The most important layer in Ecospace is the Depth layer that specifies which cells have ecosystem dynamics, and which do not. As EwE is mostly used in aquatic environments, the Depth layer uses the monikers Land to indicate cells of depths 0 where no ecosystem dynamics take place, and Water cells with positive depth values where ecosystem dynamics take place. The terms Land and Water are only labels, and can be interpreted freely to build terrestrial or mixed terrestrial/aquatic Ecospace models. Depths are implicitly expressed in meters, but any unit can be used as long as environmental response functions to depth relate to the same scales.

EwE version 6.5 and newer feature an Excluded cells layer, which indicates cells that do not have ecosystem dynamics without having to turn these cells to land: this permits to keep the Ecospace map topography intact while running Ecospace in a part of the Water domain (e.g., excluding some shallower areas or enclosed coastal ponds from model dynamics, or areas that fall outside of the model domain of a hydrodynamic model that feeds environmental output into Ecospace through the Spatial Temporal Framework).

Ecospace does not explicitly consider dynamics within the water column; besides indicating cells with ecosystem dynamics, positive depth values are used for generating recognizable maps and can be used for constraining functional groups to specific depth ranges via the HFC model (e.g. benthic, demersal, pelagic groups). Ecospace can implicitly represent the main impacts of depths without the computational overhead of explicitly representing the water column with a 3D model domain by: (a) stratifying food-web components to different depth ranges, (b) making specific groups reliant on specific types of substrate or sensitive to environmental drivers aggregated over specific depth ranges (e.g., demersal fish being driven by bottom layer temperatures), and (c) implicitly parameterizing the Ecopath diet matrix to account for life at specific depths.

Adaption

The chapter is in part adapted, with permission,  from:

De Mutsert K, Marta Coll, Jeroen Steenbeek, Cameron Ainsworth, Joe Buszowski, David Chagaris, Villy Christensen, Sheila J.J. Heymans, Kristy A. Lewis, Simone Libralato, Greig Oldford, Chiara Piroddi, Giovanni Romagnoni, Natalia Serpetti, Michael Spence, Carl Walters. 2023. Advances in spatial-temporal coastal and marine ecosystem modeling using Ecopath with Ecosim and Ecospace. Treatise on Estuarine and Coastal Science, 2nd Edition. Elsevier.