Initial Evaluation of Potential Options for Managing Riparian Reserves of the Aquatic Conservation Strategy of the Northwest Forest Plan.

摘要

The Aquatic Conservation Strategy (ACS) of the Northwest Forest Plan guides management of riparian and aquatic ecosystems on federal lands in western Oregon, western Washington, and northern California. We applied new scientific findings and tools to evaluate two potential options, A and B, for refining interim riparian reserves to meet ACS goals and likely challenges of climate change while supporting other management goals, including timber production. Interim riparian reserves are retained in late-successional reserves and other special land designations in the options. In lands designated as matrix, the area for aquatic conservation extends upslope one site-potential tree-height along all streams, divided into an inner zone devoted solely to achieving ACS goals and an outer zone managed to achieve ACS and other goals. Option A uses a fixed-width approach and option B a context-dependent approach, with partitioning of zones based on the ecological sensitivity of stream reaches. Based on simulations of the area of interim riparian reserves in six watersheds in western Oregon with lands managed by the Bureau of Land Management (BLM): (1) about 76 percent under option A and 72 percent under option B remain solely devoted to ACS goals; (2) 15 percent under option A and 19 percent under option B should be able to meet ACS goals and also contribute toward matrix goals such as timber production; and (3) 9 percent would be returned to matrix. A large percentage of streams with high ecological sensitivity occurred on nonfederal lands, a circumstance that merits further analysis in the context of landscape-scale considerations for biodiversity and recovery of species listed under the Endangered Species Act. Information needs remain with regard to the application and effectiveness of these options, and an adaptive management context is critical for continued improvement.