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Published byCalvin Lucas Modified over 9 years ago
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Swath surveys
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Linking Swath to UPC 10 points counts Species, Substrate, Relief Section 1Section 2Section 3Section 4Section 5Section 6
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Example Cable distance SideSectionSubstrate%Relief%UPC species %Swath Species counts 110Deep1Bedrock20F30Branchy Red 10Macrocystis2 110Deep1Boulder40S10Leafy Red 10Cystoseira6 110Deep1Cobble10M30Cup corals 0Patiria5 110Deep1Sand30H Sponge0Pisaster2 More
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Analytical approach
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1. Set up a raw data matrix Species12345etc. Transect/Section S 110, 1 540050 S 110, 2 371040 S 110, 3 682020 S 110, 4 600001 S 110, 5 470020 S 110, 6 600000 etc.
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2. Calculate a dissimilarity (Bray-Curtis) matrix S 110,1 S 110,2 S 110,3 S 110,4 S 110,5 S 110,6 etc. S 110,1.000 S 110,2.203.000 S 110,3.666.652.000 S 110,4.216.331.759.000 S 110,5.328.410.796.191.000 S 110,6.336.432.796.183.054.000 etc.
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Linking biological communities to other communities or environmental variables Are differences in species composition related to differences in other communities or to associated environmental variables?
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BIO-ENV procedure Samples Species abundances Env variables Euclidean Bray-Curtis Subsets of variables Rank correlation - Spearman - Weighted Spearman Similarity/Dissimilarity matrix
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Swath Matrix UPC Species Matrix UPC Habitat Matrix = 110, 1 vs 110, 2 Cable distance, section
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SAMPLE1SAMPLE2HABITATUPC SpeciesSwath Species 100Deep1100Deep226.4575131145.6466020826.75672112 100Deep1100Deep342.4264068732.12078841.53649771 100Deep1100Deep426.4575131162.8397017330.77990704 100Deep1100Deep533.166247948.0998497444.91068164 100Deep1100Deep628.2842712550.1552227835.84000683 100Deep1100Shallow13056.116854849.60762989 100Deep1100Shallow258.3095189552.0316686460.18648399 100Deep1100Shallow326.4575131171.7239838343.14766078 100Deep1100Shallow422.3606797763.2747286954.24428506 100Deep1100Shallow553.8516480761.0748873173.81040148 100Deep1100Shallow642.4264068757.5859757554.99411833 Dissimilarity Habitat dissimilarity Swath Species Dissimilarity ?
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Habitat dissimilarity Swath Species Dissimilarity UPC species dissimilarity Prediction Habitat dissimilarity Swath Species Dissimilarity UPC species dissimilarity Null Hypothesis
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If there is a match Look at specific species to determine if associations make sense – For example: is Macrocysitis found in sandy habitats – Species selected Marcrocystis and Cystoseira Balanus nubilus and Styela Cryptochiton and Lithopoma Patiria and Pisaster giganteus
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Questions to be addressed Is there an association between Swath species composition and (1) UPC species composition and/or (2) habitat attributes? – This needs to be motivated in intro and discussed in discussion. Why would we be interested in this question? Why is it important? What would you predict? Do the associations differ in relative strength? – This needs to be motivated in intro and discussed in discussion. What is the essential question here? Is there a basis for a prediction? For select species are there a set of strong associations/dis- associations and do these make sense? – This needs to be motivated in intro and discussed in discussion. Can you make predictions? Why would we care about this?
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