Aquatic Prioritization and Mapping Tool
Data and Methods

The regional priorities and mapping tool presented here is a result of a multi-year process that included an extensive data collection, standardization, and analysis process as well development of the tool itself. The inputs into the tool and the prioritization modeling process include: Compilation of existing data for aquatic species of interest; review of existing climate change research pertaining to effects to aquatic species and determination of vulnerability to climate change at the 4th-field sub-basin scale; review of watershed condition mapping approaches and analysis of watershed condition at the 4th-field sub-basin scale; compilation of aquatic invasive species and development of methods pertaining to mapping invasibility at the 4th-field sub-basin scale, and; implementation of a decision support model, coupled with the development of the online tool. Each of these processes is briefly described below with links to more detailed documentation describing step-by-step methodologies.

Please see the data dictionary for a detailed list of data sources used in the prioritization process.

Focal fish species data development

Core to the prioritization process is the set of fish species for which we are prioritizing. As such, we included a wide variety of fish species distribution data in the tool, from wide-ranging, iconic northwest species to locally endemic fishes found in a single sub-basin. These data were collected from a variety of sources, at varying scales and units of analyses. See the detailed documentation on focal fish species for additional information.

Mapping of watershed condition

Healthy, functioning watersheds are essential for sustaining fish populations as well as fundamental ecosystem services. We relied on common indicators of watershed condition, including water quality and human disturbance, to classify the relative condition of each sub-basin. The relative watershed condition scores, if selected by the user in the prioritization process, will drive priorities toward less impaired sub-basins. We developed our watershed condition index based on an amalgamation of well vetted existing approaches. Please see the detailed documentation for a description of our approach to watershed condition mapping.

Climate change vulnerability analysis

Climate change has the potential to alter freshwater habitat in complex ways that we have yet to fully understand. These changes will greatly affect the health and distribution of fish species, particularly those adapted to cold water. To address these potential effects, we identified vulnerability to climate change based on projected changes in air temperature, stream flow regime, and wildfire risk. Areas that are relatively more vulnerable to climate change then are avoided (if possible) in the prioritization process when climate change vulnerability is considered. We have also provided several additional climate-related data layers for users to view separately from the prioritization process. See the detailed documentation on climate change vulnerability for additional information.

Aquatic invasibility analysis

The introduction of non-native species is a major threat to the biodiversity of aquatic ecosystems, second only to habitat loss from development. An understanding of current and potential invasion is essential for conservation planning efforts. In this tool, we modeled vulnerability to aquatic species invasion using current non-native species distribution, water quality, and the proximity to common sources of invasion. Please see the detailed description of our aquatic invasibility analysis for additional information.

Prioritization process

We used a multi-objective decision support model based on computational heuristics to identify regional priorities at the 4th field, sub-basin scale. The heuristic draws on a simulated annealing algorithm to approximate an optimal configuration (or prioritization schematic) given a mathematically defined set of objectives (referred to as an objective function). This target-based approach selects for a set of priority sub-basins avoiding those areas that have poor watershed condition, or are highly vulnerable to climate change effects or aquatic invasives. Please see the detailed description of the prioritization process for additional information.

Surrogate Species Module

The concept of surrogate species was adopted by the U.S. Fish and Wildlife Service (USFWS) as a strategic approach to attempt to protect / restore as many species as possible through focusing efforts on habitats associated with a small number of species. In this tool, a surrogate species module is available in the scenario output summary to a selection of USFWS staff. This module is designed for testing how well a prioritization scenario represents the habitats of all species included in the tool, by identifying the targeted and non-targeted species represented in the scenario. Please see the detailed description of the Surrogate Species Module for additional information.

Regional aquatic priorities

Once inputs and the prioritization model were incorporated into the tool, Ecotrust and USFWS developed the set of regional priorities. Using the tool, an array of priority scenarios were developed using varying levels of proportional goals for all species (please see detailed documentation on the prioritization process for a description of setting goal proportions and importance weighting). These goals were set equally for all species and were modified after each scenario was developed (starting with a goal proportion of 10% and incrementally increasing the goal to 100%). Because of the stochastic nature of the analytical process, multiple runs for each scenario are conducted. Watersheds that are selected in all runs are considered highly important for meeting the specified goals for each species. Watersheds selected in less runs are less important. Sub-basins with poor relative watershed condition, high relative climate change vulnerability, and high relative invasibility were all considered as constraints (i.e., these sub-basins were avoided if possible). After all scenarios were created, each resulting data layer was merged and an aggregate score representing the sum of the number of times any given sub-basin was selected for all model runs was used to create categories of the degree of relative prioritization. The following table represents the number of times any given sub-basin was selected and the respective priority category, the parameters of which were defined so as to contain an equal number of sub-basins.

Number of times
sub-basin was selected
Relative importance
0 - 26
low priority
27 - 43
medium low
44 - 59
60 - 79
medium high
80 - 100
high priority

These regional priorities are automatically loaded into the map viewer when the tool is launched, and can also be found on the "Data" tab under "Sub-basin priorities." You can click on each sub-basin in the map for additional information specific to the level of importance, sub-basin name and area and prioritization constraints such as watershed condition, vulnerability to climate change, and vulnerability to aquatic invasive species. The "Legend" tab shows the priority level associated with each sub-basin color.