Spatial modeling
As aquatic and terrestrial habits and landscape conditions are altered at the regional and site specific scales, there is often a need to implement predictive approaches for estimating environmental conditions and the factors that effect these conditions. The results of predictive models may be used to effectively and efficiently guide land and habitat management and conservation strategies.
A spatial model is a simplified depiction of existing and or future ground conditions, which is formulated through the manipulation and analysis of geographic data into a computer simulation. In addition to describing existing and future ground conditions, spatial models are also useful in supporting an understanding of the existing relationships between geographic data. Spatial models may address a wide range of environmental scenarios including land suitability, erosion potential, habitat potential and watershed condition. The environmental variables that are considered by a spatial model are specific to the environmental issue(s) being examined by the model. Importantly, users should consider the fact that because spatial models integrate uncertainties, the results are capable of statistical errors and that the utilization of a spatial model often requires a deep understanding of the environmental issue in question, time and technical expertise.
One example of a spatial model and the implementation of this model is the California North Coast Watershed Assessment Program’s (NCWAP) use of the Ecological Management Decision Support (EMDS) (Reynolds 1999) system model to evaluate and synthesize data on watershed and stream conditions. Specifically, EMDS was used to help identify factors that limit the production of salmonid populations in California North Coast watersheds. The spatial nature of EMDS enabled NCWAP scientists to understand the relationships and interactions among limiting factors that occur throughout a watershed (for example, upslope and instream). The final products of EMDS is an overall watershed rating as well as detailed information about each of the individual factors that effected the overall rating. It is important to note that the EMDS products are intended to be used as one set of supporting materials in combination with additional materials and analysis to support the determination of salmonid limiting factors in North Coast watersheds. For more information on the NCWAP process and their use of EMDS, please visit http://www.ncwatershed.ca.gov/emds_overview.html.
