Feeding ecology of benthic invertebrates in an intermittently open estuary

Abundances of benthic invertebrates in the Hopkins River estuary were not affected by connection to the ocean, but by freshwater discharge and sediment properties. The bivalve Soletellina alba was identified as a suspension feeder. Invertebrate food sources were derived mainly from estuarine organic matter, but also contained marine and freshwater/terrestrial plants despite reduced river flow during drought conditions.

The value of oral history in natural resource management : the Balcombe Estuary Reserve, Mount Martha, Victoria

This study investigates the benefits of using oral history as a tool for the sustainable management of estuaries. Twenty-two semi-structured interviews were conducted to generate oral history records for the Balcombe Estuary Reserve, a small estuary in a periurban zone on the Mornington Peninsula, Victoria. These interviews establish a more complete picture of changes in land use and ecological change to the estuary since European settlement of the area, and document community values. The interviews were followed with a survey to further explore management issues in the area. Use of oral history was found to be an effective approach to assist holistic estuarine management, especially when complemented by other sources of information.

Integrating knowledge systems in local coastal management; the case of an estuary entrance management support system (EEMSS) in Australia

The management of social, economic, and ecological assets in coastal zones is fundamental to the maintenance and sustainability of coastal resources. A significant issue in this discussion is the role of governance structures. In Australia the governance of the coastal zone includes a range of institutional authorities, processes, and procedures that set the context for decision making about coastal management. As well as the formal institutional arrangements there is also a maze of other interests such as development commissions, NGOs, Indigenous Native Title holders and other stakeholders including recreational interests. A major issue for governance arrangements is the considerable gap that often exists between how those interests interpret and develop their positions especially when the knowledge is derived from different systems – scientific, managerial, lay and indigenous. This paper will explore the development of an Estuary Entrance Management Support System (EEMSS) in south west Victoria Australia. The EEMSS is a decision support tool to assist estuary managers in determining whether to artificially open a river mouth. A significant part of the process adopted was community participation which involved a ‘steps’ approach to engage local community groups and landholders. It is the process of engaging different knowledge systems in a meaningful conversation that has led to a system that now gains support from all of the stakeholders in the management of different estuaries. The paper will discuss the processes that surround the EEMSS and outline some lessons that arise in context of the ‘project state’.

Perceptions of climate change and adaptation responses in a local community : the Barwon Estuary Complex, Victoria

The climate change focus in Australia has shifted from mitigation to adaptation with an emphasis on place-specific case studies. The Barwon Estuary Complex (BEC) on the Bellarine Peninsula, central Victoria, was the focus of this place-specific study in which 37 local stakeholders were consulted through a series of semi-structured interviews on the impacts of climate change on their coastal community. Overall there was uniformity in stakeholder perceptions of the climate change impacts and vulnerabilities pertaining to the BEC. In contrast, discussion on adaptation drew a diversity of responses. While 53 per cent of stakeholders indicated a need to limit the use of hard structures, and rather plan around a changing estuarine environment, opinion amongst the community group was divided. Some believed ‘retreat is the only option’ whilst others felt ‘there won’t be much leaving’. The present level of confusion around adaptation highlights the imperative of commencing discussions now to allow sufficient time to develop strategies which are both environmentally and socially responsible. This is important as ultimately it will be the community that will determine whether adaptation strategies are adopted or met with resistance.

Estuary environmental flows assessment methodology : final specification report

This report provides a consistent and systematic approach to the determination of environmental water requirements for estuaries in Victoria.

Victoria’s limited water resources are subject to competing demands. These demands, including town water supplies and irrigation requirements, often deplete the flow entering estuaries and put their environmental values at risk.

The Estuary Environmental Flows Assessment Methodology (EEFAM) is a standard methodology which can be applied in a consistent manner across all Victorian estuaries, according to their priority. It is not anticipated that this method would be used for the Gippsland Lakes or Port Phillip or Western Port Bay.

Towards more integrated and participatory coastal management : insights from Victoria’s Estuary Entrance Management Support System.

