Belinda Robson

As pressures on Australia's inland waters intensify from population growth, expanding resource development and climate change, there is an urgent need to manage and protect these special areas. Understanding their ecology underpins their wise management and conservation. Australian Freshwater Ecology vividly describes the physical, chemical and biological features of wetlands, lakes, streams, rivers and groundwaters in Australia.  It presents the principles of aquatic ecology linked to practical management and conservation, and explains the causes, mechanisms, effects and management of serious environmental problems such as altered water regimes, eutrophication, salinization, acidification and sedimentation of inland waters. Key features: contributions from a diverse, highly qualified team of aquatic ecologists whose expertise spans the ecology and management of standing and running waters in Australia sections covering groundwaters, biodiversity, temporary and tropical waters, climate change, invasive species and freshwater conservation numerous Australian case-studies and guest 'text-boxes' showing management in practice concise descriptions of ecological processes and conceptual models illustrated with original, high- quality diagrams and photographs  Readable and logically structured, this text supports undergraduate and postgraduate courses in aquatic ecology and management. It is a valuable reference for consultants, restoration ecologists, water resource managers, science teachers, and other professionals with an interest in the ecology of surface and groundwaters.

Southern Australia is becoming warmer and drier as climate change progresses, creating serious threats to freshwater ecosystems that are dependent on the presence of water for their existence. The overall aim of this research project was to develop and evaluate four potential methods for enhancing the role, function and resilience of refuges for freshwater biodiversity in southern Australia. It focussed on means to maintain the physical conditions in refuges within ranges tolerable for species and to maintain connectivity that allows species to retreat to, and expand from, refuges. The four approaches studied were: • the feasibility of using cool-water releases (CWR) from reservoirs and shandying to control water temperature in rivers; • a method for deciding where streamside re-vegetation should occur in catchments to ensure maximum long-term negative effects on stream temperature; • the potential for artificial urban wetlands (i.e. anthropogenic habitat) to act as refuges for freshwater biodiversity against climate change; • a method for identifying redundant river regulation infrastructure and prioritizing artificial structures for removal during river restoration to improve connectivity along river channels for fauna movement. These four approaches were found to have the potential to address a range of objectives for refuge management, such as: reduce temperatures in refuges (1 & 2), increase number of refuges that act as colonization sources (all), assist dispersal into and out of refuges (all), increase biodiversity within refuges (all), increase permanence or resilience of refuges (all) and increase resistance or resilience of refuges during extreme events (1, 2 & 3). In particular, CWR could potentially be used to mimic natural thermal regimes, reduce the frequency and duration of extreme high temperature events and to assist movement of fish between thermal refuges, but further information and trials are required (1). Riparian planting can be used to reduce in-stream temperatures over the long-term and the tool developed here permits users to determine the optimal planting locations within catchments to maximise cooling effects for a given replanting investment (2). Perennial artificial wetlands can be used to provide refuges for biodiversity from wetland drying, and artificial wetlands can be modified to support higher biodiversity (3). The removal or modification of in-stream barriers can be used to create, protect or link refuges for freshwater species, especially fish, and the method developed here allows users to determine which artificial barriers have priority for removal within catchments (4). There are synergies with catchment restoration, such as environmental flows (CWR, barrier removal and modification), and revegetation (riparian replanting, anthropogenic refuges).Therefore, the four refuge management approaches described in this project should be integrated into existing river and wetland restoration practices within catchments. Refuges across all types of waterbodies in catchments should be managed in an integrated way, comprising multiple waterbodies of each type to provide the diversity of habitat types required by freshwater species.

The objective of this research was to develop and test a risk assessment and decision-making framework for managing groundwater dependent ecosystems (GDEs) with declining water levels due to climate change, anthropogenic extraction, land use and land management. The framework was developed by a multidisciplinary team of ecologists, modellers and hydrogeologists in south-western Australia, a biodiversity hotspot that has already suffered three decades of below average rainfall and consequently declining groundwater levels due to increased groundwater abstraction and land use change. This has provided a ‘living experiment’ providing validation of the framework against observed changes (not just modelled projections). The combination of this research together with input from a suite of end-users, other scientists and experts from across Australia has provided a robust and adaptable framework. The report outlines how the framework was developed and tested on three different types of GDEs: surface expression of groundwater in 1) wetlands on the Gnangara Groundwater System in Perth and 2) the Blackwood River, and 3) the subterranean expression of groundwater in the Leeuwin Naturaliste Ridge Cave System. However, the framework could be adapted to any type of GDE or surface water system. The framework integrates a standard risk assessment protocol enabling the approach to be easily transferred to sites within Australia and internationally. The framework is based around the construction of a conceptual model which identifies the interrelationships between climate, hydrology, water quality and/or biotic resources and the biota in an ecosystem. Before the framework is undertaken, management issues are identified and the site is characterised in terms of the type of GDE, its spatial extent, hydrogeology and assets within the site location. The framework then proceeds through five steps: identify the hazard, determine the exposure and vulnerability of the GDE, assess the effects of the hazard, characterise risk and then manage the risk. A suite of tools are provided by this framework for managing risk and climate change adaptation including: the identification of hazards and their cause(s), exposure and vulnerability of GDEs to hydrological stress, key drivers that cause ecosystem change, thresholds of tolerance of the biota for these key drivers, conceptual models, and risk assessment and decision-making tools in the form of Bayesian Belief networks and spatial models of risk.