Using traits to assess threatened plant species response to climate change

Climate change poses significant challenges to the long-term management of threatened species. Pre-emptive assessments of the capacity for threatened species to adapt to climate change are essential for choosing appropriate management actions that minimise extinction risk. Here, we use species traits and range metrics linked to ecological performance to assess the capacity to respond to climate change of 342 plant species, listed as threatened under IUCN-compatible criteria in the Australian state of New South Wales (NSW). Traits capturing variation in phenology, morphology, physiology and geographic range were used to assess species’ response(s) to four factors likely to influence their climate change response: Reproduction, Movement Capability, Abiotic Niche Specialisation, and risk spreading across Spatial Coverage. Assessment scores were combined into high, medium and low rankings based on two complementary approaches for assessing climate change risk: (i) fully precautionary, where species were classified as high risk if any one of the four response factors was high; and (ii) integrative, combining scores across all four response factors to assign an overall risk ranking. 84% of threatened species assessed had a high risk ranking for at least one response factor, whereas 30, 55 and 15% of species were ranked high, medium or low respectively, based on our integrative measure of risk. Importantly, basic information for at least one trait for an additional 237 threatened plants in NSW was not available, despite thorough searching across 727 resources. This lack of fundamental baseline data for threatened plants may have wide-ranging implications for their management, including an inability to assess their response capacity to threats, and plan accordingly.