摘要：The emerging perspective of ecosystems as both non-equilibrium and dynamic fits aquatic ecosystems as well as terrestrial systems. It is increasingly recognized that watersheds historically passed through different conditions over time. Habitat conditions varied in quantity and quality, primarily as a function of the time since the last major disturbance and the legacy of that disturbance. Thus, to match the effects of historical processes, we would expect a variety of conditions to exist across the watersheds in a region at any time. Additionally, watersheds have different potentials to provide habitat for given fish species because of variation in physical features. This developing ecological understanding is often preempted by social desires to bring all watersheds to a “healthy” condition, which in turn is reflected in a common regulatory approach mandating a single condition as the long-term goal for all watersheds. Matching perceptions and regulations to the way aquatic systems actually change and evolve through time will be a major challenge in the future.
关键词：aquatic ecosystems; legacy of disturbance; non-equilibrium ecosystem dynamics
