1 Hydrobiologia

2

3 A spatial approach to matching species richness and abundance with habitat features

4

5 Chouinard, P.-M.1, J.-D. Dutil, S. Proulx, D. Borcard2, J. Crocker

1 1 Corresponding author [email protected], Phone 418-721-0288 2 2 Département des sciences biologiques, Université de Montréal, C.P. 6128, succursale Centre-ville, 3 Montréal, Québec, Canada H3C 3J7 6 Supplementary material 7 8 9 Figure 1. Undersea features of the Gulf of St. Lawrence. Depth >200 m: Laurentian

10 Channel, Anticosti Channel, Esquiman Channel. Depth <200 m: Gaspe Shelf, North Shore

11 Shelf, Anticosti Shelf, Beaugé Bank, Newfoundland Shelf, Magdalen Shelf, Miscou Bank,

12 Mécatina Trough, Chaleur Bay Trough, Shediac Valley Trough, Cape Breton Trough,

13 Bradelle Troughs. The northern region is separated from the southern Gulf by the 200 m

14 isobath (black line). The southern features are drawn approximately. 15 Cluster analysis

16 List of 25 variables describing the results of the spatial analysis of plaice data (2002–2010).

17 These variables were used as cell descriptors in the cluster analysis. Each cell was also

18 ascribed to one of 12 megahabitat categories as described in Dutil et al. (2011) and

19 megahabitat categories were considered as samples in the analysis (megahabitat "F",

20 representing only 6 coastal cells, was excluded).

21  Variables based on relative occurrence 22 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 23

24  Variables based on abundance 25 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

26

27 SRT and MRT

28 List of variables used in the simple (SRT) and multivariate (MRT) regression tree analysis.

29 Regression trees were used to identify groups of cells on the basis of landscape-

30 oceanographic variables (adapted from Dutil et al. 2011) and American plaice

31 abundance (SRT) or the abundance of 70 fish species (MRT). The habitat descriptors

32 are listed below.

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34  Quantitative and continuous variables 35 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 36

37  Categorical variables 38 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 39 40 Dutil, J.-D., S. Proulx, P.-M. Chouinard & D. Borcard, 2011. A hierarchical classification of the

41 seabed based on physiographic and oceanographic features in the St. Lawrence. Canadian

42 technical report of fisheries and aquatic sciences 2916:vii + 72 pages.