Managing interacting disturbances: Lessons from a case study in Australian forests

Abstract

1. Ecosystems are shaped by a range of drivers including human and natural disturbances. They also may be subject to interactions between disturbances which can affect ecological processes, biodiversity and ecosystem condition; yet few ecosystems have been subject to multiple studies of the effects of interacting disturbances. This limits the understanding of ways to mitigate the impacts of interacting disturbances. 2. Over the past 37 years, we have completed a range of studies of interacting effects in the Mountain Ash Eucalyptus regnans forests of south-eastern Australia. Here we summarize evidence for interacting disturbances in this ecosystem. This includes evidence of linked or coupled disturbances (termed interaction chains; sensu Foster et al., Global Change Biology, 22, 2016, 1325) between logging and subsequent fire severity. We also describe effects of other interacting disturbances such as those resulting from post-fire (salvage) logging as well as landscape-level, spatio-temporal changes in forest cover associated with logging and wildfires. 3. Policy implications. Insights from research in Mountain Ash forests provide broader lessons for managing interacting disturbances in forest ecosystems. These include the importance of cataloguing and mapping multiple disturbances in both space and time and developing conceptual models of ecosystem dynamics and ecological processes. Where there is a high risk of interactions between disturbances, appropriate management actions could include: (a) eliminating some drivers or reassessing levels of human extraction of resources, (b) reducing the spatial and/or temporal overlap of drivers and (c) identifying leverage points where management actions are most likely to be effective.