1) Is the area presently lacking hydrophytic 

 vegetation or hydrologic indicators due to annual, 

 seasonal, or long-term fluctuations in precipitation, 

 surface water, or ground-water levels? 



2) Are hydrophytic vegetation indicators 

 lacking due to seasonal fluctuations in temperature 

 (e.g., seasonality of plant growth)? 



If the answer to either of these questions is YES or 

 uncertain, proceed to the section on problem area 

 wetland determinations (p. 55), then return to this 

 method and continue the wetiand determination. If 

 the answer to both questions is NO, normal condi- 

 tions are assumed to be present, so proceed to Step 



0. 



Step 8. Characterize the vegetation of the 

 vegetation unit or the plant community along the 

 transect. 



If analyzing vegetation units, meander through the 

 unit making visual estimates of the percent area 

 covered for each species in the herb, shrub, 

 sapling, woody vine, and tree strata; alternatively, 

 for the tree stratum determine basal area using the 

 Bitterlich method (Dilwonh and Bell 1978; Avery 

 and Burkhart 1983). Then: 



1) Within each stratum determine and record 

 the cover class of each species and its correspond- 

 ing midpoint. The cover classes (and midpoints) 

 are: T = <1% (none); 1 = 1-5% (3.0); 2 = 6-15% 

 (10.5); 3 = 16-25% (20.5); 4 = 26-50% (38.0); 5 

 = 51-75% (63.0); 6 = 76-95% (85.5); 7 = 96- 

 100% (98.0). 



2) Rank the species within each stratum 

 according to their midpoints. (Note: If two or more 

 species have the same midpoints and the same or 

 essentially the same recorded percent areal cover, 

 rank them equal; use absolute areal cover values as 

 a tie-breaker only if they are obviously different.) 



3) Sum the midpoint values of all species 

 within each stratum. 



4) Multiply the total midpoint values for 

 each stratum by 50 percent. (Note: This number 

 represents the dominance threshold number and is 

 used to determine dominant species.) 



5) Compile the cumulative total of the 

 ranked species in each stratum until 50 percent of 



the sum of the midpoints (i.e., the dominance 

 threshold number), for the herb, woody vine, 

 shrub, sapling, and tree strata (or alternatively 

 basal area for trees) is immediately exceeded. All 

 species contributing areal cover or basal area to the 

 50 percent threshold are considered dominants, 

 plus any additional species representing 20 percent 

 or more of the total cover class midpoint values for 

 each stratum or the basal area for tree stratum. 

 (Note: If the threshold is reached by two or more 

 equally ranked species, consider them all domi- 

 nants, along with any higher ranked species. If all 

 species are equally ranked, consider them all domi- 

 nants.) 



6) Record all dominant species on an appro- 

 priate data sheet and list indicator status of each. 

 Proceed to Step 9. 



If using the transect approach, sample vegetation in 

 each stratum (e.g., tree, shrub, herb, etc.) occur- 

 ring in the sample plots using the following quadrat 

 sizes: (1) a 5-foot radius for bryophytes and herbs, 

 and (2) a 30-foot radius for trees, saplings, shrubs, 

 and woody vines. Plot size and shape may be 

 changed as necessary to meet site conditions. 

 Determine dominant species for each stratum by 

 estimating one or more of the following as appro- 

 priate: (1) relative basal area (trees); (2) areal cover 

 (trees, saplings, shrubs, herbs, woody vines, and 

 bryophytes); or (3) stem density (shrubs, saplings, 

 herbs, and woody vines). (Note: Dominant species 

 within each stratum are the most abundant plant 

 species that when ranked in descending order of 

 abundance and cumulatively totaled immediately 

 exceed 50 percent of the total dominance measure 

 for the stratum, plus any additional species com- 

 prising 20 percent or more of the total dominance 

 measure.) Record all dominant species on an 

 appropriate data sheet and list the indicator status of 

 each. Proceed to Step 9. 



Step 9. Determine whether the hydrophytic 

 vegetation criterion is met. When more than 50 per- 

 cent of the dominant species in the vegetation unit 

 or sample plot have an indicator status of OBL, 

 FACW, and/or FAC, hydrophytic vegetation is 

 present. If the vegetation fails to be dominated by 

 these types of species, the unit or plot is usually 

 not wetland. However, this vegetation unit or plot 

 may constitute hydrophytic vegetation under certain 

 circumstances (refer to the disturbed areas or prob- 

 lem area wedand determination sections on pp. 50- 

 59). If hydrophytic vegetation is present, proceed 



37 



