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Table 1 Characteristics of five sample station groups as classified by hierarchical clustering with group-average linking

From: Prediction of benthic community structure from environmental variables in a soft-sediment tidal basin (North Sea)

Cluster no. 1 2 3 4 5
Number of samples in cluster 74 106 103 11 10
  Occurrence of benthic species (% present)
Arenicola marina (6 classes) 93 97 100 73 30
Cerastoderma edule (ind./m2) 91 78 40 55 100
Lanice conchilega (3 classes) 4 28 7 100 20
Diatoms (% bottom cover) 36 14 5 9 100
Zostera marina (% bott. cover) 85 8 2
Zostera noltii (% bottom cover) 91 5 2
Enteromorpha spp. (% bott. co.) 31 94 1 45 20
Ulva lactuca (3 classes) 35 82 1 18 80
Fucus spp. (3 classes) 8 8 5 10
Porphyra spp. (3 classes) 1 10
Salicornia europaea (3 classes) 3
Spartina anglica (3 classes) 7 1
Mytilus edulis (6 classes) 7 25 2 27 30
  Sample means ± standard deviations of environmental data
Emersion time “dry” (%) 41 ± 17 21 ± 17 20 ± 19 8 ± 5 13 ± 14
τ meanc (N/m2) 0.037 ± 0.026 0.069 ± 0.027 0.091 ± 0.041 0.099 ± 0.028 0.031 ± 0.005
τ maxc (N/m2) 0.28 ± 0.14 0.40 ± 0.16 0.55 ± 0.25 0.44 ± 0.12 0.19 ± 0.03
τ meanw (N/m2) 0.25 ± 0.06 0.29 ± 0.05 0.30 ± 0.10 0.31 ± 0.07 0.26 ± 0.02
τ maxw (N/m2) 1.43 ± 0.21 1.51 ± 0.15 1.60 ± 0.32 1.61 ± 0.19 1.50 ± 0.04
10th percentile grain-size D10 (μm) 85 + 100/−46 116 + 37/−28 138 + 61/−42 100 + 85/−46 41 + 42/−21
Median grain-size D50 (μm) 156 + 86/−55 166 + 37/−30 201 + 59/−46 173 + 21/−19 72 + 70/−36
90th percentile grain-size D90 (μm) 245 + 172/−101 235 + 76/−57 308 + 142/−97 274 + 83/−64 175 + 89/−59
Sediment grain-size sorting D90/D10 2.89 + 2.5/−1.3 2.04 + 0.7/−0.5 2.23 + 1.0/−0.7 2.74 + 2.8/−1.4 4.29 + 1.7/−1.2
  1. For each cluster group, the occurrences (% present) of the single species are given. Bold presence numbers indicate the characteristic species of each cluster group. The lower part of the table shows the sample means and the standard deviations of the environmental variables within the cluster groups. The means and the standard deviations of the sediment grain-size data were calculated in logarithmic terms; thereafter, the antilogarithms were taken. For each environmental variable, both the maximum sample mean and the minimum sample mean are indicated using bold text