The impacts of climate variability on the niche concept and distributions of species

Ecological demographers know that year-to-year climate variability influences the long-term growth of populations and thus their viability. Despite this, species distribution models (SDMs), widely used to project species’ geographic distributions based on climate, typically ignore inter-annual climate variability. Here, we show that climate variability plays a crucial role in determining current and future distributions of species. We achieved this by developing a new SDM framework, XSDM, that accounts for variability when assessing the ecological niche and distribution of species. XSDM outperforms traditional SDMs in simulation studies. Using XSDM, we assessed the impacts of variability on 10 example species. Variability reduces species potential distributions by an average of 22%, up to 45%. Moreover, sensitivities of distributions to potential changes in average temperature and in its variability were comparable in magnitude. To avoid biases, future SDMs should consider the effects of variability through a demographic approach such as XSDM. As global change alters climate variability, e.g., through increased frequency of extreme events, XSDM provides better tools for countering biodiversity losses.