetation criterion.) 



Procedures to be used to determine 

 the presence of hydrophytic vegetation 

 under the criterion are In the 

 Appendices identified as the Point 

 Intercept Sampling Proceedure. 



Hydric Soil Criterion 



An area has hydric soil when, based 

 on field verification, it has either 



1. SoUs listed by series in "Hydric 

 Soils of the United States" (1987 and 

 amendments), or 



2. Organic soils (Histosols, except 

 Folists), or 



3. Mineral soils classifying as 

 Sulfaquents, Hydraquents, or Histic 

 subgroups of Aquic suborders, or 



4. Other soils that meet the National 

 Technical Committee for Hydric Soils' 

 criteria for hydric soil. 



An area meets the hydric soil criterion 

 when, based on field verification, it has 

 one or more of the following: 



1. Where soil survey maps are 

 available, the subject area is within: 



a. A hydric soil map unit identified on 

 the county list of hydric soil map imits 

 that is verified by landscape position 

 and soil morphology against the series 

 description of the hydric soil, or 



b. A soil map unit vtdth hydric soil 

 inclusions identified on the county list of 

 hydric soil map units, and the landscape 

 position of the inclusion and the soil 

 morphology for the identified soil series 

 as a hydric soil inclusion are verified, or, 

 if no series is designated, then either 



(1) The soil classified to the series 

 level, is on the national list of hydric 

 soils, or 



(2) The soil, classified according to 

 "Soil Taxonomy", is a Histosol (except 

 Folists). Sulfaquent. Hydraquent, or 

 Histic Subgroup of Aquic Suborders, or 



(3) Regional indicators of significant 

 soil satiuation (as developed and 

 approved by Soil Conservation Service 

 soil scientists and the Federal 

 Interagency Conunittee for WeUands 

 Delineation] are materially present or 



2. Where soil maps are not available, 

 and the landscape position is likely to 

 contain hydric soil (e.g., floodplain. 



