The PACFISH/INFISH Biological Opinion (PIBO) Effectiveness Monitoring Program and Invasive Plant Species Detection: A Retrospective Summary 2003-2011

Abstract

Invasive species pose a serious threat to aquatic and riparian habitats around the world. Inherently, invasive species detection and monitoring are an integral part of a robust riparian monitoring program. Within the Interior Columbia River and Upper Missouri River Basins, invasive species have the potential to alter and degrade riparian areas within steelhead (Oncorhynchus mykiss) and bull trout (Salvelinus confluentus) habitat. The USDA Forest Service’s PACFISH/INFISH Biological Opinion Effectiveness Monitoring program (PIBO) is tasked with assessing the integrity of riparian and in-stream habitat that supports these and other fish. We report the PIBO vegetation program’s biological invasion detections for study years 2003-2011 to highlight current and potential threats to riparian resources. We compiled stream locations with at least one invasive weed occurrence and assessed invasion richness and intensity. We report the proportion of reaches invaded based on their management classification (reference, managed for natural resources or designated grazing monitoring areas), and mapped invasive plant richness within each PIBO reach. We conclude that current riparian condition and vegetation communities within the Columbia and Missouri River Basins have been altered by biological invasions and that these invasions may threaten long-term ecosystem integrity within the PIBO study area.