The coarse filter/fine filter approach centrally recognizes the need to conserve biological diversity in part by conserving the natural disturbance regimes that contribute to the diversity of any given landscape. However, ecosystems everywhere today face disturbances of both unusual patterns and types as a result of climate change, the introduction of chemical pollutants and non-native species, among others. Consequently, management plans must also address the need to conserve both the “resistance” and “resilience” in ecosystems. Resistance refers to the capacity of ecosystems to tolerate disturbances without exhibiting significant change in structure and composition. Resilience, in turn, refers to the ability of a system to recover from disturbance, if the disturbance exceeds the capacity of the system to resist changing at all (Holling 1973, De Leo, G. A., and S. Levin. 1997, Lindenmayer, D. and others, 2008).
The central tenet of an ecological integrity assessment is that ecosystems with greater ecological integrity, as defined here, will be more resistant and resilient to the effects of changing patterns and types of disturbance (Parrish, Braun et al. 2003).
The concept of ecological integrity, associated measurement and monitoring approaches, and other closely related topics are addressed in more detail in Chapter 8.