Objectives

• Identify landscape-level habitat metrics associated with native fish presence in the Lower Colorado River Basin (LCRB).

• Develop a classification hierarchy for aquatic habitats for determining conservation areas

• Create an ecological risk index based on anthropogenic stressors; and maintain an online database on unpublished documents related to the LCRB.

Overview

Non-native introductions and habitat alteration have substantially changed the native fish fauna in the Lower Colorado River Basin. Identifying the areas that have the highest loss of native fish diversity (or highest increase in non-native fish diversity) can help identify areas that resource managers may focus on for conservation. Although anthropogenic activities often influence ecosystem processes and biotic communities, rarely are they integrated into conservation planning due to the difficulty in quantifying threats to biotic integrity. Over 1.5 million fish records have been collected and complied into a database. Various landscape-level habitat metrics and anthropogenic stressors have also been calculated. To date, all stressor and landscape level metrics have been summarized by catchment and upstream watershed. Stressor data are currently being related to fish metrics. The boundaries for the classification hierarchy have been completed and are under review by regional biologists. Ultimately, these data will be synthesized to allow land managers to set conservation priorities. This project is part of the national Aquatic Gap Analysis Program.