Impact Assessment Methods
This online system dynamically calculates the impact of each scenario on each species. This is done using a straightforward map overlay approach.
- We combine habitat presense/absence maps for each species with scenarios. In technical terms, we code habitat presence as a raster grid with value 1, and absence as 0. We then multiply this with a categorical raster of land use change. The resulting grid represents the "exposure" of habitat to change.
- Next, we characterize the impacts of the change. In this study, we consider "development" of any kind and habitat change from sea level rise to be a uniform negative impacts on species habitat. Similarly, we consider public and private "conservation" of any kind to be a uniform positive. Said another way, we do not distinguish levels of impact, or quality of conservation and restoration practices.
- Lastly, we summarize impacts by geographic summary areas. These can include watersheds, counties, parcels, or arbitrary sampling units such as hexagons and grids. Based on stakeholder feedback, we have selected a simple uniform grid as the summary unit for this study. The number of acres of positive and negative habitat change are then summarized for each geography.
- Summary reports are generated highlighting the "top 3" conservation and impact areas in each scenario. Tables showing comprehensive impacts for all areas are also generated, but for brevity are collapsed by default.