Identifying species at risk from climate change

Posted on March 10, 2014

Which aquatic species are the most vulnerable to the impacts of climate change? In theory, traits such as physiological tolerance, life history attributes, dispersal abilities and dietary and habitat requirements could be useful indicators of the vulnerability of a species to climate warming, but this possibility needs to be tested for different types of organisms. One such analysis focussed on the freshwater fish of the Murray-Darling river system in Australia, and drew on monitoring data for 39 species, plus data on 14 biological traits for the same species compiled from the literature. Of those traits, 11 showed a significant relationship with changes in species abundance observed in 2004-2010 during a period of extended drought. Trait-based rankings of drought vulnerability also agreed well with species vulnerability assessments from previous studies. The most vulnerable fish species had relatively low heat tolerance and low minimum spawning temperatures. They tended to be small-bodied species (e.g. galaxiids, pygmy perches) that feed on invertebrates, which suggested that omnivores that consume more detritus and plant material have more success in finding food during drought. Vulnerable species also tended to mature early and have a short life-span, an extended spawning season and low fecundity. These are normally considered to be “opportunistic” features typical of species adapted to unpredictable environments, but it seems that that this type of opportunism doesn’t extend to coping with long, multi-year droughts. In prolonged droughts, larger species with delayed maturation are better equipped to survive and breed later. Vulnerability rankings based on a range of traits can help to identify species at risk and prioritise conservation actions.

Reference: Chessman, B. 2013. Identifying species at risk from climate change: traits predict the drought vulnerability of freshwater fishes. Biological Conservation 160, 40–49.