Federal Register / Vol. 56. No. 157 / Wednesday. August 14. 1991 / Proposed Rules 40469 



characterize the site will vary due to the 



• area's size and complexity of habitats. 

 In general, it is best to divide the 

 baseline into a number of equal 

 segments and use the mid-point of each 

 baseline segment as the transect starting 

 point. For example, if the baseline is 

 1.600 feet in length, four transects will 

 be established; one at 200 feet one at 

 600 feet, one at 1,000 feet, and one at 

 1,400 feet &om the baseline starting 

 point Each transect should extend 

 perpendicular to the baseline. 



Use the following as a guide to 

 determine the minimum number of 

 baseline segments: 



• If the baseline exceeds five miles, 

 baseline segments should be 0.5 mile in 

 length. 



Make sure that each pleint community 

 type is included in at least one transect; 

 if not modify the sampling design 

 accordingly by relocating one or more 

 transect lines or by establishing 

 additioned transects. When the starting 

 points for all required transects have 

 been established, go to the beginning of 

 the first transect and proceed to Step 5. 



Step 5. Identify sample plots along the 

 transect. Along each transect, sample 

 plots may be established in two ways: 

 (1) Within each plant conununity 

 encountered (the plant community 

 transect sampling approach); or (2) at 

 fixed intervals (the fixed interval 

 transect sampling approach); these plots 

 will be used to assess vegetation, soils, 

 and hydrology. 



When employing the plant community 

 transect sampling approach, two 

 techniques for identifying sample plots 

 may be followed: (1) WaLc the entire 

 length of the transect tEdcing note of the 

 number, type, and location of plant 

 communities present (flag the locations, 

 if necessary) and on the way back to the 

 baseline, record the length of the 

 transect identify sample plots and 

 perform sampling; or (2) identify plant 

 communities as the transect is walked, 

 sample the plot at that time ("sample as 

 you go"), and record the length of the 

 transect 



When conducting the fixed interval 

 transect sampling approach, estabUsh 

 sample plots along each transect using 

 the following as a guide: 



The first sample plot should be 

 established at a distance of 50 feet from 

 the baseline. When obvious 

 nonweUands occupy a long segment of 

 the transect from the baseline, begin the 

 first plot in the nonwedand at 

 approximately 300 feet from the point 

 where the nonweUand begins to 

 intergrade into a potential weUand 

 communify type. Keep in mind that 

 additional plots wrill be required to 

 determine the weUand-nonweUand 



boundary between fixed points. In large 

 areas having a mosaic of plant 

 communities, one transect may contain 

 several wetland boundaries. 



If obstacles such as a body of water or 

 impenetrable thicket prevent access 

 through the length of the transect 

 access from the opposite side of the 

 project area may be necessary to 

 complete the transect take appropriate 

 compass reading and location data. At 

 each sample plot (i.e., plant communify 

 or fixed interval area), proceed to Step 

 6. 



Step 6. Consider the following: 



(1) Is the area presendy 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 temperatures (e.g., 

 seasonalify of plant growth)? 



If the answer to either of these 

 questions is Yes or uncertain, and the 

 area meets the description of one of the 

 exceptions in this manual, proceed to 

 the appropriate section of this manual. If 

 the answer to both questions is No, 

 proceed to Step 7 when following the 

 plant communify transect approach. If 

 following the fixed interval approach, go 

 to the appropriate fixed point along the 

 transect and proceed to Step 8. 



[Note: In some cases, normal climatic 

 conditions, such as snow cover or frozen 

 soils, may prevent an accurate assessment of 

 the wetland criteria; one must use best 

 professional judgment to determine if 

 delaying the wetland delineation is 

 appropriate.) 



Step 7. Locate a sample plot in the 

 plant communify type encountered. 

 Choose a representative location along 

 the transect in this plant communify. 

 Select an area that is no closer than 50 

 feet from the baseline or from any 

 perceptible change in the plant 

 commimify type. Mark the center of the 

 sample plot on the base map or photo 

 and flag the point in the field. Additional 

 sample plots shoidd be established 

 writhin the plant communify at 300-foot 

 intervals along the transect or sooner if 

 a different plant commimify is 

 encountered. 



(Note: In large-sized plant communities, a 

 sampling interval larger than 300 feet may be 

 appropriate, but try to use 300-foot intervals 

 first) 



Proceed to Step 8. 



Step 8. Lay out the boundary of the 

 sample plot A circular sample plot with 

 a 30-foot radius should usuaUy be 

 estabhshed. however, the size and 

 shape of the plot may be changed to 

 match local conditions (e.g., narrow 



ridges and swales) as necessary. At the 

 flagged center of the plot use a compass 

 to divide the circular plot into four equal 

 sampling units at 90*. 180*, 270*, and 

 360*. Mark the outer points of the plot 

 with flagging. Proceed to Step 9. 



Step 9. Characterize the vegetation 

 and determine dominant species within 

 the sample plot Sample the vegetation 

 in each layer or stratiun (i.e.. tree, 

 sapling, shrub, herb, woody vine, and 

 bryophyte) within the plot using the 

 following procedures for each vegetative 

 stratum and enter data on appropriate 

 data sheet: 



(1) Herb stratiun 



(A) Sample this stratum using 

 corresponding approach: 



(1) Plant communify transect sampling 

 approach: 



(a) Select one of the following designs: 

 (i) Eight (8) — 8" x 20" sample quadrats 



(two for each sampling unit within the 

 circular plot); or 



(ii) Four (4)— 20" x 20" sample 

 quadrats (one for each sample unit 

 within the plot); or 



(iii) Four (4)---40" x 40" sample 

 quadrats (one for each sample unit). 



(Note: Alternate shapes of sample quadrats 

 are acceptable provided they are similar in 

 area to those listed above.) 



(b) Randomly toss the quadrat frame 

 into the understory of the appropriate 

 sample unit of the plot 



(c) Record percent areal cover of each 

 plant species. 



(d) Repeat (b) and (c) as required by 

 the sampling scheme. 



(e) Construct a species area curve for 

 the plot to determine whether the 

 number of quadrats sampled sufficienUy 

 represent the vegetation in the stratum: 

 the number of samples necessary 

 corresponds to the point at which the 

 curve levels off horizontally; if 

 necessary, setmple additional quadrats 

 vinthin the plot until the curve levels off. 



(f) For each plant species sampled, 

 determine the average percent areal 

 cover by summing the percent areal 

 cover for all sample quadrats within the 

 plot and dividing by the total number of 

 quadrats. Proceed to Step B below. 



(2) Fixed interval sampling approach: 



(a) Place one [I}— iff' X 40" sample 

 quadrat centered on the transect point 



(b) Determine percent areal coverage 

 for each species. Proceed to substep B 

 below. 



(B) Rank plant species by their 

 average percent areal cover, beginning 

 with the most abundant species. 



(C) Sum the percent cover (fixed 

 interval sampling approach) or average 

 percent cover (plant communify transect 

 sampling approach). 



