Aquatic Conservation Strategy of the Northwest Forest Plan 20 Years Later: Using a Nearest Neighbour Approach to Assess Changes in Watershed Condition

The Aquatic Conservation Strategy (ACS) of the Northwest Forest Plan (NWFP) is a regional strategy designed to restore and maintain ecological processes for aquatic and riparian areas across federal lands within the range of the northern spotted owl. ACS was designed, in the short term, to protect watersheds in good condition and, long term, to develop a network of watersheds able to support aquatic organisms broadly across the plan area. We evaluated stream monitoring data using a nearest neighbor reference condition approach that defined site level expectations based on a minimally managed reference network of environmentally similar sites. In the 20 years since the inception of the strategy, physical habitat watershed condition changed little, while modest improving trends were detected for water temperature and macroinvertebrates. Watershed condition was highest in areas with the most broad scale land-use protections offered by the NWFP. These results were consistent with expectations as changes were not expected for several decades. In the end, if we hope to understand expectations from the local level we must understand changes in the broad extent. Substantial baseline data and evaluation tools exist to continue to assess longer-term broad-scale changes that drive ecosystem level processes across these federal lands.