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Hydrobiologia
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A spatial approach to matching species richness and abundance with habitat features
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Chouinard, P.-M.1, J.-D. Dutil, S. Proulx, D. Borcard2, J. Crocker
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Corresponding author pchouinard1@hotmail.com, Phone 418-721-0288
Département des sciences biologiques, Université de Montréal, C.P. 6128, succursale Centre-ville, Montréal,
Québec, Canada H3C 3J7
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Supplementary material
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Figure 1. Undersea features of the Gulf of St. Lawrence. Depth >200 m: Laurentian
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Channel, Anticosti Channel, Esquiman Channel. Depth <200 m: Gaspe Shelf, North Shore
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Shelf, Anticosti Shelf, Beaugé Bank, Newfoundland Shelf, Magdalen Shelf, Miscou Bank,
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Mécatina Trough, Chaleur Bay Trough, Shediac Valley Trough, Cape Breton Trough,
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Bradelle Troughs. The northern region is separated from the southern Gulf by the 200 m
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isobath (black line). The southern features are drawn approximately.
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Cluster analysis
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List of 25 variables describing the results of the spatial analysis of plaice data (2002–2010).
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These variables were used as cell descriptors in the cluster analysis. Each cell was also
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ascribed to one of 12 megahabitat categories as described in Dutil et al. (2011) and
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megahabitat categories were considered as samples in the analysis (megahabitat "F",
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representing only 6 coastal cells, was excluded).
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Variables based on relative occurrence
Number of cells in which the species occurred, expressed as a proportion of the total number
of cells in that megahabitat
Number of cells with more than 50% of their planimetric area located within the 90% kernel
density contour line and outside of the 50% volume contour, expressed as a proportion of the
total number of cells in that megahabitat
Subset of the above including only cells in which the species occurred
Number of cells with more than 50% of their planimetric area located within the 50% kernel
density contour line, expressed as a proportion of the total number of cells in that megahabitat
Subset of the above including only cells in which the species occurred
Proportion of cells classified as cold spots (negative Gi* score significant at =0.10
Subset of the above including only cells in which the species occurred
Proportion of cells classified as hot spots (positive Gi* score significant at =0.10
Subset of the above including only cells in which the species occurred
Mean Gi* score
Subset of the above including only cells in which the species occurred
Mean relative occurrence
Subset of the above including only cells in which the species occurred
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Variables based on abundance
Number of cells with more than 50% of their planimetric area located within the 90% kernel
density contour line and outside of the 50% volume contour, expressed as a proportion of the
total number of cells in that megahabitat
Subset of the above including only cells in which the species occurred
Number of cells with more than 50% of their planimetric area located within the 50% kernel
density contour line, expressed as a proportion of the total number of cells in that megahabitat
Subset of the above including only cells in which the species occurred
Proportion of cells classified as cold spots (negative Gi* score significant at =0.10
Subset of the above including only cells in which the species occurred
Proportion of cells classified as hot spots (positive Gi* score significant at =0.10
Subset of the above including only cells in which the species occurred
Mean Gi* score
Subset of the above including only cells in which the species occurred
Mean abundance (based on sets with catch > 0)
Subset of the above including only cells in which the species occurred
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SRT and MRT
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List of variables used in the simple (SRT) and multivariate (MRT) regression tree analysis.
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Regression trees were used to identify groups of cells on the basis of landscape-
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oceanographic variables (adapted from Dutil et al. 2011) and American plaice abundance
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(SRT) or the abundance of 70 fish species (MRT). The habitat descriptors are listed below.
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Quantitative and continuous variables
Surface area of sheltered environment
Surface area of semi-exposed environment
Distance from the coast
Mean cell depth
Variability in cell depth
Minimum cell depth
Maximum cell depth
Mean slope of the seafloor
Variability in slope of the seafloor
Minimum slope of the seafloor
Maximum slope of the seafloor
Surface area of humps
Surface area of pits
Mean annual salinity at mean cell depth
Minimum monthly salinity at mean cell depth
Maximum monthly salinity at mean cell depth
Mean annual salinity at minimum cell depth
Minimum monthly salinity at minimum cell depth
Maximum monthly salinity at minimum cell depth
Mean annual salinity at maximum cell depth
Minimum monthly salinity at maximum cell depth
Maximum monthly salinity at maximum cell depth
Mean annual temperature at mean cell depth
Minimum monthly temperature at mean cell depth
Maximum monthly temperature at mean cell depth
Mean annual temperature at minimum cell depth
Minimum monthly temperature at minimum cell depth
Maximum monthly temperature at minimum cell depth
Mean annual temperature at maximum cell depth
Minimum monthly temperature at maximum cell depth
Maximum monthly temperature at maximum cell depth
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Categorical variables
Diversity of megahabitats
8 classes
Variability of the relief
9 classes
Dissolved oxygen class
4 classes
Landscape category
3 classes
Soft sediments (relative size)
4 classes
Presence of rock outcrops
2 classes
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Dutil, J.-D., S. Proulx, P.-M. Chouinard & D. Borcard, 2011. A hierarchical classification of the
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seabed based on physiographic and oceanographic features in the St. Lawrence. Canadian
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technical report of fisheries and aquatic sciences 2916:vii + 72 pages.