Case studies of successful adaptive management generally focus on examples that have frameworks for adaptive management embedded from project conception. In contrast, this paper outlines an example of emergent adaptive management. We describe an approach whereby targeted research and collaboration among stakeholders assisted learning, and ultimately the development of interim operational guidelines for increased within-channel flow variability in the highly regulated Mitta Mitta River, which is managed as part of the River Murray System in the Murray–Darling Basin, Australia. Environmental monitoring of four variable flow trials evaluated the response of water column microbial activity, benthic and water column metabolism, the structure and composition of algal biofilms, and benthic macroinvertebrates to increased flow variability created by varying the release from Dartmouth Reservoir. Each trial built upon lessons from previous trials, with collaboration among key stakeholders occurring before, during and after each trial. Institutional conditions encouraged a shift to adaptive management over time that helped to achieve environmental, social and economic objectives downstream of the dam. A key lesson is that adaptive management does not have to be specified a priori, but can emerge within a trusting relationship between stakeholders as long as they are willing and able to change their operational paradigm.
In this chapter we reflect on a relatively small but influential example of adaptive management which seeks to enhance the environmental benefits of the flow regime in the highly regulated Mitta Mitta River in Australia's MurrayDarling Basin. In 1999 an operational review recommended the reintroduction of greater in-stream flow variability in the Mitta Mitta River in an attempt to improve river health. The river managers have worked towards this through managed variable releases from Dartmouth Dam. These variable releases have been trialled four times from [2001][2002][2003][2004][2005][2006][2007][2008], with the explicit intention of learning more about the ecological impacts of variable flows while still achieving operational goals for the River Murray System overall. The ecological impact of the variable releases was studied via a series of consultancies by a University freshwater ecology team. They concluded that variable flow improved ecological condition compared with the condition after periods of relatively constant flow for greater than 1 month, although the benefits of it are relatively short-lived. Principles were developed over time through discussions between river managers and the research team. These principles are being progressively refined and incorporated into the current operational plan for the river, and learning continues. We suggest that three key ingredients enabled and supported adaptive management in this particular case; aspects of the operational context, the people involved and the trusting relationships that developed.
IntroductionHumans have substantially altered landscapes across the globe, generating novel ecosystems with varying states of modification. The principles of reconciliation ecology emphasise that such novel ecosystems must also be considered for conservation outcomes. This requires an understanding of how anthropogenic habitat alterations in a novel ecosystem may disrupt life cycle processes of key biota, thereby enabling the development of management strategies that may bypass or ameliorate potential bottlenecks in life history stages. We explore this by assessing Murray cod (Maccullochella peelii), a native fish species of considerable cultural, recreational and conservation significance in a severely altered river reach in south-eastern Australia. This species was considered to have disappeared in the reach following alterations to the river’s thermal profile (cold water pollution - CWP), but instead has persisted.MethodsWe examined the life cycle of Murray cod and use multiple lines of evidence to assess the impacts of CWP pollution on key processes such as adult migration, recruitment and juvenile survival. We also evaluated the potential for recovery and persistence of the species in this novel system using mitigation measures such as flow management and stocking and opportunistically tested their effectiveness.ResultsWe found the key impact pathway of CWP on the Murray cod population is via its effects on the key processes influencing natural recruitment. Conversely, the effects of CWP on emigration and survival of larger juveniles and adults did not appear to be a major bottleneck for the population. Using a stochastic population model, we showed that the population could be sustained by stocking and opportunistic water management while still meeting irrigation demands. Monitoring to test our recommendations showed natural recruitment and improved survival of stocked fish during years with limited flow releases, thereby corroborating our predictions.DiscussionOur use of multiple lines of evidence to assess a species’ responses to impacts of habitat alteration in a novel ecosystem enabled the formulation of recommendations for management that could then be tested. The success of such actions add to the growing body of literature that shows species of conservation significance can be maintained in novel ecosystems which should be specifically considered within the context of conservation planning across the landscape.
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