Predictive relationships between seabed species & environment Roland Pitcher, GBR Roland Pitcher, GBR Peter Lawton, GoMA Peter Lawton, GoMA Lew Incze, GoMA Lew Incze, GoMA Stephen Smith, DFO, Can Stephen Smith, DFO, Can Nick Ellis, CSIRO, Aus Nick Ellis, CSIRO, Aus Tom Shirley, GoMEX Tom Shirley, GoMEX Chin-Lei Wei, Comarge/GoMEX Chin-Lei Wei, Comarge/GoMEX Main contact: Roland Pitcher

Objectives: For defined seabed “biological patterns” (individ. species, multi-species assemblages, and some diversity attributes) sampled over mesoscales: 1.Examine extent to which physical surrogates may explain biological patterns; 2.Rank importance of physical variables for structuring biological patterns; 3.Examine common biological responses to physical gradients; 4.Identify critical values for physical variables corresponding to 'threshold' changes Key Approaches: Bootstrapped randomized tree-based method Scope of analysis: GBR: Databases available (sled and trawl sampling/28 physical environment variables); prior development of statistical approach and simulations. GoMA: Benthic invertebrate database of Theroux & Wigley (1998) being cleaned; coverages of physical datasets for Gulf of Maine being pursued. GoMEX: Databases for 4 largest surveys of continental shelf benthos collated; accompanying oceanographic & physical data being pursued. Comarge: Deep GoMEX Biodiversity project already has suitable biological and physical databases in place Still open to discussion with other programs Still open to discussion with other programs

1 2 3 A 4 A 1.Biomass distribution for 1 sp displayed on coverage of % mud 2.Single tree model for same sp (build randomized forest of 1000’s) 3.“Importance” weighted split points and data frequency for two physical variables (A: mud; B: benthic stress) for 10 spp. 4.Cumulative distribution of weighted splits for same variables 3 B 4 B

5. Pattern of biological change-response on the top 8 physical gradients for 90 species, scaled by aggregate variable importance  Transform to ecological gradients to characterise (map) region directly from physical surrogates…  Compare/contrast/accumulate across Programs… 5

Planned timelines Oct 2008: First workshop (Halifax, NS, Canada) Feb – March, 2009: Final collation, simulations and statistical analyses April 1, 2009: key analytical results & emerging synthesis points to Paul Snelgrove Late April – early May, 2009: Team workshop, Saint Andrews, NB, Canada or Portland, ME, USA Mid April – mid July: Roland Pitcher on sabbatical in Canada Mid August: draft manuscript for publication Planned outputs: Cross-region Synthesis paper, other papers (technical, within region, detailed)