Novel methods for managing freshwater refuges against climate change in southern Australia. Final Report
|Title||Novel methods for managing freshwater refuges against climate change in southern Australia. Final Report|
|Year of Publication||2013|
|Authors||Robson, BJ, Chester, ET, Allen, M, Beatty, S, Chambers, JM, Close, P, Cook, B, Cummings, CR, Davies, PM, Lester, RE, Lymbery, A, Matthews, TG, Morgan, D, Stock, M|
|Institution||National Climate Change Adaptation Research Facility|
|Keywords||cool-water release, experiments, Freshwater, Freshwater Biodiversity, in-stream barrier, refuges, riparian planting, Southern Australia, urban wetlands|
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:
1. the feasibility of using cool-water releases (CWR) from reservoirs and shandying to control water temperature in rivers;
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.