Contribution of climate change to degradation and loss of critical fish habitats in Australian marine and freshwater environments

Abstract

Abstract. Australia's aquatic ecosystems are unique, supporting a high diversity of species and high levels of endemism; however, they are also extremely vulnerable to climate change. The present review assesses climate-induced changes to structural habitats that have occurred in different aquatic ecosystems. Climatic impacts are often difficult to discern against the background of habitat degradation caused by more direct anthropogenic impacts. However, climate impacts will become more pronounced with ongoing changes in temperature, water chemistry, sea level, rainfall patterns and ocean currents. Each of these factors is likely to have specific effects on ecosystems, communities or species, and their relative importance varies across different marine and freshwater habitats. In the Murray-Darling Basin, the greatest concern relates to declines in surface water availability and riverine flow, owing to declining rainfall and increased evaporative loss. On the Great Barrier Reef, increasing temperatures and ocean acidification contribute to sustained and ongoing loss of habitat-forming corals. Despite the marked differences in major drivers and consequences of climate change, the solution is always the same. Greenhouse-gas emissions need to be reduced as a matter of urgency, while also minimising nonclimatic disturbances. Together, these actions will maximise opportunities for adaptation by species and increase ecosystem resilience.

Detecting range shifts among Australian fishes in response to climate change

“…Together with land-use change and other anthropogenic impacts, hydrologic alteration has already led to substantial range contractions for many freshwater fish in Australia (Mallen-Cooper 1992). Modelling suggests that in areas with significant agricultural development, the pre-existing impacts of human water use on stream flows far exceed the magnitude of changes resulting from climate change alone (CSIRO 2008;Pratchett et al 2011). Nonetheless, impacts from climate change will increase periods of cease to flow in low-rainfall areas, further decreasing habitat availability in many rivers during dry periods .…”

“…In many parts of Australia, existing hydrologic stress due to human water use is already high, and these impacts are likely to intensify under expected climate scenarios (CSIRO 2008;Pratchett et al 2011). Together with land-use change and other anthropogenic impacts, hydrologic alteration has already led to substantial range contractions for many freshwater fish in Australia (Mallen-Cooper 1992).…”

“…Climate-change drivers such as temperature and rainfall can operate directly to affect range or indirectly through effects on habitat or food resources of fishes (e.g. Morrongiello et al 2011;Pratchett et al 2011) or on their reproduction (Pankhurst and Munday 2011). Climatechange drivers can also interact with other factors such as overfishing, habitat removal, disease and pollution to reduce or spatially shift species.…”

Climate change impacts and adaptation of commercial marine fisheries in Australia: a review of the science

“…Observational and modelling studies suggest that the greatest impacts of climate change on fishery stocks are likely to manifest in southeast Australian marine waters , and for some fisheries in tropical regions (Pratchett et al 2009(Pratchett et al , 2011a. The nexus between tropical and temperate systems-the subtropics-is an important zone also likely to experience changes to species abundances and community composition.…”

“…prawns, mud crabs, coral trout and aquarium species), are likely to change as a result of climate-related impacts on these habitats MacNeil et al 2010;Donnelly 2011;Pratchett et al 2011a;Bell et al 2013). For example, barramundi (L. calcarifer) landings correlated with an index of climate variability (Balston 2009a) flag the possible effects on early life stages as rainfall, river flow and temperature variability influence nutrient availability and nursery habitat productivity (Balston 2009b).…”