Key words: drought, refuge, native fish, Native Fish Strategy
Threats and Impacts: From 1996 to 2009, the Murray-Darling Basin (MDB) experienced severe drought conditions. As the impacts of the drought worsened, the need for improved and co-ordinated management responses became increasingly important to protect key ecological assets and critical aquatic habitats and ecosystems. Within the MDB it was uncertain whether an adequate network of drought refuges (e.g. flowing perennial river reaches, deep waterholes) remained to preserve native fish species/populations through extended drought. This project was established to address this knowledge gap.
Aims: The broad aims of the project were to:
- define, identify and explore the current status and management of drought refuges in the MDB (Figs 1 and 2); and,
- develop guidelines and an approach to identify, prioritise and protect drought refuges for native fish that can be implemented across the MDB.
Methods: The current status and management of refuges were explored using a number of techniques including questionnaires, an expert/management workshop and a review of relevant literature and management programs. This process identified the types of habitats that serve as drought refuges across the MDB, the key native fish species that have been targeted for protection under drought response programs, key threats and the current management responses/actions undertaken for refuge protection. In order to catalogue refuge sites, a preliminary list of critical sites was developed in collaboration with managers and experts.
An approach to identify and protect refuges was developed in conjunction with regional agencies and jurisdictions from two pilot valleys: the Goulburn Broken catchment in northern Victoria and the Moonie catchment in south-eastern Queensland. Under this phase of the project, definitions and criteria for identifying and prioritising refuges were developed in conjunction with management agencies. A management tool was developed for collating refuge values and habitat attributes, as well as threats to the maintenance and improvement of these important characteristics. This approach may be used for the prioritisation of interventions based on key management principles, including: threatened species, protection of habitat biodiversity, water allocation, catchment management actions, fisheries management actions and restoration.
Based on the information elicited from the pilot valley analyses, a template was produced to assist in refuge identification and management across the MDB. This template documents a process that can be integrated into regional natural resource management frameworks across the MDB, acknowledging that different states and regions are subject to various legislative and policy environments and possesses varying levels of information, data, planning structures and intervention opportunities that relate to aquatic habitat protection.
Findings: A wide range of aquatic habitats were considered important as drought refuges, with unregulated waterways the most commonly identified habitat type, and of the greatest concern to managers. In some instances, key native fish species were used to identify particular drought refuges. The protection and/or management of the refuges for these species either followed a ‘single species’ approach (more common in the drier, southern MDB) or ‘multi-species/community’ approach (more common in the northern MDB).
Refuges were defined and identified at larger spatial scales in the northern MDB and at smaller, site-specific scales in the southern MDB. The reason for these different approaches reflects the varying intensity of drought impacts across the MDB. These different approaches to the management and protection of drought refuges reflect the different aspects of native fish ecology, in terms of resistance versus resilience.
This study concluded that a holistic approach to drought management was required with drought refuge protection plans incorporating enough flexibility to identify and invest in emergency short-term responses during peak drought periods as well as having guidelines in place aimed at broader scales to promote long-term resilience in native fish populations.
Lessons learned and future directions: This study has reinforced that priority areas which act as drought refuges require adequate management to ensure the long term survival of native fish populations. This study identified the two scales at which drought management operates and the strengths of each scale to address both short and long-term impacts of drought on native fish and their habitats. This information will ultimately lead to better drought management regarding native fish and their habitats, which will minimise the risk of loss of native fish species and populations and preserve native fish habitats.
Stakeholders and Funding bodies: This project was funded through the Murray-Darling Basin Authority’s Native Fish Strategy.
Contact: Dr Dale McNeil, South Australian Research and Development Institute. Tel: + 61 8 8207 5342, Email: firstname.lastname@example.org
Figure 2: A drying refuge (Photo courtesy of Luke Pearce)