Using species distribution models to infer potential climate change-induced range shifts of freshwater fish in south-eastern Australia

Abstract

Abstract. There are few quantitative predictions for the impacts of climate change on freshwater fish in Australia. We developed species distribution models (SDMs) linking historical fish distributions for 43 species from Victorian streams to a suite of hydro-climatic and catchment predictors, and applied these models to explore predicted range shifts under future climate-change scenarios. Here, we present summary results for the 43 species, together with a more detailed analysis for a subset of species with distinct distributions in relation to temperature and hydrology. Range shifts increased from the lower to upper climate-change scenarios, with most species predicted to undergo some degree of range shift. Changes in total occupancy ranged from À38% to þ63% under the lower climate-change scenario to À47% to þ182% under the upper climate-change scenario. We do, however, caution that range expansions are more putative than range contractions, because the effects of barriers, limited dispersal and potential life-history factors are likely to exclude some areas from being colonised. As well as potentially informing more mechanistic modelling approaches, quantitative predictions such as these should be seen as representing hypotheses to be tested and discussed, and should be valuable for informing longterm strategies to protect aquatic biota.

Detecting range shifts among Australian fishes in response to climate change

“…In contrast, several cool-water native species, including river blackfish (Gadopsis marmoratus) and two-spined blackfish (G. bispinosus), will likely contract in range towards more southerly or higher altitude streams (e.g. Bond et al 2011).…”

“…Several studies have demonstrated the importance of cease-to-flow events in excluding certain species from some rivers (e.g. Dodds et al 2004;Bond et al 2010Bond et al , 2011. Such patterns are likely to arise from both direct habitat loss (drying) and the rapid changes in water quality (increasing temperatures and decreased dissolved oxygen) when flows cease (Boulton and Lake 1990).…”

“…Researchers are now beginning to consider the impacts of climate change on ecologically important aspects of flow regimes, as well as runoff per se (Sanborn and Bledsoe 2006;Gibson et al 2005), and incorporation of this information into species-distribution models highlights the importance of hydrology in predicting range shifts (e.g. Lyons et al 2010;Bond et al 2011).…”

“…Historically, these have been an underutilised resource; however, increasingly they are being used as a source of data for examining species distribution patterns via more quantitative modelling approaches, incorporating GIS to link species records to spatial information layers on climate, runoff and other environmental variables (e.g. Growns 2008;Bond et al 2011). Shortcomings in relying on these sources of data include the range of sampling approaches used, varied sampling objectives and variable collection intensity, all of which may render them inadequate for detection of subtle or early beginnings of range shifting.…”

Human effects on ecological connectivity in aquatic ecosystems: Integrating scientific approaches to support management and mitigation

“…However, as mentioned above, the potential effects of altered hydrological 520 regimes (e.g., increased frequency of drought) and higher temperatures are well documented, and are likely drivers of change in species distributions. Statistical models linking historical and current distributional information to hydro-climatic and catchment data in freshwater ecosystems have predicted general shifts in species distributions towards higher altitudes and higher latitudes (e.g., Bond et al 2011).…”