Ecological Archives A021-026-A2

Ilana L. Abrahamson, Cara R. Nelson, and David L. R. Affleck. 2011. Assessing the performance of sampling designs for measuring the abundance of understory plants. Ecological Applications 21:452–464.

Appendix B. A table showing observed mean cover, constancy, and required sample size for each sampling design, and time-to-sample estimates for grouped vegetation variables and for individual species.

TABLE B1. For each sampling design (Daubenmire transect [DT], modified Whittaker plot [MWP], point–line intercept transect [PLIT], and strip adaptive cluster sampling [SACS]), observed mean cover and constancy (number of stands, range of 1–6) for grouped vegetation variables and individual species, and sample size (number of plots or transects) and time-to-sample (h) required for estimation of mean cover within 50% and 25% of the observed mean. For cover < 0.005%, "t" indicates trace.

Species Design Cover Constancy Sample size (#) Time (h)
      (%) (no. of stands) 50% 25% 50% 25%
Grouped vegetation variables              
Total vegetation DT 35.60 6 1 2 2 4
    MWP 36.02 6 1 4 4 17
    PLIT 57.61 6 2 5 2 4
Forbs DT 6.52 6 10 38 22 85
    MWP 5.94 6 10 38 43 162
    PLIT 8.81 6 36 143 31 124
Graminoids DT 4.62 6 4 16 9 36
    MWP 4.10 6 3 11 13 47
    PLIT 22.63 6 4 16 3 14
Shrubs DT 10.17 6 3 12 7 27
    MWP 8.22 6 3 11 13 47
    PLIT 13.28 6 4 15 3 13
Natives DT 20.80 6 2 7 4 16
    MWP 17.81 6 2 7 9 30
    PLIT 43.93 6 3 9 3 8
Nonnatives DT 0.61 5 60 240 135 539
    MWP 0.44 5 43 171 183 729
    PLIT 1.58 3 29 113 25 98
Common Species              
Arnica cordifolia1 DT 4.58 6 11 41 25 92
    MWP 4.34 6 10 39 43 166
    PLIT 5.62 6 12 48 10 42
Calamagrostis rubescens2 DT 3.30 6 7 28 16 63
    MWP 2.92 6 5 17 21 72
    PLIT 16.97 6 6 24 5 21
Carex geyeri2 DT 1.30 6 6 24 13 54
    MWP 1.18 6 6 24 26 102
    PLIT 5.62 6 7 25 6 22
Fragaria virginiana1 DT 0.56 6 10 37 22 83
    MWP 0.42 6 11 41 47 175
    PLIT 1.07 6 27 105 23 91
Mahonia repens3 DT 3.68 6 6 23 13 52
    MWP 3.03 6 3 12 13 51
    PLIT 4.03 6 6 24 5 21
Penstemon albertinus1 DT 0.50 6 12 46 27 103
    MWP 0.48 6 11 43 47 183
    PLIT 0.77 6 30 120 26 104
Symphoricarpos albus3 DT 6.49 6 6 23 13 52
    MWP 5.19 6 5 20 21 85
    PLIT 9.24 6 7 27 6 23
Less-common species            
Bromus tectorum* DT t 4 249 993 560 2232
    MWP   0        
    PLIT   0        
    SACS 0.01 1 11 43 8 31
Campanula rotundifolia1 DT 0.02 5 146 583 328 1310
    MWP 0.06 1 59 234 252 998
    PLIT 0.09 2 88 351 76 304
Carduus nutans2* DT 0.01 2 133 531 299 1193
    MWP 0.03 3 86 344 367 1467
    PLIT 0.04 1 174 693 151 601
Centaurea maculosa1* DT 0.12 4 101 404 227 908
    MWP 0.04 4 79 313 337 1335
    PLIT 0.40 3 67 267 58 231
Cirsium arvense1* DT 0.06 2 173 691 389 1553
    MWP 0.36 1 43 170 183 725
    PLIT 0.04 1 174 693 151 601
    SACS 0.05 2 8 29 6 21
Cirsium vulgare1* DT 0.49 2 98 391 220 879
    MWP 0.30 2 2 109 9 465
    PLIT 0.58 2 57 225 49 195
Cynoglossum officinale*1 DT t 2 261 1042 587 2342
    MWP 0.01 1 79 316 337 1347
    PLIT   0        
Heuchera cylindrica1 DT 0.05 6 131 523 294 1175
    MWP 0.03 5 68 271 290 1156
    PLIT 0.14 5 115 459 100 398
    SACS 0.05 6 1 4 1 3
Lithospermum  ruderale1 DT 0.06 2 63 249 142 560
    MWP 0.10 2 70 279 298 1190
    PLIT 0.13 2 102 406 88 352
Luzula campestris2 DT 0.02 4 69 276 155 620
    MWP 0.01 3 25 98 107 418
    PLIT 0.15 2 58 231 50 200
Osmorhiza berteroi1 DT 0.07 1 54 215 121 483
    MWP 0.06 1 32 128 136 546
    PLIT 0.23 1 51 201 44 174
Potentilla glandulosa1 DT 0.02 3 96 381 216 856
    MWP t 1 79 316 337 1347
    PLIT   0        
Potentilla gracilis1 DT 0.37 3 48 191 108 429
    MWP 0.26 3 106 423 452 1804
    PLIT 0.54 3 38 150 33 130
Potentilla recta1* DT 0.36 3 38 151 85 339
    MWP 0.13 4 35 140 149 597
    PLIT 0.63 3 220 55 191 48
Smilacina racemosa1 DT 0.02 3 161 642 362 1443
    MWP 0.50 1 87 347 371 1480
    PLIT 0.04 1 174 693 151 601
    SACS 0.01 3 8 30 6 22
Valeriana dioica1 DT 0.03 5 71 283 160 636
    MWP 0.04 4 42 168 179 716
    PLIT 0.08 3 81 324 70 281
Verbascum thapsus1* DT 0.11 3 102 407 229 915
    MWP 0.11 4 89 356 379 1518
    PLIT 0.41 1 58 229 50 198

1Forb
2Graminoid
3Shrub
*Nonnative


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