Participation and integration are core elements of coastal management. A key argument is that involving stakeholders from the broader community in collaborative coastal management allows for a more reflexive approach to consideration of ecological science outputs. However the role of stakeholder participation is still problematic especially when the involvement is short term and limited in its knowledge co-production. We argue for the development of a participatory logic that includes five key elements: the institutionalization of the processes that derive from stakeholder co-production and co-management; the ability and capacity to make meaningful decisions about issues of importance in an on-going way; the inclusion of all stakeholders in the process; the flexibility of central policies that enable participation by stakeholders at local level; the allowance for pathways for the uptake of all knowledge systems. Using this approach we report in this paper on the Estuary Entrance Management Support System (EEMSS) and ask whether this is a model system for answering the following questions as part of participatory logic: What types of collaborative activities can be used to improve the management of coastal zones? Are these activities a sufficient pathway for integrating different knowledge forms including science into coastal management? How important is stakeholder participation to science uptake? How can stakeholder participation be institutionalized in coastal management?

Stakeholder participation in estuary management: the development of Victoria's Estuary Entrance Management Support System

Stakeholder involvement in the management of estuaries is a necessary element of good environmental governance. In Victoria, Australia, a key challenge for estuary managers is whether or not estuaries should be artificially opened since many river mouths close ‘naturally’ from time to time. Estuary closure resulting in raised estuarine water levels leads to economic and social impacts on local communities. In the past these effects have been addressed by artificial river mouth openings, often without reference to associated environmental impacts. This article discusses the development and features of an Estuary Entrance Management Support System and considers its performance against principles of effective environmental management. It concludes that, in bringing together technical information with stakeholder input through a structured process, such a system makes a useful contribution to improving estuary entrance management.

Scenarios involving future climate and water extraction: ecosystem states in the estuary of Australia's largest river

 

Estuary environmental flows assessment methodology for Victoria

This report sets out a method to determine the environmental water requirements of estuaries in Victoria. The estuary environmental flows assessment method (EEFAM) is a standard methodology which can be applied consistently across Victorian estuaries.
The primary objective of EEFAM is to define a flow regime to maintain or enhance the ecological health of an estuary. The method is used to inform Victorian water resource planning processes.
The output of EEFAM is a recommended flow regime for estuaries. This recommendation is developed from the known dependence of the estuary’s flora, fauna, biogeochemical and geomorphological features on the flow regime. EEFAM is an evidence-based methodology. This bottom-up or ‘building block’ approach conforms to the asset-based approach of the Victorian River Health Strategy and regional river health strategies.
EEFAM is based on and expands on FLOWS, the Victorian method for determining environmental water requirements in rivers. The list of tasks has been modified and re-ordered in EEFAM to reflect environmental and management issues specific to estuaries. EEFAM and FLOWS can be applied
simultaneously to a river and its estuary as part of a whole-of-system approach to environmental flow requirements. Like the FLOWS method, EEFAM is modular, and additional components can be readily incorporated.

Utilization of organic matter by invertebrates along an estuarine gradient in an intermittently open estuary

In intermittently open estuaries, the sources of organic matter sustaining benthic invertebrates are likely to vary seasonally, particularly between periods of connection and disconnection with the ocean and higher and lower freshwater flows. This study investigated the contribution of allochthonous and autochthonous primary production to the diet of representative invertebrate species using stable isotope analysis (SIA) during the austral summer and winter (2008, 2009) in an intermittently open estuary on the south-eastern coast of Australia. As the study was conducted towards the end of a prolonged period of drought, a reduced influence of freshwater/terrestrial organic matter was expected. Sampling was conducted along an estuarine gradient, including upper, middle and lower reaches and showed that the majority of assimilated organic matter was derived from autochthonous estuarine food sources. Additionally, there was an input of allochthonous organic matter, which varied along the length of the estuary, indicated by distinct longitudinal trends in carbon and nitrogen stable isotope signatures along the estuarine gradient. Marine seaweed contributed to invertebrate diets in the lower reaches of the estuary, while freshwater/terrestrial organic matter had increased influence in the upper reaches. Suspension-feeding invertebrates derived large parts of their diet from freshwater/terrestrial material, despite flows being greatly reduced in comparison with non-drought years.