Chapter 11. Inherent Disturbance Regimes

Summary A science-based ecosystem management approach requires valid reference points to assess the long-term maintenance of forest systems. Historical range of variability (HRV) in vegetation patterns has served as the initial reference point and has support in the coarse-filter approach to conserving biodiversity (Hunter 1991). The HRV becomes less useful as a reference with increasing human disturbance on the landscape, public aversion to treatments to restore historical states, and continued public expectations for non-historical conditions. The inherent disturbance regime (IDR) is put forward as an alternative or to be used in combination with HRV as a suitable reference point for evaluating long-term maintenance of human-altered ecosystems. The IDR is defined by the types of disturbance; their frequency, intensity, and extent in turn defines the vegetation composition and structure supported over time. Although public expectations for vegetation conditions may differ from historical, these altered s...