Conservation Assessment for Native Fish in the Upper Colorado River Basin

Fishes of the Upper Colorado River Basin have one of the highest levels of endemism in the United States. The range and abundance of these fish has declined over the last century and continues to decline as a result of legacy impacts from past management practices, current water management, interactions with non-natives, and other impacts. We applied a complementarity-based approach to develop priority ranks (0 – 1; low to high) for catchments in the Upper Colorado River Basin. We used methods and a framework that we had previously developed for the Lower Colorado River Basin so both basins could be integrated into a cohesive unit. Our approach incorporated an anthropogenic threat index, fish species distribution models, and other metrics (i.e., habitat fragmentation, non‐native species richness) potentially impacting conservation value of the riverscape. The intent was to provide an ecologically-based conservation assessment using the distribution of native fish species and the threats to persistence that could be used by land managers in the decision-making process to strategically place conservation efforts. Potential uses are: a) identify focal conservation areas, b) identify conservation strategies (e.g., non-native removal, habitat restoration, native species reintroduction, land protection), and c) compare/contrast factors influencing the conservation value.