Benthic Communities at Horns Rev Before, During and After Con

More documents

Recommendations

Info

Horns Rev. Benthic communities Page 38 The Bray-Curtis index is calculated as: BC = ∑ k ∑ k x − x ik jk ∑ x + x ik jk k where i and j are sub-samples and k is the number of species in the sub-samples. Similarity was expressed as 1 - BC. At maximum similarity, BC = 0 and at maximum dissimilarity, BC = 1. The BC values are used for presenting data in 2-dimensional plots using a non-metric Multidimensional Scaling (MDS) ordination. For further description of the MDS technique, see: http://www.statsoft.com/textbook/stmulsca.html. In MDS plots, usually a stress factor (0-0.5) is displayed as the distortion between the similarity rankings and the corresponding distance rankings in the ordination plot. Low stress 0.1-0.2 corresponds to a good agreement between the calculated similarity rankings and the ordination shown. A formal test for differences between areas and campaigns was made for each subset using a non-parametric permutation procedure applied to the similarity matrix underlying the ordination. To evaluate the relative importance of the different species, the average contribution to the overall similarity within groups and the average contribution to the overall dissimilarity between groups were calculated for each species. The results are presented listing the most important species first. To link sediment characteristics to species composition, two different approaches were used. First, a dissimilarity matrix was calculated between samples based on all sediment characteristics using the Euclidean distance as the dissimilarity measure. This matrix was tested for agreement with the dissimilarity matrix based on species composition using the weighted Spearman rank correlation, see: http://www.statsoft.com/textbook/stnonpar.html#correlations. Second, the same test for agreement was performed on combinations of sediment characteristics at steadily increasing levels of complexity to find the combination with the highest rank correlation. No legislative environmental criteria has been established for either the indicators or level of significance for a monitoring programme at Horns Rev. As a consequence, the monitoring programme established for the benthic infauna was reduced to enable only major changes in the community structure of the infauna. The monitoring programme included multivariate analysis of the combined input from each species with respect to biomass and abundance, which have increased the sensitivity of the statistical analysis considerably. A variance test (ANOVA) on logarithm transformed data was used for analysing differences in abundance and biomass for selected dominant and character species between surveys. The software package PRIMER was used for statistical analysis (Clarke & Warwick, 1994). A formal test for differences between sites was made for each subset using a nonparametric permutation procedure applied to the similarity matrix underlying the ordination. To evaluate the relative importance of the different species, the average contribution Doc. No. 2572-03-005 rev. 4
Horns Rev. Benthic communities Page 39 to the overall similarity within groups and the average contribution to the overall dissimilarity between groups were calculated for each species. Doc. No. 2572-03-005 rev. 4
Page 2 and 3: Published: Benthic Communities at H
Page 4 and 5: Horns Rev. Benthic communities Page
Page 88 and 89:
Horns Rev. Benthic communities Page
Page 90 and 91:
Page 92 and 93:
Page 94 and 95:
Page 96 and 97:
Page 98 and 99:
Page 100 and 101:
Page 102 and 103:
Page 104 and 105:
Doc. No. 2572-03-005 rev. 4 Appendi
Page 106 and 107:
Doc. No. 2572-03-005 rev. 4 2005 Me
Page 108 and 109:
Doc. No. 2572-03-005 rev. 4 2003-Au
Page 110 and 111:
Doc. No. 2572-03-005 rev. 4 2004-Au
Page 112 and 113:
Doc. No. 2572-03-005 rev. 4 2005-Au
Page 114 and 115:
Doc. No. 2572-03-005 rev. 4 2004 Sp
Page 116 and 117:
Doc. No. 2572-03-005 rev. 4 8.4.4.
Page 118 and 119:
Doc. No. 2572-03-005 rev. 4 2004-Sp
Page 120 and 121:
Doc. No. 2572-03-005 rev. 4 2005-Sp
Page 122 and 123:
Doc. No. 2572-03-005 rev. 4 8.4.5.
Page 124 and 125:
Doc. No. 2572-03-005 rev. 4 2005 Sp
Page 126 and 127:
Doc. No. 2572-03-005 rev. 4 2003-Au
Page 128 and 129:
Doc. No. 2572-03-005 rev. 4 2004-Au
Page 130 and 131:
Doc. No. 2572-03-005 rev. 4 2005-Au
Page 132 and 133:
Doc. No. 2572-03-005 rev. 4 2004 Sp
Page 134:
Doc. No. 2572-03-005 rev. 4 Horns R
show all

Benthic Communities at Horns Rev Before, During and After Con

Create successful ePaper yourself

Delete template?

Save as template?