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

Abstract

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. 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. 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 re‐assessing 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.

Synergistic impacts of aggressive species on small birds in a fragmented landscape

“…For example, structurally complex vegetation can mitigate the impacts of introduced predators on native animals, meaning that restoring complex vegetation—or suppressing fire—can help prey species to persist despite high predator densities (Doherty et al., 2015). Interventions that target interacting threats therefore have the potential to markedly affect the progress of biodiversity loss in fragmented ecosystems (Lindenmayer et al., 2020; Newmark et al., 2017).…”

Forest restoration in a time of fire: perspectives from tall, wet eucalypt forests subject to stand-replacing wildfires

“…logging) influences another (fire) through elevating forest flammability [41]. Such feedbacks between drivers have the potential to make restoration increasingly difficult and push ecosystems closer to collapse [16]. Indeed, in some cases, the impacts of multiple, interacting drivers may trigger forest ecosystem collapse and transition to another ecosystem type.…”

“…(ii) Improved fire detection and suppression Some forested ecosystems are burning more severely, extensively or frequently than previously occurred under natural fire regimes [13,21,84]. These include tall, wet temperate forest ecosystems in Australia [16] and some boreal and temperate forests in North America and northern Asia [21,84]. Efforts to limit such fire effects may be aided by new technology like fleets of drones and satellite sensors for rapid detection of human and lightning-generated ignitions, and the application of autonomous aerial vehicles for targeted fire suppression [85].…”

“…Forest restoration in these ecosystems entails reversal of drivers of disturbance that have led to widespread loss of stand structure, historically low levels of old growth cover, and rapid biodiversity decline [15]. These changes are set against a background of increasing forest flammability, increasingly frequent high-severity wildfire and shifts in climate [16]. We emphasize here that, in mountain ash and alpine ash ecosystems, forests have been degraded (such as through the loss of old growth forest, large living and dead standing trees and fallen logs), as has occurred within forests in many other parts of the world [7].…”

Kuala Lumpur Green Space Fragmentation Index Analysis and Green Corridors Suggestion using Geographic Information System

“…Due to large-scale land clearances, studies on the connectivity of green spaces have increased (Lindenmayer et al, 2020) and have become a challenging issue, especially since the early 21st century (Cobbinah et al, 2015). Connectivity studies involve establishing corridors to connect one area or space to another, addressing landscape changes (Haas and Ban, 2014).…”