An individual landscape prioritization tool is a landscape metric or index that generates an output corresponding to one or more prioritization objectives based on a set of data factor inputs. As defined here, landscape prioritization tools are GIS-based approaches for identifying priority sites for aquatic resource restoration or protection based on EPA's "Level 1" condition assessment approach. The two types of landscape prioritization tools evaluated in this study included single-objective and multi-objective tools.
Single-objective tools integrate a set of input factors to derive an output representing a singleprioritization objective (Figure 1). Eighty-three of the 115 tools examined in this study were single-objective tools.
Figure 1. Single-objective tools integrate multiple input factors to produce a prioritization output that evaluates a single prioritization objective.
Multi-objective tools integrate multiple input factors as part of their analysis like single-objective tools. However, the prioritization output obtained using a multi-objective tool represents multiple prioritization objectives (Figure 2). Thirty-two of the 115 tools examined in this study were multi-objective tools.
Figure 2. Multi-objective tools integrate multiple input factors to produce a prioritization output that evaluates multiple prioritization objectives.
A subset of multi-objective tools combines outputs of other single- and multi-objective tools to produce an output representing multiple objectives ( Figure 3 ). For example, the Kramer et al. (2012) Potential Wetland Bank Site Index combines outputs from several other tools, such as the Kramer et al. (2012) Connectivity to Existing Conservation Lands Tool (which itself prioritizes for habitat quality and social values) to assess prioritization objectives that include habitat quality, water quality, flood mitigation, feasibility of restoration, and social values.
Figure 3. A subset of multi-objective tools integrate input factors that include the prioritization outputs of other prioritization tools to obtain a multi-objective output.