Ecospace: Who’s Eating Whom, When, and Where?
Ecospace is a dynamic, spatial version of Ecopath, incorporating all key elements of Ecosim. It relies on benthic habitat information derived from a geographic information system and explicit links between biomass groups and preferred habitat types. With the already established values of fishing, trophic and physical interactions in Ecopath and Ecosim, Ecospace allows the user to establish species-habitat associations, rates of dispersal and migration as well as examine how spatially-located marine managed areas affect biomasses through time. It works by dynamically allocating biomass across a user-defined grid map while accounting for:
- Symmetrical movements from a cell to its four adjacent cells modified by whether a cell is defined as “preferred habitat” or not
- User-defined increased predation risk and reduced feeding rate in non-preferred habitat
- A level of fishing effort that is proportional, in each cell, to the overall probability of fishing in that cell, and whose distribution is sensitive to spatial fishing costs
Ecospace allows users to explore the potential role of Marine Protected Areas (MPAs) and other spatially-explicit policies as tools to manage fisheries and the various ecosystem effects of fishing.
The first step in aligning the Pacific Northwest Coast ecoregion database with Ecospace was to import our stratification units (also called subregions) directly into the model. In this way we could readily compare output from Marxan and Ecospace for each subregion.
The actual spatial information exchange between Marxan and Ecospace consisted of importing Marxan solutions, or potential conservation priority areas, as Ecospace protected areas. This is illustrated in the second example in Putting it Together. These imported solutions allowed us to examine biomasses in and outside of these proposed protected areas within each subregion.
It is important to note that although Ecospace primarily refers to these proposed protected areas as MPAs, the model allows the user to examine multiple management schemes within these areas. Therefore this information exchange furthers the utility of regional assessments that recognize other strategies must be implemented beyond MPAs to ensure that biodiversity conservation objectives are met.