Part 



Field Indicators and 

 Other Available 

 Information 



3.0. When conducting a field inspec- 

 tion to make a wetland determination, 

 the three identification criteria, listed in 

 Part n of this manual, alone may not 

 provide enough information for users to 

 document whether or not the criteria 

 themselves (i.e., hydrophytic vegetation, hydric 

 soils, and wetland hydrology) are met. Various 

 physical propenies or other signs can be readily 

 observed in the field to determine whether the three 

 wedand identification criteria are satisfied. Besides 

 these field indicators, good baseline information 

 may be available from site-specific studies, pub- 

 lished reports, or other written material on wet- 

 lands. In the following sections, field indicators 

 and primary sources of information for each of the 

 three criteria are presented to help the user identify 

 wetiands. 



Hydrophytic Vegetation 



3.1. All plants growing in wetiands have adapted 

 in one way or another to life in permanentiy or per- 

 iodically inundated or saturated soils. Some plants 

 have developed structural or morphological adapta- 

 tions to inundation or saturation. These features, 

 while indicative of hydrophytic vegetation, are 

 used as indicators of wetiand hydrology in this 

 manual, since they are a response to inundation and 

 soil saturation. Probably all plants growing in wet- 

 lands possess physiological mechanisms to cope 

 with prolonged periods of anaerobic soil condi- 

 tions. Because they are not observable in the field, 

 physiological and reproductive adaptations are not 

 included in this manual. 



3.2. Persons making wetiand determinations 

 should be able to identify at least the dominant wet- 

 land plants in each stratum (layer of vegetation) of 

 a plant community. Plant identification requires use 



of field guides or more technical taxonomic manu- 

 als (see Appendix A for sample list). When neces- 

 sary, seek help in identifying difficult species. 

 Once a plant is identified to genus and species, one 

 should then consult the appropriate Federal list of 

 plants that occur in wetlands to determine the "wet- 

 land indicator status" of the plant (see p. 5). This 

 information will be used to help determine if hy- 

 drophytic vegetation is present. 



Dominant Vegetation 



3.3. Dominance as used in this manual refers 

 strictiy to the spatial extent of a species that is di- 

 rectiy discemable or measurable in the field. When 

 identifying dominant vegetation within a given 

 plant community, one should consider dominance 

 within each stratum. All dominants are treated 

 equally in characterizing the plant community to de- 

 termine whether hydrophytic vegetation is present. 

 The most abundant plant species (when ranked in 

 descending order of abundance and cumulatively 

 totaled) tiiat immediately exceed 50 percent of the 

 total dominance measure for a given stratum, plus 

 any additional species comprising 20 percent or 

 more of the total dominance measure for that stra- 

 tum are considered dominant species for the stra- 

 tum. Dominance measures include percent areal 

 coverage and basal area, for example. 



3.4. Vegetative strata for which dominants should 

 be determined may include: (1) tree (>5.0 inches 

 diameter at breast height (dbh) and 20 feet or tall- 

 er); (2) sapling (0.4 to <5.0 inches dbh and 20 feet 

 or taller); (3) shrub (usually 3 to 20 feet tall includ- 

 ing multi-stemmed, bushy shrubs and small trees 

 and saplings); (4) woody vine; and (5) herb (herba- 

 ceous plants including graminoids, forbs, ferns, 

 fern allies, herbaceous vines, and tree seedlings). 

 Bryophytes (mosses, homed liverworts, and true 

 liverworts) should be sampled as a separate stratum 

 in certain wetiands, including shrub bogs, moss- 

 lichen wetiands, and wooded swamps where bryo- 

 phytes are abundant and represent an important 

 component of the community; in most other wet- 

 lands, bryophytes should be included within the 

 herb stratum due to their scarcity. 



3.5. There are many ways to quantify dominance 

 measures; Part IV provides recommended ap- 

 proaches. Alternatively, one may wish to visually 

 estimate percent coverage when possible or per- 

 form a frequency analysis of all species within a 



